Zoom lens and imaging apparatus

Abstract

To provide a compact and lightweight zoom lens having a maximum focal distance and a high variable power ratio.SOLUTION: A zoom lens comprises: a positive first lens group L1 that does not move for zooming; an intermediate group including at least three lens groups that move for zooming; and a positive final lens group that does not move for zooming. The first lens group L1 includes: a positive first sub lens group L11; a positive second sub lens group L12 that moves for focusing; and a negative third sub lens group L13. The intermediate group includes a lens group having positive refractive power on a side closest to an image. A focal distance of the first lens group is f1, a focal distance of a specific negative lens group having the strongest negative refractive power in the intermediate group is f2, and a distance from a lens surface closest to the image side to a rear principal point in the first lens group is ok1. Conditions of -8.0≤f1 / f2≤-4.0 and 0.10≤(f1+ok1) / f1≤0.80 are satisfied.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] There is a zoom lens of a full-length fixed type in which the first lens group on the object side does not move during zooming, and an inner focus type in which the lens on the image side moves during focusing more than the lens on the object side. Patent Document 1 discloses a zoom lens having a four-group configuration, a half angle of view at the telephoto end of about 2.07°, and a zoom ratio of about 3 times. Patent Document 2 discloses a zoom lens having a four-group configuration, a half angle of view at the telephoto end of about 1.01°, and a zoom ratio of about 18 times.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, it is difficult for the zoom lenses disclosed in Patent Documents 1 and 2 to satisfy all the conditions of having a long maximum focal length, a high zoom ratio, and being small and light.

[0005] The present invention provides a small and light zoom lens while having a long maximum focal length and a high zoom ratio.

Means for Solving the Problems

[0006] A zoom lens according to one aspect of the present invention includes a first lens group having a positive refractive power that does not move for zooming, an intermediate group including at least three lens groups that move for zooming, and a final lens group having a positive refractive power that does not move for zooming, which are arranged in order from the object side to the image side, and is a zoom lens in which the interval between adjacent lens groups changes during zooming. The first lens group has a first sub-lens group having a positive refractive power, a second sub-lens group having a positive refractive power that moves for focusing, and a third sub-lens group having a negative refractive power, which are arranged in order from the object side to the image side. The intermediate group has a lens group with a positive refractive power on the most image side.

[0007] When the focal length of the first lens group is f1, the focal length of the specific negative lens group with the strongest refractive power among at least one lens group with a negative refractive power included in the intermediate group is f2, and the distance on the optical axis from the most image-side lens surface in the first lens group to the rear principal point of the first lens group is ok1 when the direction from the object side to the image side is defined as positive, -8.0 ≦ f1 / f2 ≦ -4.0 0.10 ≦ (f1 + ok1) / f1 ≦ 0.80 It is characterized by satisfying the following conditions. An imaging device equipped with the above zoom lens also constitutes another aspect of the present invention.

Advantages of the Invention

[0008] The present invention can provide a small and lightweight zoom lens while having a long maximum focal length and a high magnification ratio.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0010] Hereinafter, examples of the present invention will be described with reference to the drawings. First, prior to the description of specific Examples 1 to 6, matters common to each example will be described.

[0011] The zoom lens of each example is used in various imaging devices such as a cinema camera, a broadcast camera, a video camera, a surveillance camera, a digital still camera, and a silver halide film camera.

[0012] In a zoom lens, a lens group is a collection of one or more lenses that move together or do not move during zooming (changing magnification) between a wide-angle end and a telephoto end. That is, the distance between adjacent lens groups changes during zooming. The lens group may include an aperture stop. Also, the wide-angle end and the telephoto end respectively indicate the zoom states of the maximum angle of view (shortest focal length) and the minimum angle of view (longest focal length) when the lens group that moves during zooming is located at both ends of the range where it can move mechanically or controllably on the optical axis.

[0013] FIG. 1, FIG. 3, FIG. 5, FIG. 7, FIG. 9, and FIG. 11 each show a cross-section of the zoom lens of Examples 1 to 6 in a state of being focused on an infinite object (hereinafter referred to as an infinite focus state) and at the wide-angle end. In each figure, the left side is the object side (front side), and the right side is the image side (rear side). OA indicates the optical axis of the zoom lens. Li is the i-th lens group counted from the object side, and L1m is the m-th sub-lens group counted from the object side in the first lens group L1. SP is the aperture stop, and I is the image plane. On the image plane I, the imaging surface (light-receiving surface) of the imaging element in the imaging device or the film surface (photosensitive surface) of the silver halide film is arranged. Also, under the lens group that moves during zooming, the movement locus of the lens group during zooming from the wide-angle end to the telephoto end is indicated by an arrow. Further, under the lens group (sub-lens group) that moves during focusing, the movement direction of the lens group during focusing from infinity to the closest distance is indicated by an arrow marked with FOCUS.

[0014] The zoom lens of each example includes a first lens group L1 with a positive refractive power that does not move for zooming, an intermediate group including at least three lens groups L2 to L4 (or L5) that move for zooming, and a final lens group L5 (or L6) with a positive refractive power that does not move for zooming, which are arranged in order from the object side to the image side.

[0015] The first lens group L1 includes a first sub-lens group L11 with positive refractive power, a second sub-lens group L12 with positive refractive power that moves for focusing, and a third sub-lens group L13 with negative refractive power, which are arranged in order from the object side to the image side. The intermediate group has a lens group with positive refractive power on the most image side.

[0016] In the above configuration, let the focal length of the first lens group L1 be f1, and the focal length of the specific negative lens group with the strongest refractive power among at least one lens group with negative refractive power included in the intermediate group be f2. Also, when the direction from the object side to the image side is defined as positive, let the distance on the optical axis from the most image-side lens surface in the first lens group L1 to the rear principal point of the first lens group L1 be ok1. At this time, the zoom lens of each embodiment satisfies the conditions of the following formulas (1) and (2).

[0017] -8.0 ≦ f1 / f2 ≦ -4.0 (1) 0.10 ≦ (f1 + ok1) / f1 ≦ 0.80 (2) The condition of formula (1) shows an appropriate relationship between the focal lengths of the first lens group L1 and the specific negative lens group in the intermediate group. By satisfying the condition of formula (1), it is possible to achieve a refractive power arrangement that is advantageous for miniaturization and high magnification ratio in a telephoto zoom lens with a long maximum focal length. If f1 / f2 exceeds the upper limit of formula (1), the refractive power of the specific negative lens group, which is the main zooming group, becomes too weak compared to the refractive power of the first lens group L1, making it difficult to achieve a high magnification ratio, which is not preferable. If f1 / f2 is below the lower limit of formula (1), the refractive power of the specific negative lens group becomes too strong, resulting in a large aberration variation during zooming or difficulty in achieving miniaturization and light weight to suppress the aberration variation, which is not preferable.

[0018] The condition of Equation (2) indicates an appropriate relationship between the focal length of the first lens group L1 and the distance to the rear principal point position. When (f1 + ok1) / f1 exceeds the upper limit of Equation (2), the rear principal point position of the first lens group L1 will be excessively located on the image side, and the absolute value of the lateral magnification of the specific negative lens group at the wide-angle end will become small. As a result, the movement amount of the specific negative lens group during zooming will increase, and the zoom lens will become larger, which is not preferable. Or the focal length of the first lens group L1 becomes too short, making it difficult to keep various aberrations within the allowable range at the telephoto end, which is not preferable. When (f1 + ok1) / f1 is below the lower limit of Equation (2), the image-side principal point position of the first lens group L1 will be excessively located on the object side, and the entrance pupil position at the wide-angle end will be located on the image side, and the first lens group L1 will become larger, which is not preferable. Or the focal length of the first lens group L1 becomes too long, the lateral magnification of the specific negative lens group at the wide-angle end becomes small, the movement amount of the specific negative lens group during zooming increases, and the zoom lens becomes larger, which is not preferable.

[0019] Note that it is more preferable to set the numerical ranges of Equations (1) and (2) as follows.

[0020] -7.5 ≦ f1 / f2 ≦ -4.5 (1a) 0.20 ≦ (f1 + ok1) / f1 ≦ 0.77 (2a) Also, it is even more preferable to set the numerical ranges of Equations (1) and (2) as follows.

[0021] -7.0 ≦ f1 / f2 ≦ -5.0 (1b) 0.30 ≦ (f1 + ok1) / f1 ≦ 0.74 (2b) By satisfying the above configuration and conditions, it is possible to realize a zoom lens that is long in maximum focal length, has a high magnification ratio, is small and lightweight, and can also be compatible with a large imaging device.

[0022] Also, the zoom lens (and the imaging device equipped with the zoom lens) of each embodiment preferably satisfies at least one of the conditions of the following Equations (3) to (12).

[0023] 0.20 ≤ D1 / f1 ≤ 0.90 (3) -0.50 ≤ β2w ≤ -0.15 (4) 4.5 ≤ β2t / β2w ≤ 20.0 (5) 0.0 ≤ f1 / f11 ≤ 1.0 (6) 0.4 ≤ f1 / f12 ≤ 2.1 (7) -1.0 ≤ f1 / f13 ≤ -0.1 (8) -6.0 ≤ f1 / f3 ≤ -0.4 (9) 1.0 ≤ f1 / f4 ≤ 4.5 (10) 1.5 ≤ f1 / fw ≤ 8.0 (11) 1.4 ≤ fw / IS ≤ 7.0 (12) In formulas (3) to (12), D1 is the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side in the first lens group L1. β2w is the lateral magnification at the wide-angle end of the specific negative lens group, and β2t is the lateral magnification at the telephoto end of the specific negative lens group. f11 is the focal length of the first sub-lens group L11 in the first lens group L1, f12 is the focal length of the second sub-lens group L12, and f13 is the focal length of the third sub-lens group L13. f3 is the focal length of the lens group adjacent to the specific negative lens group on the image side, and f4 is the focal length of the lens group further adjacent to the lens group adjacent to the specific negative lens group on the image side on the image side. fw is the focal length at the wide-angle end of the zoom lens. IS is the diagonal length of the effective imaging surface of the imaging element provided in the imaging device.

[0024] The condition of formula (3) shows an appropriate relationship between the focal length and the thickness on the optical axis of the first lens group L1. By satisfying the condition of formula (3), a configuration suitable for a compact and lightweight telephoto zoom lens can be achieved. If D1 / f1 exceeds the upper limit of formula (3), the thickness of the first lens group L1 becomes too large and it becomes difficult to achieve compactness and lightweight, which is not preferable. If D1 / f1 is below the lower limit of formula (3), the refractive power of the first lens group L1 becomes too strong and it becomes difficult to correct various aberrations, which is not preferable.

[0025] The condition of Equation (4) indicates an appropriate range of the lateral magnification at the wide-angle end of the specific negative lens group. By satisfying the condition of Equation (4), it is possible to achieve a high magnification ratio and optimize the focal length at the wide-angle end as a telephoto zoom lens. If β2w exceeds the upper limit of Equation (4), the movement amount of the specific negative lens group during zooming increases, and the zoom lens becomes larger, which is not preferable. If β2w is below the lower limit of Equation (4), the aberration variation associated with zooming increases due to maintaining small size and light weight, which is not preferable.

[0026] The condition of Equation (5) indicates an appropriate relationship between the lateral magnifications at the wide-angle end and the telephoto end of the specific negative lens group. By satisfying the condition of Equation (5), it is possible to achieve a high magnification ratio while shortening the movement amount of the specific negative lens group during zooming. If β2t / β2w exceeds the upper limit of Equation (5), the refractive power of the specific negative lens group becomes too strong, making it difficult to correct aberrations during zooming, which is not preferable. If β2t / β2w is below the lower limit of Equation (5), the magnification ratio borne by the specific negative lens group, which is the main variable magnification group, becomes too small, making it difficult to achieve a high magnification, which is not preferable.

[0027] The condition of Equation (6) indicates an appropriate relationship between the focal length of the first lens group L1 and the focal length of the first sub-lens group L11. By satisfying the condition of Equation (6), it is possible to achieve an appropriate configuration of the first lens group L1 in realizing a telephoto zoom lens. If f1 / f11 exceeds the upper limit of Equation (6), the refractive power of the first sub-lens group L11 becomes relatively strong compared to the refractive power of the first lens group L1, increasing various aberrations on the telephoto side, which is not preferable. If f1 / f11 is below the lower limit of Equation (3), the focal length of the first sub-lens group L11 becomes relatively too long compared to the focal length of the first lens group L1, increasing the movement amount of the second sub-lens group L12, which is the focus group, which is not preferable.

[0028] The condition of Equation (7) indicates an appropriate relationship between the focal length of the first lens group L1 and the focal length of the second sub-lens group L12. By satisfying the condition of Equation (7), the size of the first lens group L1 and the refractive power of the second sub-lens group L12, which is the focusing group, can be optimized. If f1 / f12 exceeds the upper limit of Equation (7), the refractive power of the second sub-lens group L12 becomes too strong, resulting in a large aberration variation during focusing, which is not preferable. If f1 / f12 is below the lower limit of Equation (7), the movement amount of the second sub-lens group L12 during focusing increases, leading to an increase in the size of the zoom lens, which is not preferable.

[0029] The condition of Equation (8) indicates an appropriate relationship between the focal length of the first lens group L1 and the focal length of the third sub-lens group L13. By satisfying the condition of Equation (8), miniaturization and weight reduction of the zoom lens can be achieved. If f1 / f13 exceeds the upper limit of Equation (8), the refractive power of the third sub-lens group L13 becomes weak, and the image-side principal point position of the first lens group L1 is excessively located on the image side, leading to an increase in the size of the zoom lens, which is not preferable. If f1 / f13 is below the lower limit of Equation (8), the refractive power of the third sub-lens group L13 becomes strong, and the image-side principal point position of the first lens group L1 is excessively located on the object side, and the entrance pupil position at the wide-angle end is excessively located on the image side, leading to an increase in the size of the first lens group L1, which is not preferable.

[0030] The condition of Equation (9) indicates an appropriate relationship between the focal length of the first lens group L1 and the focal length of the lens group (hereinafter referred to as lens group LM) adjacent to the specific negative lens group on the image side. By satisfying the condition of Equation (9), miniaturization, lightweight, high magnification ratio, and high optical performance can be achieved. If f1 / f3 exceeds the upper limit of Equation (9), the refractive power of the lens group LM becomes too strong relative to the positive refractive power of the first lens group L1, increasing the variation of various aberrations such as spherical aberration and coma aberration during zooming, and it becomes difficult to reduce the variation of these aberrations, which is not preferable. If f1 / f3 is below the lower limit of Equation (9), the movement amount of the lens group LM during zooming increases, making it difficult to achieve a high magnification ratio and miniaturization and weight reduction of the entire zoom lens, which is not preferable.

[0031] The condition of Equation (10) shows an appropriate relationship between the focal length of the first lens group L1 and the focal length of the lens group (herein referred to as lens group LN) adjacent to the image side of lens group LM. By satisfying the condition of Equation (10), it is possible to achieve miniaturization and weight reduction of the first lens group L1 and suppression of aberration variation during zooming. If f1 / f4 exceeds the upper limit of Equation (10), the refractive power of lens group LN becomes too strong, increasing the variation of spherical aberration during zooming, which is not preferable. If f1 / f4 is below the lower limit of Equation (10), the focal length of the first lens group L1 becomes relatively too short compared to the focal length of lens group LN, making it difficult to suppress the ray height of off-axis rays incident on the first lens group L1. As a result, the lens diameter of the first lens group L1 increases, which is not preferable.

[0032] The condition of Equation (11) shows an appropriate relationship between the first lens group L1 and the focal length at the wide-angle end of the zoom lens. By satisfying the condition of Equation (11), it is possible to achieve both miniaturization and high optical performance of the zoom lens. If f1 / fw exceeds the upper limit of Equation (11), the refractive power of the first lens group L1 becomes weak and the lens diameter becomes large, making it difficult to miniaturize the zoom lens, which is not preferable. If f1 / fw is below the lower limit of Equation (11), the refractive power of the first lens group L1 becomes strong, increasing the curvature of the lens surfaces constituting the first lens group, making it difficult to achieve high optical performance, which is not preferable.

[0033] The condition of Equation (12) shows an appropriate relationship between the focal length at the wide-angle end of the zoom lens and the diagonal length of the imaging device when the zoom lens of each embodiment is used in the imaging device. By satisfying the condition of Equation (12), it is possible to realize appropriate specifications according to the imaging device. If fw / IS is below the lower limit of Equation (12), it becomes an overly wide-angle zoom lens, making it difficult to correct off-axis aberrations such as distortion aberration and lateral chromatic aberration, which is not preferable. If fw / IS exceeds the upper limit of Equation (12), it becomes an overly telephoto zoom lens, making it difficult to correct various aberrations including axial chromatic aberration at the telephoto end, which is not preferable.

[0034] In addition, it is more preferable that the numerical ranges of formulas (3) to (12) are as follows.

[0035] 0.30 ≦ L1 / f1 ≦ 0.80 (3a) -0.46 ≦ β2w ≦ -0.20 (4a) 5.5 ≦ β2t / β2w ≦ 18.0 (5a) 0.1 ≦ f1 / f11 ≦ 0.9 (6a) 0.6 ≦ f1 / f12 ≦ 1.9 (7a) -0.9 ≦ f1 / f13 ≦ -0.2 (8a) -5.0 ≦ f1 / f3 ≦ -0.5 (9a) 1.5 ≦ f1 / f4 ≦ 4.0 (10a) 2.0 ≦ f1 / fw ≦ 7.0 (11a) 1.5 ≦ fw / IS ≦ 6.9 (12a) Furthermore, it is even more preferable that the numerical ranges of formulas (3) to (12) are as follows.

[0036] 0.40 ≦ L1 / f1 ≦ 0.70 (3b) -0.42 ≦ β2w ≦ -0.25 (4b) 6.5 ≦ β2t / β2w ≦ 16.0 (5b) 0.2 ≦ f1 / f11 ≦ 0.8 (6b) 0.8 ≦ f1 / f12 ≦ 1.7 (7b) -0.8 ≦ f1 / f13 ≦ -0.3 (8b) -4.0 ≦ f1 / f3 ≦ -0.6 (9b) 2.0 ≦ f1 / f4 ≦ 3.5 (10b) 2.5 ≦ f1 / fw ≦ 6.0 (11b) 1.6 ≦ fw / IS ≦ 6.8 (12b) In addition, the zoom lens of each embodiment preferably has at least one of the following configurations.

[0037] The third sub - lens group L13 preferably moves differently from the second sub - lens group L12 during focusing (in other words, moves along a different trajectory from the second sub - lens group L12). With this configuration, it becomes easy to suppress fluctuations in aberrations due to focusing.

[0038] The first sub - lens group L11 preferably includes at least two negative lenses. Here, even when a negative lens is joined with a positive lens to form a positive cemented lens, it is counted as one negative lens. With this configuration, it becomes easy to appropriately correct various aberrations on the wide - angle side and the telephoto side.

[0039] The intermediate group is preferably composed of a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, arranged in order from the object side to the image side. Or the intermediate group is preferably composed of a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. With these configurations, a zoom lens having high optical performance over the entire zoom range with a high magnification ratio can be realized.

[0040] Hereinafter, the zoom lenses of each embodiment will be specifically described. After Example 6, Numerical Examples 1 - 6 corresponding to each of Examples 1 - 6 are shown.

Example

[0041] The zoom lens of Example 1 (Numerical Example 1) shown in FIG. 1 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, an aperture stop SP, and a fifth lens group L5 with positive refractive power, arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 move for zooming and constitute the intermediate group. The fifth lens group L5 is the final lens group for imaging and does not move for zooming.

[0042] The first lens group L1 is composed of a first sub - lens group L11 with positive refractive power, a second sub - lens group L12 with positive refractive power, and a third sub - lens group L13 with negative refractive power, which are arranged in order from the object side to the image side. The second sub - lens group L12 is a focus lens group that moves toward the object side during focusing from infinity to the closest distance.

[0043] The second lens group L2 is a variator group with negative refractive power that moves toward the image side during zooming from the wide - angle end to the telephoto end, and it is a specific negative lens group. An optical unit such as an extender lens for focal length conversion may be inserted into the fifth lens group L5.

[0044] Figure 2(A) shows the longitudinal aberration (spherical aberration, astigmatism, distortion, and chromatic aberration) in the infinity - focused state and at the wide - angle end of the zoom lens of Numerical Example 1. Figure 2(B) shows the longitudinal aberration in the infinity - focused state and at the telephoto end of the zoom lens of Numerical Example 1.

[0045] In the spherical aberration diagram, Fno indicates the F - number. The solid line shows the spherical aberration for the d - line (wavelength 587.6 nm), and the two - dotted chain line shows the spherical aberration for the g - line (wavelength 435.8 nm). Also, the one - dotted chain line shows the spherical aberration for the C - line (wavelength 656.3 nm), and the long - dashed line shows the spherical aberration for the F - line (wavelength 486.1 nm). In the astigmatism diagram, the solid line S indicates the astigmatism on the sagittal image plane, and the dashed line M indicates the astigmatism on the meridional image plane. The distortion diagram shows the distortion in the d - line. The chromatic aberration diagram shows the lateral chromatic aberration in the g - line, C - line, and F - line. The astigmatism diagram and the chromatic aberration diagram show the aberration amount when the central ray of the light beam at the aperture position is taken as the chief ray. ω is the paraxial half - field angle (°). The spherical aberration is drawn on a scale of 0.4 mm, the astigmatism is 0.4 mm, the distortion is 10%, and the chromatic aberration is 0.1 mm. The explanations for the above aberration diagrams are the same for the aberration diagrams of the following numerical examples.

Example

[0046] The zoom lens of Example 2 (numerical example 2) shown in FIG. 3 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, an aperture stop SP, and a fifth lens group L5 with positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 move for zooming and constitute an intermediate group. The fifth lens group L5 is the final lens group for imaging and does not move for zooming.

[0047] The first lens group L1 is composed of a first sub-lens group L11 with positive refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with negative refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus lens group that moves toward the object side when focusing from infinity to the closest distance.

[0048] The second lens group L2 is a variator group with negative refractive power that moves toward the image side when zooming from the wide-angle end to the telephoto end, and it is a specific negative lens group. An optical unit such as an extender lens for focal length conversion may be inserted into the fifth lens group L5.

[0049] FIG. 4(A) shows the longitudinal aberration at the wide-angle end in the infinity focus state of the zoom lens of numerical example 2. FIG. 4(B) shows the longitudinal aberration at the telephoto end in the infinity focus state of the zoom lens of numerical example 2.

Example

[0050] The zoom lens of Example 3 (numerical example 3) shown in FIG. 5 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, an aperture stop SP, and a fifth lens group L5 with positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 move for zooming and constitute an intermediate group. The fifth lens group L5 is the final lens group for imaging and does not move for zooming.

[0051] The first lens group L1 is composed of a first sub-lens group L11 with positive refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with negative refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus lens group that moves when focusing from infinity to the nearest distance.

[0052] The second lens group L2 is a variator group with negative refractive power that moves toward the image side when zooming from the wide-angle end to the telephoto end, and is a specific negative lens group. An optical unit such as an extender lens for focal length conversion may be inserted into the fifth lens group L5.

[0053] FIG. 6(A) shows the longitudinal aberration in the infinity focus state and at the wide-angle end of the zoom lens of numerical example 3. FIG. 6(B) shows the longitudinal aberration in the infinity focus state and at the telephoto end of the zoom lens of numerical example 3.

Example

[0054] The zoom lens of Example 4 (numerical example 4) shown in FIG. 7 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, an aperture stop SP, and a fifth lens group L5 with positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 move for zooming and constitute an intermediate group. The fifth lens group L5 is the final lens group for imaging and does not move for zooming.

[0055] The first lens group L1 is composed of a first sub-lens group L11 with positive refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with negative refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus lens group that moves toward the object side when focusing from infinity to the nearest distance.

[0056] The second lens group L2 is a variator group with negative refractive power that moves toward the image side when zooming from the wide-angle end to the telephoto end, and it is a specific negative lens group. An optical unit such as an extender lens for changing the focal length may be inserted into the fifth lens group L5.

[0057] FIG. 8(A) shows the longitudinal aberration at the wide-angle end in the infinity-focus state of the zoom lens of numerical example 4. FIG. 8(B) shows the longitudinal aberration at the telephoto end in the infinity-focus state of the zoom lens of numerical example 4.

Example

[0058] The zoom lens of Example 5 (numerical example 5) shown in Fig. 9 is composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, a fifth lens group L5 with positive refractive power, an aperture stop SP, and a sixth lens group L6 with positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move for zooming and constitute an intermediate group. The sixth lens group L6 is the final lens group for imaging and does not move for zooming.

[0059] The first lens group L1 is composed of a first sub-lens group L11 with positive refractive power, a second sub-lens group L12 with positive refractive power, and a third sub-lens group L13 with negative refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus lens group that moves toward the image side when focusing from infinity to the nearest point.

[0060] The second lens group L2 is a varifocal group with negative refractive power that moves toward the image side when zooming from the wide-angle end to the telephoto end, and is a specific negative lens group. An optical unit such as an extender lens for changing the focal length may be inserted into the sixth lens group L6.

[0061] Fig. 10(A) shows the longitudinal aberration at the wide-angle end in the infinity-focus state of the zoom lens of numerical example 5. Fig. 10(B) shows the longitudinal aberration at the telephoto end in the infinity-focus state of the zoom lens of numerical example 5.

Example

[0062] The zoom lens of Example 3 (Numerical Example 3) shown in FIG. 5 is composed of a first lens group L1 with a positive refractive power, a second lens group L2 with a negative refractive power, a third lens group L3 with a negative refractive power, a fourth lens group L4 with a positive refractive power, an aperture stop SP, and a fifth lens group L5 with a positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move for zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 move for zooming and constitute an intermediate group. The fifth lens group L5 is the final lens group for imaging and does not move for zooming.

[0063] The first lens group L1 is composed of a first sub-lens group L11 with a positive refractive power, a second sub-lens group L12 with a positive refractive power, and a third sub-lens group L13 with a negative refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 and the third sub-lens group L13 are focus lens groups that move in different directions toward the object side when focusing from infinity to the nearest distance.

[0064] The second lens group L2 is a varifocal group with a negative refractive power that moves toward the image side when zooming from the wide-angle end to the telephoto end, and is a specific negative lens group. An optical unit such as an extender lens for changing the focal length may be inserted into the fifth lens group L5.

[0065] FIG. 12(A) shows the longitudinal aberration in the infinity-focus state and at the wide-angle end of the zoom lens of Numerical Example 6. FIG. 12(B) shows the longitudinal aberration in the infinity-focus state and at the telephoto end of the zoom lens of Numerical Example 6.

[0066] The following shows Numerical Examples 1 to 6. In each numerical example, the surface number i indicates the order of the surfaces from the object side, r represents the radius of curvature (mm) of the i-th surface, and d represents the distance (mm) on the optical axis between the i-th surface and the (i + 1)-th surface. The (variable) d indicates the distance that changes during zooming, and a separate table shows the distance according to the focal length. nd is the absolute refractive index at 1 atmosphere in the d-line of the optical material between the i-th surface and the (i + 1)-th surface. νd is the Abbe number based on the d-line of the optical material between the i-th surface and the (i + 1)-th surface. The Abbe number νd based on the d-line is defined as follows when the refractive indices in the d-line, F-line, and C-line are Nd, NF, and NC respectively: νd = (Nd - 1) / (NF - NC).

[0067] θgF is the partial dispersion ratio of the optical material between the i-th surface and the (i + 1)-th surface with respect to the g-line and F-line. The partial dispersion ratio with respect to the g-line and F-line is defined as follows when the refractive index in the g-line is Ng: θgF = (Ng - NF) / (NF - NC) and is represented by this formula.

[0068] In addition to the specifications such as the focal length and F-number of the entire zoom lens system for each numerical example, the half field angle (°) of the zoom lens is shown. BF is the back focus, which indicates the air-equivalent distance from the most image-side lens surface (the final surface) of the zoom lens to the image plane. The overall lens length is the value obtained by adding the back focus to the distance on the optical axis from the most object-side lens surface (the frontmost surface) of the zoom lens to the final surface. Furthermore, the lens group data shows the focal length of each lens group.

[0069] The "*" attached to the surface number means that the surface has an aspherical shape. The aspherical shape is represented by the following formula when X is the displacement amount from the vertex of the surface in the optical axis direction, 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 paraxial radius of curvature, k is the conic constant, and A3 to A16 are the aspherical coefficients. The "e±x" of the conic constant and the aspherical coefficients means ×10 ±x and is meant by this.

[0070] [Number]

[0071] [Numerical Example 1] Unit: mm Surface data Surface number r d nd νd θgF 1 157.902 10.02 1.48749 70.2 0.5300 2 2465.935 0.20 3 127.530 4.00 1.80518 25.4 0.6161 4 105.493 0.80 5 108.191 16.16 1.43387 95.1 0.5373 6 -285.940 6.05 7 -238.095 3.20 1.91650 31.6 0.5911 8 22942.556 15.00 9* 153.345 7.48 1.43875 94.7 0.5340 10 -982.435 0.20 11 170.055 7.53 1.48749 70.2 0.5300 12 -433.862 2.20 1.85896 22.7 0.6284 13 -712.910 0.19 14 462.272 4.48 1.89286 20.4 0.6393 15 -427.641 2.00 1.74320 49.3 0.5531 16 118.589 (Variable) 17 159.349 1.00 1.89190 37.1 0.5780 18 29.563 4.76 19 -73.592 1.00 1.59349 67.0 0.5361 20 34.688 5.60 1.85478 24.8 0.6122 21 -91.291 1.42 22 -40.220 1.00 1.88300 40.8 0.5667 23* -500.952 (Variable) 24 -61.342 1.00 1.69680 55.5 0.5434 25 96.280 3.13 1.68893 31.1 0.6004 26 -323.643 (Variable) 27 62.334 6.20 1.72916 54.1 0.5448 28* -132.395 0.19 29 72.056 1.10 1.89190 37.1 0.5780 30 34.677 6.86 1.43875 94.7 0.5340 31 441.374 (Variable) 32 (Aperture) ∞ 1.20 33 62687.980 4.09 1.48749 70.2 0.5300 34 -77.153 0.20 35 58.348 9.69 1.49700 81.5 0.5375 36 -68.880 1.80 1.85150 40.8 0.5695 37 129.683 42.60 38 106.886 5.21 1.72047 34.7 0.5834 39 -86.941 8.75 40 52.268 6.50 1.53996 59.5 0.5441 41 -47.295 1.10 1.85150 40.8 0.5695 42 44.856 3.94 43 -151.222 4.17 1.43875 94.7 0.5340 44 -33.505 1.10 1.88300 40.8 0.5667 45 -120.494 3.60 46 142.014 3.63 1.59551 39.2 0.5803 47 - 111.685 44.02 Image plane ∞ Aspherical data Surface 9 k = -1.72915e-01 A4 = -1.06424e-07 A6 = 2.30772e-11 A8 = 1.87605e-13 A10 = 2.03430e-16 A12 = 8.00041e-20 A14 = 6.97412e-23 A16 = 1.55246e-27 A3 = -3.95747e-09 A5 = 6.38644e-10 A7 = -4.17265e-12 A9 = -6.20124e-15 A11 = -4.53651e-18 A13 = -2.68817e-21 A15 = -7.20072e-25 Surface 23 k = 1.13131e+03 A4 = -3.84529e-07 A6 = -2.21153e-08 A8 = 8.63990e-10 A10 = 3.64401e-12 A12 = -4.18965e-14 A14 = 1.53350e-16 A16 = -1.47085e-19 A3 = -1.14095e-06 A5 = 2.00835e-07 A7 = -2.48764e-09 A9 = -8.88192e-11 A11 = 3.01104e-13 A13 = 4.41093e-17 A15 = -2.42292e-18 Surface 28 k = 1.87100e+01 A4 = 2.73481e-06 A6 = 5.86116e-08 A8 = 9.37053e-10 A10 = 2.49915e-12 A12 = 3.23560e-15 A14 = -2.65818e-18 A16 = -2.65017e-21 A3 = -5.32416e-07 A5 = -2.23956e-07 A7 = -9.29240e-09 A9 = -5.97014e-11 A11 = -8.64662e-14 A13 = -6.49659e-17 A15 = 1.73661e-19 Various data Zoom ratio 9.44 Wide angle, Medium, Telephoto Focal length 51.78 180.90 488.78 F-number 3.20 3.20 5.20 Half field angle (°) 15.95 4.68 1.73 Image height 14.80 14.80 14.80 Overall lens length 338.92 338.92 338.92 BF 44.02 44.02 44.02 d16 1.15 52.49 73.43 d23 59.26 2.89 2.65 d26 8.21 22.03 2.27 d31 15.96 7.16 6.22 Lens group data Group, Starting surface, Focal length 1 1 165.06 2 17 -26.06 3 24 -108.07 4 27 63.78 5 32 115.36 [Numerical example 2] Unit: mm Surface data Surface number, r, d, nd, νd, θgF 1 123.883 13.47 1.48749 70.2 0.5300 2 -2529.155 0.20 3 95.168 4.80 1.59551 39.2 0.5803 4 76.426 6.30 5 127.578 13.56 1.43387 95.1 0.5373 6 -220.129 3.17 7 -197.563 3.84 1.88300 40.8 0.5667 8 -8565.037 18.32 9* 148.050 6.79 1.43875 94.7 0.5340 10 -1540.471 0.20 11 169.510 6.15 1.49700 81.5 0.5375 12 -830.643 2.64 1.85478 24.8 0.6122 13 2759.280 0.20 14 360.799 4.39 1.89286 20.4 0.6393 15 -521.681 2.40 1.73800 32.3 0.5900 16 125.889 (variable) 17* 266.359 1.20 1.65160 58.5 0.5390 18 27.227 4.96 19 -73.130 1.20 1.43875 94.7 0.5340 20 33.595 4.13 1.74000 28.3 0.6079 21 1465.315 2.66 22 -38.338 1.20 1.75500 52.3 0.5474 23 -156.287 (variable) 24 -103.811 1.20 1.74400 44.8 0.5655 25 20670.930 1.94 1.89286 20.4 0.6393 26 -308.509 (variable) 27 73.952 5.49 1.69680 55.5 0.5434 28* -164.878 0.23 29 63.431 1.32 1.80000 29.8 0.6017 30 35.524 7.88 1.43875 94.7 0.5340 31 -242.021 (variable) 32 (Aperture) ∞ 1.20 33 235.022 2.49 1.43875 94.7 0.5340 34 ∞ 0.20 35 192.319 4.89 1.43875 94.7 0.5340 36 -70.021 2.16 1.80400 46.5 0.5577 37 563.186 40.99 38 116.959 4.06 1.71736 29.5 0.6047 39 -88.901 7.91 40 53.101 5.34 1.60342 38.0 0.5835 41 -52.288 1.32 1.89190 37.1 0.5780 42 40.090 2.56 43 158.078 4.01 1.51633 64.1 0.5353 44 -48.958 1.32 1.95375 32.3 0.5905 45 -198.452 18.13 46 70.900 3.20 1.49700 81.5 0.5375 47 621.862 44.00 Image plane ∞ Aspherical data The 9th surface k = -6.44231e+00 A4 = 2.84628e-07 A6 = 1.18990e-10 A8 = -3.70941e-14 A10 = -3.28576e-16 A12 = -2.24803e-19 A14 = 3.39950e-23 A16 = 4.97060e-29 A3 = -3.02188e-07 A5 = -3.76347e-09 A7 = -2.00154e-12 A9 = 4.92491e-15 A11 = 1.25260e-17 A13 = 6.20385e-22 A15 = -3.42691e-25 Page 17 k = -5.72778e+01 A4 = -4.59258e-09 A6 = -3.83786e-08 A8 = -3.88566e-11 A10 = 4.97152e-14 A3 = 4.62636e-06 A5 = 3.60836e-07 A7 = 2.09211e-09 A9 = -1.21936e-12 Page 28 k = 3.89013e+01 A4 = 2.14063e-06 A6 = 2.35353e-08 A8 = 2.27492e-10 A10 = 3.39825e-13 A12 = -2.54180e-17 A14 = -3.86049e-19 A16 = -1.70988e-22 A3 = -5.19561e-07 A5 = -1.21532e-07 A7 = -2.79946e-09 A9 = -1.16132e-11 A11 = -4.19747e-15 A13 = 4.65325e-18 A15 = 1.40153e-20 Various data Zoom ratio 7.60 Wide angle, Medium, Telephoto Focal length 62.21 174.19 472.83 F-number 3.20 3.20 4.90 Half field angle (°) 13.38 4.86 1.79 Image height 14.80 14.80 14.80 Overall lens length 339.01 339.01 339.01 BF 44.00 44.00 44.00 d16 1.42 41.31 60.48 d23 70.77 2.02 2.16 d26 2.00 30.86 1.82 d31 1.20 1.20 10.93 Lens group data Group starting surface focal length 1 1 160.95 2 17 -27.37 3 24 -236.41 4 27 56.72 5 32 229.09 [Numerical example 3] Unit: mm Surface data Surface number r d nd νd θgF 1 138.553 11.35 1.53775 74.7 0.5392 2 -24373.998 0.20 3 118.032 4.00 1.60342 38.0 0.5835 4 95.637 5.02 5 156.879 11.99 1.43387 95.1 0.5373 6 -258.367 7.43 7 -194.073 3.20 1.95375 32.3 0.5905 8 1427.524 17.73 9* 162.515 5.82 1.43875 94.7 0.5340 10 2168.731 0.20 11 178.844 8.78 1.53775 74.7 0.5392 12 -229.051 2.20 1.54072 47.2 0.5651 13 -338.219 0.20 14 389.071 4.01 1.92119 24.0 0.6203 15 -896.708 2.00 1.67790 55.4 0.5434 16 124.814 (variable) 17 229.721 1.00 1.88300 40.8 0.5667 18 28.790 4.59 19 -86.142 1.00 1.43875 94.7 0.5340 20 32.258 5.02 1.72825 28.5 0.6077 21 -91.711 1.42 22 -40.132 1.00 1.75500 52.3 0.5474 23* 1695.815 (variable) 24 -60.121 1.00 1.74320 49.3 0.5531 25 116.689 2.64 1.77830 23.9 0.6248 26 -526.393 (variable) 27 75.501 6.42 1.75500 52.3 0.5474 28* -125.081 0.19 29 87.229 1.10 1.90366 31.3 0.5963 30 41.474 7.17 1.43875 94.7 0.5340 31 6932.743 (variable) 32 (aperture) ∞ 1.20 33 98.088 5.97 1.43875 94.7 0.5340 34 -104.474 21.37 35 77.115 6.92 1.43875 94.7 0.5340 36 -48.116 1.80 1.74320 49.3 0.5531 37 102.688 45.11 38 186.399 5.33 1.71736 29.5 0.6047 39 -70.014 7.03 40 51.200 7.14 1.48749 70.2 0.5300 41 -52.922 1.10 1.90525 35.0 0.5848 42 54.438 3.45 43 -702.383 5.40 1.48749 70.2 0.5300 44 -33.505 1.10 1.69930 51.1 0.5552 45 -1322.386 3.48 46 123.367 4.89 1.57501 41.5 0.5767 47 -73.753 43.97 Image plane ∞ Aspherical data Surface 9 k = -3.70221e-01 A4 = -9.22715e-08 A6 = -3.36960e-11 A8 = 4.93862e-14 A10 = 3.40027e-17 A12 = 1.10153e-19 A14 = 7.60722e-23 A16 = 8.51982e-27 A3 = 3.80994e-08 A5 = 8.33386e-10 A7 = -3.47237e-13 A9 = -1.12135e-15 A11 = -2.52534e-18 A13 = -3.22237e-21 A15 = -1.21344e-24 Surface 23 k = 7.57501e+03 A4 = -2.10413e-06 A6 = -4.90515e-08 A8 = -1.57473e-09 A10 = 2.71866e-12 A12 = -2.41948e-14 A14 = 3.34456e-17 A16 = -2.85745e-19 A3 = -2.74123e-07 A5 = 6.56991e-08 A7 = 1.28106e-08 A9 = 6.45374e-11 A11 = -5.45592e-14 A13 = 3.14372e-16 A15 = 4.96687e-18 Surface 28 k = 1.29948e+01 A4 = 2.29153e-06 A6 = 5.53006e-08 A8 = 8.93011e-10 A10 = 2.50371e-12 A12 = 3.24427e-15 A14 = -2.93636e-18 A16 = -2.44600e-21 A3 = -4.54508e-07 A5 = -2.22406e-07 A7 = -8.70325e-09 A9 = -5.83596e-11 A11 = -8.82951e-14 A13 = -5.77916e-17 A15 = 1.70585e-19 Various data Zoom ratio 11.34 Wide-angle Medium Telephoto Focal length 51.82 181.33 587.73 F-number 3.20 3.20 6.22 Half field angle (°) 15.37 4.49 1.39 Image height 14.25 14.25 14.25 Overall lens length 374.65 374.65 374.65 BF 43.97 43.97 43.97 d16 1.41 56.23 81.49 d23 59.18 3.13 3.15 d26 13.38 25.08 0.98 d31 18.76 8.29 7.12 Lens group data Group Starting surface Focal length 1 1 169.95 2 17 -27.60 3 24 -94.85 4 27 66.18 5 32 128.57 [Numerical example 4] Unit mm Surface data Surface number r d nd νd θgF 1 147.623 11.05 1.48749 70.2 0.5300 2 2904.723 1.10 3 148.226 4.00 1.62004 36.3 0.5879 4 98.637 0.19 5 96.261 18.61 1.43387 95.1 0.5373 6 -259.667 5.02 7 -228.978 3.20 2.00100 29.1 0.5997 8 10514.735 14.57 9* 162.899 7.22 1.43875 94.7 0.5340 10 -1264.781 0.18 11 156.228 10.07 1.55200 70.7 0.5421 12 -210.236 2.20 1.51835 60.4 0.5420 13 -1998.643 0.09 14 475.955 4.61 1.92119 24.0 0.6203 15 -329.485 2.00 1.75500 52.3 0.5474 16 137.602 (variable) 17* 1207.202 1.00 1.90525 35.0 0.5848 18 27.519 5.07 19 -75.653 1.00 1.49700 81.5 0.5375 20 28.622 5.91 1.85896 22.7 0.6284 21 -72.202 4.16 22 -36.792 1.00 1.92119 24.0 0.6203 23 -468.730 (variable) 24 -54.188 1.00 1.78800 47.4 0.5559 25 147.663 1.93 1.89286 20.4 0.6393 26 -567.023 (variable) 27 59.458 5.96 1.73800 32.3 0.5900 28* -119.088 0.19 29 77.215 1.10 1.85478 24.8 0.6122 30 32.576 7.33 1.43875 94.7 0.5340 31 -448.189 (Variable) 32 (Aperture) ∞ 1.68 33 -315.766 3.48 1.49700 81.5 0.5375 34 -68.797 1.63 35 54.076 6.76 1.49700 81.5 0.5375 36 -68.233 1.80 1.85150 40.8 0.5695 37 118.044 44.63 38 72.975 5.38 1.72825 28.5 0.6077 39 -100.488 5.21 40 126.592 7.83 1.54814 45.8 0.5686 41 -43.655 1.10 1.86100 37.1 0.5785 42 34.954 1.94 43 45.507 7.69 1.43875 94.7 0.5340 44 -49.975 1.10 1.88300 40.8 0.5667 45 -241.107 3.47 46 55.904 3.78 1.51742 52.4 0.5564 47 316.755 43.82 Image plane ∞ Aspherical data Surface 9 k = -6.73874e-01 A4 = -5.53305e-08 A6 = 1.64337e-10 A8 = 9.76280e-15 A10 = -1.10239e-17 A12 = 6.37087e-20 A14 = 7.13766e-23 A16 = 7.07934e-27 A3 = -9.49161e-08 A5 = -3.28363e-09 A7 = -3.79779e-12 A9 = 1.05452e-15 A11 = -7.54326e-19 A13 = -2.73507e-21 A15 = -1.07796e-24 The 17th surface k = 1.05775e+03 A4 = 1.13332e-06 A6 = -1.38992e-08 A8 = -2.55978e-10 A10 = -3.65682e-13 A3 = 2.10526e-06 A5 = 1.11127e-07 A7 = 2.13043e-09 A9 = 1.56864e-11 The 28th surface k = 1.64414e+01 A4 = 3.28965e-06 A6 = 5.43033e-08 A8 = 8.61407e-10 A10 = 2.33336e-12 A12 = 3.48114e-15 A14 = -2.56696e-18 A16 = -2.58366e-21 A3 = -5.33333e-07 A5 = -2.35978e-07 A7 = -8.38150e-09 A9 = -5.55711e-11 A11 = -8.48749e-14 A13 = -7.49610e-17 A15 = 1.72374e-19 Various data Zoom ratio 9.49 Wide angle, medium, telephoto Focal length 51.83 181.32 491.79 F-number 3.25 3.25 5.20 Half field angle (°) 15.94 4.67 1.72 Image height 14.80 14.80 14.80 Overall lens length 338.98 338.98 338.98 BF 43.82 43.82 43.82 d16 1.60 48.39 65.82 d23 42.77 2.77 2.73 d26 14.79 20.54 1.69 d31 18.75 6.22 7.68 Lens group data Group Starting surface Focal length 1 1 150.09 2 17 -25.14 3 24 -81.86 4 27 56.26 5 32 122.78 [Numerical example 5] Unit: mm Surface data Surface number r d nd νd θgF 1 218.410 9.82 1.48749 70.2 0.5300 2 -785.608 0.20 3 119.260 4.00 1.85478 24.8 0.6122 4 101.410 0.96 5 105.386 17.02 1.43387 95.1 0.5373 6 -231.780 6.17 7 -189.968 3.20 1.90525 35.0 0.5848 8 5392.233 14.22 9* 135.549 7.02 1.43875 94.7 0.5340 10 8096.252 3.19 11 184.591 7.46 1.52841 76.5 0.5396 12 -319.196 2.20 1.89286 20.4 0.6393 13 -385.413 0.19 14 430.706 3.98 1.89286 20.4 0.6393 15 -745.854 2.00 1.62299 58.2 0.5458 16 97.195 (Variable) 17* 109.359 1.00 1.88300 40.8 0.5667 18 27.596 4.88 19 -61.137 1.00 1.53775 74.7 0.5392 20 33.496 4.25 1.85478 24.8 0.6122 21 -190.160 1.75 22 -39.836 1.00 1.88300 40.8 0.5668 23 -221.971 (Variable) 24 -65.703 1.00 1.80400 46.5 0.5577 25 221.825 2.28 1.89286 20.4 0.6393 26 -442.477 (Variable) 27 62.875 6.02 1.75500 52.3 0.5474 28* -139.554 (Variable) 29 81.812 1.10 1.89190 37.1 0.5780 30 37.923 7.24 1.43875 94.7 0.5340 31 -354.133 (Variable) 32 (Aperture) ∞ 1.20 33 7744.375 4.38 1.51633 64.1 0.5353 34 -67.448 0.20 35 62.804 10.98 1.49700 81.5 0.5375 36 -50.280 1.80 1.85150 40.8 0.5695 37 122.916 42.75 38 86.309 5.42 1.72047 34.7 0.5834 39 -94.878 7.28 40 81.307 5.84 1.53996 59.5 0.5441 41 -47.888 1.10 1.85150 40.8 0.5695 42 37.286 3.36 43 198.160 4.34 1.43875 94.7 0.5340 44 -53.336 1.10 1.88300 40.8 0.5667 45 -153.483 5.65 46 86.907 3.91 1.59551 39.2 0.5803 47 -196.814 43.97 Image plane ∞ Aspherical data Surface 9 k =-5.17752e-01 A 4=-5.86311e-08 A 6= 5.18109e-11 A 8=-5.97908e-14 A10=-1.92249e-17 A12= 2.67386e-19 A14= 1.33390e-22 A16= 1.03145e-26 A 3=-1.51314e-07 A 5=-1.20662e-09 A 7=-1.00923e-12 A 9= 3.96823e-15 A11=-5.64702e-18 A13=-7.03352e-21 A15=-1.70949e-24 Surface 17 k = 1.43716e+01 A 4=-1.50567e-06 A 6=-7.21445e-09 A 8=-1.06626e-10 A10=-2.93969e-13 A12=-8.90059e-17 A 3= 3.38313e-06 A 5= 1.05095e-07 A 7= 6.28531e-10 A 9= 8.61326e-12 A11= 4.40110e-15 Surface 28 k = 1.64286e+01 A4 = 2.74212e-06 A6 = 5.91146e-08 A8 = 8.99724e-10 A10 = 2.28384e-12 A12 = 3.34436e-15 A14 = -1.55120e-18 A16 = -2.33722e-21 A3 = -5.58454e-07 A5 = -2.45358e-07 A7 = -9.06776e-09 A9 = -5.63264e-11 A11 = -7.92013e-14 A13 = -8.82360e-17 A15 = 1.46082e-19 Various data Zoom ratio 9.49 Wide angle Middle Telephoto Focal length 51.82 181.29 491.74 F-number 3.20 3.20 5.20 Half field angle (°) 15.94 4.67 1.72 Image height 14.80 14.80 14.80 Overall lens length 338.99 338.99 338.99 BF 43.97 43.97 43.97 d16 1.09 50.79 71.71 d23 61.40 2.79 2.80 d26 6.28 20.71 1.97 d28 1.45 2.00 0.20 d31 12.32 6.27 5.88 Lens group data Group Starting surface Focal length 1 1 162.50 2 17 -25.29 3 24 -102.32 4 27 58.16 5 29 3764.48 6 32 125.02 [Numerical example 6] Unit: mm Surface data Surface number r d nd νd θgF 1 94.486 14.62 1.63980 34.5 0.5922 2 609.448 3.33 3 120.981 2.80 1.85478 24.8 0.6122 4 96.429 10.40 1.43875 94.7 0.5340 5 488.404 2.52 6 -2002.445 2.50 1.72047 34.7 0.5834 7 79.708 20.76 8* 108.808 10.78 1.43875 94.7 0.5340 9 -406.435 0.20 10 109.055 8.76 1.43387 95.1 0.5373 11 -1327.198 0.99 12 530.672 2.50 1.51633 64.1 0.5353 13 149.844 (variable) 14* -1118.564 1.00 1.69680 55.5 0.5434 15 26.425 1.53 16 28.011 6.71 1.69895 30.1 0.6030 17 -118.993 1.00 1.69680 55.5 0.5434 18 45.793 4.15 19 -43.977 1.00 1.67790 55.3 0.5472 20 193.404 (variable) 21 -62.279 1.00 1.67790 55.4 0.5434 22 148.673 2.40 1.92119 24.0 0.6203 23 1355.630 (variable) 24 81.209 5.86 1.77030 47.4 0.5562 25* -111.156 0.19 26 69.344 1.10 2.00100 29.1 0.5997 27 38.704 6.58 1.52841 76.5 0.5396 28 548.375 (variable) 29 (Diaphragm) ∞ 1.20 30 84.119 5.76 1.43875 94.7 0.5340 31 -103.062 12.65 32 114.039 5.32 1.45600 90.3 0.5340 33 -53.372 1.80 1.89190 37.1 0.5780 34 287.432 41.29 35 198.802 4.71 1.89286 20.4 0.6393 36 -82.316 2.70 37 51.883 7.55 1.60342 38.0 0.5835 38 -52.248 1.10 1.96300 24.1 0.6212 39 46.180 8.17 40 -328.380 6.10 1.67270 32.1 0.5988 41 -29.422 1.10 1.89190 37.1 0.5780 42 326.110 0.65 43 62.134 4.93 1.73800 32.3 0.5900 44 -171.392 44.00 Image plane ∞ Aspherical data The 8th surface k = 6.64969e-01 A 4=-1.32330e-07 A 6= 2.03425e-10 A 8= 2.16151e-13 A10= 1.78354e-17 A 3 = -2.18817e-07, A 5 = -3.54523e-09, A 7 = -8.67658e-12, A 9 = -3.01838e-15 The 14th surface k = -9.94030e+02, A 4 = 1.10802e-06, A 6 = 5.15617e-08, A 8 = 5.22178e-10 A10 = 2.74306e-13 A 3 = 3.39498e-06, A 5 = -1.14763e-07, A 7 = -7.33932e-09, A 9 = -1.88060e-11 The 25th surface k = 2.70985e+00, A 4 = 1.77264e-06, A 6 = 5.90512e-08, A 8 = 9.09606e-10 A10 = 2.25233e-12, A12 = 3.02694e-15, A14 = -1.94263e-18, A16 = -2.36803e-21 A 3 = -4.05897e-07, A 5 = -2.34879e-07, A 7 = -9.21634e-09, A 9 = -5.63458e-11 A11 = -7.55571e-14, A13 = -7.24750e-17, A15 = 1.50699e-19 Various data Zoom ratio 9.49 Wide angle, medium, telephoto Focal length 51.84, 181.35, 491.83 F number 3.20, 3.20, 5.20 Half field angle (°) 15.93, 4.67, 1.72 Image height 14.80, 14.80, 14.80 Overall lens length 353.07, 353.07, 353.07 d13 1.76, 58.42, 83.06 d20 65.69, 4.34, 4.34 d23 3.75, 19.34, 2.41 d28 20.14 9.25 1.53 d44 44.00 44.00 44.00 Lens group data Group starting surface Focal length 1 1 174.46 2 14 -26.24 3 21 -100.71 4 24 56.46 5 29 121.46 The values related to the above formulas (1) to (12) in Numerical Examples 1 to 6 are summarized in Table 1. The zoom lenses in each numerical example satisfy all the conditions of formulas (1) to (12).

[0072]

Table 1

[0073] [Imaging device] FIG. 13 schematically shows an imaging device including the zoom lenses of Examples 1 to 6 as an imaging optical system. In FIG. 13, 101 is any one of the zoom lenses of Examples 1 to 6. 124 is a camera body. 125 is an imaging device configured by attaching the zoom lens 101 to the camera body 124. The zoom lens 101 is detachable from the camera body 124. However, the zoom lens 101 may be integrally provided on the camera body 124.

[0074] The zoom lens 101 has, in order from the object side to the image side, a first lens group F, a zoom section LZ, and an imaging lens group R. The first lens group F includes a focus lens group that moves during focusing. The zoom section LZ includes at least three or more lens groups. On the image side of the zoom section LZ, a diaphragm SP, a lens group R1, and a lens group R2 are arranged. The imaging device 125 has an optical unit IE that can be inserted into the optical path between the lens group R1 and the lens group R2. By inserting the lens unit IE between the lens group R1 and the lens group R2, the range of the focal length of the entire zoom lens 101 can be displaced.

[0075] 114 and 115 are each a drive mechanism for moving the lens groups included in the first lens group F and the zoom unit LZ along the optical axis. 116 to 118 are each a motor for driving the drive mechanisms 114 and 115 and the aperture stop SP. 119 to 121 are each a detection unit for detecting the position of the first lens group F on the optical axis or the lens groups included in the zoom unit LZ, or for detecting the aperture diameter of the aperture stop SP.

[0076] In the camera body 124, 109 is a glass block such as an optical filter, and 110 is an imaging element that images a subject image formed by the zoom lens 101 (that is, the subject through the zoom lens 101). The imaging element 110 is composed of a photoelectric conversion element such as a CCD sensor or a CMOS sensor. 111 and 122 are respectively a camera CPU as a processing unit in the camera body 124 and a lens CPU as a processing unit in the zoom lens 101.

[0077] By using the compact and lightweight zoom lens of each embodiment as described above, it becomes possible to perform ultra-telephoto imaging and imaging with a high magnification ratio in a compact imaging device, and even when the imaging element 110 is large, good imaging is possible.

[0078] The above embodiments include the following configurations.

[0079] (Configuration 1) A zoom lens having a first lens group with a positive refractive power that does not move for zooming, an intermediate group including at least three lens groups that move for zooming, and a final lens group with a positive refractive power that does not move for zooming, arranged in order from the object side to the image side, and in which the interval between adjacent lens groups changes during zooming, The first lens group has a first sub-lens group with a positive refractive power, a second sub-lens group with a positive refractive power that moves for focusing, and a third sub-lens group with a negative refractive power, arranged in order from the object side to the image side, The intermediate group has a lens group with a positive refractive power on the most image side, When the focal length of the first lens group is f1, the focal length of the specific negative lens group with the strongest refractive power among at least one negative refractive power lens group included in the intermediate group is f2, and the distance on the optical axis from the most image-side lens surface in the first lens group to the rear principal point of the first lens group is ok1 when the direction from the object side to the image side is defined as positive, -8.0 ≦ f1 / f2 ≦ -4.0 0.10 ≦ (f1 + ok1) / f1 ≦ 0.80 A zoom lens characterized by satisfying the following conditions. (Configuration 2) When the distance on the optical axis from the most object-side lens surface in the first lens group to the most image-side lens surface in the first lens group is D1, 0.20 ≦ D1 / f1 ≦ 0.90 The zoom lens according to Configuration 1, characterized by satisfying the following conditions. (Configuration 3) When the lateral magnification at the wide-angle end of the specific negative lens group is β2w, -0.50 ≦ β2w ≦ -0.15 The zoom lens according to Configuration 1 or 2, characterized by satisfying the following conditions. (Configuration 4) When the lateral magnification at the wide-angle end of the specific negative lens group is β2w and the lateral magnification at the telephoto end of the specific negative lens group is β2t, 4.5 ≦ β2t / β2w ≦ 20.0 The zoom lens according to any one of Configurations 1 to 3, characterized by satisfying the following conditions. (Configuration 5) When the focal length of the first sub-lens group is f11, 0.0 ≦ f1 / f11 ≦ 1.0 The zoom lens according to any one of Configurations 1 to 4, characterized by satisfying the following conditions. (Configuration 6) When the focal length of the second sub-lens group is f12, 0.4 ≦ f1 / f12 ≦ 2.1 The zoom lens according to any one of Configurations 1 to 5, characterized by satisfying the following conditions. (Configuration 7) When the focal length of the third sub-lens group is f13, -1.0 ≦ f1 / f13 ≦ -0.1 The zoom lens according to any one of Configurations 1 to 6, characterized by satisfying the condition. (Configuration 8) When the focal length of the lens group adjacent to the specific negative lens group on the image side is f3, -6.0 ≦ f1 / f3 ≦ -0.4 The zoom lens according to any one of Configurations 1 to 7, characterized by satisfying the condition. (Configuration 9) When the focal length of the lens group adjacent to the lens group adjacent to the specific negative lens group on the image side on the image side is f4, 1.0 ≦ f1 / f4 ≦ 4.5 The zoom lens according to any one of Configurations 1 to 8, characterized by satisfying the condition. (Configuration 10) When the focal length at the wide-angle end of the zoom lens is fw, 1.5 ≦ f1 / fw ≦ 8.0 The zoom lens according to any one of Configurations 1 to 9, characterized by satisfying the condition. (Configuration 11) The zoom lens according to any one of Configurations 1 to 10, characterized in that the third sub-lens group moves differently from the second sub-lens group for focusing. (Configuration 12) The zoom lens according to any one of Configurations 1 to 11, characterized in that the first sub-lens group includes at least two negative lenses. (Configuration 13) The zoom lens according to any one of Configurations 1 to 12, characterized in that the intermediate group is composed of a second lens group with a negative refractive power, a third lens group with a negative refractive power, and a fourth lens group with a positive refractive power, which are arranged in order from the object side to the image side. (Configuration 14) The intermediate group is composed of a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a fifth lens group with positive refractive power, which are arranged in order from the object side to the image side. The zoom lens according to any one of Configurations 1 to 12, characterized in that. (Configuration 15) A zoom lens according to any one of Configurations 1 to 14, and An imaging device, characterized by having an imaging element that images a subject through the zoom lens. (Configuration 16) When the diagonal length of the effective imaging surface of the imaging element is IS, 1.4 ≦ fw / IS The imaging device according to Configuration 15, characterized by satisfying the condition.

[0080] Each of the embodiments described above is merely a representative example, and various modifications and changes can be made to each embodiment when implementing the present invention.

Explanation of Reference Numerals

[0081] L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group L5 Fifth lens group L6 Sixth lens group L11 First sub-lens group L12 Second sub-lens group L13 Third sub-lens group

Claims

1. A zoom lens having, in order from the object side to the image side, a first lens group with a positive refractive power that does not move for zooming, an intermediate group including at least three lens groups that move for zooming, and a final lens group with a positive refractive power that does not move for zooming, and in which the interval between adjacent lens groups changes during zooming, wherein the first lens group has, in order from the object side to the image side, a first sub-lens group with a positive refractive power, a second sub-lens group with a positive refractive power that moves for focusing, and a third sub-lens group with a negative refractive power, the intermediate group has a lens group with a positive refractive power closest to the image side, when the focal length of the first lens group is f1, the focal length of a specific negative lens group with the strongest refractive power among at least one negative refractive power lens group included in the intermediate group is f2, and the distance on the optical axis from the most image-side lens surface in the first lens group to the rear principal point of the first lens group is ok1 when the direction from the object side to the image side is taken as positive, -8.0 ≤ f1 / f2 ≤ -4.0 0.10 ≤ (f1 + ok1) / f1 ≤ 0.80 A zoom lens characterized by satisfying the following conditions.

2. When the distance on the optical axis from the most object-side lens surface in the first lens group to the most image-side lens surface in the first lens group is D1, 0.20 ≤ D1 / f1 ≤ 0.90 The zoom lens according to claim 1, characterized by satisfying the following conditions.

3. When the lateral magnification at the wide-angle end of the specific negative lens group is β2w, -0.50 ≤ β2w ≤ -0.15 The zoom lens according to claim 1, characterized by satisfying the following conditions.

4. When the lateral magnification at the wide-angle end of the specific negative lens group is β2w and the lateral magnification at the telephoto end of the specific negative lens group is β2t, 4.5 ≤ β2t / β2w ≤ 20.0 The zoom lens according to claim 1, characterized by satisfying the following conditions.

5. When the focal length of the first sub-lens group is f11, 0.0 ≤ f1 / f11 ≤ 1.0 The zoom lens according to claim 1, characterized by satisfying the following conditions.

6. When the focal length of the second sub-lens group is f12, 0.4 ≤ f1 / f12 ≤ 2.1 The zoom lens according to claim 1, characterized by satisfying the following conditions.

7. When the focal length of the third sub-lens group is f13, -1.0 ≤ f1 / f13 ≤ -0.1 The zoom lens according to claim 1, characterized by satisfying the following conditions.

8. When the focal length of the lens group adjacent to the specific negative lens group on the image side is f3, -6.0 ≤ f1 / f3 ≤ -0.4 The zoom lens according to claim 1, characterized by satisfying the following conditions.

9. When the focal length of the lens group further adjacent to the lens group adjacent to the specific negative lens group on the image side is f4, 1.0 ≤ f1 / f4 ≤ 4.5 The zoom lens according to claim 1, characterized by satisfying the following conditions.

10. When the focal length at the wide-angle end of the zoom lens is fw, 1.5 ≤ f1 / fw ≤ 8.0 The zoom lens according to claim 1, characterized by satisfying the following conditions.

11. The zoom lens according to claim 1, wherein the third sub-lens group moves differently from the second sub-lens group for focusing.

12. The zoom lens according to claim 1, wherein the first sub-lens group includes at least two negative lenses.

13. The intermediate group is composed of a second lens group with negative refractive power, a third lens group with negative refractive power, and a fourth lens group with positive refractive power, which are arranged in order from the object side to the image side. The zoom lens according to claim 1, characterized by this.

14. The intermediate group is composed of a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a fifth lens group with positive refractive power, which are arranged in order from the object side to the image side. The zoom lens according to claim 1, characterized by this.

15. An imaging device comprising the zoom lens according to claim 1, and an imaging element that images a subject through the zoom lens.

16. When the diagonal length of the effective imaging surface of the imaging element is IS, 1.4 ≤ fw / IS ≤ 7.0 The imaging device according to claim 15, characterized by satisfying the following conditions.

Images