Zoom lens and imaging device

Abstract

It offers a compact, high-performance zoom lens. [Solution] The zoom lens 100 has multiple lens groups, and when the lens group closest to the object among at least one lens group having negative refractive power is designated as the object-side negative lens group N, the rear group P, which includes all lens groups positioned closer to the image than the object-side negative lens group, has positive refractive power as a whole. The object-side negative lens group moves during zooming. There are three or more focus groups F1, F2, F3, which are lens groups or lenses that move during focusing. TD is the length obtained by adding the distance along the optical axis from the lens surface closest to the object of the object-side negative lens group to the final lens surface closest to the image of the rear group, to the air-equivalent distance from the final lens surface to the image plane, at the zoom position where the object-side negative lens group is closest to the image. LD is the sum of the thicknesses along the optical axis of all lenses in the object-side negative lens group and the rear group. The condition 0.403 ≤ LD / TD ≤ 0.800 is satisfied.

Description

Technical Field

[0001] The present invention relates to a zoom lens suitable for imaging.

Background Art

[0002] Some zoom lenses perform focusing by moving three lens groups, as disclosed in Patent Documents 1 and 2.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0004] There is a demand for a zoom lens that is more compact and has higher performance than conventional ones.

Means for Solving the Problem

[0005] A zoom lens as one aspect of the present invention includes multiple lens groups, and the spacing between adjacent lens groups changes during zooming. When the lens group located closest to the object among the multiple lens groups that have negative refractive power is designated as the object-side negative lens group, the rear group, which includes all lens groups located closer to the image than the object-side negative lens group, has a positive refractive power as a whole. The object-side negative lens group moves during zooming. The lens has three or more lens groups or focus groups that move during focusing. When the object-side negative lens group is located closest to the image at the zoom position, the length TD is the distance along the optical axis from the lens surface closest to the object of the object-side negative lens group to the final lens surface closest to the image of the rear group, plus the air-equivalent distance from the final lens surface to the image plane. When the total thickness along the optical axis of all lenses in the object-side negative lens group and the rear group is LD, 0.403 ≤ LD / TD ≤ 0.800 It is characterized by satisfying the following conditions.

[0006] Furthermore, as another aspect of the present invention, a zoom lens, when the largest F-number from the wide-angle end to the telephoto end is denoted as FnoN, 0.380 ≤ LD / TD ≤ 0.800 1.00 ≤ FnoN ≤ 2.70 It is characterized by satisfying the following conditions.

[0007] Furthermore, another aspect of the present invention is a zoom lens which includes multiple lens groups, and the spacing between adjacent lens groups changes during zooming. It is characterized by having three or more lens groups or focus groups which move during focusing. An imaging device equipped with the above-mentioned zoom lens also constitutes another aspect of the present invention. [Effects of the Invention]

[0008] According to the present invention, a compact and high-performance zoom lens can be provided. [Brief explanation of the drawing]

[0009] [Figure 1]This is a cross-sectional view of the optical system of Example 1 at the wide-angle end. [Figure 2] This is a cross-sectional view of the optical system of Example 1 at the wide-angle end, the intermediate zoom position, and the telephoto end. [Figure 3] This is an aberration diagram of the optical system of Example 1 in the in-focus state for infinity and at the wide-angle end. [Figure 4] This is an aberration diagram of the optical system of Example 1 in the in-focus state for infinity and at the intermediate zoom position. [Figure 5] This is an aberration diagram of the optical system of Example 1 in the in-focus state for infinity and at the telephoto end. [Figure 6] This is an aberration diagram of the optical system of Example 1 in the closest in-focus state and at the wide-angle end. [Figure 7] This is an aberration diagram of the optical system of Example 1 in the closest in-focus state and at the intermediate zoom position. [Figure 8] This is an aberration diagram of the optical system of Example 1 in the closest in-focus state and at the telephoto end. [Figure 9] This is a cross-sectional view of the optical system of Example 2 at the wide-angle end. [Figure 10] This is a cross-sectional view of the optical system of Example 2 at the wide-angle end, the intermediate zoom position, and the telephoto end. [Figure 11] This is an aberration diagram of the optical system of Example 2 in the in-focus state for infinity and at the wide-angle end. [Figure 12] This is an aberration diagram of the optical system of Example 2 in the in-focus state for infinity and at the intermediate zoom position. [Figure 13] This is an aberration diagram of the optical system of Example 2 in the in-focus state for infinity and at the telephoto end. [Figure 14] This is an aberration diagram of the optical system of Example 2 in the closest in-focus state and at the wide-angle end. [Figure 15] This is an aberration diagram of the optical system of Example 2 in the closest in-focus state and at the intermediate zoom position. [Figure 16] This is an aberration diagram of the optical system of Example 2 in the closest in-focus state and at the telephoto end. [Figure 17] This is a cross-sectional view of the optical system of Example 3 at the wide-angle end. [Figure 18] This is a cross-sectional view of the optical system of Example 3 at the wide-angle end, the intermediate zoom position, and the telephoto end. [Figure 19] This is an aberration diagram of the optical system of Example 3 in an infinity in-focus state and at the wide-angle end. [Figure 20] This is an aberration diagram of the optical system of Example 3 in an infinity in-focus state and at an intermediate zoom position. [Figure 21] This is an aberration diagram of the optical system of Example 3 in an infinity in-focus state and at the telephoto end. [Figure 22] This is an aberration diagram of the optical system of Example 3 in a closest in-focus state and at the wide-angle end. [Figure 23] This is an aberration diagram of the optical system of Example 3 in a closest in-focus state and at an intermediate zoom position. [Figure 24] This is an aberration diagram of the optical system of Example 3 in a closest in-focus state and at the telephoto end. [Figure 25] This is a cross-sectional view of the optical system of Example 4 at the wide-angle end. [Figure 26] This is a cross-sectional view of the optical system of Example 4 at the wide-angle end, an intermediate zoom position, and the telephoto end. [Figure 27] This is an aberration diagram of the optical system of Example 4 in an infinity in-focus state and at the wide-angle end. [Figure 28] This is an aberration diagram of the optical system of Example 4 in an infinity in-focus state and at an intermediate zoom position. [Figure 29] This is an aberration diagram of the optical system of Example 4 in an infinity in-focus state and at the telephoto end. [Figure 30] This is an aberration diagram of the optical system of Example 4 in a closest in-focus state and at the wide-angle end. [Figure 31] This is an aberration diagram of the optical system of Example 4 in a closest in-focus state and at an intermediate zoom position. [Figure 32] This is an aberration diagram of the optical system of Example 4 in a closest in-focus state and at the telephoto end. [Figure 33] This is a cross-sectional view of the optical system of Example 5 at the wide-angle end. [Figure 34] This is a cross-sectional view of the optical system of Example 5 at the wide-angle end, an intermediate zoom position, and the telephoto end. [Figure 35] This is an aberration diagram of the optical system of Example 5 in an infinity in-focus state and at the wide-angle end. [Figure 36]This is an aberration diagram of the optical system of Example 5 at infinity focus and an intermediate zoom position. [Figure 37] This is an aberration diagram of the optical system of Example 5 at infinity focus and at the telephoto end. [Figure 38] This is an aberration diagram of the optical system of Example 5 at its closest focus and wide-angle end. [Figure 39] This is an aberration diagram of the optical system of Example 5 at its closest focus and intermediate zoom position. [Figure 40] This is an aberration diagram of the optical system of Example 5 at its closest focus and telephoto end. [Figure 41] This is a cross-sectional view of the optical system of Example 6 at its wide-angle end. [Figure 42] These are cross-sectional views of the optical system of Example 6 at the wide-angle end, intermediate zoom position, and telephoto end. [Figure 43] This is an aberration diagram of the optical system of Example 6 at infinity focus and wide-angle end. [Figure 44] This is an aberration diagram of the optical system of Example 6 at infinity focus and an intermediate zoom position. [Figure 45] This is an aberration diagram of the optical system of Example 6 at infinity focus and at the telephoto end. [Figure 46] This is an aberration diagram of the optical system of Example 6 at its closest focus and wide-angle end. [Figure 47] This is an aberration diagram of the optical system of Example 6 at its closest focus and intermediate zoom position. [Figure 48] This is an aberration diagram of the optical system of Example 6 at its closest focus and telephoto end. [Figure 49] This is a cross-sectional view of the optical system of Example 7 at its wide-angle end. [Figure 50] These are cross-sectional views of the optical system of Example 7 at the wide-angle end, intermediate zoom position, and telephoto end. [Figure 51] This is an aberration diagram of the optical system of Example 7 at infinity focus and wide-angle end. [Figure 52] This is an aberration diagram of the optical system of Example 7 at infinity focus and an intermediate zoom position. [Figure 53] This is an aberration diagram of the optical system of Example 7 at infinity focus and at the telephoto end. [Figure 54] This is an aberration diagram of the optical system of Example 7 at its closest focus and wide-angle end. [Figure 55] This is an aberration diagram of the optical system of Example 7 at its closest focus and intermediate zoom position. [Figure 56] This is an aberration diagram of the optical system of Example 7 at its closest focus and telephoto end. [Figure 57] This is a cross-sectional view of the optical system of Example 8 at its wide-angle end. [Figure 58] These are cross-sectional views of the optical system of Example 8 at the wide-angle end, intermediate zoom position, and telephoto end. [Figure 59] This is an aberration diagram of the optical system of Example 8 at infinity focus and wide-angle end. [Figure 60] This is an aberration diagram of the optical system of Example 8 at infinity focus and an intermediate zoom position. [Figure 61] This is an aberration diagram of the optical system of Example 8 at infinity focus and at the telephoto end. [Figure 62] This is an aberration diagram of the optical system of Example 8 at its closest focus and wide-angle end. [Figure 63] This is an aberration diagram of the optical system of Example 8 at its closest focus and intermediate zoom position. [Figure 64] This is an aberration diagram of the optical system of Example 8 at its closest focus and telephoto end. [Figure 65] This is a cross-sectional view of the optical system of Example 9 at its wide-angle end. [Figure 66] These are cross-sectional views of the optical system of Example 9 at the wide-angle end, intermediate zoom position, and telephoto end. [Figure 67] This is an aberration diagram of the optical system of Example 9 at infinity focus and wide-angle end. [Figure 68] This is an aberration diagram of the optical system of Example 9 at infinity focus and an intermediate zoom position. [Figure 69] This is an aberration diagram of the optical system of Example 9 at infinity focus and at the telephoto end. [Figure 70] This is an aberration diagram of the optical system of Example 9 at its closest focus and wide-angle end. [Figure 71]This is an aberration diagram of the optical system of Example 9 at its closest focus and intermediate zoom position. [Figure 72] This is an aberration diagram of the optical system of Example 9 at its closest focus and telephoto end. [Figure 73] This is a cross-sectional view of the optical system of Example 10 at its wide-angle end. [Figure 74] These are cross-sectional views of the optical system of Example 10 at the wide-angle end, intermediate zoom position, and telephoto end. [Figure 75] This is an aberration diagram of the optical system of Example 10 at infinity focus and wide-angle end. [Figure 76] This is an aberration diagram of the optical system of Example 10 at infinity focus and an intermediate zoom position. [Figure 77] This is an aberration diagram of the optical system of Example 10 at infinity focus and at the telephoto end. [Figure 78] This is an aberration diagram of the optical system of Example 10 at its closest focus and wide-angle end. [Figure 79] This is an aberration diagram of the optical system of Example 10 at the closest focus state and intermediate zoom position. [Figure 80] This is an aberration diagram of the optical system of Example 10 at its closest focus and telephoto end. [Figure 81] This is a cross-sectional view of the optical system of Example 11 at its wide-angle end. [Figure 82] These are cross-sectional views of the optical system of Example 11 at the wide-angle end, intermediate zoom position, and telephoto end. [Figure 83] This is an aberration diagram of the optical system of Example 11 at infinity focus and wide-angle end. [Figure 84] This is an aberration diagram of the optical system of Example 11 at infinity focus and an intermediate zoom position. [Figure 85] This is an aberration diagram of the optical system of Example 11 at infinity focus and at the telephoto end. [Figure 86] This is an aberration diagram of the optical system of Example 11 at its closest focus and wide-angle end. [Figure 87] This is an aberration diagram of the optical system of Example 11 at the closest focus state and intermediate zoom position. [Figure 88]This is an aberration diagram of the optical system of Example 11 at its closest focus and telephoto end. [Figure 89] This is a schematic diagram of an imaging device equipped with a zoom lens according to Examples 1 to 11. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] Figures 1, 9, 17, 25, 33, 41, 49, 57, 65, 73, and 81 show cross-sections of the zoom lenses of Examples 1 to 11 at their wide-angle ends. The optical systems of each example are optical systems that form an image of an object on the image plane and are used to acquire (i.e., capture) an image using an image sensor or silver halide film placed on the image plane. The optical systems of each example are suitable for various imaging devices such as digital still cameras, digital video cameras, broadcast cameras, surveillance cameras, and silver halide film cameras.

[0012] In each cross-sectional view, the left side is the object side (front side or enlarged conjugate plane side), and the right side is the image side (back side or reduced conjugate plane side).

[0013] To achieve large aperture, compact size, and high imaging performance in zoom lenses, a large number of lenses are required. On the other hand, to zoom, at least two lens groups—a negative lens group with negative refractive power and a positive lens group with positive refractive power—are moved relative to each other along the optical axis to change the focal length.

[0014] To miniaturize large-aperture zoom lenses, which contain many lenses, it is necessary to bring the lens groups relatively close together. As a result, at the zoom position where the lens groups are closest together, there is no space to move the focus group (or lens) for focusing. Also, because large-aperture zoom lenses have a large light beam diameter, focusing by moving only one focus group degrades the image formation performance at close range.

[0015] Some zoom lenses employ a floating system that moves two focus groups to perform focusing. However, when miniaturizing a large aperture lens, it becomes difficult to achieve both sufficient movement speed for the focus groups and good image formation performance, even with the floating system. For this reason, as disclosed in Patent Documents 1 and 2, it is necessary to add additional focus groups.

[0016] Patent Document 1 discloses a large-aperture zoom lens with a focal length of 71.5mm to 271.25mm, an Fno of 2.88 to 4.0, and three focusing groups. However, this zoom lens is large overall because large spaces are provided in front of and behind the focusing groups.

[0017] Patent Document 2 discloses a zoom lens with a focal length of 24.7mm to 115.999mm and an Fno of 4.06 to 4.12, having three continuously arranged focus groups. However, in this zoom lens, a large space is secured in front of and behind the focus group at the telephoto end, resulting in an overall larger size.

[0018] In each embodiment, a zoom lens with high brightness and imaging performance is realized while avoiding such an increase in size.

[0019] Each embodiment of the zoom lens includes multiple lens groups. In a zoom lens, a lens group is a collection of one or more lenses that move together or remain stationary during zooming and focusing between the wide-angle and telephoto ends. That is, the distance between adjacent lens groups changes during zooming and focusing. The lens groups may include aperture diaphragms. The wide-angle and telephoto ends represent the zoom states at the maximum angle of view (shortest focal length) and minimum angle of view (longest focal length), respectively, when the lens groups that move during zooming are positioned at the ends of the range that is mechanically or controllly movable along the optical axis.

[0020] In each diagram, SP represents the aperture diaphragm, and IP represents the image plane. In each diagram, the aperture diaphragm SP is in its widest open state and determines the maximum width of the axial light rays passing through the aperture diaphragm SP. The image plane IP is located on the imaging surface (light-receiving surface) of an image sensor such as a CCD sensor or CMOS sensor, or the film surface (photosensitive surface) of a silver halide film. Also, e is a flare cut diaphragm, which cuts out unwanted light.

[0021] In each embodiment of the zoom lens, among the multiple lens groups, the lens group located closest to the object among the at least one lens group having negative refractive power is defined as the object-side negative lens group (hereinafter referred to as the object-side N group). In this case, the rear group (hereinafter referred to as the P group), which includes all lens groups located closer to the image than the object-side N group, has a positive refractive power as a whole. The object-side N group moves during zooming. The zoom lens also has three or more focus groups, which are lens groups or parts of lens groups that move during focusing.

[0022] Light entering the zoom lens from the object side diverges in the object-side N group, enters the P group, converges, and forms an image on the image plane. The object-side N group is the lens group positioned closest to the object with the most negative refractive power in the entire zoom lens system. During zooming, it moves towards the image side and approaches the P group, thereby changing the focal length of the zoom lens to the longer focal length side.

[0023] The P group includes two or more lens groups, and the combined refractive power of these two or more lens groups is positive. The spacing between the lens groups within the P group changes during zooming, thereby correcting aberration variations associated with zooming.

[0024] During zooming, the movement of the object-side N group results in the narrowest spacing between lens groups within the P group at the zoom position where the object-side N group is closest to the image (the telephoto end in each embodiment).

[0025] As mentioned earlier, achieving high performance in large-aperture zoom lenses requires the use of a large number of lens groups and lenses, and miniaturizing zoom lenses requires narrowing the spacing between lenses. In this case, it becomes difficult to secure space for the movement of the focus group within the P group, especially at the zoom position where the object-side N group is located closest to the image. Furthermore, if there is only one focus group at this zoom position, the closest focusing distance becomes longer, and the variation in field curvature due to the movement of the focus group becomes larger.

[0026] To address these challenges, three or more focus groups are used, with each group responsible for ensuring performance and reducing the minimum focusing distance.

[0027] The zoom lens of each embodiment preferably satisfies the following condition (1): TD is the length obtained by adding the distance along the optical axis from the lens surface closest to the object in the object-side N group at the zoom position where the object-side N group is located closest to the image to the final lens surface closest to the image in the P group (i.e., the zoom lens), plus the air-equivalent distance from the final lens surface to the image plane. LD is the sum of the thicknesses along the optical axis of all lenses in the object-side N group and P group.

[0028] 0.403 ≤ LD / TD ≤ 0.800 (1) The condition in equation (1) indicates the appropriate ratio of the total lens thickness to the distance (space) from the object-side N group to the image plane at the zoom position where the object-side N group is located closest to the image. If the ratio of the total lens thickness is large, the space in which the focus group can move is restricted, making it difficult to ensure performance and shorten the closest focusing distance. If LD / TD falls below the lower limit of equation (1), the spacing between lens groups or lenses (hereinafter referred to as lens spacing) within the space from the object-side N group to the image plane becomes too wide, which is undesirable because it eliminates the need for the three focus groups or makes the zoom lens larger. If LD / TD exceeds the upper limit of equation (1), the space for moving the three focus groups within the space from the object-side N group to the image plane becomes too narrow, which is undesirable because it shortens the closest focusing distance.

[0029] Furthermore, it is more preferable to set the lower limit of formula (1) to 0.404 or 0.405. Also, it is more preferable to set the upper limit of formula (1) to 0.750, 0.700, 0.650, or 0.600.

[0030] In each embodiment, the zoom lens preferably satisfies the following equations (2) and (3), where FnoN is the largest F-number (F-number at maximum aperture) from the wide-angle end to the telephoto end.

[0031] 0.380 ≤ LD / TD ≤ 0.800 (2) 1.00 ≤ FnoN ≤ 2.70 (3) The conditions in equation (2) are basically the same as those in equation (1), but the numerical range differs from that of equation (1) because the conditions in equation (3) must be satisfied. Optimization of the lens spacing is necessary by increasing the number of lenses to achieve a larger aperture. If LD / TD falls below the lower limit of equation (2), the lens spacing becomes too wide within the space from the object-side N group to the image plane, making it unnecessary to use three focus groups or resulting in a larger zoom lens, which is undesirable. If LD / TD exceeds the upper limit of equation (2), the space for moving the three focus groups within the space from the object-side N group to the image plane becomes too narrow, shortening the closest focusing distance, which is also undesirable.

[0032] Furthermore, it is more preferable to set the lower limit of formula (2) to 0.385, 0.390, 0.395, or 0.400. Also, it is more preferable to set the upper limit of formula (2) to 0.750, 0.700, 0.650, or 0.600.

[0033] If FnoN falls below the lower limit of equation (3), the diameter of the light beam passing through the zoom lens becomes too large, resulting in a larger zoom lens, which is undesirable. If FnoN exceeds the upper limit of equation (3), the zoom lens becomes too dark, or the lens spacing becomes too wide, making it unnecessary to use three or more focus groups, which is also undesirable.

[0034] Furthermore, it is more preferable to set the lower limit of equation (3) to 1.10, 1.20, or 1.30. Also, it is more preferable to set the upper limit of equation (3) to 2.60, 2.55, or 2.50.

[0035] In the zoom lens of each embodiment, the focus groups located closest to the object and the second closest to the object are designated as the first focus group F1 and the second focus group F2, respectively, among three or more focus groups. The focal length of the first focus group F1 is fF1, and the combined focal length of the first focus group F1 and the second focus group F2 at the zoom position where the object-side N group is located closest to the image is fMT. In this case, it is preferable that the zoom lens of each embodiment satisfies the following condition (4).

[0036] -10.00≦fF1 / fMT≦-0.10 (4) As mentioned above, the diverging light beam that passes through the object-side N group is converged by the P group to form an image. From the object-side N group to the P group, a lens or lens group with strong positive refractive power that converts the diverging light beam into a converged light beam is arranged, and high performance is desired by performing focusing with the focus groups before and after it. Equation (4) shows the appropriate relationship between this lens or lens group with strong positive refractive power and the focal length of the first focus group F1, which is positioned closer to the object. If fF1 / fMT exceeds the upper limit of equation (4), the refractive power of the first focus group F1 becomes too strong, resulting in excessive correction of field curvature by focusing, and high performance cannot be achieved, which is undesirable. If fF1 / fMT falls below the lower limit of equation (4), the positive refractive power between the first focus group F1 and the second focus group F2 becomes too strong, making it difficult to correct spherical aberration of the entire zoom lens system, which is also undesirable.

[0037] Furthermore, it is more preferable to set the lower limit of equation (4) to -0.90, -7.00, -5.00, or -3.00. Also, it is more preferable to set the upper limit of equation (4) to -0.20, -0.40, -0.60, or -0.80.

[0038] In each embodiment, the zoom lens preferably satisfies the following condition (5) when the focal length of the second focus group F2 is fF2.

[0039] 0.10 ≤ fF2 / fMT ≤ 10.00 (5) As mentioned above, it is desirable to improve performance by performing focusing with the focus groups before and after the lens or lens group with strong positive refractive power located in the object-side N group to P group. Equation (5) shows the appropriate relationship between this lens or lens group with strong positive refractive power and the focal length of the second focus group F2 located closer to the image. If fF2 / fMT exceeds the upper limit of equation (5), the refractive power of the second focus group F2 becomes too weak, making it difficult to shorten the closest focusing distance, which is undesirable. Also, the amount of movement of the second focus group F2 during close focusing becomes large, resulting in a larger zoom lens, which is undesirable. If fF2 / fMT falls below the lower limit of equation (5), the refractive power of the second focus group F2 becomes too strong, resulting in excessive correction of field curvature due to focusing, which is undesirable.

[0040] Furthermore, it is more preferable to set the lower limit of equation (5) to 0.30, 0.50, 0.80, or 1.00. Also, it is more preferable to set the upper limit of equation (5) to 9.00, 7.50, 5.00, or 4.00.

[0041] The zoom lens of each embodiment preferably satisfies the conditions of the following formula (6).

[0042] -7.00 ≤ fF1 / fF2 ≤ -0.10 (6) The conditions in equation (6) indicate an appropriate relationship between the focal lengths of the first focusing group F1 and the second focusing group F2. If fF1 / fF2 exceeds the upper limit of equation (6), the refractive power of the first focusing group F1 becomes too strong, resulting in excessive correction of field curvature due to the movement of the first focusing group F1, which is undesirable. If fF1 / fF2 falls below the lower limit of equation (6), the refractive power of the second focusing group F2 becomes too strong, resulting in excessive correction of field curvature due to the movement of the second focusing group F2, which is also undesirable.

[0043] Furthermore, it is more preferable to set the lower limit of equation (6) to -6.00, -5.00, -3.00, or -2.00. Also, it is more preferable to set the upper limit of equation (6) to -0.20, -0.25, or -0.30.

[0044] In each embodiment, the zoom lens preferably satisfies the following condition (7), where F1r1 is the radius of curvature of the lens surface closest to the object in the first focus group F1, and F1r2 is the radius of curvature of the lens surface closest to the image in the first focus group F1.

[0045] -1.00≦(F1r1-F1r2) / (F1r1+F1r2)≦-0.05 (7) The conditions in equation (7) indicate the appropriate shape (shape factor) of the first focus group F1. The first focus group F1 is positioned in the diverging beam, and it is preferable that image plane correction can be performed by changing the optical path length of the off-axis beam without affecting the on-axis beam during focusing. Therefore, it is preferable that the first focus group F1 has a shape close to concentric with respect to the on-axis diverging beam.

[0046] If the shape factor exceeds the upper limit of equation (7), the curvature of the lens surface closest to the object and the lens surface closest to the image in the first focusing group F1 become too close to each other. This weakens the refractive power of the first focusing group F1 too much, resulting in a large amount of movement of the first focusing group F1 during focusing. As a result, the zoom lens becomes larger, which is undesirable. Furthermore, the correction of field curvature becomes insufficient, which is also undesirable. If the shape factor falls below the lower limit of equation (7), the curvature of the lens surface closest to the object and the lens surface closest to the image in the first focusing group F1 becomes too far apart from each other, resulting in large fluctuations of on-axial rays during focusing, which is also undesirable.

[0047] Furthermore, it is more preferable to set the upper limit of equation (7) to -0.10, -0.15, or -0.18.

[0048] In each embodiment, the zoom lens preferably satisfies the following condition (8), where F2r1 is the radius of curvature of the lens surface closest to the object in the second focus group F2, and F2r2 is the radius of curvature of the lens surface closest to the image in the second focus group F2.

[0049] -1.00≦(F2r1-F2r2) / (F2r1+F2r2)≦-0.05 (8) The conditions in equation (8) indicate an appropriate shape factor for the second focus group F2. The second focus group F2 is positioned in the converging beam, and it is preferable that image plane correction can be performed by changing the optical path length of the off-axis beam without affecting the on-axis beam during focusing. Therefore, it is preferable that the second focus group F2 has a shape close to concentric with respect to the on-axis converging beam.

[0050] If the shape factor exceeds the upper limit of equation (8), the curvature of the lens surface closest to the object and the lens surface closest to the image in the second focusing group F2 become too close to each other. This weakens the refractive power of the second focusing group F2 too much, resulting in a large amount of movement of the second focusing group F2 during focusing. As a result, the zoom lens becomes larger, which is undesirable. Furthermore, the correction of field curvature becomes insufficient, which is also undesirable. If the shape factor falls below the lower limit of equation (8), the curvature of the lens surface closest to the object and the lens surface closest to the image in the second focusing group F2 becomes too far apart from each other, resulting in large fluctuations of on-axial rays during focusing, which is also undesirable.

[0051] Furthermore, it is more preferable to set the lower limit of equation (8) to -0.98, -0.97, -0.96, or -0.95. Also, it is more preferable to set the upper limit of equation (8) to -0.10, -0.15, -0.20, or -0.25.

[0052] In each embodiment, the zoom lens preferably satisfies the following condition (9), where tm1 is the amount of movement of the first focus group F1 from infinity to the closest focusing point at the zoom position where the object-side N group is located closest to the image. The amount of movement of the first focus group F1 is the difference between the position where the first focus group F1 is in focus on an object at infinity and the position where it is in focus on the closest object, and does not include the amount of movement back and forth. The amount of movement is positive when the position where the first focus group F1 is in focus on the closest object is located closer to the object than the position where the first focus group F1 is in focus on an object at infinity. The same applies to the amount of movement of the other focus groups.

[0053] -1000.00 ≤ fF1 / tm1 ≤ -5.00 (9) Equation (9) shows the appropriate relationship between the focal length of the first focus group F1 and the amount of movement during focusing. If fF1 / tm1 exceeds the upper limit of equation (9), the refractive power of the first focus group F1 becomes too strong, which is undesirable because it excessively corrects the field curvature caused by the movement of the first focus group F1. Also undesirable because the distance between the front and rear lenses of the first focus group F1 becomes too wide, making it difficult to miniaturize the zoom lens. If fF1 / tm1 falls below the lower limit of equation (9), the refractive power of the first focus group F1 becomes too weak, which is undesirable because it makes it difficult to shorten the closest focusing distance. Also undesirable because the distance between the front and rear lenses of the first focus group F1 becomes too narrow, making it difficult to focus on close objects.

[0054] Furthermore, it is more preferable to set the lower limit of equation (9) to -900.00, -700.00, -500.00, or -400.00. Also, it is more preferable to set the upper limit of equation (9) to -6.00, -7.00, -8.00, -9.00, or -10.00.

[0055] In each embodiment, the zoom lens preferably satisfies the following condition (10), where tm2 is the amount of movement of the second focus group F2 from infinity to the closest focusing point at the zoom position where the object-side N group is located closest to the image.

[0056] 1.00 ≤ fF2 / tm2 ≤ 1000.00 (10) Equation (10) shows the appropriate relationship between the focal length of the second focusing group F2 and the amount of movement during focusing. If fF2 / tm2 exceeds the upper limit of equation (10), the refractive power of the second focusing group F2 becomes too strong, which is undesirable because it excessively corrects the field curvature caused by the movement of the second focusing group F2. Also undesirable because the distance between the front and rear lenses of the second focusing group F2 becomes too wide, making it difficult to miniaturize the zoom lens. If fF2 / tm2 falls below the lower limit of equation (10), the refractive power of the second focusing group F2 becomes too weak, which is undesirable because it makes it difficult to shorten the closest focusing distance. Also undesirable because the distance between the front and rear lenses of the second focusing group F2 becomes too narrow, making it difficult to focus on close objects.

[0057] Furthermore, it is more preferable to set the lower limit of equation (10) to 2.00, 3.00, 4.00, or 5.00. Also, it is more preferable to set the upper limit of equation (10) to 700.00, 500.00, 400.00, or 300.00.

[0058] The zoom lens of each embodiment preferably satisfies the conditions of the following formula (11).

[0059] 0.05 ≤ tm1 / tm2 ≤ 10.00 (11) The conditions in equation (11) indicate an appropriate relationship between the amount of movement of the first focus group F1 and the second focus group F2 during focusing at the zoom position where the object-side N group is located closest to the image. If tm1 / tm2 exceeds the upper limit of equation (11), the amount of movement of the first focus group F1 becomes too large, increasing the lens spacing near the object-side N group and resulting in a larger zoom lens, which is undesirable. If tm1 / tm2 falls below the lower limit of equation (11), the amount of movement of the second focus group F2 becomes too large, increasing the lens spacing within the P group and resulting in a larger zoom lens, which is also undesirable.

[0060] Furthermore, it is more preferable to set the lower limit of formula (11) to 0.06, 0.08, or 0.10. Also, it is more preferable to set the upper limit of formula (11) to 8.50, 7.50, 5.00, or 3.50.

[0061] In each embodiment, the focal length of the third focus group F3, which is the third from the object side among the three or more focus groups of the zoom lens, is denoted as fF3, and the amount of movement of the third focus group F3 from infinity to the closest focusing point at the zoom position where the object-side N group is located closest to the image is denoted as tm3. In this case, it is preferable that the zoom lens of each embodiment satisfies the following condition (11).

[0062] -1000.00 ≤ fF3 / tm3 ≤ 1000.00 (12) The conditions in equation (12) indicate an appropriate relationship between the focal length of the third focus group F3 and the amount of movement during focusing. The third focus group F3 is a focus group positioned closer to the image than the second focus group F2, and it is preferable for the amount of movement of both the first focus group F1 and the second focus group F2 to be small in order to miniaturize the zoom lens. If fF3 / tm3 exceeds the upper limit of equation (12), the refractive power of the third focus group F3 becomes too strong, and the correction of field curvature due to the movement of the third focus group F3 becomes excessive, which is undesirable. Also, the distance between the front and rear lenses of the third focus group F3 becomes too wide, making it difficult to miniaturize the zoom lens, which is undesirable. If fF3 / tm3 falls below the lower limit of equation (12), the refractive power of the third focus group F3 becomes too weak, making it difficult to shorten the closest focusing distance, which is undesirable. Also, the distance between the front and rear lenses of the third focus group F3 becomes too narrow, making it difficult to focus on close objects, which is undesirable.

[0063] Furthermore, it is more preferable to set the lower limit of equation (12) to -900.00, -800.00, -700.00, or -600.00. Also, it is more preferable to set the upper limit of equation (12) to 800.00, 600.00, 300.00, or 200.00.

[0064] In the zoom lens of each embodiment, BD is the distance along the optical axis from the lens surface closest to the object in the object-side N group to the final lens surface at the zoom position where the object-side N group is located closest to the image. DM is the largest air gap along the optical axis between the lens closest to the object in the object-side N group and the lens closest to the image in the P group. In this case, it is preferable that the zoom lens of each embodiment satisfies the following condition (13).

[0065] 0.02 ≤ DM / BD ≤ 0.20 (13) The condition in equation (13) represents an appropriate ratio of the maximum air gap to the distance from the object-side lens surface to the final lens surface of the object-side N group at the zoom position where the object-side N group is located closest to the image. If the above air gap ratio is large, the zoom lens will become larger, which is undesirable. If DM / BD falls below the lower limit of equation (13), the above air gap becomes too narrow, there is insufficient space to move the focus group, and focusing on the nearest object point becomes difficult, which is undesirable. If DM / BD exceeds the upper limit of equation (13), the above air gap becomes too large, the zoom lens will become larger, which is undesirable.

[0066] Furthermore, it is more preferable to set the lower limit of formula (13) to 0.05, 0.07, 0.08, or 0.09. Also, it is more preferable to set the upper limit of formula (13) to 0.18, 0.17, 0.16, or 0.15.

[0067] In each embodiment, the zoom lens preferably satisfies the following condition (14) when the focal length of the object-side N group is fN.

[0068] 1.00 ≤ fF1 / fN ≤ 10.00 (14) The conditions in equation (14) indicate an appropriate relationship between the focal length of the object-side N group and the focal length of the first focus group F1. If fF1 / fN falls below the lower limit of equation (14), the refractive power of the first focus group F1 becomes too strong, which is undesirable because it increases the fluctuations in spherical aberration and field curvature due to the movement of the first focus group F1. If fF1 / fN exceeds the upper limit of equation (14), the refractive power of the first focus group F1 becomes too weak, which increases the amount of movement of the first focus group F1 during focusing, resulting in a larger zoom lens, which is also undesirable.

[0069] Furthermore, it is more preferable to set the lower limit of formula (14) to 1.30, 1.50, 1.70, or 1.80. Also, it is more preferable to set the upper limit of formula (14) to 9.00, 7.50, 5.00, 4.00, or 3.00.

[0070] In each embodiment, it is preferable that the zoom lens satisfies the following condition (15) when the focal length of the entire zoom lens system at the zoom position where the object-side N group is located closest to the image is fT.

[0071] -5.00 ≤ fN / fT ≤ -0.10 (15) The conditions in equation (15) indicate an appropriate relationship between the focal length of the object-side N group and the focal length of the entire system at the zoom position where the object-side N group is closest to the image. If fN / fT falls below the lower limit of equation (15), the refractive power of the object-side N group becomes weak, and the amount of movement of the object-side N group between the wide-angle and telephoto ends becomes too large, which is undesirable as it results in a larger zoom lens. If fN / fT exceeds the upper limit of equation (15), the refractive power of the object-side N group becomes strong, which is undesirable as it makes it difficult to correct spherical aberration and field curvature in large-aperture zoom lenses.

[0072] Furthermore, it is more preferable to set the lower limit of equation (15) to -4.00, -3.00, or -2.00. Also, it is more preferable to set the upper limit of equation (15) to -0.15, -0.18, or -0.20.

[0073] In the zoom lens of each embodiment, mN is the amount of movement of the object-side N group during zooming from the wide-angle end to the zoom position where the object-side N group is closest to the image. LT is the length (total optical length) obtained by adding the distance along the optical axis from the foremost lens surface on the object side to the final lens surface of the zoom lens at the zoom position where the object-side N group is closest to the image, to the air-equivalent distance from the final lens surface to the image surface. The amount of movement of the object-side N group is the difference between its position at the wide-angle end and its position at the telephoto end, and does not include round-trip movement. A positive amount of movement is defined as the object-side N group being closer to the object at the telephoto end compared to the wide-angle end.

[0074] 0.05 ≤ mN / LT ≤ 0.50 (16) The conditions in equation (16) show an appropriate relationship between the amount of movement of the object-side N group during zooming from the wide-angle end to the zoom position where it is closest to the image, and the total optical length of the zoom lens when the object-side N group is at the zoom position where it is closest to the image. If mN / LT falls below the lower limit of equation (16), the amount of movement of the object-side N group during zooming becomes too large, resulting in a larger zoom lens, which is undesirable. If mN / LT exceeds the upper limit of equation (16), the amount of movement of the object-side N group during zooming becomes too small, requiring a stronger refractive power for the object-side N group. As a result, it becomes difficult to correct spherical aberration and field curvature in large-aperture zoom lenses, which is undesirable.

[0075] Furthermore, it is more preferable to set the lower limit of formula (16) to 0.08, 0.09, or 0.10. Also, it is more preferable to set the upper limit of formula (16) to 0.40, 0.30, or 0.20.

[0076] The zoom lens of each embodiment preferably satisfies the conditions of the following formula (17).

[0077] 0.05 ≤ fMT / fT ≤ 5.00 (17) The conditions in equation (17) indicate an appropriate relationship between the combined focal length of the first focus group F1 and the second focus group F2 at the zoom position where the object-side N group is closest to the image, and the focal length of the entire system at the zoom position where the object-side N group is closest to the image. If fMT / fT falls below the lower limit of equation (17), the combined refractive power (positive refractive power) of the first focus group F1 and the second focus group F2 becomes too weak, which is undesirable because it leads to a larger zoom lens. If fMT / fT exceeds the upper limit of equation (17), the combined refractive power of the first focus group F1 and the second focus group F2 becomes too strong, which is undesirable because it makes it difficult to correct spherical aberration.

[0078] Furthermore, it is more preferable to set the lower limit of formula (17) to 0.10, 0.15, 0.25, or 0.30. Also, it is more preferable to set the upper limit of formula (17) to 4.00, 3.00, 2.00, or 1.60.

[0079] The zoom lens of each embodiment preferably satisfies the conditions of the following formula (18).

[0080] 1.00 ≤ FnoN ≤ 2.70 (18) If the largest F-number FnoN from the wide-angle end to the telephoto end falls below the lower limit of equation (18), the diameter of the light beam within the zoom lens becomes too large, resulting in a larger zoom lens, which is undesirable. If FnoN exceeds the upper limit of equation (18), the zoom lens becomes too dark, and the lens spacing becomes too large, eliminating the need for three or more focusing groups, which is also undesirable.

[0081] Furthermore, it is more preferable to set the lower limit of formula (18) to 1.10, 1.20, 1.30, or 1.40. Also, it is more preferable to set the upper limit of formula (18) to 2.60, 2.55, or 2.50.

[0082] Next, we will describe the details of the zoom lenses in Examples 1 to 11. Following Example 11, we will show numerical examples 1 to 11 corresponding to each of Examples 1 to 11. [Examples]

[0083] The zoom lens 100 of Embodiment 1 (Numerical Example 1) shown in Figure 1 is composed of a first lens group L1, a second lens group L2, an aperture diaphragm SP, a third lens group L3, and a fourth lens group L4, which are arranged in order from the object side to the image side.

[0084] The first lens group L1 has a positive refractive power, the second lens group L2 (as the object-side N group) has a negative refractive power, the third lens group L3 has a positive refractive power, and the fourth lens group L4 has a positive refractive power. The third lens group L3 and the fourth lens group L4, positioned between the second lens group L2 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0085] The first lens group L1 consists of a cemented lens of negative lens 101 and positive lens 102, and a positive lens 103, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of negative lens 104, negative lens 105, a cemented lens of positive lens 106 and negative lens 107, and a negative lens 108. The third lens group L3 consists of positive lens 109, positive lens 110, and a cemented lens of negative lens 111 and positive lens 112. The fourth lens group L4 consists of a cemented lens of negative lens 113 and positive lens 114, positive lens 115, positive lens 116, a cemented lens of positive lens 117 and negative lens 118, and a negative lens 119. The negative lens 108 acts as the first focus group F1, the positive lens 110 as the second focus group F2, and the cemented lens formed by the negative lens 113 and the positive lens 114, along with the positive lenses 115 and 116, act as the third focus group F3, moving toward the object during focusing from infinity to close range.

[0086] Figure 2 shows cross-sections of the zoom lens 100 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves towards the object and then towards the image side. The second lens group L2 moves towards the image side, and the aperture diaphragm SP moves towards the image side. The third lens group L3 moves towards the image side, and the fourth lens group L4 moves towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end. Also, during zooming, lens groups or lenses other than the first to third focus groups F1 to F3 remain stationary.

[0087] Figures 3, 4, and 5 show the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end, intermediate zoom position, and telephoto end of the zoom lens 100 of numerical example 1 when it is in focus on an object at infinity (hereinafter referred to as the infinity focus state). Figures 6, 7, and 8 show the longitudinal aberrations at the wide-angle end, intermediate zoom position, and telephoto end of the zoom lens 100 of numerical example 1 when it is in focus on the nearest object (hereinafter referred to as the nearest focus state).

[0088] In the spherical aberration diagram, Fno indicates the F number, the solid line shows the spherical aberration at the d line (wavelength 587.6 nm), and the dashed line shows the spherical aberration at the g line (wavelength 435.8 nm). In the astigmatism diagram, the solid line S shows the astigmatism at the sagittal image plane, and the dashed line M shows the astigmatism at the meridional image plane. The distortion diagram shows the distortion at the d line. The chromatic aberration diagram shows the lateral chromatic aberration at the g line. ω is the half-angle of view (°). The explanation of these aberration diagrams is the same in other embodiments described later.

[0089] The zoom lens 100 achieves its compact size by converging axial rays in the first lens group L1, which has positive refractive power. The axial rays converged in the first lens group L1 become divergent rays in the second lens group L2, which has negative refractive power, and the divergent axial rays are then converged by the positive lens 109 in the third lens group L3, which has positive refractive power.

[0090] The converged on-axis rays become nearly parallel afocal rays when they pass through the positive lens 112 of the third lens group L3, and these afocal rays are converged by the fourth lens group L4, which has positive refractive power, to form an image.

[0091] By moving the third focusing group F3 within the fourth lens group L4, into which the afocal light rays enter, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0092] The field curvature of off-axis rays changes to the under-focus side during focusing. This reduces the focusing performance towards close objects. To correct this field curvature of off-axis rays, the negative lens 108 (F1) closest to the image in the second lens group L2, which is positioned in the diverging on-axis rays, and the positive lens 110 (F2) in the third lens group L3, which is positioned in the converging on-axis rays, are moved towards the object when focusing from infinity to close. This allows the field curvature of off-axis rays to be changed to the over-focus side.

[0093] The negative lens 108 (F1) has a meniscus shape with its convex surface facing the image side, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 108 (F1) toward the object during focusing. Furthermore, the movement of the negative lens 108 (F1) during focusing changes the passage position of the off-axis central ray from the thin part of the negative lens 108 (F1) to the thick part. As a result, the optical path length is extended, which can change the field curvature to the over-angle side, and cancel out some of the under-angle field curvature caused by the movement of the third focus group F3.

[0094] The positive lens 110 (F2) has a meniscus shape with its convex surface facing the object side, resulting in a shape that is nearly concentric with respect to the on-axial rays that have become convergent rays from the positive lens 109 onwards in the third lens group L3. This suppresses fluctuations in spherical aberration caused by the movement of the positive lens 110 (F2) toward the object side during focusing. Furthermore, the movement of the positive lens 110 (F2) due to focusing changes the passage position of the off-axis central ray from the thin part to the thick part of the positive lens 110 (F2). As a result, the optical path length is extended, which can change the field curvature to the over-angle side. This can be combined with the change in the field curvature of the first focus group F1 to the over-angle side to correct the under-angle field curvature caused by the movement of the third focus group F3. This improves the focusing performance at close range.

[0095] Due to the narrow spacing between lenses in order to miniaturize the entire 100 series of zoom lenses, both the first focusing group F1 and the second focusing group F2 move within a small space during focusing. This allows for image plane changes and focusing on nearby objects through the combined action of the first focusing group F1 and the second focusing group F2.

[0096] Furthermore, by constructing both the first focus group F1 and the second focus group F2 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0097] Furthermore, in the second lens group L2 with negative refractive power, the negative lens 108(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 108(F1) from becoming extremely strong. This reduces the sensitivity to displacement of the negative lens 108(F1) in a direction perpendicular to the optical axis of the zoom lens 100.

[0098] Furthermore, in the third lens group L3, which bears a portion of the positive refractive power, the positive lens 110 (F2), which bears a portion of the positive refractive power, is moved during focusing to prevent the refractive power of the positive lens 110 (F2) from becoming excessively strong. This reduces the sensitivity of the zoom lens 100 to misalignment of the positive lens 110 (F2) in a direction perpendicular to the optical axis.

[0099] Furthermore, by appropriately setting the negative refractive power of the second lens group L2 and the amount of movement during zooming, it is possible to miniaturize the entire 100 zoom lens system. [Examples]

[0100] The zoom lens 200 of Embodiment 2 (Numerical Example 2) shown in Figure 9 is composed of a first lens group L1, a second lens group L2, an aperture diaphragm SP, a third lens group L3, and a fourth lens group L4, which are arranged in order from the object side to the image side.

[0101] The first lens group L1 has a positive refractive power, the second lens group L2 (as the object-side N group) has a negative refractive power, the third lens group L3 has a positive refractive power, and the fourth lens group L4 has a positive refractive power. The third lens group L3 and the fourth lens group L4, positioned between the second lens group L2 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0102] The first lens group L1 consists of a cemented lens of negative lens 201 and positive lens 202, and a positive lens 203, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of negative lens 204, negative lens 205, a cemented lens of positive lens 206 and negative lens 207, and a negative lens 208. The third lens group L3 consists of positive lens 209, positive lens 210, and a cemented lens of negative lens 211 and positive lens 212. The fourth lens group L4 consists of a cemented lens of negative lens 213 and positive lens 214, positive lens 215, positive lens 216, a cemented lens of positive lens 217 and negative lens 218, and a negative lens 219. The negative lens 208 acts as the first focus group F1, the positive lens 210 as the second focus group F2, and the cemented lens formed by the negative lens 213 and the positive lens 214, along with the positive lenses 215 and 216, act as the third focus group F3, moving toward the object during focusing from infinity to close range.

[0103] Figure 10 shows cross-sections of the zoom lens 200 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves towards the object and then towards the image side. The second lens group L2, the aperture diaphragm SP, and the third lens group L3 each move towards the image side, while the fourth lens group L4 moves towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end. Also, during zooming, lens groups or lenses other than the first to third focus groups F1 to F3 remain stationary.

[0104] Figures 11, 12, and 13 show the longitudinal aberrations of the zoom lens 200 of numerical example 2 at the wide-angle end, intermediate zoom position, and telephoto end when focused at infinity, respectively. Figures 14, 15, and 16 show the longitudinal aberrations of the zoom lens 200 of numerical example 2 at the wide-angle end, intermediate zoom position, and telephoto end when focused at the closest point, respectively.

[0105] The zoom lens 200 achieves its compact size by converging axial rays in the first lens group L1, which has positive refractive power. The axial rays converged in the first lens group L1 become divergent rays in the second lens group L2, which has negative refractive power, and these divergent axial rays are then converged by the positive lens 209 in the third lens group L3, which has positive refractive power.

[0106] The converged on-axis rays become nearly parallel afocal rays when they pass through the positive lens 212 of the third lens group L3, and these afocal rays are converged by the fourth lens group L4, which has positive refractive power, to form an image.

[0107] By moving the third focusing group F3 within the fourth lens group L4, into which the afocal light rays enter, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0108] The field curvature of off-axis rays changes to the under-focus side during focusing. This reduces the focusing performance towards close objects. To correct this field curvature of off-axis rays, the negative lens 208 (F1) closest to the image in the second lens group L2, which is positioned in the diverging on-axis rays, and the positive lens 210 (F2) in the third lens group L3, which is positioned in the converging on-axis rays, are moved towards the object when focusing from infinity to close. This allows the field curvature of off-axis rays to be changed to the over-focus side.

[0109] The negative lens 208 (F1) has a meniscus shape with its convex surface facing the image side, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 208 (F1) toward the object during focusing. Furthermore, the movement of the negative lens 208 (F1) during focusing changes the passage position of the off-axis central ray from the thin part of the negative lens 208 (F1) to the thick part. As a result, the optical path length is extended, which can change the field curvature to the over-angle side, and cancel out some of the under-angle field curvature caused by the movement of the third focus group F3.

[0110] The positive lens 210 (F2) has a meniscus shape with its convex surface facing the object side, resulting in a nearly concentric shape with respect to the on-axial rays that have become convergent rays from the positive lens 209 onwards in the third lens group L3. This suppresses fluctuations in spherical aberration caused by the movement of the positive lens 210 (F2) toward the object side during focusing. Furthermore, the movement of the positive lens 210 (F2) due to focusing changes the passage position of the off-axis central ray from the thin part to the thick part of the positive lens 210 (F2). As a result, the optical path length is extended, which can change the field curvature to the over-angle side. This can be combined with the change in the field curvature of the first focus group F1 to the over-angle side to correct the under-angle field curvature caused by the movement of the third focus group F3. This improves the focusing performance at close range.

[0111] Due to the narrow spacing between lenses in order to miniaturize the entire 200 series of zoom lenses, both the first focusing group F1 and the second focusing group F2 move within a small space during focusing. This allows for image plane changes and focusing on close objects through the combined action of the first focusing group F1 and the second focusing group F2.

[0112] Furthermore, by constructing both the first focus group F1 and the second focus group F2 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0113] Furthermore, in the second lens group L2 with negative refractive power, the negative lens 208(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 208(F1) from becoming extremely strong. This reduces the sensitivity to displacement of the negative lens 208(F1) in a direction perpendicular to the optical axis of the zoom lens 200.

[0114] Furthermore, in the third lens group L3, which bears a portion of the positive refractive power, the positive lens 210 (F2), which bears a portion of the positive refractive power, is moved during focusing to prevent the refractive power of the positive lens 210 (F2) from becoming excessively strong. This reduces the sensitivity of the zoom lens 200 to misalignment of the positive lens 210 (F2) in a direction perpendicular to the optical axis.

[0115] Furthermore, by appropriately setting the negative refractive power of the second lens group L2 and the amount of movement during zooming, it is possible to miniaturize the entire 200 zoom lens system. [Examples]

[0116] The zoom lens 300 of Embodiment 3 (Numerical Example 3) shown in Figure 17 is composed of a first lens group L1, a second lens group L2, a third lens group L3 including a flare cut aperture e, and a fourth lens group L4, which are arranged in order from the object side to the image side.

[0117] The first lens group L1 has a positive refractive power, the second lens group L2 (as the object-side N group) has a negative refractive power, the third lens group L3 has a positive refractive power, and the fourth lens group L4 has a positive refractive power.

[0118] The third lens group L3 and the fourth lens group L4, positioned between the second lens group L2 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0119] The first lens group L1 is composed of a cemented lens of negative lens 301 and positive lens 302, and a positive lens 303, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 is composed of negative lens 304, negative lens 305, a cemented lens of positive lens 306 and negative lens 307, and a negative lens 308. The third lens group L3 is composed of a positive lens 309, an aperture diaphragm SP, a positive lens 310, and a negative lens 311. The fourth lens group L4 is composed of a cemented lens of negative lens 312 and positive lens 313, a positive lens 314, a positive lens 315, a cemented lens of positive lens 316 and negative lens 317, and a negative lens 318. The negative lens 308 acts as the first focusing group F1, the positive lens 310 as the second focusing group F2, and the cemented lens formed by the negative lens 312 and the positive lens 313, along with the positive lenses 314 and 315, act as the third focusing group F3, moving toward the object during focusing from infinity to close.

[0120] Figure 18 shows cross-sections of the zoom lens 300 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves toward the image side. The second lens group L2, the flare cut aperture e, and the third lens group L3 move toward the image side, and the fourth lens group L4 moves toward the object side. The zoom position where the object-side N group is closest to the image is the telephoto end. Also, during zooming, lens groups or lenses other than the first to third focus groups F1 to F3 remain stationary.

[0121] Figures 19, 20, and 21 show the longitudinal aberrations of the zoom lens 300 of numerical example 3 at the wide-angle end, intermediate zoom position, and telephoto end when focused at infinity, respectively. Figures 22, 23, and 24 show the longitudinal aberrations of the zoom lens 300 of numerical example 3 at the wide-angle end, intermediate zoom position, and telephoto end when focused at the closest point, respectively.

[0122] The zoom lens 300 achieves its compact size by converging axial rays in the first lens group L1, which has positive refractive power. The axial rays converged in the first lens group L1 become divergent rays in the second lens group L2, which has negative refractive power, and these divergent axial rays are converged by the positive lens 309 in the third lens group L3, which has positive refractive power.

[0123] The converged on-axis rays become nearly parallel afocal rays when they pass through the negative lens 311 of the third lens group L3, and these afocal rays are converged by the fourth lens group L4, which has positive refractive power, to form an image.

[0124] By moving the third focusing group F3 within the fourth lens group L4, into which the afocal light rays enter, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0125] The field curvature of off-axis rays changes to the under-focus side during focusing. This reduces the focusing performance towards close objects. To correct this field curvature of off-axis rays, the negative lens 308 (F1) on the image side of the second lens group L2, which is positioned in the diverging on-axis rays, and the positive lens 310 (F2) of the third lens group L3, which is positioned in the converging on-axis rays, are moved towards the object when focusing from infinity to close. This allows the field curvature of off-axis rays to be changed to the over-focus side.

[0126] The negative lens 308 (F1) has a meniscus shape with its convex surface facing the image side, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 308 (F1) toward the object during focusing. Furthermore, the movement of the negative lens 308 (F1) during focusing changes the passage position of the off-axis central ray from the thin part of the negative lens 308 (F1) to the thick part. As a result, the optical path length is extended, which can change the field curvature to the over-angle side, and cancel out some of the under-angle field curvature caused by the movement of the third focus group F3.

[0127] The positive lens 310 (F2) has a meniscus shape with its convex surface facing the object side, resulting in a nearly concentric shape with respect to the on-axial rays that have become convergent rays from the positive lens 309 onwards in the third lens group L3. This suppresses fluctuations in spherical aberration caused by the movement of the positive lens 310 (F2) toward the object side during focusing. Furthermore, the movement of the positive lens 310 (F2) due to focusing changes the passage position of the off-axis central ray from the thin part to the thick part of the positive lens 310 (F2). As a result, the optical path length is extended, which can change the field curvature to the over-angle side. This can be combined with the change in the field curvature of the first focus group F1 to the over-angle side to correct the under-angle field curvature caused by the movement of the third focus group F3. This improves the focusing performance at close range.

[0128] Due to the narrow spacing between lenses in order to miniaturize the entire 300 series of zoom lenses, both the first focusing group F1 and the second focusing group F2 move within a small space during focusing. This allows for image plane changes and focusing on nearby objects through the combined action of the first focusing group F1 and the second focusing group F2.

[0129] Furthermore, by constructing both the first focus group F1 and the second focus group F2 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0130] Furthermore, in the second lens group L2 with negative refractive power, the negative lens 308(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 308(F1) from becoming extremely strong. This reduces the sensitivity to displacement of the negative lens 308(F1) in a direction perpendicular to the optical axis of the zoom lens 300.

[0131] Furthermore, in the third lens group L3, which bears a portion of the positive refractive power, the positive lens 310 (F2), which bears a portion of the positive refractive power, is moved during focusing to prevent the refractive power of the positive lens 310 (F2) from becoming excessively strong. This reduces the sensitivity of the zoom lens 300 to misalignment of the positive lens 310 (F2) in a direction perpendicular to the optical axis.

[0132] Furthermore, by appropriately setting the negative refractive power of the second lens group L2 and the amount of movement during zooming, it is possible to miniaturize the entire 300 zoom lens series. [Examples]

[0133] The zoom lens 400 of Embodiment 4 (Numerical Example 4) shown in Figure 25 is composed of a first lens group L1, a second lens group L2, a third lens group L3 including a flare cut aperture e, an aperture aperture SP, a fourth lens group L4, and a fifth lens group L5, which are arranged in order from the object side to the image side.

[0134] The first lens group L1 has a positive refractive power, the second lens group L2 (as the object-side N group) has a negative refractive power, the third lens group L3 has a positive refractive power, the fourth lens group L4 has a negative refractive power, and the fifth lens group L5 has a positive refractive power. The third lens group L3 to the fifth lens group L5, positioned between the second lens group L2 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0135] The first lens group L1 consists of a cemented lens of negative lens 401 and positive lens 402, and a positive lens 403, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of negative lens 404, negative lens 405, a cemented lens of positive lens 406 and negative lens 407, and a negative lens 408. The third lens group L3 consists of a positive lens 409, an aperture diaphragm SP, and a positive lens 410. The fourth lens group L4 consists of a negative lens 411. The fifth lens group L5 consists of a cemented lens of negative lens 412 and positive lens 413, a positive lens 414, a positive lens 415, a cemented lens of positive lens 416 and negative lens 417, and a negative lens 418. The negative lens 408 acts as the first focus group F1, the positive lens 410 as the second focus group F2, and the cemented lens formed by the negative lens 412 and the positive lens 413, along with the positive lenses 414 and 415, act as the third focus group F3, moving toward the object during focusing from infinity to close.

[0136] Figure 26 shows cross-sections of the zoom lens 400 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves towards the image side and then towards the object side. The second lens group L2 and the flare cut aperture e move towards the image side, while the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end. Also, during zooming, lens groups or lenses other than the first to third focus groups F1 to F3 remain stationary.

[0137] Figures 27, 28, and 29 show the longitudinal aberrations of the zoom lens 400 of numerical example 4 at the wide-angle end, intermediate zoom position, and telephoto end when it is in focus at infinity, respectively. Figures 30, 31, and 32 show the longitudinal aberrations of the zoom lens 400 of numerical example 4 at the wide-angle end, intermediate zoom position, and telephoto end when it is in close focus, respectively.

[0138] The zoom lens 400 achieves its compact size by converging axial rays in the first lens group L1, which has positive refractive power. The axial rays converged in the first lens group L1 become divergent rays in the second lens group L2, which has negative refractive power, and these divergent axial rays are then converged by the positive lens 409 in the third lens group L3, which has positive refractive power.

[0139] The converged on-axis rays become nearly parallel afocal rays when they pass through the fourth lens group L4, which has negative refractive power. These afocal rays are then converged by the fifth lens group L5, which has positive refractive power, to form an image.

[0140] By moving the third focusing group F3 within the fifth lens group L5, into which the afocal light rays enter, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0141] The field curvature of off-axis rays changes to the under-focus side during focusing. This reduces the focusing performance towards close objects. To correct this field curvature of off-axis rays, the negative lens 408 (F1) on the image side of the second lens group L2, which is positioned in the diverging on-axis rays, and the positive lens 410 (F2) of the third lens group L3, which is positioned in the converging on-axis rays, are moved towards the object when focusing from infinity to close. This allows the field curvature of off-axis rays to be changed to the over-focus side.

[0142] The negative lens 408 (F1) has a meniscus shape with its convex surface facing the image side, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 408 (F1) toward the object during focusing. Furthermore, the movement of the negative lens 408 (F1) during focusing changes the passage position of the off-axis central ray from the thin part of the negative lens 408 (F1) to the thick part. As a result, the optical path length is extended, which can change the field curvature to the over-angle side, and cancel out some of the under-angle field curvature caused by the movement of the third focus group F3.

[0143] The positive lens 410 (F2) has a meniscus shape with its convex surface facing the object side, resulting in a nearly concentric shape with respect to the on-axial rays that have become convergent rays from the positive lens 409 onwards in the third lens group L3. This suppresses fluctuations in spherical aberration caused by the movement of the positive lens 410 (F2) toward the object side during focusing. Furthermore, the movement of the positive lens 410 (F2) due to focusing changes the passage position of the off-axis central ray from the thin part to the thick part of the positive lens 410 (F2). As a result, the optical path length is extended, which can change the field curvature to the over-angle side. This can be combined with the change in the field curvature of the first focus group F1 to the over-angle side to correct the under-angle field curvature caused by the movement of the third focus group F3. This improves the focusing performance at close range.

[0144] Due to the narrow spacing between lenses in order to miniaturize the entire 400 series of zoom lenses, both the first focusing group F1 and the second focusing group F2 move within a small space during focusing. This allows for image plane changes and focusing on nearby objects through the combined action of the first focusing group F1 and the second focusing group F2.

[0145] Furthermore, by constructing both the first focus group F1 and the second focus group F2 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0146] Furthermore, in the second lens group L2 with negative refractive power, the negative lens 408(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 408(F1) from becoming extremely strong. This reduces the sensitivity to displacement of the negative lens 408(F1) in a direction perpendicular to the optical axis of the zoom lens 400.

[0147] Furthermore, in the third lens group L3, which bears a portion of the positive refractive power, the positive lens 410 (F2), which bears a portion of the positive refractive power, is moved during focusing to prevent the refractive power of the positive lens 410 (F2) from becoming excessively strong. This reduces the sensitivity of the zoom lens 400 to misalignment of the positive lens 410 (F2) in a direction perpendicular to the optical axis.

[0148] Furthermore, by appropriately setting the negative refractive power of the second lens group L2 and the amount of movement during zooming, it is possible to miniaturize the entire 400mm zoom lens series. [Examples]

[0149] The zoom lens 500 of Embodiment 5 (Numerical Example 5) shown in Figure 33 is composed of a first lens group L1, a second lens group L2, a third lens group L3 including a flare cut aperture e, an aperture aperture SP, a fourth lens group L4, a fifth lens group L5, and a sixth lens group L6, which are arranged in order from the object side to the image side.

[0150] The first lens group L1 has a positive refractive power, the second lens group L2 (as the object-side N group) has a negative refractive power, the third lens group L3 has a positive refractive power, the fourth lens group L4 has a negative refractive power, the fifth lens group L5 has a positive refractive power, and the sixth lens group L6 has a negative refractive power. The third lens group L3 to the sixth lens group L6, positioned between the second lens group L2 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0151] The first lens group L1 consists of a cemented lens of negative lens 501 and positive lens 502, and a positive lens 503, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of negative lens 504, negative lens 505, a cemented lens of positive lens 506 and negative lens 507, and a negative lens 508. The third lens group L3 consists of a positive lens 509, an aperture diaphragm SP, and a positive lens 510. The fourth lens group L4 consists of a negative lens 511. The fifth lens group L5 consists of a cemented lens of negative lens 512 and positive lens 513, a positive lens 514, and a positive lens 515. The sixth lens group L6 consists of a cemented lens of positive lens 516 and negative lens 517, and a negative lens 518. The negative lens 508 acts as the first focusing group F1, the positive lens 510 as the second focusing group F2, and the cemented lens formed by the negative lens 512 and the positive lens 513, along with the positive lenses 514 and 515 (fifth lens group L5), act as the third focusing group F3, moving toward the object during focusing from infinity to close.

[0152] Figure 34 shows cross-sections of the zoom lens 500 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves towards the image side and then towards the object side. The second lens group L2 and the flare cut aperture e move towards the image side, while the third lens group L3, fourth lens group L4, fifth lens group L5, and sixth lens group L6 move towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end. Also, during zooming, lens groups or lenses other than the first to third focus groups F1 to F3 remain stationary.

[0153] Figures 35, 36, and 37 show the longitudinal aberrations of the zoom lens 500 of numerical example 5 at the wide-angle end, intermediate zoom position, and telephoto end when it is in focus at infinity, respectively. Figures 38, 39, and 40 show the longitudinal aberrations of the zoom lens 500 of numerical example 5 at the wide-angle end, intermediate zoom position, and telephoto end when it is in close focus, respectively.

[0154] The zoom lens 500 achieves its compact size by converging axial rays in the first lens group L1, which has positive refractive power. The axial rays converged in the first lens group L1 become divergent rays in the second lens group L2, which has negative refractive power, and these divergent axial rays are then converged by the positive lens 509 in the third lens group L3, which has positive refractive power.

[0155] The converged on-axis rays become nearly parallel afocal rays when they pass through the fourth lens group L4, which has negative refractive power. These afocal rays are then converged by the fifth lens group L5, which has positive refractive power, and the sixth lens group L6, which has negative refractive power, to form an image.

[0156] By moving the third focusing group F3, which acts as the fifth lens group L5 into which the afocal light rays are incident, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0157] The field curvature of off-axis rays changes to the under-focus side during focusing. This reduces the focusing performance towards close objects. To correct this field curvature of off-axis rays, the negative lens 508 (F1) on the image side of the second lens group L2, which is positioned in the diverging on-axis rays, and the positive lens 510 (F2) of the third lens group L3, which is positioned in the converging on-axis rays, are moved towards the object when focusing from infinity to close. This allows the field curvature of off-axis rays to be changed to the over-focus side.

[0158] The negative lens 508 (F1) has a meniscus shape with its convex surface facing the image side, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 508 (F1) toward the object during focusing. Furthermore, the movement of the negative lens 508 (F1) during focusing changes the passage position of the off-axis central ray from the thin part of the negative lens 508 (F1) to the thick part. As a result, the optical path length is extended, which can change the field curvature to the over-angle side, and cancel out some of the under-angle field curvature caused by the movement of the third focus group F3.

[0159] The positive lens 510 (F2) has a meniscus shape with its convex surface facing the object, resulting in a nearly concentric shape with respect to the on-axial rays that have become convergent rays from the positive lens 509 onwards in the third lens group L3. This suppresses fluctuations in spherical aberration caused by the movement of the positive lens 510 (F2) toward the object during focusing. Furthermore, the movement of the positive lens 510 (F2) due to focusing changes the passage position of the off-axis central ray from the thin part to the thick part of the positive lens 510 (F2). As a result, the optical path length is extended, which can change the field curvature to the over-angle side. This can be combined with the change in the field curvature of the first focus group F1 to the over-angle side to correct the under-angle field curvature caused by the movement of the third focus group F3. This improves the focusing performance at close range.

[0160] Due to the narrow spacing between lenses in order to miniaturize the entire 500 series of zoom lenses, both the first focusing group F1 and the second focusing group F2 move within a small space during focusing. This allows for image plane changes and focusing on close objects through the combined action of the first focusing group F1 and the second focusing group F2.

[0161] Furthermore, by constructing both the first focus group F1 and the second focus group F2 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0162] Furthermore, in the second lens group L2 with negative refractive power, the negative lens 508(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 508(F1) from becoming extremely strong. This reduces the sensitivity of the zoom lens 500 to misalignment of the negative lens 508(F1) in a direction perpendicular to the optical axis.

[0163] Furthermore, in the third lens group L3, which bears a portion of the positive refractive power, the positive lens 510 (F2), which bears a portion of the positive refractive power, is moved during focusing to prevent the refractive power of the positive lens 510 (F2) from becoming excessively strong. This reduces the sensitivity of the zoom lens 500 to misalignment of the positive lens 510 (F2) in a direction perpendicular to the optical axis.

[0164] Furthermore, by appropriately setting the negative refractive power of the second lens group L2 and the amount of movement during zooming, it is possible to miniaturize the entire 500 series of zoom lenses. [Examples]

[0165] The zoom lens 600 of Embodiment 6 (Numerical Example 6) shown in Figure 41 is composed of a first lens group L1, a flare cut aperture e, a second lens group L2, a third lens group L3 including an aperture aperture SP, and a fourth lens group L4, which are arranged in order from the object side to the image side.

[0166] The first lens group L1, as part of the object-side N group, has a negative refractive power; the second lens group L2 has a positive refractive power; the third lens group L3 has a negative refractive power; and the fourth lens group L4 has a positive refractive power. The second to fourth lens groups L2 to L4, positioned between the first lens group L1 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0167] The first lens group L1 consists of negative lenses 601, 602, 603, and 604, arranged in order from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of 605 and 606. The third lens group L3 consists of a cemented lens of negative lens 607 and 608 and an aperture diaphragm SP. The fourth lens group L4 consists of a cemented lens of negative lens 609 and 610, 611, 612, a cemented lens of 613 and 614, and 615. Negative lens 604 acts as the first focus group F1, 606 as the second focus group F2, and the cemented lens of negative lens 609 and 610, 611, and 612 as the third focus group F3, moving towards the object side when focusing from infinity to close.

[0168] Figure 42 shows cross-sections of the zoom lens 600 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1 and the flare cut aperture e move towards the image side, while the second lens group L2, the third lens group L3, and the fourth lens group L4 move towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end. Also, during zooming, lens groups or lenses other than the first to third focus groups F1 to F3 remain stationary.

[0169] Figures 43, 44, and 45 show the longitudinal aberrations of the zoom lens 600 of numerical example 6 at the wide-angle end, intermediate zoom position, and telephoto end when it is in focus at infinity, respectively. Figures 46, 47, and 48 show the longitudinal aberrations of the zoom lens 600 of numerical example 6 at the wide-angle end, intermediate zoom position, and telephoto end when it is in close focus, respectively.

[0170] The zoom lens 600 diverges axial rays in the first lens group L1, which has negative refractive power, and the diverged axial rays are converged by the positive lens 605 in the second lens group L2, which has positive refractive power.

[0171] The converged on-axis rays become nearly parallel afocal rays as they pass through the third lens group L3, which has negative refractive power. These afocal rays are then converged by the fourth lens group L4, which has positive refractive power, to form an image.

[0172] By moving the third focusing group F3 within the fourth lens group L4, into which the afocal light rays enter, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0173] The field curvature of off-axis rays changes to the under-focus side during focusing. This reduces the focusing performance towards close objects. To correct this field curvature of off-axis rays, the negative lens 604 (F1) closest to the image in the first lens group L1, which is positioned in the diverging on-axis rays, and the positive lens 606 (F2) in the second lens group L2, which is positioned in the converging on-axis rays, are moved towards the object when focusing from infinity to close. This allows the field curvature of off-axis rays to be changed to the over-focus side.

[0174] The negative lens 604(F1) has a meniscus shape with its convex surface facing the image side, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 604(F1) toward the object during focusing. Furthermore, the movement of the negative lens 604(F1) during focusing changes the passage position of the off-axis central ray from the thin part of the negative lens 604(F1) to the thick part. As a result, the optical path length is extended, which can change the field curvature to the over-angle side, and cancel out some of the under-angle field curvature caused by the movement of the third focus group F3.

[0175] The positive lens 606 (F2) has a meniscus shape with its convex surface facing the object side, resulting in a nearly concentric shape with respect to the on-axial rays that have become convergent rays from the positive lens 605 onwards in the second lens group L2. This suppresses fluctuations in spherical aberration caused by the movement of the positive lens 606 (F2) toward the object side during focusing. Furthermore, the movement of the positive lens 606 (F2) due to focusing changes the passage position of the off-axis central ray from the thin part to the thick part of the positive lens 606 (F2). As a result, the optical path length is extended, which can change the field curvature to the over-angle side. This can be combined with the change in the field curvature of the first focus group F1 to the over-angle side to correct the under-angle field curvature caused by the movement of the third focus group F3. This improves the focusing performance at close range.

[0176] Due to the narrow spacing between lenses in order to miniaturize the entire 600 series of zoom lenses, both the first focusing group F1 and the second focusing group F2 move within a small space during focusing. This allows for image plane changes and focusing on close objects through the combined action of the first focusing group F1 and the second focusing group F2.

[0177] Furthermore, by constructing both the first focus group F1 and the second focus group F2 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0178] Furthermore, in the first lens group L1 with negative refractive power, the negative lens 604(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 604(F1) from becoming extremely strong. This reduces the sensitivity of the zoom lens 600 to misalignment of the negative lens 604(F1) in a direction perpendicular to the optical axis.

[0179] Furthermore, in the second lens group L2, which bears a portion of the positive refractive power, the positive lens 606(F2), which bears a portion of the positive refractive power, is moved during focusing to prevent the refractive power of the positive lens 606(F2) from becoming excessively strong. This reduces the sensitivity of the zoom lens 600 to misalignment of the positive lens 606(F2) in a direction perpendicular to the optical axis.

[0180] Furthermore, by appropriately setting the negative refractive power of the first lens group L1 and the amount of movement during zooming, it is possible to miniaturize the entire 600 zoom lens series. [Examples]

[0181] The zoom lens 700 of Embodiment 7 (Numerical Example 7) shown in Figure 49 is composed of a first lens group L1, a second lens group L2 including a flare cut aperture e, and a third lens group L3, which are arranged in order from the object side to the image side.

[0182] The first lens group L1, as part of the object-side N group, has a negative refractive power, the second lens group L2 has a positive refractive power, and the third lens group L3 has a positive refractive power. The second lens group L2 and the third lens group L3, positioned between the first lens group L1 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0183] The first lens group L1 consists of negative lenses 701, 702, 703, and 704, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of 705, 706, a cemented lens of negative lenses 707 and 708, and an aperture diaphragm SP. The third lens group L3 consists of a cemented lens of negative lens 709 and 710, 711, 712, a cemented lens of 713 and 714, and 715. Negative lens 704 acts as the first focus group F1, positive lens 706 as the second focus group F2, and the cemented lens of negative lens 709 and 710, positive lenses 711 and 712 as the third focus group F3, moving towards the object side when focusing from infinity to close.

[0184] Figure 50 shows cross-sections of the zoom lens 700 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1 and the flare cut aperture e move towards the image side, while the second lens group L2 and the third lens group L3 move towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end. Also, during zooming, lens groups or lenses other than the first to third focus groups F1 to F3 remain stationary.

[0185] Figures 51, 52, and 53 show the longitudinal aberrations of the zoom lens 700 of numerical example 7 at the wide-angle end, intermediate zoom position, and telephoto end when it is in focus at infinity, respectively. Figures 54, 55, and 56 show the longitudinal aberrations of the zoom lens 700 of numerical example 7 at the wide-angle end, intermediate zoom position, and telephoto end when it is in close focus, respectively.

[0186] The zoom lens 700 diverges axial rays in the first lens group L1, which has negative refractive power, and the diverged axial rays are converged by the positive lens 705 in the second lens group L2, which has positive refractive power.

[0187] The converged on-axis rays become nearly parallel afocal rays when they exit the second lens group L2, which has positive refractive power. These afocal rays are then converged by the third lens group L3, which also has positive refractive power, to form an image.

[0188] By moving the third focusing group F3 within the third lens group L3, into which the afocal light rays enter, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0189] The field curvature of off-axis rays changes to the under-focus side during focusing. This reduces the focusing performance towards close objects. To correct this field curvature of off-axis rays, the negative lens 704 (F1) closest to the image in the first lens group L1, which is positioned in the diverging on-axis rays, and the positive lens 706 (F2) in the second lens group L2, which is positioned in the converging on-axis rays, are moved towards the object when focusing from infinity to close. This allows the field curvature of off-axis rays to be changed to the over-focus side.

[0190] The negative lens 704 (F1) has a meniscus shape with its convex surface facing the image side, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 704 (F1) toward the object during focusing. Furthermore, the movement of the negative lens 704 (F1) during focusing changes the passage position of the off-axis central ray from the thin part of the negative lens 704 (F1) to the thick part. As a result, the optical path length is extended, which can change the field curvature to the over-angle side, and cancel out some of the under-angle field curvature caused by the movement of the third focus group F3.

[0191] The positive lens 706 (F2) has a meniscus shape with its convex surface facing the object side, resulting in a nearly concentric shape with respect to the on-axial rays that have become convergent rays from the positive lens 705 onwards in the second lens group L2. This suppresses fluctuations in spherical aberration caused by the movement of the positive lens 706 (F2) toward the object side during focusing. Furthermore, the movement of the positive lens 706 (F2) due to focusing changes the passage position of the off-axis central ray from the thin part to the thick part of the positive lens 706 (F2). As a result, the optical path length is extended, which can change the field curvature to the over-angle side. This can be combined with the change in the field curvature of the first focus group F1 to the over-angle side to correct the under-angle field curvature caused by the movement of the third focus group F3. This improves the focusing performance at close range.

[0192] Due to the narrow spacing between lenses in order to miniaturize the entire 700 series of zoom lenses, both the first focusing group F1 and the second focusing group F2 move within a small space during focusing. This allows for image plane changes and focusing on close objects through the combined action of the first focusing group F1 and the second focusing group F2.

[0193] Furthermore, by constructing both the first focus group F1 and the second focus group F2 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0194] Furthermore, in the first lens group L1 with negative refractive power, the negative lens 704(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 704(F1) from becoming extremely strong. This reduces the sensitivity of the zoom lens 700 to misalignment of the negative lens 704(F1) in a direction perpendicular to the optical axis.

[0195] Furthermore, in the second lens group L2, which bears a portion of the positive refractive power, the positive lens 706(F2), which bears a portion of the positive refractive power, is moved during focusing to prevent the refractive power of the positive lens 706(F2) from becoming excessively strong. This reduces the sensitivity of the zoom lens 700 to misalignment of the positive lens 706(F2) in a direction perpendicular to the optical axis.

[0196] Furthermore, by appropriately setting the negative refractive power of the first lens group L1 and the amount of movement during zooming, it is possible to miniaturize the entire 700 series of zoom lenses. [Examples]

[0197] The zoom lens 800 of Embodiment 8 (Numerical Example 8) shown in Figure 57 is composed of a first lens group L1, a flare cut aperture e, a second lens group L2, a third lens group L3 including an aperture aperture SP, a fourth lens group L4, and a fifth lens group L5, which are arranged in order from the object side to the image side.

[0198] The first lens group L1, as part of the object-side N group, has a negative refractive power; the second lens group L2 has a positive refractive power; the third lens group L3 has a negative refractive power; the fourth lens group L4 has a positive refractive power; and the fifth lens group L5 has a negative refractive power. The second to fifth lens groups L2 to L5, positioned between the first lens group L1 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0199] The first lens group L1 consists of negative lenses 801, 802, 803, and 804, arranged in order from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of 805 and 806. The third lens group L3 consists of a cemented lens of negative lens 807 and 808, and an aperture diaphragm SP. The fourth lens group L4 consists of a cemented lens of negative lens 809 and 810, 811, and 812. The fifth lens group L5 consists of a cemented lens of 813 and 814, and 815. The negative lens 804 acts as the first focusing group F1, the positive lens 806 as the second focusing group F2, and the cemented lens formed by the negative lens 809 and the positive lens 810, along with the positive lenses 811 and 812 (fourth lens group L4), act as the third focusing group F3, moving toward the object during focusing from infinity to close.

[0200] Figure 58 shows cross-sections of the zoom lens 800 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1 and the flare cut aperture e move towards the image side. The second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end. Also, during zooming, lens groups or lenses other than the first to third focus groups F1 to F3 remain stationary.

[0201] Figures 59, 60, and 61 show the longitudinal aberrations of the zoom lens 800 of numerical example 8 at the wide-angle end, intermediate zoom position, and telephoto end when it is in focus at infinity, respectively. Figures 62, 63, and 64 show the longitudinal aberrations of the zoom lens 800 of numerical example 8 at the wide-angle end, intermediate zoom position, and telephoto end when it is in close focus, respectively.

[0202] The zoom lens 800 diverges axial rays in the first lens group L1, which has negative refractive power, and these diverged axial rays are converged by the positive lens 805 of the second lens group L2, which has positive refractive power. When the converged axial rays pass through the third lens group L3, which has negative refractive power, they become nearly parallel afocal rays, and these afocal rays are converged by the fourth lens group L4, which has positive refractive power, and the fifth lens group L5, which has negative refractive power, to form an image.

[0203] By moving the third focusing group F3 within the fourth lens group L4, into which the afocal light rays enter, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0204] The field curvature of off-axis rays shifts to the under-focus side during focusing. This reduces the focusing performance towards close objects. To correct this field curvature of off-axis rays, the negative lens 804 (F1) closest to the image in the first lens group L1, which is positioned in the diverging on-axis rays, and the positive lens 806 (F2) in the second lens group L2, which is positioned in the converging on-axis rays, are moved towards the object when focusing from infinity to close. This allows the field curvature of off-axis rays to be changed to the over-focus side.

[0205] The negative lens 804(F1) has a meniscus shape with a convex orientation towards the image, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 804(F1) toward the object during focusing. Furthermore, the movement of the negative lens 804(F1) during focusing changes the passage position of the off-axis central ray from the thin part of the negative lens 804(F1) to the thick part. As a result, the optical path length is extended, which can change the field curvature to the over-angle side, and cancel out some of the under-angle field curvature caused by the movement of the third focus group F3.

[0206] The positive lens 806 (F2) has a meniscus shape with its convex surface facing the object side, resulting in a nearly concentric shape with respect to the on-axial rays that have become convergent rays from the positive lens 805 onwards in the second lens group L2. This suppresses fluctuations in spherical aberration caused by the movement of the positive lens 806 (F2) toward the object side during focusing. Furthermore, the movement of the positive lens 806 (F2) due to focusing changes the passage position of the off-axis central ray from the thin part to the thick part of the positive lens 806 (F2). As a result, the optical path length is extended, which can change the field curvature to the over-angle side. This can be combined with the change in the field curvature of the first focus group F1 to the over-angle side to correct the under-angle field curvature caused by the movement of the third focus group F3. This improves the focusing performance at close range.

[0207] Due to the narrow spacing between lenses in order to miniaturize the entire 800 series of zoom lenses, both the first focusing group F1 and the second focusing group F2 move within a small space during focusing. As a result, the combined action of the first focusing group F1 and the second focusing group F2 enables image plane changes and focusing on nearby objects.

[0208] Furthermore, by constructing both the first focus group F1 and the second focus group F2 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0209] Furthermore, in the first lens group L1 with negative refractive power, the negative lens 804(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 804(F1) from becoming excessively strong. This reduces the sensitivity of the zoom lens 800 to misalignment of the negative lens 804(F1) in a direction perpendicular to the optical axis.

[0210] Furthermore, in the second lens group L2, which bears a portion of the positive refractive power, the positive lens 806(F2), which bears a portion of the positive refractive power, is moved during focusing to prevent the refractive power of the positive lens 806(F2) from becoming excessively strong. This reduces the sensitivity of the zoom lens 800 to misalignment of the positive lens 806(F2) in a direction perpendicular to the optical axis.

[0211] Furthermore, by appropriately setting the negative refractive power of the first lens group L2 and the amount of movement during zooming, it is possible to miniaturize the entire 400mm zoom lens series. [Examples]

[0212] The zoom lens 900 of Embodiment 9 (Numerical Example 9) shown in Figure 65 is composed of a first lens group L1, a second lens group L2, a third lens group L3 including an aperture diaphragm SP, a fourth lens group L4, a fifth lens group L5, a sixth lens group L6, a seventh lens group L7, and an eighth lens group L8, which are arranged in order from the object side to the image side.

[0213] The first lens group L1 has a positive refractive power, the second lens group L2 (as the object-side N group) has a negative refractive power, the third lens group L3 has a positive refractive power, and the fourth lens group L4 has a positive refractive power. The fifth lens group L5 has a positive refractive power, the sixth lens group L6 has a negative refractive power, the seventh lens group L7 has a negative refractive power, and the eighth lens group L8 has a negative refractive power. The third lens group L3 to the eighth lens group L8, positioned between the second lens group L2 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0214] The first lens group L1 consists of a cemented lens of negative lens 901 and positive lens 902, and a positive lens 903, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of negative lenses 904, 905, 906, and 907. The third lens group L3 consists of a positive lens 908, a cemented lens of negative lens 909 and positive lens 910, an aperture diaphragm SP, and a cemented lens of negative lens 911 and negative lens 912 and positive lens 913. The fourth lens group L4 consists of a positive lens 914 and a cemented lens of positive lens 915 and negative lens 916. The fifth lens group L5 consists of a positive lens 917. The sixth lens group L6 consists of a cemented lens of positive lens 918 and negative lens 919, and a positive lens 920. The seventh lens group L7 consists of a negative lens 921. The eighth lens group L8 consists of a negative lens 922 and a positive lens 923.

[0215] The negative lens 907 acts as the first focusing group F1, the positive lens 917 (fifth lens group L5) as the second focusing group F2, and the negative lens 921 (seventh lens group L7) as the third focusing group F3, all of which move toward the object when focusing from infinity to close.

[0216] Figure 66 shows cross-sections of the zoom lens 900 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1, the third lens group L3, and the eighth lens group L8 remain stationary. The second lens group L2 moves towards the image side, and the fourth lens group L4 moves towards the object side. The fifth lens group L5 moves towards the image side, and the sixth lens group L6 and the seventh lens group L7 each move towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end.

[0217] Figure 67, Figure 68 and Figure 69 respectively show the longitudinal aberrations at the wide-angle end, the intermediate zoom position and the telephoto end when the zoom lens 900 of Numerical Example 9 is in the infinite focus state. Figure 70, Figure 71 and Figure 72 respectively show the longitudinal aberrations at the wide-angle end, the intermediate zoom position and the telephoto end when the zoom lens 900 of Numerical Example 9 is in the closest focus state.

[0218] The zoom lens 900 is miniaturized as a whole by converging on-axis rays with the first lens group L1 having positive refractive power. The on-axis rays converged by the first lens group L2 become diverging rays by the second lens group L2 having negative refractive power, and the diverging on-axis rays are converged by the third lens group L3 and the fourth lens group L4 each having positive refractive power, respectively.

[0219] The converged on-axis rays form an image through the fifth lens group L5 having positive refractive power, the sixth lens group L6 having negative refractive power, the seventh lens group L7 having negative refractive power, and the eighth lens group L8 having negative refractive power.

[0220] By performing focusing by moving the negative lens 917(F3) as the seventh lens group L7 with weak negative refractive power, it is possible to suppress the variation of spherical aberration due to focusing.

[0221] The negative lens 907(F1) has a meniscus shape with a convex surface facing the image side, which is a substantially concentric shape with respect to the diverging on-axis rays. Thereby, the variation of spherical aberration caused by the movement of the negative lens 907(F1) toward the object side during focusing can be suppressed.

[0222] Further, the positive lens 917(F2) has a meniscus shape with a convex surface facing the object side, which is a substantially concentric shape with respect to on-axis rays. Thereby, the variation of spherical aberration caused by the movement of the positive lens 917(F2) toward the object side during focusing can be suppressed.

[0223] Due to the narrow spacing between lenses in order to miniaturize the entire 900 series of zoom lenses, the first, second, and third focusing groups F1, F2, and F3 all move within a small space during focusing. As a result, the combined action of the first, second, and third focusing groups F1, F2, and F3 corrects spherical aberration and enables focusing on close objects.

[0224] Furthermore, by constructing the first focus group F1, the second focus group F2, and the third focus group F3 with single lenses, the weight of each focus group can be reduced, and the drive mechanism for each focus group using actuators such as motors can be miniaturized.

[0225] Furthermore, in the second lens group L2 with negative refractive power, the negative lens 907(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 907(F1) from becoming extremely strong. This reduces the sensitivity of the zoom lens 900 to misalignment of the negative lens 907(F1) in a direction perpendicular to the optical axis.

[0226] Furthermore, the positive lens 917 (F2) is positioned following the third lens group L3 and the fourth lens group L4, which each have positive refractive power, and shares the positive refractive power with the third lens group L3 and the fourth lens group L4. As a result, the refractive power of the positive lens 917 (F2) does not become extremely strong. Consequently, the sensitivity of the positive lens 917 (F2) to misalignment in the direction perpendicular to the optical axis of the zoom lens 900 can be reduced.

[0227] Furthermore, by appropriately setting the negative refractive power of the second lens group L2 and the amount of movement during zooming, it is possible to achieve a smaller overall size for the entire 900 series of zoom lenses. [Examples]

[0228] The zoom lens 1000 of Embodiment 10 (Numerical Example 10) shown in Figure 73 is composed of a first lens group L1, a second lens group L2, a third lens group L3 including an aperture diaphragm SP, a fourth lens group L4, a fifth lens group L5, a sixth lens group L6, a seventh lens group L7, and an eighth lens group L8, which are arranged in order from the object side to the image side.

[0229] The first lens group L1 has a positive refractive power, the second lens group L2 (as the object-side N group) has a negative refractive power, the third lens group L3 has a positive refractive power, and the fourth lens group L4 has a positive refractive power. The fifth lens group L5 has a positive refractive power, the sixth lens group L6 has a negative refractive power, the seventh lens group L7 has a negative refractive power, and the eighth lens group L8 has a positive refractive power. The third lens group L3 to the eighth lens group L8, positioned between the second lens group L2 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0230] The first lens group L1 consists of a cemented lens of negative lens 1001 and positive lens 1002, and a positive lens 1003, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of negative lenses 1004, 1005, 1006, and 1007. The third lens group L3 consists of a positive lens 1008, a cemented lens of negative lens 1009 and positive lens 1010, an aperture diaphragm SP, and a cemented lens of negative lens 1011 and negative lens 1012 and positive lens 1013. The fourth lens group L4 consists of a positive lens 1014 and a cemented lens of positive lens 1015 and negative lens 1016. The fifth lens group L5 consists of a positive lens 1017. The sixth lens group L6 consists of a cemented lens of positive lens 1018 and negative lens 1019, and a positive lens 1020. The seventh lens group L7 is composed of a negative lens 1021. The eighth lens group L8 is composed of a negative lens 1022 and a positive lens 1023.

[0231] The negative lens 1007 acts as the first focusing group F1, the positive lens 1017 (fifth lens group L5) acts as the second focusing group F2, and the negative lens 1021 (seventh lens group L7) acts as the third focusing group F3, all of which move toward the object during focusing from infinity to close range.

[0232] Figure 74 shows cross-sections of the zoom lens 1000 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1, the third lens group L3, and the eighth lens group L8 remain stationary. The second lens group L2 moves towards the image side, and the fourth lens group L4 moves towards the object side. The fifth lens group L5 moves towards the image side, and the sixth lens group L6 and the seventh lens group L7 each move towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end.

[0233] Figures 74, 75, and 76 show the longitudinal aberrations of the zoom lens 1000 of numerical example 10 at the wide-angle end, intermediate zoom position, and telephoto end when focused at infinity, respectively. Figures 77, 78, and 79 show the longitudinal aberrations of the zoom lens 900 of numerical example 10 at the wide-angle end, intermediate zoom position, and telephoto end when focused at closest distance, respectively.

[0234] The Zoom Lens 1000 achieves its compact size by converging axial rays with the first lens group L1, which has positive refractive power. The axial rays converged by the first lens group L1 become divergent rays with the second lens group L2, which has negative refractive power, and these divergent axial rays are then converged by the third lens group L3 and the fourth lens group L4, which have positive refractive power, respectively.

[0235] The converged on-axis rays are imaged through the fifth lens group L5 with positive refractive power, the sixth lens group L6 with negative refractive power, the seventh lens group L7 with negative refractive power, and the eighth lens group L8 with positive refractive power.

[0236] By moving the negative lens 1017 (F3), which acts as the seventh lens group L7 with a weak negative refractive power, and performing focusing, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0237] The negative lens 1007 (F1) has a meniscus shape with its convex surface facing the image side, which is a substantially concentric shape with respect to on-axis diverging light rays. This makes it possible to suppress variations in spherical aberration caused by the movement of the negative lens 1007 (F1) toward the object side during focusing.

[0238] Further, the positive lens 1017 (F2) has a meniscus shape with its convex surface facing the object side, which is a substantially concentric shape with respect to on-axis light rays. This makes it possible to suppress variations in spherical aberration caused by the movement of the positive lens 1017 (F2) toward the object side during focusing.

[0239] Since the lens intervals are narrow for miniaturization of the entire zoom lens 1000 system, each of the first focus group F1, the second focus group F2, and the third focus group F3 is moved within a small space during focusing. Thereby, correction of spherical aberration and focusing on a close object are achieved by the combined action of the first focus group F1, the second focus group F2, and the third focus group F3.

[0240] Furthermore, by configuring each of the first focus group F1, the second focus group F2, and the third focus group F3 with a single lens, each focus group can be reduced in weight, and the drive mechanism for each focus group using an actuator such as a motor can be miniaturized.

[0241] In addition, by moving the negative lens 1007 (F1), which shares part of the negative refractive power in the second lens unit L2 having negative refractive power, during focusing, the refractive power of the negative lens 1007 (F1) is prevented from becoming extremely strong. This makes it possible to reduce the sensitivity to the displacement of the negative lens 1007 (F1) in the direction orthogonal to the optical axis of the zoom lens 1000.

[0242] Furthermore, the positive lens 1017 (F2) is positioned following the third lens group L3 and the fourth lens group L4, which each have positive refractive power, and shares the positive refractive power with the third lens group L3 and the fourth lens group L4. As a result, the refractive power of the positive lens 1017 (F2) does not become extremely strong. Consequently, the sensitivity of the positive lens 1017 (F2) to misalignment in the direction perpendicular to the optical axis of the zoom lens 1000 can be reduced.

[0243] Furthermore, by appropriately setting the negative refractive power of the second lens group L2 and the amount of movement during zooming, it is possible to miniaturize the entire 1000 zoom lens series. [Examples]

[0244] The zoom lens 1100 of Embodiment 11 (Numerical Example 11) shown in Figure 81 is composed of a first lens group L1, a second lens group L2, a third lens group L3 including an aperture diaphragm SP, a fourth lens group L4, a fifth lens group L5, a sixth lens group L6, a seventh lens group L7, and an eighth lens group L8, which are arranged in order from the object side to the image side.

[0245] The first lens group L1 has a positive refractive power, the second lens group L2 (as the object-side N group) has a negative refractive power, the third lens group L3 has a positive refractive power, and the fourth lens group L4 has a positive refractive power. The fifth lens group L5 has a positive refractive power, the sixth lens group L6 has a negative refractive power, the seventh lens group L7 has a negative refractive power, and the eighth lens group L8 has a positive refractive power. The third lens group L3 to the eighth lens group L8, positioned between the second lens group L2 and the image plane IP, constitute the P group, and their combined refractive power (the refractive power of the P group as a whole) is positive.

[0246] The first lens group L1 consists of a cemented lens of negative lens 1101 and positive lens 1102, and a positive lens 1103, arranged sequentially from the object side to the image side (the same applies to the following lens groups). The second lens group L2 consists of negative lenses 1104, 1105, 1106, and 1107. The third lens group L3 consists of a positive lens 1108, a cemented lens of negative lens 1109 and positive lens 1110, an aperture diaphragm SP, and a cemented lens of negative lens 1111 and negative lens 1112 and positive lens 1113. The fourth lens group L4 consists of a positive lens 1114 and a cemented lens of positive lens 1115 and negative lens 1116. The fifth lens group L5 consists of a positive lens 1117. The sixth lens group L6 consists of a cemented lens of positive lens 1118 and negative lens 1119, and a positive lens 1120. The seventh lens group L7 is composed of a negative lens 1121. The eighth lens group L8 is composed of a negative lens 1122 and a positive lens 1123.

[0247] The negative lens 1107 acts as the first focus group F1, the positive lens 1117 (fifth lens group L5) acts as the second focus group F2, and the negative lens 1121 (seventh lens group L7) acts as the third focus group F3, moving towards the object when focusing from infinity to close. Additionally, the negative lens 1122 and the positive lens 1123 (eighth lens group L8) act as the fourth focus group F4, moving towards the image when focusing from infinity to close.

[0248] Figure 82 shows cross-sections of the zoom lens 1100 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. When zooming from the wide-angle end to the telephoto end, the first lens group L1, the third lens group L3, and the eighth lens group L8 remain stationary. The second lens group L2 moves towards the image side, and the fourth lens group L4 moves towards the object side. The fifth lens group L5 moves towards the image side, and the sixth lens group L6 and the seventh lens group L7 each move towards the object side. The zoom position where the object-side N group is closest to the image is the telephoto end.

[0249] Figures 83, 84, and 85 show the longitudinal aberrations of the zoom lens 1100 of numerical example 11 at the wide-angle end, intermediate zoom position, and telephoto end when it is in focus at infinity, respectively. Figures 86, 87, and 88 show the longitudinal aberrations of the zoom lens 1100 of numerical example 11 at the wide-angle end, intermediate zoom position, and telephoto end when it is in close focus, respectively.

[0250] The 1100 zoom lens achieves its compact size by converging axial rays with the first lens group L1, which has positive refractive power. The axial rays converged by the first lens group L1 become divergent rays with the second lens group L2, which has negative refractive power, and these divergent axial rays are then converged by the third lens group L3 and the fourth lens group L4, which have positive refractive power, respectively.

[0251] The converged on-axis rays are imaged through the fifth lens group L5 with positive refractive power, the sixth lens group L6 with negative refractive power, the seventh lens group L7 with negative refractive power, and the eighth lens group L8 with positive refractive power.

[0252] By moving negative lenses 1117 (F3) and 1122 (F4), each with a weak negative refractive power, and performing focusing, it is possible to suppress fluctuations in spherical aberration caused by focusing.

[0253] The negative lens 1107 (F1) has a meniscus shape with a convex surface facing the image side, resulting in a shape that is almost concentric with respect to divergent rays on the axis. This suppresses fluctuations in spherical aberration caused by the movement of the negative lens 1107 (F1) toward the object during focusing.

[0254] Furthermore, the positive lens 1117 (F2) has a meniscus shape with its convex surface facing the object, resulting in a shape that is almost concentric with respect to the on-axis light rays. This makes it possible to suppress fluctuations in spherical aberration caused by the movement of the positive lens 1117 (F2) toward the object during focusing.

[0255] Due to the narrow spacing between lenses in order to miniaturize the entire 1100 zoom lens series, the first, second, third, and fourth focusing groups F1, F2, F3, and F4 all move within a small space during focusing. As a result, the combined action of the first, second, third, and fourth focusing groups F1, F2, F3, and L4 corrects spherical aberration and enables focusing on close objects.

[0256] Furthermore, the first, second, and third focus groups F1, F2, and F3 are all composed of single lenses, while the fourth focus group F4 is composed of two thin lenses. This allows for weight reduction of each focus group and miniaturization of the drive mechanism for each focus group, which is controlled by an actuator such as a motor.

[0257] Furthermore, in the second lens group L2 with negative refractive power, the negative lens 1107(F1), which bears a portion of the negative refractive power, is moved during focusing to prevent the refractive power of the negative lens 1107(F1) from becoming excessively strong. This reduces the sensitivity to displacement of the negative lens 1107(F1) in a direction perpendicular to the optical axis of the zoom lens 1100.

[0258] Furthermore, the positive lens 1117(F2) is positioned following the third lens group L3 and the fourth lens group L4, which each have positive refractive power, and shares the positive refractive power with the third lens group L3 and the fourth lens group L4. As a result, the refractive power of the positive lens 1117(F2) does not become extremely strong. Consequently, the sensitivity of the positive lens 1117(F2) to misalignment in the direction perpendicular to the optical axis of the zoom lens 1100 can be reduced.

[0259] Furthermore, by appropriately setting the negative refractive power of the second lens group L2 and the amount of movement during zooming, it is possible to miniaturize the entire 1100 zoom lens system.

[0260] Numerical examples 1 to 11 are shown below. In the surface data for each numerical example, surface number i indicates the order of the surfaces counted from the object side. r is the radius of curvature of the i-th surface (mm), d is the lens thickness or air gap between the i-th and (i+1)-th surfaces (mm), and nd is the refractive index of the optical material between the i-th and (i+1)-th surfaces at the d-line. νd is the Abbe number of the optical material between the i-th and (i+1)-th surfaces with respect to the d-line. The Abbe number νd with respect to the d-line is expressed as νd = (Nd-1) / (NF-NC), where Nd, NF, and NC are the refractive indices at the Fraunhofer lines d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm), respectively. The effective diameter is the diameter (mm) of the region of the i-th lens surface through which the light ray contributing to imaging passes.

[0261] The various data include focal length (mm), F-number, half-angle of view (°), and image height (mm). BF represents back focus (mm). Back focus is the distance along the optical axis from the final lens surface closest to the image on the zoom lens to the paraxial image plane, expressed in air-equivalent length. The total lens length is the distance along the optical axis from the front lens surface closest to the object on the zoom lens to the final lens surface, plus the back focus, and corresponds to the total optical length.

[0262] The asterisk (*) next to the surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following formula, where X is the displacement in the direction of the optical axis at a height H from the optical axis, relative to the surface vertex, R is the radius of paraxial curvature, K is the cone constant, and Ai (i=2,4,6,8,…) are the aspherical coefficients of each order. The cone constant and aspherical coefficients "e±x" are multiplied by 10⁻¹⁴. ±x It means...

[0263]

number

[0264] (Numerical example 1) Unit: mm Surface data Face number rd nd νd Effective diameter 1 129.475 2.40 1.86966 20.0 69.39 2 86.330 7.75 1.75500 52.3 66.89 3 417.710 0.00 65.62 4 71.617 7.60 1.43875 94.7 60.77 5 299.585 (Variable) 58.71 6 99.380 1.50 1.77250 49.6 40.07 7 33.360 8.48 37.67 8* -96.560 1.50 1.76450 49.1 37.88 9 81.353 0.50 39.35 10 64.274 7.51 2.00069 25.5 40.73 11 -129.006 1.50 1.53775 74.7 40.92 12 -465.475 7.49 40.91 13* -43.420 1.50 1.86100 37.1 40.78 14 -102.470 (variable) 42.81 15 (aperture) ∞ (variable) 44.42 16 61.125 9.44 1.60300 65.4 48.34 17 -159.311 3.50 48.24 18* 98.276 3.40 1.58313 59.4 46.36 19 287.990 1.50 45.81 20 103.236 1.50 1.66565 35.6 44.81 21 32.835 7.36 1.53775 74.7 42.29 22 77.308 (Variable) 41.60 23 -52.701 1.50 1.56732 42.8 39.87 24 40.982 10.37 1.59282 68.6 42.29 25 -159.275 0.50 43.06 26* 82.479 8.92 1.49700 81.5 47.10 27* -74.567 0.50 48.32 28 78.676 16.05 1.43875 94.7 51.88 29 -50.947 0.50 52.29 30 63.192 6.41 2.05090 26.9 47.06 31 540.073 1.50 1.66565 35.6 45.62 32 27.761 19.94 38.89 33* -914.566 2.00 1.58313 59.4 38.22 34* 70.117 (variable) 39.64 Image plane ∞ Aspherical data Side 8 K = 0.00000e+00 A 4= 1.14576e-06 A 6= 3.78420e-10 A 8= 7.68027e-13 Page 13 K = 0.00000e+00 A 4=-3.67108e-07 A 6=-1.97616e-10 A 8= 3.24682e-13 Page 18 K = 0.00000e+00 A 4=-1.48646e-06 A 6=-4.22635e-10 A 8=-1.46433e-13 Page 26 K = 0.00000e+00 A 4=-2.61143e-06 A 6= 6.85349e-10 A 8= 9.33231e-13 Page 27 K = 0.00000e+00 A 4= 2.95711e-06 A 6= 1.30525e-10 A 8= 2.41002e-12 Page 33 K = 0.00000e+00 A 4=-3.64933e-05 A 6= 1.01820e-07 A 8=-2.95481e-10 A10= 7.14851e-13 A12=-1.22372e-15 A14= 9.48913e-19 Page 34 K = 0.00000e+00 A 4=-3.49681e-05 A 6= 9.12933e-08 A 8=-2.44999e-10 A10= 5.49212e-13 A12=-8.77608e-16 A14= 6.49038e-19 Various data Zoom ratio 1.60 Wide-angle, Medium, Telephoto Focal length 51.50 64.00 82.52 F number 1.46 1.46 1.46 Half-angle (°): 22.79, 18.68, 14.69 Image height 21.64 21.64 21.64 Lens length: 196.75 200.00 198.27 BF 13.53 12.87 13.97 d 5 0.50 15.32 25.44 d14 7.49 10.98 1.00 d15 9.63 1.00 1.00 d22 23:00 17:23 14:25 d34 13.53 12.87 13.97 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 121.42 17.75 0.85 -10.09 2 6 -38.79 29.98 7.83 -13.49 SP 15 ∞ 0.00 0.00 -0.00 3 16 70.34 26.69 -2.83 -19.89 4 23 70.22 68.18 -8.43 -42.91 Single lens data Lens starting plane, focal length 1 1 -305.82 2 2 142.70 3 4 212.35 4 6 -65.66 5 8 -57.54 6 10 43.72 7 11 -332.40 8 13 -88.55 9 16 74.46 10 18 254.16 11 20 -72.96 12 21 100.34 13 23 -40.40 14 24 56.06 15 26 80.31 16 28 73.24 17 30 67.63 18 31 -44.02 19 33 -111.60 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point): 500, 650, 800 d12 6.61 6.50 5.98 d14 8.37 11.97 2.51 d17 1.00 0.88 0.40 d19 4.00 4.12 4.60 d22 19.05 13.08 9.28 d29 4.45 4.65 5.47 (Numerical example 2) Unit: mm Surface data Face number rd nd νd Effective diameter 1 126.776 2.40 1.86966 20.0 69.65 2 86.874 7.59 1.75500 52.3 67.18 3 374.632 0.00 65.91 4 81.736 6.87 1.43875 94.7 61.82 5 313.697 (Variable) 59.89 6 87.003 1.50 1.77250 49.6 40.19 7 33.810 8.50 37.93 8* -97.250 1.50 1.76450 49.1 38.13 9 85.177 0.50 39.55 10 63.688 7.46 2.00069 25.5 41.02 11 -138.890 1.50 1.53775 74.7 41.15 12 -346.823 6.88 41.10 13* -46.594 1.50 1.86100 37.1 40.84 14 -144.330 (variable) 42.74 15 (aperture) ∞ (variable) 44.02 16 62.471 8.45 1.60300 65.4 47.45 17 -230.309 3.62 47.39 18* 84.711 4.55 1.58313 59.4 46.13 19 753.515 1.00 45.60 20 100.990 1.50 1.66565 35.6 44.47 21 33.043 6.56 1.53775 74.7 41.89 22 65.554 (Variable) 41.17 23 -62.711 1.50 1.56732 42.8 39.92 24 37.706 10.01 1.59282 68.6 41.84 25 -299.630 0.50 42.27 26* 87.697 7.13 1.49700 81.5 44.83 27* -75.999 0.50 45.80 28 80.589 17.22 1.43875 94.7 49.51 29 -47.902 0.50 50.45 30 74.503 9.64 2.05090 26.9 46.56 31 -416.677 1.50 1.66565 35.6 43.90 32 27.838 18.42 37.70 33* 71.202 2.03 1.58313 59.4 38.01 34* 36.556 (variable) 39.65 Image plane ∞ Aspherical data Side 8 K = 0.00000e+00 A 4= 1.08250e-06 A 6= 3.31003e-10 A 8= 8.32141e-13 Page 13 K = 0.00000e+00 A 4=-4.51718e-07 A 6=-2.05684e-10 A 8= 2.39473e-13 Page 18 K = 0.00000e+00 A 4=-1.42936e-06 A 6=-3.38221e-10 A 8=-1.30751e-13 Page 26 K = 0.00000e+00 A 4=-2.97168e-06 A 6= 6.59166e-10 A 8= 1.24438e-12 Page 27 K = 0.00000e+00 A 4= 2.94149e-06 A 6= 2.52026e-10 A 8= 3.07722e-12 Page 33 K = 0.00000e+00 A 4=-6.07489e-05 A 6= 1.03402e-07 A 8= 5.58851e-11 A10=-8.88987e-13 A12= 1.89060e-15 A14=-1.40364e-18 Page 34 K = 0.00000e+00 A 4=-6.35001e-05 A 6= 1.11374e-07 A 8=-6.91653e-12 A10=-6.38425e-13 A12= 1.39038e-15 A14=-9.82046e-19 Various data Zoom ratio 1.60 Wide-angle, Medium, Telephoto Focal length 51.50 64.00 82.53 F number 1.46 1.46 1.46 Half-angle (°): 22.79, 18.68, 14.69 Image height 21.64 21.64 21.64 Lens length: 194.29, 199.38, 199.17 BF 13.00 12.63 13.81 d 5 0.50 16.77 28.31 d14 9.21 4.02 1.00 d15 7.72 7.66 1.00 d22 23.04 17:47 14:22 d34 13.00 12.63 13.81 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 133.33 16.86 0.36 -9.97 2 6 -40.77 29.35 8.66 -12.10 SP 15 ∞ 0.00 0.00 -0.00 3 16 70.99 25.67 -3.07 -19.29 4 23 68.60 68.94 -9.46 -43.25 Single lens data Lens starting plane, focal length 1 1 -326.51 2 2 148.12 3 4 249.68 4 6 -72.48 5 8 -59.18 6 10 44.45 7 11 -431.89 8 13 -80.49 9 16 82.39 10 18 163.26 11 20 -74.44 12 21 115.73 13 23 -41.28 14 24 57.13 15 26 83.12 16 28 71.39 17 30 60.75 18 31 -39.15 19 33 -131.67 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point): 500, 650, 800 d12 6.02 5.84 5.31 d14 10.08 5.06 2.57 d17 0.80 0.59 0.40 d19 3.82 4.03 4.22 d22 18.91 13.19 9.04 d29 4.63 4.78 5.68 (Numerical example 3) Unit: mm Surface data Face number rd nd νd Effective diameter 1 108.376 2.40 1.86966 20.0 86.00 2 82.941 10.60 1.43875 94.7 82.93 3 418.817 0.00 82.12 4 94.156 7.84 1.69680 55.5 77.72 5 396.332 (Variable) 76.70 6 123.163 1.50 1.77250 49.6 57.35 7 37.582 13.67 48.92 8* -83.157 1.50 1.76450 49.1 47.79 9 80.327 0.50 46.21 10 74.988 14.58 2.00069 25.5 46.30 11 -43.736 1.50 1.92119 24.0 45.07 12 -172.193 7.32 43.84 13* -48.334 1.50 1.86100 37.1 43.88 14 -84.469 (variable) 45.56 15 ∞ (variable) 47.12 16 55.269 8.82 1.60300 65.4 49.74 17 -267.946 1.00 49.46 18 (aperture) ∞ 3.50 48.67 19* 70.526 3.51 1.58313 59.4 46.14 20 124.630 5.28 45.23 21 120.603 1.50 1.66565 35.6 42.96 22 53.224 (Variable) 41.42 23 -61.461 1.50 1.66565 35.6 39.60 24 43.310 9.47 1.59282 68.6 41.53 25 -131.113 0.50 42.16 26* 68.405 11.88 1.49700 81.5 44.06 27* -80.961 0.50 46.42 28 99.047 18.84 1.43875 94.7 49.25 29 -50.921 0.50 50.58 30 51.209 8.57 2.00069 25.5 46.70 31 170.494 1.50 1.66565 35.6 43.87 32 25.690 15.18 37.75 33* 54.453 2.00 1.58313 59.4 38.17 34* 32.295 (variable) 39.58 Image plane ∞ Aspherical data Side 8 K = 0.00000e+00 A 4= 7.44225e-07 A 6=-1.35998e-11 A 8= 1.77923e-13 Page 13 K = 0.00000e+00 A 4=-8.25924e-08 A 6= 1.41207e-10 A 8=-3.09075e-16 Page 19 K = 0.00000e+00 A 4=-1.37413e-06 A 6=-7.25210e-10 A 8=-1.22599e-13 Page 26 K = 0.00000e+00 A 4=-2.52352e-06 A 6= 1.45976e-09 A 8= 2.43189e-13 Page 27 K = 0.00000e+00 A 4= 2.04156e-06 A 6= 1.00128e-09 A 8= 1.25879e-12 Page 33 K = 0.00000e+00 A 4=-7.49123e-05 A 6= 1.98306e-07 A 8=-3.52435e-10 A10= 1.33779e-13 A12= 8.18357e-16 A14=-1.26309e-18 Page 34 K = 0.00000e+00 A 4=-8.29460e-05 A 6= 2.27283e-07 A 8=-4.96964e-10 A10= 5.78947e-13 A12=-4.20826e-17 A14=-4.73586e-19 Various data Zoom ratio 1.86 Wide-angle, Medium, Telephoto Focal length 44.29 63.12 82.52 F number 1.46 1.46 1.46 Half-angle (°): 26.03, 18.92, 14.69 Image height 21.64 21.64 21.64 Lens length: 230.00 227.67 226.89 BF 14.00 16.29 16.72 d 5 0.50 18.18 29.99 d14 21.67 1.06 1.00 d15 12.53 14.47 1.00 d22 24.33 20.70 21.21 d34 14.00 16.29 16.72 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 135.03 20.85 3.45 -9.90 2 6 -47.27 42.07 6.40 -23.35 e 15 ∞ 0.00 0.00 -0.00 3 16 87.78 23.61 -7.91 -23.59 4 23 68.68 70.44 -3.18 -39.03 Single lens data Lens starting plane, focal length 1 1 -425.04 2 2 233.47 3 4 175.36 4 6 -70.55 5 8 -53.23 6 10 29.41 7 11 -64.00 8 13 -133.80 9 16 76.77 10 19 272.11 11 21 -144.40 12 23 -37.95 13 24 56.05 14 26 76.63 15 28 79.70 16 30 70.60 17 31 -45.63 18 33 -140.78 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point): 500, 650, 800 d12 6.03 6.57 6.63 d14 22.96 1.81 1.69 d18 1.82 1.27 0.80 d20 6.97 7.51 7.98 d22 20.51 15.81 14.97 d29 4.32 5.39 6.74 (Numerical example 4) Unit: mm Surface data Face number rd nd νd Effective diameter 1 138.335 2.40 1.86966 20.0 90.00 2 101.768 10.50 1.43875 94.7 87.03 3 563.713 0.00 85.89 4 110.156 8.89 1.69680 55.5 81.90 5 626.333 (Variable) 80.29 6 170.423 1.50 1.77250 49.6 64.93 7 40.146 15.83 53.65 8* -81.705 1.50 1.76450 49.1 52.19 9 85.627 0.50 50.26 10 80.868 18.29 2.00069 25.5 50.33 11 -41.265 1.50 1.92119 24.0 48.59 12 -146.445 7.16 45.92 13* -50.982 1.50 1.86100 37.1 46.06 14 -95.288 (variable) 47.91 15 ∞ (variable) 49.67 16 49.949 11.41 1.60300 65.4 53.49 17 -386.001 1.00 52.87 18 (aperture) ∞ 2.25 52.01 19* 59.582 3.64 1.58313 59.4 48.95 20 103.859 (Variable) 47.96 21 97.321 1.50 1.66565 35.6 45.60 22 49.466 (Variable) 43.63 23 -63.175 1.50 1.66565 35.6 42.08 24 39.491 10.90 1.59282 68.6 43.88 25 -210.039 0.50 44.57 26* 58.540 8.90 1.49700 81.5 45.93 27* -85.131 0.50 45.71 28 120.296 18.30 1.43875 94.7 47.52 29 -49.871 0.50 49.03 30 52.822 8.14 2.00069 25.5 45.69 31 179.651 1.50 1.66565 35.6 43.12 32 26.153 14.14 37.55 33* 75.754 2.00 1.58313 59.4 38.02 34* 42.120 (variable) 39.65 Image plane ∞ Aspherical data Side 8 K = 0.00000e+00 A 4= 4.82384e-07 A 6=-9.48438e-11 A 8= 1.16384e-13 Page 13 K = 0.00000e+00 A 4=-9.18263e-09 A 6= 1.93003e-10 A 8=-1.18093e-13 Page 19 K = 0.00000e+00 A 4=-1.45288e-06 A 6=-8.94691e-10 A 8=-3.10095e-13 Page 26 K = 0.00000e+00 A 4=-2.92706e-06 A 6= 1.29474e-09 A 8= 9.90401e-13 Page 27 K = 0.00000e+00 A 4= 2.61314e-06 A 6= 6.58855e-10 A 8= 2.16817e-12 Page 33 K = 0.00000e+00 A 4=-6.31646e-05 A 6= 1.57216e-07 A 8=-3.61282e-10 A10= 5.33794e-13 A12=-2.63915e-16 A14=-3.18221e-19 Page 34 K = 0.00000e+00 A 4=-6.81426e-05 A 6= 1.78615e-07 A 8=-4.69975e-10 A10= 9.05520e-13 A12=-1.03533e-15 A14= 4.36212e-19 Various data Zoom ratio 2.29 Wide-angle, Medium, Telephoto Focal length 36.06 59.67 82.52 F number 1.46 1.46 1.46 Half-angle (°): 30.97, 19.93, 14.69 Image height 21.64 21.64 21.64 Lens length: 238.87 234.18 238.08 BF 13.00 19.15 20.85 d 5 0.50 22.98 38.65 d14 22.94 1.11 1.00 d15 24.82 15.64 1.05 d20 4.20 4.37 4.52 d22 17.18 14.68 15.76 d34 13.00 19.15 20.85 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 154.76 21.79 4.21 -9.69 2 6 -46.85 47.78 6.25 -27.03 e 15 ∞ 0.00 0.00 -0.00 3 16 57.42 18.29 2.46 -10.36 4 21 -153.05 1.50 1.85 0.94 5 23 77.95 66.88 -1.28 -37.27 Single lens data Lens starting plane, focal length 1 1 -456.63 2 2 281.10 3 4 190.48 4 6 -68.33 5 8 -54.48 6 10 29.51 7 11 -62.80 8 13 -129.37 9 16 74.07 10 19 232.64 11 21 -153.05 12 23 -36.29 13 24 57.00 14 26 71.26 15 28 83.08 16 30 72.45 17 31 -46.16 18 33 -166.33 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point) 500 650 800 d12 5.09 4.55 4.15 d14 25.00 3.72 4.01 d18 1.51 1.43 1.25 d20 4.94 5.19 5.52 d22 14.50 10.80 10.51 d29 3.18 4.37 5.75 (Numerical example 5) Unit: mm Surface data Face number rd nd νd Effective diameter 1 138.340 2.40 1.86966 20.0 90.00 2 101.858 10.55 1.43875 94.7 87.25 3 569.482 0.00 86.11 4 110.381 8.90 1.69680 55.5 82.09 5 625.318 (variable) 80.48 6 170.498 1.50 1.77250 49.6 64.87 7 40.109 15.78 53.60 8* -81.751 1.50 1.76450 49.1 52.17 9 85.478 0.50 50.25 10 80.731 18.11 2.00069 25.5 50.32 11 -41.332 1.50 1.92119 24.0 48.63 12 -146.373 7.16 45.92 13* -50.998 1.50 1.86100 37.1 45.97 14 -95.438 (variable) 47.81 15 ∞ (variable) 49.56 16 49.909 11.39 1.60300 65.4 53.33 17 -386.316 1.00 52.71 18 (aperture) ∞ 2.20 51.86 19* 59.588 3.65 1.58313 59.4 48.84 20 103.919 (Variable) 47.84 21 97.156 1.50 1.66565 35.6 45.52 22 49.371 (variable) 43.55 23 -63.181 1.50 1.66565 35.6 42.01 24 39.492 10.88 1.59282 68.6 43.80 25 -210.954 0.50 44.50 26* 58.528 8.91 1.49700 81.5 45.87 27* -85.097 0.50 45.64 28 120.225 18.30 1.43875 94.7 47.48 29 -49.870 (variable) 48.99 30 52.780 8.11 2.00069 25.5 45.67 31 179.388 1.50 1.66565 35.6 43.12 32 26.152 14.25 37.55 33* 77.121 2.00 1.58313 59.4 38.01 34* 42.516 (variable) 39.65 Image plane ∞ Aspherical data Side 8 K = 0.00000e+00 A 4= 4.79470e-07 A 6=-9.48336e-11 A 8= 1.17653e-13 Page 13 K = 0.00000e+00 A 4=-5.71405e-09 A 6= 1.89646e-10 A 8=-1.17325e-13 Page 19 K = 0.00000e+00 A 4=-1.45496e-06 A 6=-8.91373e-10 A 8=-3.10919e-13 Page 26 K = 0.00000e+00 A 4=-2.92349e-06 A 6= 1.30202e-09 A 8= 9.95428e-13 Page 27 K = 0.00000e+00 A 4= 2.62006e-06 A 6= 6.65962e-10 A 8= 2.17462e-12 Page 33 K = 0.00000e+00 A 4=-6.34464e-05 A 6= 1.59573e-07 A 8=-3.72473e-10 A10=5.67195e-13 A12=-3.17908e-16 A14=-2.87336e-19 Page 34 K = 0.00000e+00 A 4=-6.84566e-05 A 6= 1.81441e-07 A 8=-4.82855e-10 A10= 9.40997e-13 A12=-1.08728e-15 A14= 4.64917e-19 Various data Zoom ratio 2.29 Wide-angle, Medium, Telephoto Focal length 36.06 59.62 82.52 F number 1.46 1.46 1.46 Half-angle (°): 30.96, 19.94, 14.69 Image height 21.64 21.64 21.64 Lens length: 238.83, 234.02, 237.90 BF 13.06 19.07 20.49 d 5 0.50 22.96 38.79 d14 22.95 1.00 1.00 d15 25.00 15.88 1.00 d20 4.20 4.37 4.47 d22 17.11 14.60 15.79 d29 0.41 0.55 0.77 d34 13.06 19.07 20.49 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 154.84 21.86 4.23 -9.72 2 6 -46.80 47.55 6.24 -26.90 e 15 ∞ 0.00 0.00 -0.00 3 16 57.37 18.24 2.44 -10.32 4 21 -152.71 1.50 1.85 0.94 5 23 52.92 40.59 22.86 -1.96 6 30 -83.76 25.86 23.51 0.91 Single lens data Lens starting plane, focal length 1 1 -458.15 2 2 280.79 3 4 191.01 4 6 -68.24 5 8 -54.45 6 10 29.51 7 11 -62.95 8 13 -129.22 9 16 74.02 10 19 232.49 11 21 -152.71 12 23 -36.30 13 24 57.04 14 26 71.24 15 28 83.06 16 30 72.41 17 31 -46.17 18 33 -166.02 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point) 500 650 800 d12 5.11 4.57 4.14 d14 25.00 3.58 4.01 d18 1.48 1.38 1.19 d20 4.92 5.19 5.48 d22 14.43 10.73 10.52 d29 3.08 4.42 6.05 (Numerical example 6) Unit: mm Surface data Face number rd nd νd Effective diameter 1 58.934 1.50 1.69680 55.5 57.14 2 32.695 18.34 50.38 3* -59.886 1.50 1.58313 59.4 49.84 4* 101.845 1.00 50.37 5 158.226 8.14 2.05090 26.9 50.53 6 -89.717 7.89 50.36 7 -46.390 1.50 1.86966 20.0 45.88 8 -71.933 (variable) 46.42 9 ∞ (variable) 46.25 10 52.536 9.84 1.60300 65.4 49.40 11 -293.004 5.17 49.01 12* 54.163 4.98 1.55332 71.7 45.36 13 136.972 (Variable) 44.27 14 85.952 1.50 1.57501 41.5 43.20 15 33.892 4.39 1.43875 94.7 40.24 16 47.083 7.51 39.27 17 (aperture) ∞ (variable) 38.34 18 -35.893 1.50 1.66565 35.6 37.36 19 39.978 11.28 1.61800 63.3 41.26 20 -99.565 0.50 42.44 21* 95.217 9.05 1.59201 67.0 43.68 22* -48.534 0.51 44.34 23 66.266 12.09 1.48071 85.3 42.45 24 -52.224 0.51 40.87 25 84.822 5.85 1.94594 18.0 33.36 26 1248.581 1.50 1.66565 35.6 32.14 27 26.956 13.35 30.18 28* 852.133 2.00 1.58313 59.4 32.90 29* 105.181 (variable) 34.08 Image plane ∞ Aspherical data 3rd page K = 0.00000e+00 A 4= 3.58129e-07 A 6= 1.65492e-10 A 8=-5.53912e-13 Side 4 K = 0.00000e+00 A 4=-2.12077e-06 A 6= 1.24847e-10 A 8=-8.07769e-13 Side 12 K = 0.00000e+00 A 4=-1.25989e-06 A 6=-6.55665e-10 A 8=-2.22795e-13 Page 21 K = 0.00000e+00 A 4=-5.93032e-06 A 6=-3.45849e-10 A 8=-1.24126e-12 Page 22 K = 0.00000e+00 A 4= 1.78403e-06 A 6=-1.71736e-09 A 8= 3.27587e-14 Page 28 K = 0.00000e+00 A 4=-2.87840e-05 A 6= 8.61630e-08 A 8=-2.88738e-10 A10=5.74228e-13 A12=-5.47916e-16 Page 29 K = 0.00000e+00 A 4=-3.14492e-05 A 6= 7.64377e-08 A 8=-2.32210e-10 A10=4.08520e-13 A12=-3.69441e-16 Various data Zoom ratio 1.33 Wide-angle, Medium, Telephoto Focal length 36.50 42.85 48.44 F number 1.46 1.46 1.46 Half-angle (°): 28.92, 25.79, 23.43 Image height 20.17 20.70 20.99 Lens length: 185.01 x 172.26 x 164.93 BF 14.58 18.77 22.39 d 8 12.52 4.51 0.58 d 9 16.46 7.92 1.00 d13 0.59 0.79 0.94 d17 9.45 8.86 8.62 d29 14.58 18.77 22.39 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 -78.42 39.87 6.08 -26.65 e 9 ∞ 0.00 0.00 -0.00 2 10 52.65 20.00 3.73 -11.10 3 14 -154.14 13.40 6.36 -5.26 4 18 71.75 58.14 7.07 -26.72 Single lens data Lens starting plane, focal length 1 1 -107.92 2 3 -64.45 3 5 55.41 4 7 -154.44 5 10 74.68 6 12 158.51 7 14 -98.35 8 15 250.31 9 18 -28.19 10 19 47.63 11 21 55.60 12 23 62.84 13 25 95.97 14 26 -41.41 15 28 -205.98 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point) 500 500 500 d6 7.51 7.48 7.47 d8 12.89 4.92 1.00 d11 2.96 2.41 1.87 d13 2.80 3.55 4.23 d17 7.95 7.02 6.44 d24 2.01 2.36 2.69 (Numerical example 7) Unit: mm Surface data Face number rd nd νd Effective diameter 1 59.329 1.50 1.69680 55.5 57.24 2 32.800 18.14 50.48 3* -60.590 1.50 1.58313 59.4 50.02 4* 105.807 1.06 50.54 5 159.535 7.92 2.05090 26.9 50.72 6 -95.456 9.05 50.53 7 -44.921 1.50 1.86966 20.0 45.57 8 -65.913 (variable) 46.19 9 ∞ (variable) 46.61 10 53.194 10.06 1.60300 65.4 49.76 11 -252.710 3.74 49.38 12* 55.071 4.98 1.55332 71.7 45.99 13 136.972 1.50 44.89 14 86.985 1.50 1.57501 41.5 43.48 15 33.173 4.59 1.43875 94.7 40.37 16 46.838 7.51 39.38 17 (aperture) ∞ (variable) 38.46 18 -36.075 1.50 1.66565 35.6 37.50 19 40.089 11.40 1.61800 63.3 41.40 20 -96.151 0.50 42.58 21* 96.661 9.04 1.59201 67.0 43.79 22* -48.792 0.54 44.43 23 65.969 12.49 1.48071 85.3 42.40 24 -52.808 0.54 40.59 25 84.656 5.48 1.94594 18.0 33.09 26 1495.346 1.50 1.66565 35.6 31.99 27 26.890 13.43 30.05 28* 430.150 2.00 1.58313 59.4 32.85 29* 93.596 (variable) 34.05 Image plane ∞ Aspherical data 3rd page K = 0.00000e+00 A 4= 2.95084e-07 A 6= 2.64173e-10 A 8=-6.26430e-13 Side 4 K = 0.00000e+00 A 4=-2.13754e-06 A 6= 2.00189e-10 A 8=-9.18245e-13 Side 12 K = 0.00000e+00 A 4=-1.18632e-06 A 6=-6.27473e-10 A 8=-1.78475e-13 Page 21 K = 0.00000e+00 A 4=-5.87937e-06 A 6=-4.24623e-10 A 8=-9.93035e-13 Page 22 K = 0.00000e+00 A 4= 1.66162e-06 A 6=-1.72508e-09 A 8= 1.55474e-13 Page 28 K = 0.00000e+00 A 4=-3.15896e-05 A 6= 9.04690e-08 A 8=-2.86687e-10 A10=5.36738e-13 A12=-4.92998e-16 Page 29 K = 0.00000e+00 A 4=-3.43505e-05 A 6= 8.16995e-08 A 8=-2.35991e-10 A10= 3.91745e-13 A12=-3.40745e-16 Various data Zoom ratio 1.33 Wide-angle, Medium, Telephoto Focal length 36.50 42.89 48.48 F number 1.46 1.46 1.46 Half-angle (°): 28.92, 25.76, 23.41 Image height 20.17 20.70 20.99 Lens length: 185.00 172.51 165.45 BF 14.54 18.75 22.37 d 8 12.09 3.60 0.54 d 9 16.74 8.71 1.00 d17 8.66 8.48 8.57 d29 14.54 18.75 22.37 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 -78.60 40.67 6.18 -27.34 e 9 ∞ 0.00 0.00 -0.00 2 10 67.92 33.89 -4.89 -28.77 3 18 71.96 58.41 7.03 -26.94 Single lens data Lens starting plane, focal length 1 1 -107.78 2 3 -65.85 3 5 57.75 4 7 -167.76 5 10 73.79 6 12 162.92 7 14 -94.22 8 15 235.10 9 18 -28.30 10 19 47.29 11 21 56.07 12 23 63.17 13 25 94.69 14 26 -41.15 15 28 -205.59 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point) 500 500 500 d6 8.64 8.60 8.59 d8 12.50 4.04 1.00 d11 1.57 1.03 0.50 d13 3.67 4.21 4.74 d17 7.17 6.64 6.41 d24 2.04 2.38 2.70 (Numerical example 8) Unit: mm Surface data Face number rd nd νd Effective diameter 1 57.464 1.50 1.69680 55.5 57.15 2 32.477 18.50 50.39 3* -60.420 1.50 1.58313 59.4 49.78 4* 106.599 1.00 50.22 5 153.169 8.03 2.05090 26.9 50.39 6 -92.970 8.22 50.16 7 -45.895 1.50 1.86966 20.0 45.39 8 -70.535 (variable) 45.91 9 ∞ (Variable) 46.08 10 54.422 9.76 1.60300 65.4 49.00 11 -229.832 3.79 48.65 12* 54.277 4.98 1.55332 71.7 45.33 13 136.972 (Variable) 44.25 14 83.264 1.50 1.57501 41.5 42.94 15 32.829 4.35 1.43875 94.7 39.88 16 44.721 7.51 38.90 17 (aperture) ∞ (variable) 38.04 18 -35.231 1.50 1.66565 35.6 37.05 19 41.081 11.05 1.61800 63.3 40.99 20 -95.289 0.50 42.19 21* 99.534 8.77 1.59201 67.0 43.42 22* -49.442 0.50 44.10 23 67.510 10.89 1.48071 85.3 42.46 24 -51.824 (variable) 41.40 25 86.145 5.76 1.94594 18.0 33.22 26 2106.416 1.50 1.66565 35.6 32.08 27 26.961 13.46 30.17 28* 241.683 2.00 1.58313 59.4 33.15 29* 87.723 (variable) 34.33 Image plane ∞ Aspherical data 3rd page K = 0.00000e+00 A 4= 3.66026e-07 A 6= 2.34508e-10 A 8=-6.56136e-13 Side 4 K = 0.00000e+00 A 4=-2.02989e-06 A 6= 1.38785e-10 A 8=-9.55476e-13 Side 12 K = 0.00000e+00 A 4=-1.15563e-06 A 6=-6.25932e-10 A 8=-2.08811e-13 Page 21 K = 0.00000e+00 A 4=-5.94763e-06 A 6=-4.21345e-10 A 8=-1.27423e-12 Page 22 K = 0.00000e+00 A 4= 1.60596e-06 A 6=-1.75267e-09 A 8=-1.72552e-14 Page 28 K = 0.00000e+00 A 4=-3.33701e-05 A 6= 9.78104e-08 A 8=-3.25176e-10 A10=6.43760e-13 A12=-6.52906e-16 Page 29 K = 0.00000e+00 A 4=-3.65546e-05 A 6= 8.97681e-08 A 8=-2.75857e-10 A10= 4.92356e-13 A12=-4.71214e-16 Various data Zoom ratio 1.33 Wide-angle, Medium, Telephoto Focal length 36.46 42.93 48.44 F number 1.46 1.46 1.46 Half-angle (°): 28.95, 25.74, 23.43 Image height 20.17 20.70 20.99 Lens length: 185.02 x 170.59 x 162.98 BF 14.69 18.19 21.30 d 8 13.49 3.61 0.55 d 9 17.53 9.16 1.00 d13 1.30 1.31 1.24 d17 8.59 8.44 8.80 d24 1.36 1.81 2.02 d29 14.69 18.19 21.30 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 -80.58 40.24 6.30 -26.75 e 9 ∞ 0.00 0.00 -0.00 2 10 51.97 18.53 3.37 -9.92 3 14 -145.33 13.36 6.26 -5.34 4 18 37.19 33.21 19.42 2.31 5 25 -56.62 22.72 10.38 -8.08 Single lens data Lens starting plane, focal length 1 1 -109.90 2 3 -65.91 3 5 55.99 4 7 -155.47 5 10 73.93 6 12 159.06 7 14 -95.29 8 15 253.16 9 18 -28.27 10 19 47.93 11 21 57.05 12 23 62.85 13 25 94.82 14 26 -41.04 15 28 -237.29 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point) 500 500 500 d6 7.83 7.79 7.77 d8 13.88 4.04 1.00 d11 1.63 1.05 0.50 d13 3.45 4.05 4.53 d17 7.09 6.56 6.56 d24 2.86 3.69 4.26 (Numerical example 9) Unit: mm Surface data Face number rd nd νd Effective diameter 1 144.832 2.45 1.96300 24.1 94.17 2 107.946 13.03 1.49700 81.5 92.51 3 -977.544 0.23 92.29 4 92.089 10.04 1.52841 76.5 88.81 5 359.909 (Variable) 88.08 6 87.405 2.00 1.80000 29.8 53.86 7 40.306 10.99 49.57 8 -189.051 1.70 1.59522 67.7 49.51 9 86.528 0.10 49.91 10 58.634 5.86 1.86966 20.0 50.98 11 225.118 13.51 50.68 12 -81.411 1.80 1.71300 53.9 49.04 13 -95420.815 (variable) 49.88 14* 59.994 7.89 1.53775 74.7 51.45 15* -1501.757 0.25 51.13 16 41.451 1.60 1.67270 32.1 49.10 17 33.053 9.62 1.45860 90.2 46.82 18 128.259 2.82 45.77 19 (aperture) ∞ 1.00 45.30 20 170.583 1.50 1.43875 94.7 43.80 21 44.087 9.70 41.17 22 -59.622 1.50 1.72047 34.7 40.89 23 157.912 3.66 1.94594 18.0 41.83 24 -229.696 (variable) 41.96 25* 170.268 5.83 1.71300 53.9 42.00 26* -64.348 0.10 41.99 27 88.851 6.88 1.53775 74.7 38.96 28 -60.419 1.50 1.77830 23.9 38.18 29 116.457 (Variable) 36.32 30 45.480 4.58 1.59522 67.7 33.59 31 1439.047 (Variable) 32.90 32 430.041 3.55 1.88300 40.8 27.46 33 -52.058 1.30 1.64850 53.0 27.28 34 33.389 2.54 26.44 35* 206.685 2.65 1.51823 58.9 26.56 36* -211.166 (variable) 26.83 37 -123.004 1.30 1.59522 67.7 29.96 38 1169.874 (Variable) 30.51 39 -27.195 1.30 1.95375 32.3 32.09 40 -42.697 0.10 34.52 41 68.295 4.02 1.89286 20.4 39.91 42 635.246 (Variable) 40.02 Image plane ∞ Aspherical data Side 14 K = 0.00000e+00 A 4=-9.67957e-08 A 6=-5.14650e-10 A 8= 2.27682e-13 Page 15 K = 0.00000e+00 A 4= 5.79546e-07 A 6=-8.34093e-10 A 8= 4.26417e-13 Page 25 K = 0.00000e+00 A 4=-1.08115e-06 A 6=-2.19786e-09 A 8=-7.90850e-13 A10 = 5.03223e-16 Page 26 K = 0.00000e+00 A 4= 9.21913e-07 A 6=-2.24163e-09 A 8=-3.07187e-13 Page 35 K = 0.00000e+00 A 4= 7.80160e-06 A 6=-1.87390e-08 A 8= 1.10708e-11 Page 36 K = 0.00000e+00 A 4= 5.94653e-06 A 6=-1.67093e-08 A 8= 7.42785e-12 Various data Zoom ratio 2.71 Wide-angle, Medium, Telephoto Focal length 71.65 118.25 194.00 F-number 2.06 2.06 2.06 Half-angle (°): 16.80, 10.37, 6.36 Image height 21.64 21.64 21.64 Lens length 240.16 240.16 240.16 BF 16.24 16.24 16.24 d 5 3.32 27.43 46.44 d13 43.61 19.51 0.50 d24 4.97 3.23 1.00 d29 6.40 8.76 17.09 d31 6.74 6.99 1.00 d36 13.89 13.08 1.46 d38 8.07 8.01 19.52 d42 16.24 16.24 16.24 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 141.11 25.75 4.84 -11.99 2 6 -48.78 35.96 13.72 -14.00 3 14 155.29 39.54 -45.51 -60.11 4 25 85.66 14.31 -2.47 -10.69 5 30 78.81 4.58 -0.09 -2.96 6 32 -131.81 10.04 1.65 -5.39 7 37 -186.92 1.30 0.08 -0.74 8 39 -3960.38 5.43 -82.86 -87.53 Single lens data Lens starting plane, focal length 1 1 -454.95 2 2 196.38 3 4 231.20 4 6 -95.30 5 8 -99.50 6 10 89.70 7 12 -114.28 8 14 107.47 9 16 -262.64 10 17 94.10 11 20 -136.00 12 22 -59.90 13 23 99.38 14 25 66.18 15 27 67.97 16 28 -50.92 17 30 78.81 18 32 52.77 19 33 -31.18 20 35 201.99 21 37 -186.92 22 39 -81.89 23 41 85.42 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point) 500 750 1000 d11 6.27 6.68 6.27 d13 50.85 26.34 7.74 d29 1.00 1.07 1.60 d31 12.14 14.68 16.50 d36 12.48 14.49 1.14 d38 9.48 6.60 19.84 (Numerical example 10) Unit: mm Surface data Face number rd nd νd Effective diameter 1 142.795 2.45 1.96300 24.1 77.60 2 102.907 9.54 1.49700 81.5 76.39 3 -1018.074 0.23 76.21 4 84.451 8.09 1.52841 76.5 74.19 5 365.627 (Variable) 73.55 6 79.674 2.00 1.80000 29.8 49.06 7 37.652 9.08 44.16 8 -216.560 1.70 1.59522 67.7 43.69 9 78.259 0.10 43.76 10 53.556 5.15 1.86966 20.0 44.60 11 199.404 14.59 44.30 12 -77.520 1.80 1.71300 53.9 42.49 13 -100000.000 (variable) 43.14 14* 53.192 7.21 1.53775 74.7 44.37 15* -725.887 0.25 44.02 16 43.781 1.60 1.67270 32.1 42.46 17 34.284 7.95 1.45860 90.2 40.80 18 227.897 2.82 39.82 19 (aperture) ∞ 2.58 38.63 20 684.114 1.50 1.43875 94.7 36.91 21 45.507 6.54 34.87 22 -66.008 1.50 1.72047 34.7 34.67 23 110.781 3.05 1.94594 18.0 35.07 24 -472.994 (variable) 35.11 25* 138.942 5.01 1.71300 53.9 35.09 26* -62.076 0.10 34.98 27 96.417 5.67 1.53775 74.7 32.67 28 -54.481 1.50 1.77830 23.9 31.79 29 114.385 (variable) 30.31 30 49.841 3.22 1.59522 67.7 27.67 31 573.700 (Variable) 27.28 32 1174.865 3.77 1.88300 40.8 27.23 33 -45.856 1.30 1.64850 53.0 27.17 34 35.858 2.11 26.38 35* 105.252 3.60 1.51823 58.9 26.53 36* -263.333 (variable) 26.78 37 -72.867 1.30 1.59522 67.7 28.80 38 -15705.203 (variable) 29.53 39 -24.913 1.30 1.95375 32.3 31.78 40 -41.232 0.10 34.69 41 94.394 4.97 1.89286 20.4 40.11 42 -166.143 (variable) 40.44 Image plane ∞ Aspherical data Side 14 K = 0.00000e+00 A 4=-2.50760e-07 A 6=-3.15147e-10 A 8= 6.76311e-14 Page 15 K = 0.00000e+00 A 4= 6.07078e-07 A 6=-5.51758e-10 A 8= 2.97779e-13 Page 25 K = 0.00000e+00 A 4=-1.52862e-06 A 6=-1.45086e-09 A 8=-1.68596e-12 A10 = 5.03223e-16 Page 26 K = 0.00000e+00 A 4= 6.68433e-07 A 6=-1.42840e-09 A 8=-1.30394e-12 Page 35 K = 0.00000e+00 A 4= 4.23919e-06 A 6=-8.71323e-09 A 8=-2.24374e-11 Page 36 K = 0.00000e+00 A 4= 2.11795e-06 A 6=-9.35288e-09 A 8=-2.41312e-11 Various data Zoom ratio 2.69 Wide-angle, Medium, Telephoto Focal length 72.00 118.00 194.00 F-number 2.50 2.50 2.50 Half-angle (°): 16.72, 10.39, 6.36 Image height 21.64 21.64 21.64 Lens length 223.00 223.00 223.00 BF 15.51 15.51 15.51 d 5 0.50 23.37 41.94 d13 41.94 19.08 0.50 d24 6.24 3.99 1.01 d29 6.13 8.59 17.59 d31 7.91 8.00 1.00 d36 13.28 11.76 1.79 d38 7.82 9.04 19.98 d42 15.51 15.51 15.51 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 133.38 20.32 3.84 -9.37 2 6 -48.10 34.42 13.46 -13.22 3 14 136.43 34.98 -40.49 -52.89 4 25 83.98 12.29 -2.38 -9.47 5 30 91.49 3.22 -0.19 -2.20 6 32 -197.72 10.78 0.20 -7.17 7 37 -122.99 1.30 -0.00 -0.82 8 39 1352.40 6.37 54.89 53.73 Single lens data Lens starting plane, focal length 1 1 -394.44 2 2 188.58 3 4 205.77 4 6 -91.17 5 8 -96.37 6 10 82.83 7 12 -108.81 8 14 92.46 9 16 -252.02 10 17 86.87 11 20 -111.19 12 22 -57.21 13 23 95.13 14 25 60.81 15 27 65.60 16 28 -47.23 17 30 91.49 18 32 50.05 19 33 -30.84 20 35 145.59 21 37 -122.99 22 39 -68.67 23 41 68.03 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point) 500 750 1000 d11 4.90 5.23 5.50 d13 51.63 28.44 9.59 d29 1.00 1.09 1.54 d31 13.04 15.49 17.05 d36 12.66 12.56 2.55 d38 8.43 8.24 19.23 (Numerical example 11) Unit: mm Surface data Face number rd nd νd Effective diameter 1 148.114 2.45 1.96300 24.1 84.28 2 107.630 10.69 1.49700 81.5 82.94 3 -882.074 0.23 82.77 4 90.400 8.22 1.52841 76.5 80.29 5 335.363 (variable) 79.71 6 82.666 2.00 1.80000 29.8 53.52 7 38.562 10.15 47.80 8 -212.121 1.70 1.59522 67.7 47.50 9 83.815 0.10 45.89 10 56.085 5.36 1.86966 20.0 46.78 11 221.449 16.20 46.50 12 -80.504 1.80 1.71300 53.9 44.48 13 -49693.311 (variable) 45.17 14* 58.056 8.47 1.53775 74.7 46.44 15* 22654.677 0.25 45.90 16 43.504 1.60 1.67270 32.1 44.57 17 33.736 9.53 1.45860 90.2 42.76 18 858.494 2.82 41.80 19 (aperture) ∞ 1.00 40.14 20 9109.278 1.50 1.43875 94.7 39.48 21 45.986 8.97 37.10 22 -56.562 1.50 1.72047 34.7 36.59 23 168.058 3.48 1.94594 18.0 37.37 24 -191.925 (variable) 37.52 25* 251.117 4.92 1.71300 53.9 37.54 26* -62.795 0.10 37.52 27 77.856 6.22 1.53775 74.7 35.26 28 -59.772 1.50 1.77830 23.9 34.53 29 116.553 (Variable) 33.02 30 46.826 5.25 1.59522 67.7 30.10 31 537.868 (Variable) 28.82 32 320.641 4.15 1.88300 40.8 26.71 33 -49.868 1.30 1.64850 53.0 26.61 34 33.796 3.13 25.83 35* 455.683 2.96 1.51823 58.9 26.09 36* -157.733 (variable) 26.56 37 -94.234 1.30 1.59522 67.7 29.78 38 -1287.314 (variable) 30.44 39 -27.942 1.30 1.95375 32.3 32.51 40 -42.014 0.10 34.82 41 69.969 3.94 1.89286 20.4 40.10 42 897.595 (Variable) 40.20 Image plane ∞ Aspherical data Side 14 K = 0.00000e+00 A 4=-7.52025e-08 A 6=-3.24124e-10 A 8= 1.05167e-13 Page 15 K = 0.00000e+00 A 4= 4.97402e-07 A 6=-6.18925e-10 A 8= 2.42317e-13 Page 25 K = 0.00000e+00 A 4=-9.47613e-07 A 6=-1.64311e-09 A 8=-1.24469e-12 A10 = 5.03223e-16 Page 26 K = 0.00000e+00 A 4= 8.08677e-07 A 6=-1.54066e-09 A 8=-8.59045e-13 Page 35 K = 0.00000e+00 A 4= 5.22022e-06 A 6=-2.00065e-08 A 8=-1.27305e-11 Page 36 K = 0.00000e+00 A 4= 4.12855e-06 A 6=-1.99491e-08 A 8=-9.62631e-12 Various data Zoom ratio 2.69 Wide-angle, Medium, Telephoto Focal length 72.11 118.05 193.84 F-number 2.30 2.30 2.30 Half-angle (°): 16.70, 10.39, 6.37 Image height 21.64 21.64 21.64 Lens length 241.35 241.35 241.35 BF 17.00 17.00 17.00 d 5 5.03 28.89 48.21 d13 43.65 19.79 0.47 d24 7.00 5.24 2.99 d29 7.11 8.80 16.12 d31 6.91 7.01 0.93 d36 13.45 12.43 0.94 d38 7.01 8.01 20.50 d42 17.00 17.00 17.00 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 142.98 21.59 4.04 -10.01 2 6 -49.41 37.32 14.29 -14.62 3 14 150.16 39.11 -42.69 -57.75 4 25 88.13 12.74 -2.22 -9.60 5 30 85.83 5.25 -0.31 -3.59 6 32 -144.18 11.54 1.81 -6.40 7 37 -170.89 1.30 -0.06 -0.88 8 39 881.71 5.34 19.52 17.10 Single lens data Lens starting plane, focal length 1 1 -421.42 2 2 193.70 3 4 231.53 4 6 -92.21 5 8 -100.72 6 10 85.08 7 12 -113.09 8 14 108.22 9 16 -239.12 10 17 76.30 11 20 -105.35 12 22 -58.57 13 23 95.17 14 25 70.92 15 27 63.89 16 28 -50.58 17 30 85.83 18 32 49.13 19 33 -30.87 20 35 226.48 21 37 -170.89 22 39 -91.60 23 41 84.80 Lens spacing at closest focus Wide-angle, Medium, Telephoto Object point (from image point) 500 750 1000 d11 4.46 7.23 6.92 d13 55.39 28.77 9.75 d29 2.41 1.25 1.28 d31 11.61 14.56 15.77 d36 12.73 13.45 3.34 d38 13.30 6.98 18.11 d42 11.01 16.65 16.30 Tables 1 and 2 summarize the values ​​corresponding to the conditions of equations (1) to (18) mentioned above in numerical examples 1 to 11. The zoom lenses in each numerical example satisfy all the conditions of equations (1) to (18).

[0265] [Table 1]

[0266] [Table 2]

[0267] [Imaging device] Figure 89 shows a digital still camera, which is an example of an imaging device using the zoom lenses of Examples 1 to 11 as the imaging optical system. 10 is the camera body, and 11 is the imaging optical system composed of the zoom lenses of Examples 1 to 11. 12 is an image sensor, such as a CCD sensor or CMOS sensor, built into the camera body 10, which converts the subject image formed by the imaging optical system 11 into photoelectric data (i.e., images the subject through the zoom lens).

[0268] The camera body 10 may be a single-lens reflex camera with a quick-turn mirror, or a mirrorless camera without a quick-turn mirror.

[0269] Furthermore, the zoom lenses in each embodiment can be used not only in digital still cameras, but also in video cameras, distance detection cameras in smartphones, camera viewfinders, and cameras for gaze detection, biometric recognition, and facial recognition in XR devices. They can also be used in cameras for external environment recognition in robots.

[0270] The above embodiments include the following configuration.

[0271] (Composition 1) A zoom lens comprising multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, When the lens group located closest to the object among the multiple lens groups having negative refractive power is designated as the object-side negative lens group, the rear group, which includes all lens groups located closer to the image than the object-side negative lens group, has a positive refractive power as a whole. During zooming, the negative lens group on the object side moves, It has three or more lens groups or focusing groups that move during focusing, When the object-side negative lens group is positioned furthest towards the image at the zoom position, the length TD is the distance along the optical axis from the lens surface closest to the object in the object-side negative lens group to the final lens surface closest to the image in the rear group, plus the air-equivalent distance from the final lens surface to the image plane, and the sum of the optical axis thicknesses of all lenses in the object-side negative lens group and the rear group is denoted as LD, 0.403 ≤ LD / TD ≤ 0.800 A zoom lens characterized by satisfying the following conditions. (Configuration 2) A zoom lens comprising multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, When the lens group located closest to the object among the multiple lens groups having negative refractive power is designated as the object-side negative lens group, the rear group, which includes all lens groups located closer to the image than the object-side negative lens group, has a positive refractive power as a whole. During zooming, the negative lens group on the object side moves, It has three or more lens groups or focusing groups that move during focusing, When the length TD is the sum of the distance along the optical axis from the lens surface closest to the object in the object-side negative lens group to the final lens surface closest to the image in the rear group at the zoom position where the object-side negative lens group is located closest to the image, and the air-equivalent distance from the final lens surface to the image plane, the LD is the sum of the optical axis thicknesses of all lenses in the object-side negative lens group and the rear group, and FnoN is the largest F-number from the wide-angle end to the telephoto end, 0.380 ≤ LD / TD ≤ 0.800 1.00 ≤ FnoN ≤ 2.70 A zoom lens characterized by satisfying the following conditions. (Composition 3) The zoom lens according to configuration 1 or 2, characterized in that the lens closest to the object among all the lenses included in the zoom lens remains stationary during focusing. (Composition 4) Of the three or more focus groups mentioned above, the focus group closest to the object and the focus group second from the object are designated as the first focus group and the second focus group, respectively. When the focal length of the first focus group is fF1, and the combined focal length of the first and second focus groups at the zoom position where the object-side negative lens group is located closest to the image is fMT, -10.00 ≤ fF1 / fMT ≤ -0.10 A zoom lens according to any one of configurations 1 to 3, characterized by satisfying the following conditions. (Composition 5) Of the three or more focus groups mentioned above, the focus group closest to the object and the focus group second from the object are designated as the first focus group and the second focus group, respectively. When the focal length of the second focus group is fF2, and the combined focal length of the first and second focus groups at the zoom position where the object-side negative lens group is located closest to the image is fMT, 0.10 ≤ fF2 / fMT ≤ 10.00 A zoom lens according to any one of configurations 1 to 4, characterized by satisfying the following conditions. (Composition 6) Of the three or more focus groups mentioned above, the focus group closest to the object and the focus group second from the object are designated as the first focus group and the second focus group, respectively. When the focal length of the first focus group is fF1 and the focal length of the second focus group is fF2, -7.00 ≤ fF1 / fF2 ≤ -0.10 A zoom lens according to any one of configurations 1 to 5, characterized by satisfying the following conditions. (Composition 7) When the radius of curvature of the lens surface closest to the object in the first focus group, which is positioned closest to the object among the three or more focus groups, is F1r1, and the radius of curvature of the lens surface closest to the image in the first focus group is F1r2, -1.00≦(F1r1-F1r2) / (F1r1+F1r2)≦-0.05 A zoom lens according to any one of configurations 1 to 6, characterized by satisfying the following conditions. (Composition 8) When the radius of curvature of the lens surface closest to the object in the second focus group, which is the second to the object side among the three or more focus groups, is F2r1, and the radius of curvature of the lens surface closest to the image in the second focus group is F2r2, -1.00≦(F2r1-F2r2) / (F2r1+F2r2)≦-0.05 A zoom lens according to any one of configurations 1 to 7, characterized by satisfying the following conditions. (Composition 9) When the focal length of the first focus group, which is positioned closest to the object among the three or more focus groups, is fF1, and the amount of movement of the first focus group from infinity to closest focusing at the zoom position where the object-side negative lens group is positioned closest to the image, -1000.00 ≤ fF1 / tm1 ≤ -5.00 A zoom lens according to any one of configurations 1 to 8, characterized by satisfying the following conditions. (Composition 10) When the focal length of the second focus group, which is positioned second from the object side among the three or more focus groups, is fF2, and the amount of movement of the second focus group from infinity to the closest focusing point at the zoom position where the object-side negative lens group is located closest to the image, 1.00 ≤ fF2 / tm2 ≤ 1000.00 A zoom lens according to any one of configurations 1 to 9, characterized by satisfying the following conditions. (Composition 11) When the object-side negative lens group is located at the zoom position where it is closest to the image, the amount of movement of the first and second focus groups, which are the closest to the object and second from the object side, in focusing from infinity to the closest point is tm1 and tm2, respectively. 0.05 ≤ tm1 / tm2 ≤ 10.00 A zoom lens according to any one of configurations 1 to 10, characterized by satisfying the following conditions. (Composition 12) When the focal length of the third focus group, which is the third from the object side among the three or more focus groups, is fF3, and the amount of movement of the third focus group from infinity to the closest focusing point at the zoom position where the object-side negative lens group is located closest to the image, -1000.00 ≤ fF3 / tm3 ≤ 1000.00 A zoom lens according to any one of configurations 1 to 11, characterized by satisfying the following conditions. (Composition 13) When the object-side negative lens group is located at the zoom position where it is closest to the image, the distance along the optical axis from the lens surface closest to the object of the object-side negative lens group to the final lens surface is BD, and the largest air gap along the optical axis between the lens closest to the object of the object-side negative lens group and the lens closest to the image of the rear group is DM, 0.02 ≤ DM / BD ≤ 0.20 A zoom lens according to any one of configurations 1 to 12, characterized by satisfying the following conditions. (Composition 14) When the focal length of the object-side negative lens group is fN, 1.00 ≤ fF1 / fN ≤ 10.00 A zoom lens according to any one of configurations 1 to 13, characterized by satisfying the following conditions. (Composition 15) The zoom lens according to any one of configurations 1 to 14, wherein the first focus group, which is positioned closest to the object among the three or more focus groups, is a lens that constitutes part of the object-side negative lens group, and moves within the object-side negative lens group during focusing. (Composition 16) When the focal length of the zoom lens at the zoom position where the object-side negative lens group is located closest to the image is fT, -5.00 ≤ fN / fT ≤ -0.10 A zoom lens according to any one of configurations 1 to 15, characterized by satisfying the following conditions. (Composition 17) When mN is the amount of movement during zooming from the wide-angle end of the object-side negative lens group to the zoom position where the object-side N group is located closest to the image, and LT is the length obtained by adding the distance on the optical axis from the lens surface closest to the object of the zoom lens to the final lens surface at the zoom position where the object-side negative lens group is located closest to the image, to the air-equivalent distance from the final lens surface to the image plane, 0.05 ≤ mN / LT ≤ 0.50 A zoom lens according to any one of configurations 1 to 16, characterized by satisfying the following conditions. (Composition 18) Of the three or more focus groups mentioned above, the focus group closest to the object and the focus group second from the object are designated as the first focus group and the second focus group, respectively. When the combined focal length of the first focus group and the second focus group at the zoom position where the object-side negative lens group is located closest to the image is fMT, and the focal length of the zoom lens at the zoom position where the object-side negative lens group is located closest to the image is fT, 0.05 ≤ fMT / fT ≤ 5.00 A zoom lens according to any one or two of configurations 1 to 17, characterized by satisfying the following conditions. (Composition 19) When FnoN is the largest F-number from the wide-angle end to the telephoto end, 1.00 ≤ FnoN ≤ 2.70 A zoom lens according to any one of configurations 1 to 18, characterized by satisfying the following conditions. (Composition 20) A zoom lens comprising multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, A zoom lens characterized by having three or more lens groups or focus groups that move during focusing. (Composition 21) A zoom lens described in any one of configurations 1 to 20, An imaging device characterized by having an image sensor that captures an image of a subject through the zoom lens.

[0272] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of symbols]

[0273] L1-L8: Lens groups 1-8 N object-side negative lens group P posterior group F1-F4 1st-4th focus groups SP aperture diaphragm

Claims

1. A zoom lens comprising multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, When the lens group located closest to the object among the multiple lens groups having negative refractive power is designated as the object-side negative lens group, the rear group, which includes all lens groups located closer to the image than the object-side negative lens group, has a positive refractive power as a whole. During zooming, the negative lens group on the object side moves, It has three or more lens groups or focus groups that move during focusing, When the object-side negative lens group is positioned furthest towards the image at the zoom position, the length TD is the distance along the optical axis from the lens surface closest to the object in the object-side negative lens group to the final lens surface closest to the image in the rear group, plus the air-equivalent distance from the final lens surface to the image plane, and LD is the sum of the optical axis thicknesses of all lenses in the object-side negative lens group and the rear group, 0.403 ≤ LD / TD ≤ 0.800 A zoom lens characterized by satisfying the following conditions.

2. A zoom lens comprising multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, When the lens group located closest to the object among the multiple lens groups having negative refractive power is designated as the object-side negative lens group, the rear group, which includes all lens groups located closer to the image than the object-side negative lens group, has a positive refractive power as a whole. During zooming, the negative lens group on the object side moves, It has three or more lens groups or focus groups that move during focusing, When the object-side negative lens group is located at the zoom position where it is closest to the image, the length TD is the distance along the optical axis from the lens surface closest to the object in the object-side negative lens group to the final lens surface closest to the image in the rear group, plus the air-equivalent distance from the final lens surface to the image plane; LD is the sum of the optical axis thicknesses of all lenses in the object-side negative lens group and the rear group; and FnoN is the largest F-number from the wide-angle end to the telephoto end, 0.380 ≤ LD / TD ≤ 0.800 1.00 ≤ FnoN ≤ 2.70 A zoom lens characterized by satisfying the following conditions.

3. The zoom lens according to claim 1 or 2, characterized in that the lens closest to the object among all the lenses included in the zoom lens remains stationary during focusing.

4. Of the three or more focus groups mentioned above, the focus group closest to the object and the focus group second from the object are designated as the first focus group and the second focus group, respectively. When the focal length of the first focus group is fF1, and the combined focal length of the first and second focus groups at the zoom position where the object-side negative lens group is closest to the image is fMT, -10.00 ≤ fF1 / fMT ≤ -0.10 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

5. Of the three or more focus groups mentioned above, the focus group closest to the object and the focus group second from the object are designated as the first focus group and the second focus group, respectively. When the focal length of the second focus group is fF2, and the combined focal length of the first focus group and the second focus group at the zoom position where the object-side negative lens group is located closest to the image is fMT, 0.10 ≤ fF2 / fMT ≤ 10.00 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

6. Of the three or more focus groups mentioned above, the focus group closest to the object and the focus group second from the object are designated as the first focus group and the second focus group, respectively. When the focal length of the first focus group is fF1 and the focal length of the second focus group is fF2, -7.00 ≤ fF1 / fF2 ≤ -0.10 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

7. When the radius of curvature of the lens surface closest to the object in the first focus group, which is positioned closest to the object among the three or more focus groups, is F1r1, and the radius of curvature of the lens surface closest to the image in the first focus group is F1r2, -1.00≦(F1r1-F1r2) / (F1r1+F1r2)≦-0.05 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

8. When the radius of curvature of the lens surface closest to the object in the second focus group, which is the second focus group from the object side among the three or more focus groups, is F2r1, and the radius of curvature of the lens surface closest to the image in the second focus group is F2r2, -1.00≦(F2r1-F2r2) / (F2r1+F2r2)≦-0.05 A zoom lens according to claim 1 or 2, characterized by satisfying the conditions.

9. When the focal length of the first focus group, which is positioned closest to the object among the three or more focus groups, is fF1, and the amount of movement of the first focus group from infinity to closest focusing at the zoom position where the object-side negative lens group is positioned closest to the image, -1000.00 ≤ fF1 / tm1 ≤ -5.00 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

10. When the focal length of the second focus group, which is positioned second from the object side among the three or more focus groups, is fF2, and the amount of movement of the second focus group from infinity to the closest focusing point at the zoom position where the object-side negative lens group is located closest to the image, 1.00 ≤ fF2 / tm2 ≤ 1000.00 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

11. When the object-side negative lens group is located at the zoom position where it is closest to the image, the amount of movement of the first and second focus groups, which are the closest to the object and second from the object side, in focusing from infinity to the closest point is tm1 and tm2, respectively. 0.05 ≤ tm1 / tm2 ≤ 10.00 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

12. When the focal length of the third focus group, which is positioned third from the object side among the three or more focus groups, is fF3, and the amount of movement of the third focus group from infinity to the closest focusing point at the zoom position where the object-side negative lens group is located closest to the image, -1000.00 ≤ fF3 / tm3 ≤ 1000.00 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

13. When the distance along the optical axis from the lens surface closest to the object of the object-side negative lens group to the final lens surface at the zoom position where the object-side negative lens group is located closest to the image, and DM is the largest air gap along the optical axis between the lens closest to the object of the object-side negative lens group and the lens closest to the image of the rear group, 0.02 ≤ DM / BD ≤ 0.20 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

14. When the focal length of the object-side negative lens group is fN, 1.00 ≤ fF1 / fN ≤ 10.00 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

15. The zoom lens according to claim 1 or 2, wherein the first focus group, which is positioned closest to the object among the three or more focus groups, is a lens that constitutes part of the object-side negative lens group, and moves within the object-side negative lens group during focusing.

16. When the focal length of the zoom lens at the zoom position where the object-side negative lens group is located closest to the image is fT, -5.00 ≤ fN / fT ≤ -0.10 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

17. When mN is the amount of movement during zooming from the wide-angle end of the object-side negative lens group to the zoom position where the object-side N group is located closest to the image, and LT is the length obtained by adding the distance on the optical axis from the lens surface closest to the object of the zoom lens to the final lens surface at the zoom position where the object-side negative lens group is located closest to the image, to the air-equivalent distance from the final lens surface to the image plane, 0.05 ≤ mN / LT ≤ 0.50 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

18. Of the three or more focus groups mentioned above, the focus group closest to the object and the focus group second from the object are designated as the first focus group and the second focus group, respectively. When the combined focal length of the first and second focus groups at the zoom position where the object-side negative lens group is located closest to the image is fMT, and the focal length of the zoom lens at the zoom position where the object-side negative lens group is located closest to the image is fT, 0.05 ≤ fMT / fT ≤ 5.00 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

19. When the largest F-number from the wide-angle end to the telephoto end is denoted as FnoN, 1.00 ≤ FnoN ≤ 2.70 A zoom lens according to claim 1 or 2, characterized by satisfying the following conditions.

20. A zoom lens comprising multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, A zoom lens characterized by having three or more lens groups or focus groups that move during focusing.

21. A zoom lens according to any one of claims 1 to 20, An imaging device characterized by having an image sensor that captures an image of a subject through the zoom lens.

Images