Zoom lens and imaging device

Abstract

To provide a zoom lens with a high zoom ratio, compact size, light weight, and high optical performance. [Solution] The zoom lens is composed of a positive first lens group that is fixed for zooming, arranged sequentially from the object side to the image side, an intermediate group including three or more lens groups that move for zooming, and a positive rear lens group that is fixed for zooming. The intermediate group includes at least two lens groups having negative refractive power and at least one lens group having positive refractive power. When the focal length of the zoom lens at the telephoto end is ft, the focal length of the first lens group is f1, and bok1 is the distance on the optical axis from the lens surface closest to the image of the first lens group to the rear principal point of the first lens group when focused on an object at infinity, the conditions 2.50≦ft / f1≦8.00 and 0.55≦(f1+bok1) / f1≦0.85 are satisfied.

Description

Technical Field

[0001] The present invention relates to a zoom lens used in an imaging device.

Background Art

[0002] Zoom lenses are required to have a high zoom ratio, be small and lightweight, and further have high optical performance. The zoom lens disclosed in Patent Document 1 includes a first lens group having a positive refractive power that is stationary for zooming, a second lens group having a negative refractive power that moves for zooming, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power, which are arranged in order from the object side to the image side, and a fifth lens group having a positive refractive power that is stationary for zooming.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a need for a zoom lens that has a higher zoom ratio, is smaller and lighter, and has higher optical performance than the zoom lens disclosed in Patent Document 1.

Means for Solving the Problems

[0005] A zoom lens as one aspect of the present invention comprises a first lens group having a fixed positive refractive power for zooming, arranged sequentially from the object side to the image side; an intermediate group including three or more lens groups that move for zooming; and a rear lens group having a fixed positive refractive power for zooming, wherein the spacing between adjacent lens groups changes during zooming. The intermediate group includes at least two lens groups having negative refractive power and at least one lens group having positive refractive power. When the focal length of the zoom lens at the telephoto end is ft, the focal length of the first lens group is f1, and the distance on the optical axis from the image-side lens surface of the first lens group to the rear principal point of the first lens group when focused on an object at infinity is bok1, 2.50 ≤ ft / f1 ≤ 8.00 0.55 ≤ (f1 + bok1) / f1 ≤ 0.85 The present invention satisfies both or one of the above conditions. Furthermore, an imaging device equipped with the above-mentioned zoom lens also constitutes another aspect of the present invention. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a zoom lens that has a high zoom ratio, is compact and lightweight, and has high optical performance. [Brief explanation of the drawing]

[0007] [Figure 1] Cross-sectional view of the zoom lens of Example 1. [Figure 2] Aberration diagram of the zoom lens in Example 1. [Figure 3] Cross-sectional view of the zoom lens of Example 2. [Figure 4] Aberration diagram of the zoom lens in Example 2. [Figure 5] Cross-sectional view of the zoom lens of Example 3. [Figure 6] Aberration diagram of the zoom lens in Example 3. [Figure 7] Cross-sectional view of the zoom lens of Example 4. [Figure 8] Aberration diagram of the zoom lens in Example 4. [Figure 9]Cross-sectional view of the zoom lens of Example 5. [Figure 10] Aberration diagram of the zoom lens in Example 5. [Figure 11] Cross-sectional view of the zoom lens of Example 6. [Figure 12] Aberration diagram of the zoom lens in Example 6. [Figure 13] A diagram showing the configuration of the imaging device. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0009] Before describing specific examples 1 to 6, we will explain the points common to each example using Figure 1, which shows the zoom lens of Example 1. The zoom lenses of each example are used in various imaging devices such as broadcast cameras, cinema cameras, video cameras, surveillance cameras, digital still cameras, and silver halide film cameras.

[0010] Figure 1 shows the configuration of the zoom lens of Example 1 at its wide-angle end and in focus on an object at infinity (hereinafter referred to as the infinity focus state). In a zoom lens, a lens group is a collection of one or more lenses that move together or remain stationary during zooming (magnification) between the wide-angle and telephoto ends. That is, the distance between adjacent lens groups changes during zooming. The lens group may include an aperture diaphragm. 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 group that moves during zooming is positioned at the ends of the range that is mechanically or controllly movable along the optical axis.

[0011] The zoom lens of each embodiment is composed of a first lens group U1, an intermediate group including three or more lens groups, and a rear lens group (relay lens group) as the final lens group on the most image side, which are arranged in order from the object side to the image side. The rear lens group includes an aperture stop SP. The zoom lens of each embodiment has a high zoom ratio of about 9 to 100 times.

[0012] The first lens group U1 is stationary (does not move) for zooming and has a positive refractive power. The first lens group U1 is preferably composed of five or more lenses. For a cemented lens in which N lenses are cemented, the number of lenses is N.

[0013] The intermediate group includes three or more lens groups that move for zooming. In Embodiments 1, 3, and 5, the intermediate group includes three lens groups (U2 to U4), and in Embodiments 2, 4, and 6, the intermediate group includes four lens groups (U2 to U5). Furthermore, the intermediate group may include other lens groups that move during zooming. That is, the intermediate group includes at least two lens groups having a negative refractive power and at least one lens group having a positive refractive power. In the figure, the movement trajectories of each lens group included in the intermediate group during zooming from the wide-angle end to the telephoto end are indicated by arrows.

[0014] The second lens group U2, which is the most object-side lens group in the intermediate group (and further the third lens group U3 in Embodiments 2, 4, and 6), moves monotonically toward the image side during zooming from the wide-angle end to the telephoto end. The other lens groups in the intermediate group move non-monotonically during zooming so as to draw a convex-shaped trajectory toward at least one of the object side and the image side during zooming.

[0015] The rear lens group is stationary for zooming and has a positive refractive power. The aperture stop SP is stationary during zooming. I is the image plane. On the image plane I, the imaging surface (light-receiving surface) of the imaging device or the film surface (photosensitive surface) of the silver halide film is arranged. A glass block such as a prism or an optical filter may be arranged between the rear lens group LR and the image plane I.

[0016] Furthermore, a portion of the first lens group L1 (the two lenses on the image side) moves for focusing. In the diagram, the direction of movement of the portion of the first lens group L1 when focusing from infinity to near distance is indicated by arrows labeled FOUCS. However, the entire first lens group L1 may also move during focusing.

[0017] Furthermore, it is preferable that the zoom lens of each embodiment satisfies the following conditions. Let ft be the focal length of the zoom lens at the telephoto end, f1 be the focal length of the first lens group U1, and bok1 be the distance on the optical axis from the image-side lens surface of the first lens group U1 to the rear principal point of the first lens group U1 when in focus at infinity. At this time, 2.50 ≤ ft / f1 ≤ 8.00 (1) 0.55≦(f1+bok1) / f1≦0.85 (2) It is preferable that the following conditions be satisfied.

[0018] The conditions in equation (1) indicate an appropriate relationship between the focal length of the first lens group U1 and the total focal length of the zoom lens system at the telephoto end. By satisfying the conditions in equation (1), it is possible to achieve a high zoom ratio while simultaneously realizing compactness, light weight, and high optical performance, as described above. If ft / f1 exceeds the upper limit of equation (1), the focal length of the first lens group U1 becomes too short relative to the total focal length of the system at the telephoto end, increasing the magnification of aberrations generated in the first lens group U1 and making it difficult to suppress aberrations at the telephoto end, which is undesirable. If ft / f1 falls below the lower limit of equation (1), the focal length of the first lens group U1 becomes too long relative to the total focal length of the system at the telephoto end, increasing the amount of movement of the focus lens during focusing and resulting in a larger zoom lens, which is also undesirable.

[0019] Furthermore, it is more preferable to set the lower limit of equation (1) to 2.60, 2.80, 3.00, or 4.00. It is even more preferable to set the upper limit of equation (1) to 7.80, 7.60, or 7.20.

[0020] The condition in equation (2) indicates an appropriate relationship between the focal length of the first lens group U1 and the position of its rear principal point. By satisfying the condition in equation (2), it is possible to achieve a high zoom ratio while maintaining a compact and lightweight design and high optical performance. If (f1+bok1) / f1 exceeds the upper limit of equation (2), the rear principal point of the first lens group U1 will be positioned excessively towards the image. This causes the absolute value of the horizontal magnification at the wide-angle end of the second lens group U2, which is the closest lens group to the object among the intermediate lens groups that move for zooming, to become too small. As a result, the amount of movement of the second lens group U2 increases, making the zoom lens larger, which is undesirable. Furthermore, the focal length of the first lens group U1 becomes too short, making it difficult to keep various aberrations within acceptable limits at the telephoto end, which is also undesirable. If (f1+bok1) / f1 falls below the lower limit of equation (2), the rear principal point of the first lens group U1 will be positioned excessively towards the object, and the entrance pupil at the wide-angle end will be positioned excessively towards the image. As a result, the diameter of the first lens group U1 will increase, making it difficult to miniaturize and lighten the lens, which is undesirable. Also, if the focal length of the first lens group U1 becomes too long, the absolute value of the lateral magnification of the second lens group U2 at the wide-angle end will become too small, resulting in a large amount of movement of the second lens group U2, which is undesirable as it leads to a larger zoom lens.

[0021] It is more preferable to set the lower limit of equation (2) to 0.60, 0.63, or 0.66. It is more preferable to set the upper limit of equation (2) to 0.84 or 0.835.

[0022] Furthermore, it is preferable that the zoom lens of each embodiment satisfies at least one of the following conditions of equations (3) to (11).

[0023] In each embodiment, when the focal length of the zoom lens at the wide-angle end is fw, 2.50 ≤ f1 / fw ≤ 20.00 (3) It is preferable that the following conditions be satisfied.

[0024] The conditions in equation (3) indicate an appropriate relationship between the focal length of the first lens group U1 and the total focal length of the zoom lens system at the wide-angle end. By satisfying the conditions in equation (3), it is possible to achieve a high zoom ratio and wide angle of view while also realizing compactness, light weight, and high optical performance. If f1 / fw exceeds the upper limit of equation (3), the focal length of the first lens group U1 becomes too long, increasing the diameter of the first lens group U1 and making compactness and light weight difficult, which is undesirable. If f1 / fw falls below the lower limit of equation (3), the focal length of the first lens group U1 becomes too short, making aberration correction difficult, which is undesirable. Furthermore, if the total focal length of the system at the wide-angle end becomes too long, making it difficult to obtain a wide-angle zoom lens, which is also undesirable.

[0025] Furthermore, it is more preferable to set the lower limit of equation (3) to 3.00, 3.25, or 3.50. It is also more preferable to set the upper limit of equation (3) to 16.00, 14.00, 10.00, or 8.00.

[0026] In each embodiment, when the focal length of the second lens group U2, which is closest to the object among the intermediate lens groups, is f2, -1.20 ≤ f1 / f2 ≤ 0.50 (4) It is preferable to satisfy the following conditions. The conditions in equation (4) indicate an appropriate relationship between the focal lengths of the first lens group U1 and the second lens group U2. By satisfying the conditions in equation (4), it is possible to achieve a high zoom ratio and wide angle of view while also realizing compactness, light weight, and high optical performance. If f1 / f2 exceeds the upper limit of equation (4), the focal length of the first lens group U1 becomes too short, which is advantageous in terms of widening the angle of view, but it is undesirable because it becomes difficult to correct the aberrations that occur in the first lens group U1 at the telephoto end. If f1 / f2 falls below the lower limit of equation (4), the focal length of the first lens group U1 becomes too long, which is undesirable because it becomes difficult to widen the angle of view at the wide-angle end. Also, the diameter of the first lens group U1 becomes larger, which is undesirable because it becomes difficult to achieve compactness and light weight.

[0027] Furthermore, it is preferable to set the lower limit of equation (4) to -1.00, -0.90, or -0.80. It is also preferable to set the upper limit of equation (4) to 0.20, 0.00, or -0.10.

[0028] In each embodiment, when the horizontal magnification of the second lens group U2 at the wide-angle end is β2w, -100.00 ≤ β2w ≤ 100.00 (5) It is preferable to satisfy the following conditions. By satisfying the conditions of equation (5), it is possible to achieve a small size, light weight, and high optical performance while maintaining a high zoom ratio. If β2w exceeds the upper limit of equation (5), the divergence of the light beam emitted from the second lens group U2 becomes too strong, which increases the fluctuation of various aberrations during zooming, and is therefore undesirable. If β2w falls below the lower limit of equation (5), the lateral magnification of the second lens group U2 becomes too small, which increases the amount of movement of the second lens group U2 and makes the zoom lens larger, and is therefore undesirable.

[0029] Furthermore, it is preferable to set the lower limit of equation (5) to -50.00, -30.00, -10.00, or -8.00. It is also preferable to set the upper limit of equation (5) to 75.00, 50.00, 0.00, -0.10, -0.18, or -0.20.

[0030] In each embodiment, when the lateral magnification of the second lens group U2 at the telephoto end is β2w, -1000.00 ≤ β2t ≤ 10.00 (6) It is preferable to satisfy the following conditions. By satisfying the conditions of equation (6), it is possible to achieve a small size and light weight while maintaining a high zoom ratio. If β2t exceeds the upper limit of equation (6), the magnification at the telephoto end becomes too small, resulting in a small zoom ratio, which is undesirable. Also, if the zoom ratio is increased, the magnification at the telephoto end of the lens group on the image side of the second lens group U2 in the intermediate group becomes too large, resulting in a larger zoom lens, which is undesirable. If β2t falls below the lower limit of equation (6), the image point change of the second lens group U2 at the telephoto end becomes too large. Therefore, the amount of movement required for image point correction of the lens group on the image side of the second lens group U2 in the intermediate group becomes large, resulting in a larger zoom lens, which is undesirable.

[0031] Furthermore, it is preferable to set the lower limit of equation (6) to -500.00, -300.00, -100.00, or -10.00. It is also preferable to set the upper limit of equation (6) to 8.00, 6.00, 5.00, 4.00, or 2.00.

[0032] The zoom lens in each embodiment is 9.00 ≤ ft / fw ≤ 100.00 (7) It is preferable that the following conditions be satisfied. That is, it is preferable that the zoom lens has a high zoom ratio that satisfies the conditions of equation (7).

[0033] Furthermore, it is more preferable to set the lower limit of equation (7) to 10.0, 12.00, 15.00, or 20.00. It is also more preferable to set the upper limit of equation (7) to 75.00, 50.00, 45.00, or 40.00.

[0034] In each embodiment, the zoom lens has a positive lens as the first lens closest to the object in the first lens group U1, and when the Abbe number with respect to the d line of the first lens is νd11, 65.00 ≤ νd11 ≤ 96.00 ···(8) It is preferable that the following conditions be satisfied.

[0035] The condition in equation (8) indicates the appropriate Abbe number for the first lens with respect to achromaticity of the first lens group U1. By satisfying the condition in equation (8), high optical performance can be achieved even with a high zoom ratio. In particular, by satisfying the condition in equation (8) for the Abbe number of the first lens, which is the positive lens with the highest axial rays at the telephoto end, axial chromatic aberration and other aberrations can be suppressed at the telephoto end.

[0036] The Abbe number νd, with respect to the d-line, is defined as νd = (Nd-1) / (NF-NC), where the refractive indices of the F-line (wavelength 486.1 nm), d-line (wavelength 587.6 nm), and C-line (wavelength 656.3 nm) are NF, Nd, and NC, respectively.

[0037] Furthermore, it is preferable to set the lower limit of equation (8) to 68.00, 70.00, 75.00, or 80.00. It is also preferable to set the upper limit of equation (8) to 95.00, 93.00, or 92.00.

[0038] In each embodiment, when νd1P is the average value of the Abbe numbers with respect to the d line of all positive lenses included in the first lens group U1, 70.00 ≤ νd1P ≤ 96.00 (9) It is preferable to satisfy the following conditions. The condition in equation (9) indicates the appropriate average Abbe number of all positive lenses in the first lens group U1 with respect to the achromaticity of the first lens group U1. By satisfying the condition in equation (9), high optical performance can be achieved by suppressing axial chromatic aberration and other aberrations at the telephoto end, even with a high zoom ratio.

[0039] Furthermore, it is more preferable to set the lower limit of formula (9) to 75.00, 80.00, 85.00, or 90.00. It is also more preferable to set the upper limit of formula (9) to 94.00, 93.00, or 92.00.

[0040] In the zoom lens of each embodiment, the average value of the partial dispersion ratios of all positive lenses included in the first lens group U1 with respect to the g-line and F-line is θgF1P, and the average value of the partial dispersion ratios of all negative lenses included in the first lens group U1 with respect to the g-line and F-line is θgF1N. At this time, 0.000≦θgF1N-θgF1P≦0.060 (10) It is preferable to satisfy the following conditions. The condition in equation (10) shows an appropriate relationship between the average partial dispersion ratio of all positive lenses and all negative lenses within the first lens group U1 with respect to chromatic aberration in the first lens group U1. By satisfying the condition in equation (10), it is possible to suppress axial chromatic aberration at the telephoto end and avoid increasing the size of the first lens group U1, even with a high zoom ratio.

[0041] The partial dispersion ratio θgF for the g-line and F-line is defined by θgF = (Ng-NF) / (NF-NC), where the refractive indices for the F-line (wavelength 486.1 nm), C-line (wavelength 656.3 nm), and g-line (wavelength 435.8 nm) are NF, Nd, and Ng, respectively.

[0042] Furthermore, it is more preferable to set the lower limit of equation (10) to 0.005, 0.008, or 0.010. It is also more preferable to set the upper limit of equation (10) to 0.050, 0.045, or 0.040.

[0043] In the zoom lenses of Examples 1, 3, and 5, the amount of change (movement) between the position of the second lens group U2 at the wide-angle end and the telephoto end is denoted as mv. In addition, in the zoom lenses of Examples 2, 4, and 6, the amount of change between the position of the second lens group U2 and the third lens group U3 that is the largest is denoted as mv. Note that the change in position of a lens group is considered positive if the lens group is located closer to the image at the telephoto end compared to the wide-angle end.

[0044] At this time, 3.00 ≤ ft / |mv| ≤ 17.00 (11) It is preferable to satisfy the following conditions. The condition in equation (11) shows an appropriate relationship between the amount of change in position of the second lens group U2 (or third lens group), which moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end, and the focal length of the zoom lens at the telephoto end. By satisfying the condition in equation (11), the effect is obtained that the amount of movement of the second lens group U2 (or third lens group) does not become too large, or that the fluctuations of various aberrations do not become too large.

[0045] Furthermore, it is more preferable to set the lower limit of formula (11) to 3.50, 4.00, or 4.20. It is even more preferable to set the upper limit of formula (11) to 16.00, 15.00, or 14.00.

[0046] The zoom lenses of Examples 1 to 6 will be described in detail below. Furthermore, numerical examples 1 to 6 corresponding to each of Examples 1 to 6 will be shown after Example 6.

[0047] In each numerical example, the surface number i indicates the order of the optical surfaces counted from the object side. In the surface data, 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 with respect to the d-line of the optical material between the i-th and (i+1)th surfaces, and is defined as described above. θgF is the partial dispersion ratio of the optical material between the i-th and (i+1)th surfaces with respect to the g-line and F-line, and is defined as described above.

[0048] BF stands for back focus (mm), which is the distance along the optical axis from the image-side lens surface (final surface) of the zoom lens to the paraxial image plane, expressed in terms of air-equivalent length. The total lens length (mm) is the distance along the optical axis from the object-side lens surface (frontmost surface) to the final surface of the zoom lens, plus the back focus.

[0049] 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 from the surface vertex in the direction of the optical axis, H is the height from the optical axis in the direction perpendicular to the optical axis, the direction of light propagation is positive, R is the radius of paraxial curvature, K is the cone constant, and A4 to A16 are the aspherical coefficients. The cone constant and aspherical coefficients "e±Z" are "×10 ±Z It means "...".

[0050]

number

[0051] Table 1 summarizes the values ​​related to the conditions of equations (1) to (11) for the zoom lenses in the numerical examples 1 to 6 above. Each of the zoom lenses in the numerical examples satisfies all the conditions of equations (1) to (11). [Examples]

[0052] The zoom lens of Embodiment 1 (Numerical Example 1) shown in Figure 1 has a first lens group U1 with a fixed positive refractive power arranged in order from the object side to the image side for zooming, a second lens group U2 with a negative refractive power that moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end, and a third lens group U3 with a negative refractive power that moves non-monotonically during zooming. It also has a fourth lens group U4 with a positive refractive power that moves non-monotonically in conjunction with the movement of the second lens group U2 and the third lens group U3 to correct image plane fluctuations associated with zooming. The second to fourth lens groups U2 to U4 constitute an intermediate group. Furthermore, it has a fifth lens group U5 as a rear lens group with a positive refractive power that has a fixed imaging function for zooming. The aperture diaphragm SP is included in the fifth lens group U5.

[0053] The first lens group U1 has surfaces 1 through 12. The second lens group U2 has surfaces 13 through 19. The third lens group U3 has surfaces 20 through 22. The fourth lens group U4 has surfaces 23 through 27. The fifth lens group U5 has surfaces 28 through 47, including the aperture diaphragm SP on surface 33.

[0054] Figure 2 shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lens of Numerical Example 1 at infinity focus in (a) wide-angle end, (b) intermediate zoom position (focal length 537.9 mm), and (c) telephoto end. The spherical aberration diagram shows spherical aberration at the d line (wavelength 587.6 nm) and g line (wavelength 435.8 nm) by solid and dashed lines, respectively. The astigmatism diagram shows astigmatism at the meridional image plane M and sagittal image plane S by dashed and solid lines, respectively. The distortion diagram shows distortion at the d line. The chromatic aberration diagram shows lateral chromatic aberration at the g line. Fno represents the F number, and ω represents the half-angle of view (°).

[0055] The full scale of the horizontal axis in the spherical aberration diagram is ±0.400 mm, and the full scale of the horizontal axis in the astigmatism diagram is also ±0.400 mm. The full scale of the horizontal axis in the distortion diagram is ±5.000%. The full scale of the horizontal axis in the chromatic aberration diagram is ±0.100 mm. The above explanations for the aberration diagrams are the same for the other numerical examples described later. [Examples]

[0056] Figure 3 shows the configuration of the zoom lens in Example 2 (Numerical Example 2) at its wide-angle end and infinity focus state.

[0057] The zoom lens of this embodiment has a first lens group U1 with a fixed positive refractive index arranged sequentially from the object side to the image side for zooming, a second lens group U2 and a third lens group U3 with negative refractive power that move monotonically toward the image side when zooming from the wide-angle end to the telephoto end, and a fourth lens group U4 with negative refractive power that moves non-monotonically when zooming. It also has a fifth lens group U5 with positive refractive power that moves non-monotonically in conjunction with the movement of the second lens group U2, the third lens group U3, and the fourth lens group U4 to correct image plane fluctuations associated with zooming. The second to fifth lens groups U2 to U5 constitute an intermediate group. Furthermore, it has a sixth lens group U6 as a rear lens group with positive refractive power that has a fixed imaging function for zooming. The aperture diaphragm SP is included in the sixth lens group U6.

[0058] The second lens group U2 and the third lens group U3 move monotonically toward the image side while their distance from the wide-angle end to the telephoto end changes slightly (smaller than the change in distance between other lens groups) as the zooming motion progresses. Alternatively, the second lens group U2 and the third lens group U3 may be treated as two sub-lens groups constituting a single second lens group. In this case, the fourth to sixth lens groups U4 to U6 become the third to fifth lens groups, respectively. This is also true for embodiments 4 and 6 described later.

[0059] The first lens group U1 has surfaces 1 through 12. The second lens group U2 has surfaces 13 through 18. The third lens group U3 has surfaces 19 and 20. The fourth lens group U4 has surfaces 21 through 23. The fifth lens group U5 has surfaces 24 through 27. The sixth lens group U6 has an aperture diaphragm SP on surface 28 and surfaces 29 through 44. Surfaces 45 and 46 are surfaces of the glass block.

[0060] Figure 4 shows the longitudinal aberrations of the zoom lens of numerical example 2 at (a) the wide-angle end, (b) the intermediate zoom position (focal length 200.0 mm), and (c) the telephoto end when the lens is in focus at infinity. [Examples]

[0061] Figure 5 shows the configuration of the zoom lens in Example 3 (Numerical Example 3) at its wide-angle end and infinity focus state.

[0062] The zoom lens of this embodiment has a first lens group U1 with a fixed positive refractive power arranged sequentially from the object side to the image side for zooming, a second lens group U2 with a negative refractive power that moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end, and a third lens group U3 with a negative refractive power that moves non-monotonically during zooming. It also has a fourth lens group U4 with a positive refractive power that moves non-monotonically in conjunction with the movement of the second and third lens groups U2 and U3 to correct image plane fluctuations associated with zooming. The second to fourth lens groups U2 to U4 constitute an intermediate group. Furthermore, it has a fifth lens group U5 as a rear lens group with a fixed positive refractive power that has an image-forming function for zooming. The aperture diaphragm SP is included in the fifth lens group U5.

[0063] The first lens group U1 has surfaces 1 through 12. The second lens group U2 has surfaces 13 through 19. The third lens group U3 has surfaces 20 through 23. The fourth lens group U4 has surfaces 24 and 28. The fifth lens group U5 has surfaces 29 through 46, including the aperture diaphragm SP of surface 33.

[0064] Figure 6 shows the longitudinal aberrations of the zoom lens of numerical example 3 at (a) the wide-angle end, (b) the intermediate zoom position (focal length 436.9 mm), and (c) the telephoto end when the lens is in focus at infinity. [Examples]

[0065] Figure 7 shows the configuration of the zoom lens in Example 4 (Numerical Example 4) at its wide-angle end and infinity focus state.

[0066] The zoom lens of this embodiment has a first lens group U1 with a fixed positive refractive power arranged in order from the object side to the image side for zooming, a second lens group U2 and a third lens group U3 with negative refractive power that move monotonically toward the image side when zooming from the wide-angle end to the telephoto end, and a fourth lens group U4 with negative refractive power that moves non-monotonically when zooming. The second lens group U2 and the third lens group U3 move monotonically toward the image side while slightly changing the distance between them when zooming from the wide-angle end to the telephoto end.

[0067] Furthermore, the zoom lens of this embodiment has a fifth lens group U5 with positive refractive power that moves non-monotonically in conjunction with the movement of the second lens group U2, the third lens group U3, and the fourth lens group U4, and corrects image plane fluctuations associated with zooming. The second to fifth lens groups U2 to U5 constitute an intermediate group. In addition, for zooming, there is a sixth lens group U6 as a rear lens group with positive refractive power that has a fixed image-forming function. The aperture diaphragm SP is included in the sixth lens group U6.

[0068] The first lens group U1 has surfaces 1 through 12. The second lens group U2 has surfaces 13 through 17. The third lens group U3 has surfaces 18 and 19. The fourth lens group U4 has surfaces 20 through 24. The fifth lens group U5 has surfaces 25 through 29. The sixth lens group U6 has surfaces 30 through 49, including the aperture diaphragm SP of surface 35.

[0069] Figure 8 shows the longitudinal aberrations of the zoom lens of numerical example 4 at (a) the wide-angle end, (b) the intermediate zoom position (focal length 538.0 mm), and (c) the telephoto end when the lens is in focus at infinity. [Examples]

[0070] Figure 9 shows the configuration of the zoom lens in Example 5 (Numerical Example 5) at its wide-angle end and infinity focus state.

[0071] The zoom lens of this embodiment has a first lens group U1 with a fixed positive refractive power arranged sequentially from the object side to the image side for zooming, a second lens group U2 with a negative refractive power that moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end, and a third lens group U3 with a negative refractive power that moves non-monotonically during zooming. It also has a fourth lens group U4 with a positive refractive power that moves non-monotonically in conjunction with the movement of the second and third lens groups U2 and U3 to correct image plane fluctuations associated with zooming. The second to fourth lens groups U2 to U4 constitute an intermediate group. Furthermore, it has a fifth lens group U5 as a rear lens group with a fixed positive refractive power that has an image-forming function for zooming. The aperture diaphragm SP is included in the fifth lens group U5.

[0072] The first lens group U1 has surfaces 1 through 16. The second lens group U2 has surfaces 17 through 23. The third lens group U3 has surfaces 24 through 26. The fourth lens group U4 has surfaces 27 through 31. The fifth lens group U5 has an aperture diaphragm SP on surface 32 and surfaces 33 through 47.

[0073] Figure 10 shows the longitudinal aberrations of the zoom lens of numerical example 5 at (a) the wide-angle end, (b) the intermediate zoom position (focal length 229.7 mm), and (c) the telephoto end when the lens is in focus at infinity. [Examples]

[0074] Figure 11 shows the configuration of the zoom lens in Example 6 (Numerical Example 6) at its wide-angle end and infinity focus state.

[0075] The zoom lens of this embodiment has a first lens group U1 with a fixed positive refractive power arranged in order from the object side to the image side for zooming, a second lens group U2 and a third lens group U3 with negative refractive power that move monotonically toward the image side when zooming from the wide-angle end to the telephoto end, and a fourth lens group U4 with negative refractive power that moves non-monotonically when zooming. The second lens group U2 and the third lens group U3 move monotonically toward the image side while slightly changing the distance between them when zooming from the wide-angle end to the telephoto end.

[0076] Furthermore, the zoom lens of this embodiment has a fifth lens group U5 with positive refractive power that moves non-monotonically in conjunction with the movement of the second lens group U2, the third lens group U3, and the fourth lens group U4, and corrects image plane fluctuations associated with zooming. The second to fifth lens groups U2 to U5 constitute an intermediate group. In addition, for zooming, there is a sixth lens group U6 as a rear lens group with positive refractive power that has a fixed image-forming function. The aperture diaphragm SP is included in the sixth lens group U6.

[0077] The first lens group U1 has surfaces 1 through 12. The second lens group U2 has surfaces 13 through 17. The third lens group U3 has surfaces 18 and 21. The fourth lens group U4 has surfaces 22 through 24. The fifth lens group U5 has surfaces 25 through 29. The sixth lens group U6 has surfaces 30 through 49, including the aperture diaphragm SP of surface 35.

[0078] Figure 12 shows the longitudinal aberrations of the zoom lens of numerical example 6 at (a) the wide-angle end, (b) the intermediate zoom position (focal length 459.8 mm), and (c) the telephoto end when the lens is in focus at infinity. [Numerical Example 1] Unit: mm Surface data Face number rd nd νd θgF 1 161.744 16.14 1.49700 81.5 0.5375 2 -945.183 0.20 3 171.025 4.00 1.77250 49.6 0.5520 4 100.433 3.60 5 103.958 16.19 1.43387 95.1 0.5373 6 1652.079 8.59 7 -252.458 3.20 1.72916 54.7 0.5444 8 389.317 15.64 9 320.892 12.16 1.43387 95.1 0.5373 10 -233.789 0.15 11 145.547 9.37 1.43387 95.1 0.5373 12 972.415 (variable) 13* -300.623 1.20 1.59522 67.7 0.5442 14 33.310 6.82 15 -65.532 1.00 1.59522 67.7 0.5442 16 27.612 8.48 1.72047 34.7 0.5834 17 -47.840 2.45 18 -30.044 1.20 1.77250 49.6 0.5520 19 939.772 (variable) 20 -69.555 1.00 1.77250 49.6 0.5520 21 131.301 3.26 1.92119 24.0 0.6203 22 -2541.674 (variable) 23* 294.622 7.11 1.43875 94.7 0.5340 24 -63.903 0.20 25 50.963 1.20 2.05090 26.9 0.6054 26 40.873 7.64 1.59522 67.7 0.5442 27 141.224 (variable) 28 103.768 5.95 1.51860 69.9 0.5318 29 -127.657 0.20 30 60.913 5.66 1.43875 94.7 0.5340 31 -899.148 1.20 2.00100 29.1 0.5997 32 154.012 3.99 33 (aperture) ∞ 31.53 34 -474.731 4.20 1.80810 22.8 0.6307 35 -22.168 0.80 1.95375 32.3 0.5905 36 97.342 37.60 37 47.039 7.89 1.51860 69.9 0.5318 38 -35.571 0.18 39 -112.048 4.21 1.60342 38.0 0.5835 40 -28.448 1.00 1.88300 40.8 0.5667 41 27.283 1.80 42 29.699 11.47 1.76182 26.5 0.6136 43 -19.164 1.00 2.00100 29.1 0.5997 44 83.983 0.65 45 52.658 9.20 1.64769 33.8 0.5938 46 -26.670 1.10 1.98612 16.5 0.6657 47 -38.206 48.48 Image plane ∞ Aspherical data Page 13 K =-2.00603e+00 A 4= 4.08902e-06 A 6= 7.31495e-10 A 8=-5.29790e-12 A10= 5.10291e-14 A12=-1.26109e-16 A14= 1.02367e-19 A16= 7.25485e-23 Page 23 K = 0.00000e+00 A 4=-1.13111e-06 A 6= 2.38854e-11 A 8=-1.52990e-13 Various data Zoom ratio 29.98 Wide-angle, Medium, Telephoto Focal length 40.01 537.89 1199.25 F-number 4.60 4.60 10.00 Half-angle (°): 20.30, 1.58, 0.71 Image height 14.80 14.80 14.80 Lens length 455.11 455.11 455.11 BF 48.48 48.48 48.48 d12 1.63 112.76 121.63 d19 116.20 4.20 7.04 d22 13.00 27.27 1.97 d27 15.39 1.99 15.58 d47 48.48 48.48 48.48 Lens group data Group starting plane focal length 1 1 195.06 2 13 -24.98 3 20 -104.21 4 23 70.75 5 28 251.52 [Numerical Example 2] Unit: mm Surface data Face number rd nd νd θgF 1 157.799 9.02 1.43875 94.7 0.5340 2 479.915 1.00 3 225.030 3.00 1.88300 40.8 0.5667 4 110.892 1.07 5 109.943 17.41 1.43387 95.1 0.5373 6 -1548.725 11.15 7 127.671 8.01 1.43387 95.1 0.5373 8 306.492 0.20 9 102.505 6.41 1.43387 95.1 0.5373 10 161.473 0.20 11 151.404 5.56 1.43387 95.1 0.5373 12 293.076 (variable) 13 60.910 1.00 2.00100 29.1 0.5997 14 25.211 8.72 15 -38.725 0.90 1.72916 54.7 0.5444 16 62.788 0.70 17 33.434 6.74 1.80810 22.8 0.6307 18 -48.560 (variable) 19 -36.548 1.10 1.77250 49.6 0.5520 20 45.722 (Variable) 21 -117.012 1.30 1.80100 35.0 0.5864 22 51.711 6.44 1.84649 23.9 0.6217 23 422.084 (variable) 24 -272.626 5.13 1.76634 35.8 0.5792 25 -105.261 0.15 26 59.416 4.59 1.78472 25.7 0.6161 27 104.080 (Variable) 28 (aperture) ∞ 1.00 29 189.141 9.43 1.43875 94.7 0.5340 30 -50.029 1.50 1.96300 24.1 0.6212 31 -66.456 0.15 32 69.440 8.31 1.43875 94.7 0.5340 33 -63.106 1.50 2.00100 29.1 0.5997 34 -545.212 50.00 35 65.975 4.64 1.56732 42.8 0.5731 36 -58.361 2.54 37 -42.276 1.20 1.83481 42.7 0.5648 38 32.043 6.50 1.63980 34.5 0.5922 39 -32.159 2.01 40 -174.789 5.44 1.64769 33.8 0.5938 41 -25.826 1.20 2.00100 29.1 0.5997 42 -1842.715 0.67 43 33.856 4.04 1.61800 63.3 0.5441 44 184.270 3.80 45 ∞ 34.37 1.60859 46.4 0.5664 46 ∞ 13.75 1.51680 64.2 0.5347 47 ∞ 7.00 Image plane ∞ Various data Zoom ratio 40.00 Wide-angle, Medium, Telephoto Focal length 11.00 200.00 440.00 F-number 2.10 2.10 4.10 Half-angle (°): 26.56, 1.58, 0.72 Image height 5.50 5.50 5.50 Lens length 400.17 400.17 400.17 BF 7.00 7.00 7.00 d12 0.69 92.17 97.67 d18 0.83 1.39 1.49 d20 126.24 10.14 36.50 d23 10.04 33.27 3.18 d27 3.50 4.33 2.47 d47 7.00 7.00 7.00 Lens group data Group starting plane focal length 1 1 149.13 2 13 -156.44 3 19 -26.14 4 21 -124.71 5 24 94.48 6 28 80.29 [Numerical Example 3] Unit: mm Surface data Face number rd nd νd θgF 1 97.798 21.08 1.49700 81.5 0.5375 2* 1172.125 0.20 3 92.132 4.00 1.75500 52.3 0.5474 4 69.952 5.69 5 82.337 20.53 1.43387 95.1 0.5373 6 -737.415 0.13 7 -3693.360 3.20 1.77250 49.6 0.5520 8 87.550 9.24 9 88.518 15.48 1.43387 95.1 0.5373 10 -496.943 0.15 11 84.571 7.18 1.43387 95.1 0.5373 12 161.096 (variable) 13* -116.043 1.20 1.69930 51.1 0.5552 14 20.048 6.19 15 -43.897 1.00 1.53775 74.7 0.5392 16 22.160 6.44 1.73800 32.3 0.5900 17 -42.916 1.49 18 -25.237 1.20 1.72916 54.7 0.5444 19 -276.242 (variable) 20 66.392 2.31 1.84666 23.8 0.6205 21 104.128 3.18 22 -97.131 1.20 1.72916 54.7 0.5444 23 164.734 (variable) 24* 59.594 6.37 1.59522 67.7 0.5442 25 -94.597 0.20 26 88.373 1.20 2.00069 25.5 0.6136 27 51.338 6.31 1.49700 81.5 0.5375 28 -144.158 (variable) 29 114.216 4.32 1.43875 94.7 0.5340 30 -99.494 0.20 31 -187.673 1.20 2.00100 29.1 0.5997 32 -15228.482 2.71 33 (aperture) ∞ 31.17 34 145.379 4.77 1.80810 22.8 0.6307 35 -39.501 0.80 1.95375 32.3 0.5905 36 91.402 37.60 37 43.463 7.68 1.57501 41.5 0.5767 38 -39.869 0.19 39 -83.192 4.67 1.56732 42.8 0.5731 40 -24.582 1.00 1.88300 40.8 0.5667 41 27.249 0.13 42 26.782 12.09 1.63980 34.5 0.5922 43 -17.129 1.00 2.00100 29.1 0.5997 44 708.087 0.96 45 106.979 9.58 1.56732 42.8 0.5731 46 -26.950 44.38 Image plane ∞ Aspherical data 2nd side K =-1.24095e+02 A 4= 8.17595e-08 A 6=-6.67050e-13 Page 13 K = 2.09069e+00 A 4= 1.11712e-05 A 6=-1.21661e-08 A 8= 2.95407e-11 A10=-9.08091e-14 A12= 3.64879e-16 A14=-9.43510e-19 A16= 1.70242e-21 Page 24 K = 0.00000e+00 A 4=-2.60834e-06 A 6= 5.77850e-10 A 8=-2.89819e-13 Various data Zoom ratio 23.73 Wide-angle, Medium, Telephoto Focal length 40.00 436.90 949.11 F-number 4.60 4.59 8.28 Half-angle (°): 20.30 1.94 0.89 Image height 14.80 14.80 14.80 Lens length 381.91 381.91 381.91 BF 44.38 44.38 44.38 d12 1.99 67.17 71.98 d19 86.45 1.92 1.91 d23 1.94 21.30 1.92 d28 1.92 1.91 16.49 d46 44.38 44.38 44.38 Lens group data Group starting plane focal length 1 1 143.54 2 13 -17.05 3 20 -146.63 4 24 48.49 5 29 244.85 [Numerical Example 4] Unit: mm Surface data Face number rd nd νd θgF 1 177.756 15.35 1.49700 81.5 0.5375 2 -839.693 0.20 3 195.766 4.00 1.77250 49.6 0.5520 4 111.467 3.48 5 115.416 14.46 1.43387 95.1 0.5373 6 1203.596 8.75 7 -253.932 3.20 1.72916 54.7 0.5444 8 509.424 18.11 9 386.528 11.55 1.43387 95.1 0.5373 10 -246.182 0.15 11 154.149 9.72 1.43875 94.9 0.5340 12 1266.590 (variable) 13* -1191.495 1.20 1.43875 94.7 0.5340 14 32.786 7.47 15 -178.081 1.00 1.72916 54.7 0.5444 16 24.671 9.91 1.76634 35.8 0.5792 17 -87.253 (variable) 18 -33.256 1.20 1.72916 54.7 0.5444 19 * 378.597 (variable) 20 -126.065 1.00 1.77250 49.6 0.5520 21 56.747 4.73 1.78880 28.4 0.6009 22 -193.559 2.20 23 -64.805 1.20 1.88300 40.8 0.5667 24 -383.553 (variable) 25* 533.797 8.35 1.43875 94.7 0.5340 26 -57.794 0.20 27 59.230 1.20 2.00069 25.5 0.6136 28 48.195 7.46 1.59522 67.7 0.5442 29 130.945 (variable) 30 82.475 8.08 1.49700 81.5 0.5375 31 -132.206 0.20 32 55.654 7.24 1.43875 94.7 0.5340 33 -499.933 1.20 2.00100 29.1 0.5997 34 190.572 3.95 35 (aperture) ∞ 29.55 36 200.932 4.81 1.80810 22.8 0.6307 37 -24.456 0.80 1.95375 32.3 0.5905 38 46.680 37.60 39 53.871 7.41 1.48749 70.2 0.5300 40 -29.266 0.16 41 -85.053 4.67 1.62588 35.7 0.5893 42 -22.174 1.00 1.88300 40.8 0.5667 43 28.430 1.56 44 29.491 11.36 1.78472 25.7 0.6161 45 -17.061 1.00 2.00100 29.1 0.5997 46 57.355 0.89 47 44.835 11.02 1.63980 34.5 0.5922 48 -21.971 1.10 1.95906 17.5 0.6598 49 -31.373 46.42 Image plane ∞ Aspherical data Page 13 K =-1.80508e+00 A 4= 3.61405e-06 A 6=-2.79871e-09 A 8= 3.00628e-11 A10=-1.46271e-13 A12= 3.89449e-16 A14=-5.19813e-19 A16= 2.79373e-22 Page 19 K = 0.00000e+00 A 4=-6.52714e-07 A 6=-9.45845e-09 A 8= 2.08079e-10 A10=-2.34165e-12 A12= 1.40832e-14 A14=-4.28703e-17 A16= 5.19868e-20 Page 25 K = 0.00000e+00 A 4=-1.00324e-06 A 6= 5.55930e-11 A 8=-1.11197e-13 Various data Zoom ratio 37.47 Wide-angle, Medium, Telephoto Focal length 40.01 537.96 1499.07 F-number 4.68 4.67 12.90 Half-angle (°): 20.30, 1.58, 0.57 Image height 14.80 14.80 14.80 Lens length 480.65 480.65 480.65 BF 46.42 46.42 46.42 d12 1.06 124.08 136.77 d17 4.90 3.99 3.79 d19 111.18 3.10 3.11 d24 24.21 31.42 1.88 d29 23.18 1.94 18.99 d49 46.42 46.42 46.42 Lens group data Group starting plane focal length 1 1 210.72 2 13 -166.83 3 18 -41.87 4 20 -75.51 5 25 77.86 6 30 244.92 [Numerical Example 5] Unit: mm Surface data Face number rd nd νd θgF 1 162.240 10.24 1.48749 70.2 0.5300 2 878.097 0.20 3 130.754 4.00 1.80518 25.4 0.6161 4 105.225 1.53 5 113.108 18.18 1.43387 95.1 0.5373 6 -307.889 6.64 7 -237.137 3.20 1.91650 31.6 0.5911 8 -93160.246 15.32 9* 152.726 9.48 1.43875 94.7 0.5340 10 -597.025 0.20 11 170.366 8.59 1.48749 70.2 0.5300 12 -442.235 2.20 1.85896 22.7 0.6284 13 -609.762 0.20 14 378.781 4.06 1.89286 20.4 0.6393 15 -594.687 2.00 1.74320 49.3 0.5531 16 125.943 (variable) 17 221.192 1.00 1.89190 37.1 0.5780 18 29.773 5.54 19 -69.517 1.00 1.59349 67.0 0.5361 20 37.311 5.54 1.85478 24.8 0.6122 21 -76.042 2.33 22 -40.308 1.00 1.88300 40.8 0.5667 23* -511.537 (variable) 24 -60.869 1.00 1.69680 55.5 0.5434 25 94.371 3.31 1.68893 31.1 0.6004 26 -315.782 (variable) 27 61.772 5.78 1.72916 54.1 0.5448 28* -141.687 0.19 29 72.905 1.10 1.89190 37.1 0.5780 30 34.850 6.53 1.43875 94.7 0.5340 31 595.488 (variable) 32 (aperture) ∞ 1.20 33 -12009.319 3.95 1.48749 70.2 0.5300 34 -76.048 0.20 35 56.043 7.35 1.49700 81.5 0.5375 36 -64.621 1.80 1.85150 40.8 0.5695 37 125.822 35.67 38 107.952 4.86 1.72047 34.7 0.5834 39 -85.413 10.45 40 55.078 6.13 1.53996 59.5 0.5441 41 -46.847 1.10 1.85150 40.8 0.5695 42 45.387 7.62 43 -289.139 4.28 1.43875 94.7 0.5340 44 -33.802 1.10 1.88300 40.8 0.5667 45 -108.267 0.20 46 133.350 3.15 1.59551 39.2 0.5803 47 -168.519 45.02 Image plane ∞ Aspherical data 9th page K =-1.27680e-01 A 4=-1.03379e-07 A 6= 3.41216e-11 A 8= 1.82405e-13 A10= 2.07735e-16 A12= 8.05740e-20 A14= 6.97082e-23 A16= 2.81178e-27 A 3= 6.89308e-10 A 5= 2.54163e-10 A 7=-4.02383e-12 A 9=-6.41593e-15 A11=-4.53014e-18 A13=-2.64314e-21 A15=-8.02933e-25 Page 23 K = 1.11588e+03 A 4=-7.16326e-07 A 6=-1.11920e-08 A 8= 7.91137e-10 A10= 4.01538e-12 A12=-4.13307e-14 A14= 1.40646e-16 A16=-7.24225e-20 A 3=-6.05608e-07 A 5= 1.46199e-07 A 7=-2.75515e-09 A 9=-8.94883e-11 A11= 3.18804e-13 A13=-3.88515e-17 A15=-2.92260e-18 Page 28 K = 1.83485e+01 A 4= 2.58093e-06 A 6= 5.86844e-08 A 8= 9.38370e-10 A10= 2.49932e-12 A12= 3.23382e-15 A14=-2.64994e-18 A16=-2.65279e-21 A 3=-6.23543e-07 A 5=-2.26430e-07 A 7=-9.32316e-09 A 9=-5.97030e-11 A11=-8.66148e-14 A13=-6.46703e-17 A15= 1.73242e-19 Various data Zoom ratio 9.43 Wide-angle, Medium, Telephoto Focal length 45.96 229.73 433.31 F-number 3.20 3.20 5.15 Half-angle (°): 17.85, 3.69, 1.96 Image height 14.80 14.80 14.80 Lens length 339.89 339.89 339.89 BF 45.02 45.02 45.02 d16 1.26 62.96 74.40 d23 64.78 2.89 2.94 d26 6.71 18.14 4.67 d31 12.71 1.47 3.45 d47 45.02 45.02 45.02 Lens group data Group starting plane focal length 1 1 163.44 2 17 -25.52 3 24 -107.69 4 27 64.16 5 32 109.86 [Numerical Example 6] Unit: mm Surface data Face number rd nd νd θgF 1 151.106 17.39 1.49700 81.5 0.5375 2 -761.566 0.20 3 143.279 4.00 1.77250 49.6 0.5520 4 92.745 3.84 5 97.608 14.28 1.43387 95.1 0.5373 6 640.254 9.14 7 -244.565 3.20 1.69100 54.8 0.5449 8 284.752 15.55 9 253.937 11.59 1.43387 95.1 0.5373 10 -234.195 0.15 11 166.509 7.35 1.43387 95.1 0.5373 12 1040.524 (variable) 13* -152.248 1.20 1.59522 67.7 0.5442 14 23.216 10.29 15 -33.537 1.00 1.59522 67.7 0.5442 16 101.857 5.60 1.72047 34.7 0.5834 17 -56.107 (variable) 18 31.382 1.17 1.77250 49.6 0.5520 19 34.450 5.63 20 -122.040 2.00 1.48749 70.2 0.5300 21 -265.849 (variable) 22 -79.959 1.00 1.77250 49.6 0.5520 23 200.779 2.81 1.92119 24.0 0.6203 24 -598.574 (variable) 25* 75.701 8.22 1.43875 94.7 0.5340 26 -98.467 0.20 27 80.699 1.20 2.05090 26.9 0.6054 28 56.789 6.52 1.43875 94.9 0.5340 29 611.936 (variable) 30 86.475 3.99 1.51860 69.9 0.5318 31 665.455 0.20 32 81.253 5.00 1.43875 94.7 0.5340 33 -430.446 1.20 2.00100 29.1 0.5997 34 6149.340 2.81 35 (aperture) ∞ 30.68 36 42.705 3.90 1.80810 22.8 0.6307 37 -84.936 0.80 1.95375 32.3 0.5905 38 25.578 37.60 39 88.303 7.13 1.51860 69.9 0.5318 40 -31.148 0.20 41 -184.388 5.13 1.60342 38.0 0.5835 42 -23.723 1.00 1.88300 40.8 0.5667 43 37.187 0.96 44 31.116 10.35 1.76182 26.5 0.6136 45 -22.073 1.00 2.00100 29.1 0.5997 46 46.688 1.51 47 47.196 9.04 1.64769 33.8 0.5938 48 -25.893 1.10 1.98612 16.5 0.6657 49 -35.699 49.35 Image plane ∞ Aspherical data Page 13 K = 1.89484e+00 A 4= 5.04981e-06 A 6=-2.19657e-09 A 8=-2.88738e-11 A10= 2.47009e-13 A12=-1.03901e-15 A14= 2.18279e-18 A16=-1.81459e-21 Page 25 K = 0.00000e+00 A 4=-1.00095e-06 A 6= 8.65058e-11 A 8= 2.47643e-15 Various data Zoom ratio 24.98 Wide-angle, Medium, Telephoto Focal length 40.01 459.82 999.27 F-number 4.60 4.60 8.82 Half-angle (°): 20.30, 1.84, 0.85 Image height 14.80 14.80 14.80 Lens length 455.26 455.26 455.26 BF 49.35 49.35 49.35 d12 2.22 108.69 117.22 d17 1.98 2.09 1.99 d21 118.00 3.13 3.03 d24 24.62 32.92 1.97 d29 1.99 1.98 24.60 d49 49.35 49.35 49.35 Lens group data Group starting plane focal length 1 1 194.61 2 13 -31.42 3 18 2147.94 4 22 -136.07 5 25 84.97 6 30 297.22

[0079] [Table 1]

[0080] [Imaging device] Figure 13 shows an example configuration of the imaging device 125. In Figure 13, 101 is a zoom lens from one of Examples 1 to 6. 124 is the camera body. The zoom lens 101 is detachable from the camera body 124. In this figure, the first lens group U1 is shown as lens group F, the intermediate group as lens group LZ, and the rear lens group as lens group R. SP is the aperture diaphragm. 114 and 115 are drive mechanisms that drive the lens group that moves for focusing and the lens group LZ that moves for zooming, respectively, and include helicoids, cams, etc.

[0081] 116-118 are motors (actuators) that drive the drive mechanisms 114 and 115 and the aperture diaphragm SP. 119-121 are detectors for detecting the position of the lens group for focusing and the lens group LZ, and the aperture diameter of the aperture diaphragm SP, and are composed of encoders, potentiometers, photosensors, etc.

[0082] In the camera body 124, 109 is a glass block such as a prism or optical filter. 110 is an image sensor, such as a CCD sensor or CMOS sensor, which is a photoelectric conversion element that converts the subject image formed by the zoom lens 101 into photoelectric data (imaging the subject through the zoom lens 101). 111 and 122 are processing units that perform various processes and controls in the camera body 124 and the zoom lens 101, respectively, and include a processor such as a CPU.

[0083] By using the zoom lenses described in Examples 1 to 6 above, a compact and lightweight imaging device 125 that can obtain good captured images can be provided.

[0084] The above-described embodiment includes the following configuration. (Composition 1) A zoom lens comprising a first lens group arranged sequentially from the object side to the image side, having a fixed positive refractive power for zooming; an intermediate group including three or more lens groups that move for zooming; and a rear lens group having a fixed positive refractive power for zooming, wherein the spacing between adjacent lens groups changes during zooming. The intermediate group includes a lens group having at least two negative refractive powers and a lens group having at least one positive refractive power. When the focal length of the zoom lens at the telephoto end is ft, the focal length of the first lens group is f1, and the distance along the optical axis from the image-side lens surface of the first lens group to the rear principal point of the first lens group when in focus on an object at infinity is bok1, 2.50 ≤ ft / f1 ≤ 8.00 0.55 ≤ (f1 + bok1) / f1 ≤ 0.85 A zoom lens characterized by satisfying the following conditions. (Configuration 2) The zoom lens according to configuration 1, characterized in that the first lens group is composed of five or more lenses. (Composition 3) When the focal length of the zoom lens at the wide-angle end is fw, 2.50 ≤ f1 / fw ≤ 20.00 A zoom lens according to configuration 1 or 2, characterized by satisfying the following conditions. (Composition 4) When the focal length of the second lens group is f2, -1.20 ≤ f1 / f2 ≤ 0.50 A zoom lens according to any one of configurations 1 to 3, characterized by satisfying the following conditions. (Composition 5) When the lateral magnification of the second lens group at the wide-angle end is β2w, -100.00 ≤ β2w ≤ 100.00 A zoom lens according to any one of configurations 1 to 4, characterized by satisfying the following conditions. (Composition 6) When the lateral magnification of the second lens group at the telephoto end is β2t, -1000.00 ≤ β2t ≤ 10.00 The zoom lens according to any one of Configurations 1 to 5, characterized by satisfying the condition. (Configuration 7) When the focal length of the zoom lens at the wide-angle end is fw, 9.00 ≤ ft / fw ≤ 100.00 The zoom lens according to any one of Configurations 1 to 6, characterized by satisfying the condition. (Configuration 8) The first lens on the object side in the first lens group is a positive lens, When the Abbe number based on the d-line of the first lens is νd11, 65.00 ≤ νd11 ≤ 96.00 The zoom lens according to any one of Configurations 1 to 7, characterized by satisfying the condition. (Configuration 9) The average value of the Abbe numbers based on the d-line of all the positive lenses included in the first lens group is νd1P, when 70.00 ≤ νd1P ≤ 96.00 / / The zoom lens according to any one of Configurations 1 to 8, characterized by satisfying the condition. (Configuration 10) When the average value of the partial dispersion ratios with respect to the g-line and F-line of all the positive lenses included in the first lens group is θgF1P, and the average value of the partial dispersion ratios with respect to the g-line and F-line of all the negative lenses included in the first lens group is θgF1N, 0.000 ≤ θgF1N - θgF1P ≤ 0.060 The zoom lens according to any one of Configurations 1 to 9, characterized by satisfying the condition. (Configuration 11) When mv is the amount of change between the position at the wide-angle end and the telephoto end of the second lens group, which is positioned closest to the object among the intermediate groups and moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end, or when mv is the amount of change between the position at the wide-angle end and the telephoto end of the third lens group, which is positioned toward the image side of the second lens group and has a negative refractive power that moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end, and the lens group whose change between the position at the wide-angle end and the telephoto end is the largest, 3.00 ≤ ft / |mv| ≤ 17.00 A zoom lens according to any one of configurations 1 to 10, characterized by satisfying the following conditions. (Composition 12) The second lens group, which has negative refractive power and is positioned closest to the object among the aforementioned intermediate groups, moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end. The zoom lens according to any one of configurations 1 to 11, characterized in that the third lens group having negative refractive power and the fourth lens group having positive refractive power, which are positioned on the image side of the second lens group among the intermediate group, move non-monotonically when zooming from the wide-angle end to the telephoto end. (Composition 13) The second and third lens groups, which are positioned closest to the object and image, respectively, within the aforementioned intermediate group and have negative refractive power, move monotonically toward the image side when zooming from the wide-angle end to the telephoto end. The zoom lens according to any one of configurations 1 to 11, characterized in that the fourth lens group having negative refractive power and the fifth lens group having positive refractive power, which are positioned on the image side of the third lens group among the intermediate groups, move non-monotonically when zooming from the wide-angle end to the telephoto end. (Composition 14) A zoom lens comprising a first lens group arranged sequentially from the object side to the image side, having a fixed positive refractive power for zooming; an intermediate group including three or more lens groups that move for zooming; and a rear lens group having a fixed positive refractive power for zooming, wherein the spacing between adjacent lens groups changes during zooming. The intermediate group includes a lens group having at least two negative refractive powers and a lens group having at least one positive refractive power. When the focal length of the zoom lens at the telephoto end is ft and the focal length of the first lens group is f1, 2.50 ≤ ft / f1 ≤ 8.00 A zoom lens characterized by satisfying the following conditions. (Composition 15) A zoom lens described in any one of configurations 1 to 14, An imaging device characterized by having an image sensor that captures an image of a subject through the aforementioned zoom lens.

[0085] 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]

[0086] U1 First Lens Group U2 Second Lens Group U3 Third Lens Group U4 4th lens group U5 5th lens group U6 6th lens group SP aperture diaphragm I image plane

Claims

1. A zoom lens comprising a first lens group arranged sequentially from the object side to the image side and having a fixed positive refractive power for zooming, an intermediate group including three or more lens groups that move for zooming, and a rear lens group having a fixed positive refractive power for zooming, wherein the spacing between adjacent lens groups changes during zooming, The intermediate group includes a lens group having at least two negative refractive powers and a lens group having at least one positive refractive power. When the focal length of the zoom lens at the telephoto end is ft, the focal length of the first lens group is f1, and bok1 is the distance along the optical axis from the image-side lens surface of the first lens group to the rear principal point of the first lens group when in focus on an object at infinity, 2.50 ≤ ft / f1 ≤ 8.00 0.55≦(f1+bok1) / f1≦0.85 A zoom lens characterized by satisfying the following conditions.

2. The zoom lens according to claim 1, characterized in that the first lens group is composed of five or more lenses.

3. When the focal length of the zoom lens at the wide-angle end is fw, 2.50 ≤ f1 / fw ≤ 20.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

4. When the focal length of the second lens group is f2, -1.20 ≤ f1 / f2 ≤ 0.50 The zoom lens according to claim 1, characterized by satisfying the following conditions.

5. When the lateral magnification of the second lens group at the wide-angle end is β2w, -100.00 ≤ β2w ≤ 100.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

6. When the lateral magnification of the second lens group at the telephoto end is β2t, -1000.00 ≤ β2t ≤ 10.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

7. When the focal length of the zoom lens at the wide-angle end is fw, 9.00 ≤ ft / fw ≤ 100.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

8. The first lens in the first lens group that is closest to the object is a positive lens. When the Abbe number with respect to the d line of the first lens is denoted as νd11, 65.00 ≤ νd11 ≤ 96.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

9. The average value of the Abbe numbers with respect to the d line of all positive lenses included in the first lens group is When νd1P is used, 70.00 ≤ νd1P ≤ 96.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

10. When the average value of the partial dispersion ratios of all positive lenses included in the first lens group with respect to the g-line and F-line is θgF1P, and the average value of the partial dispersion ratios of all negative lenses included in the first lens group with respect to the g-line and F-line is θgF1N, 0.000 ≤ θgF1N - θgF1P ≤ 0.060 The zoom lens according to claim 1, characterized by satisfying the following conditions.

11. When, among the aforementioned intermediate group, the amount of change in position between the wide-angle end and the telephoto end of the second lens group, which is positioned closest to the object and moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end, or when, among the third lens group, which is positioned toward the image side of the second lens group and has a negative refractive power and moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end, the amount of change in position between the wide-angle end and the telephoto end of the lens group with the largest change in position between the wide-angle end and the telephoto end, is denoted as mv, 3.00≦ft / |mv|≦17.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

12. The second lens group, which has negative refractive power and is positioned closest to the object among the aforementioned intermediate groups, moves monotonically toward the image side when zooming from the wide-angle end to the telephoto end. The zoom lens according to claim 1, characterized in that the third lens group having negative refractive power and the fourth lens group having positive refractive power, which are positioned on the image side of the second lens group among the intermediate group, move non-monotonically when zooming from the wide-angle end to the telephoto end.

13. The second and third lens groups, which are positioned closest to the object and image, respectively, within the aforementioned intermediate group and have negative refractive power, move monotonically toward the image side when zooming from the wide-angle end to the telephoto end. The zoom lens according to claim 1, characterized in that the fourth lens group having negative refractive power and the fifth lens group having positive refractive power, which are positioned on the image side of the third lens group among the intermediate group, move non-monotonically when zooming from the wide-angle end to the telephoto end.

14. A zoom lens comprising a first lens group arranged sequentially from the object side to the image side and having a fixed positive refractive power for zooming, an intermediate group including three or more lens groups that move for zooming, and a rear lens group having a fixed positive refractive power for zooming, wherein the spacing between adjacent lens groups changes during zooming, The intermediate group includes a lens group having at least two negative refractive powers and a lens group having at least one positive refractive power. When the focal length of the zoom lens at the telephoto end is ft and the focal length of the first lens group is f1, 2.50 ≤ ft / f1 ≤ 8.00 A zoom lens characterized by satisfying the following conditions.

15. A zoom lens according to any one of claims 1 to 14, An imaging device characterized by having an image sensor that captures an image of a subject through the aforementioned zoom lens.

Images