Zoom lens and imaging device

Abstract

This zoom lens offers advantages in terms of its compact size, light weight, high magnification ratio with a wide angle of view at the wide-angle end, and high optical performance across the entire zoom range. [Solution] The system has, in order from the object side to the image side, a first lens group with positive refractive power that does not move for magnification, two or more movable lens groups that move for magnification, and a rear lens group with positive refractive power that does not move for magnification, the spacing between adjacent lens groups all changes for magnification, and the focal length at the telephoto end, the focal length of the first lens group, the distance on the optical axis from the final surface of the first lens group when it is in focus at infinity to the rear principal point of the first lens group, and the lateral magnification at the wide-angle end of the negative refractive power lens group located closest to the object among the two or more movable lens groups are appropriately set.

Description

[Technical Field]

[0001] This invention relates to a zoom lens and an imaging device. [Background technology]

[0002] In recent years, zoom lenses used in imaging devices such as television cameras, movie cameras, still cameras, and video cameras are required to be small and lightweight for high operability, have a high magnification ratio, and possess high optical performance.

[0003] As a high-magnification zoom lens with such characteristics, a positive-lead type zoom lens is known in which the first lens group with positive refractive power is positioned closest to the object. Patent Document 1 discloses a zoom lens with a magnification ratio of approximately 4 to 22 times, composed of, in order from the object side, a first lens group with positive refractive power that is stationary during magnification, a moving lens group consisting of two or more lens groups that move for magnification, and a rear lens group with positive refractive power that is stationary during magnification. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-173530 [Overview of the project] [Problems that the invention aims to solve]

[0005] In a positive-lead type zoom lens with the configuration described above, in order to achieve both a small size and light weight, a high magnification ratio accompanied by a wide angle of view at the wide-angle end, and high optical performance, it is important to appropriately set the configuration and paraxial amount of the first and second lens groups. However, the zoom lens disclosed in Patent Document 1 has a negatively large lateral magnification at the wide-angle end of the second lens group, which is disadvantageous for achieving a high magnification ratio accompanied by a wide angle of view at the wide-angle end, and if this is attempted, it becomes difficult to maintain a small size and light weight while also maintaining high optical performance.

[0006] Therefore, the present invention aims to provide a zoom lens that is advantageous in terms of being small and lightweight, having a high magnification ratio with a wide angle of view at the wide-angle end, and having high optical performance across the entire zoom range. [Means for solving the problem]

[0007] To achieve the above objective, a zoom lens as one aspect of the present invention has, in order from the object side to the image side, a first lens group with positive refractive power that does not move for magnification, two or more movable lens groups that move for magnification, and a rear lens group with positive refractive power that does not move for magnification, wherein the distance between adjacent lens groups changes for magnification, and when the focal length at the telephoto end is ft, the focal length of the first lens group is f1, the distance on the optical axis from the final surface of the first lens group when it is in focus at infinity to the rear principal point of the first lens group is bok1, and the lateral magnification at the wide-angle end of the second lens group, which is the negative refractive power lens group located closest to the object among the two or more movable lens groups, β2w, 3.50 ≤ ft / f1 ≤ 7.00 0.10 ≤ (f1 + bok1) / f1 ≤ 0.69 -0.36 ≤ β2w ≤ -0.10 It is characterized by satisfying the following conditions. As another aspect of the present invention, a zoom lens comprises, in order from the object side to the image side, a first lens group with positive refractive power that does not move for magnification, two or more moving lens groups that move for magnification, and a rear lens group with positive refractive power that does not move for magnification, wherein the distance between adjacent lens groups changes for magnification, and when the focal length of the first lens group is f1 and the distance on the optical axis from the final surface of the first lens group at infinity focus to the rear principal point of the first lens group is bok1, 0.10 ≤ (f1 + bok1) / f1 ≤ 0.69 It is characterized by satisfying the following conditions. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a zoom lens that is advantageous in terms of being small and lightweight, having a high magnification ratio with a wide angle of view at the wide-angle end, and having high optical performance across the entire zoom range.

Brief Description of Drawings

[0009] [Figure 1] It is a cross-sectional view of the wide-angle end of the zoom lens in Numerical Example 1 at infinity focus. [Figure 2] It is an aberration diagram of the zoom lens in Numerical Example 1 at infinity focus at (a) the wide-angle end, (b) f = 319.6 mm, and (c) the telephoto end. [Figure 3] It is a cross-sectional view of the wide-angle end of the zoom lens in Numerical Example 2 at infinity focus. [Figure 4] It is an aberration diagram of the zoom lens in Numerical Example 2 at infinity focus at (a) the wide-angle end, (b) f = 303.3 mm, and (c) the telephoto end. [Figure 5] It is a cross-sectional view of the wide-angle end of the zoom lens in Numerical Example 3 at infinity focus. [Figure 6] It is an aberration diagram of the zoom lens in Numerical Example 3 at infinity focus at (a) the wide-angle end, (b) f = 319.3 mm, and (c) the telephoto end. [Figure 7] It is a cross-sectional view of the wide-angle end of the zoom lens in Numerical Example 4 at infinity focus. [Figure 8] It is an aberration diagram of the zoom lens in Numerical Example 4 at infinity focus at (a) the wide-angle end, (b) f = 319.6 mm, and (c) the telephoto end. [Figure 9] It is a cross-sectional view of the wide-angle end of the zoom lens in Numerical Example 5 at infinity focus. [Figure 10] It is an aberration diagram of the zoom lens in Numerical Example 5 at infinity focus at (a) the wide-angle end, (b) f = 295.7 mm, and (c) the telephoto end. [Figure 11] It is a cross-sectional view of the wide-angle end of the zoom lens in Numerical Example 6 at infinity focus. [Figure 12] It is an aberration diagram of the zoom lens in Numerical Example 6 at infinity focus at (a) the wide-angle end, (b) f = 318.9 mm, and (c) the telephoto end. [Figure 13] It is a schematic diagram of the main part of the imaging device of the present invention.

Embodiments for Carrying Out the Invention

[0010] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. First, the features of the zoom lens of the present invention will be explained according to each conditional equation.

[0011] The zoom lens of the present invention specifies the configuration of the first and second lens groups, the focal length, and the lateral magnification at the wide-angle end in order to achieve both compactness, light weight, a high magnification ratio with a wide angle of view at the wide-angle end, and high optical performance across the entire zoom range. Specifically, it makes it possible to provide a zoom lens with a magnification ratio of approximately 22 to 26 times, which is compact, lightweight, has a high magnification ratio, and high optical performance.

[0012] The zoom lens of the present invention comprises, in order from the object side to the image side, a first lens group with positive refractive power that does not move for magnification, two or more movable lens groups that move for magnification, and a rear lens group with positive refractive power that does not move for magnification. The spacing between adjacent lens groups all changes for magnification. When the focal length at the telephoto end is ft, the focal length of the first lens group is f1, the distance on the optical axis from the final surface of the first lens group when it is in focus at infinity to the rear principal point of the first lens group is bok1, and the lateral magnification at the wide-angle end of the second lens group, which is the negative refractive power lens group located closest to the object among the two or more movable lens groups, β2w, 3.50 ≤ ft / f1 ≤ 7.00 ···(1) 0.10≦(f1+bok1) / f1≦0.69 ···(2) -0.36 ≤ β2w ≤ -0.10 ···(3) The conditions are met.

[0013] Here, we will explain the technical significance of conditions (1) to (3). Condition (1) specifies the ratio of the focal length of the first lens group to the focal length of the zoom lens at the telephoto end. By satisfying condition (1), it is possible to achieve both a compact and lightweight design, a high magnification ratio, and high optical performance.

[0014] If the upper limit of condition (1) is not met, the focal length of the first lens group becomes relatively too short, which increases the magnification of aberrations generated in the first lens group, making it difficult to suppress aberrations at the telephoto end. If the lower limit of condition (1) is not met, the focal length of the first lens group becomes relatively too long, which increases the amount of extension required when focusing, resulting in a larger lens.

[0015] Condition (2) defines the relationship between the focal length of the first lens group and the position of the rear principal point. By satisfying condition (2), it is possible to achieve both compact size, light weight, high magnification ratio, and high optical performance.

[0016] If the upper limit of condition (2) is not met, the rear principal point of the first lens group will be positioned excessively towards the image, the absolute value of the lateral magnification of the second lens group at the wide-angle end will become excessively small, and the amount of movement of the second lens group will increase, resulting in an excessively large zoom lens. Alternatively, the focal length of the first lens group will become excessively short, making it difficult to keep aberrations within acceptable limits at the telephoto end.

[0017] If the lower limit of condition (2) is not met, the rear principal point of the first lens group will be positioned excessively towards the object, and the entrance pupil at the wide-angle end will be positioned excessively towards the image, resulting in the first lens group becoming excessively large. Alternatively, the focal length of the first lens group will become excessively long, the absolute value of the lateral magnification of the second lens group at the wide-angle end will become excessively small, and the amount of movement of the second lens group will become large, resulting in the zoom lens becoming excessively large.

[0018] Condition (3) specifies the lateral magnification of the second lens group at the wide-angle end. If the upper limit of condition (3) is not met, the absolute value of the lateral magnification of the second lens group at the wide-angle end becomes excessively small, and the amount of movement of the second lens group becomes large, causing the zoom lens to become excessively large. If the lower limit of condition (3) is not met, the absolute value of the lateral magnification of the second lens group at the wide-angle end becomes excessively large, making it difficult to widen the field of view at the wide-angle end.

[0019] Preferably, the conditional expressions (1), (2), and (3) should be set as follows. 3.50≦ft / f1≦6.00 (1a) 0.50≦(f1+bok1) / f1≦0.69 (2a) -0.36≦β2w≦-0.20 (3a)

[0020] More preferably, the conditional expressions (1a), (2a), and (3a) should be set as follows. 3.50≦ft / f1≦5.50 (1b) 0.55≦(f1+bok1) / f1≦0.69 (2b) -0.36≦β2w≦-0.25 (3b)

[0021] Furthermore, in the zoom lens of the present invention, when the focal length of the second lens group, which is a lens group arranged adjacent to the image side of the first lens group among the movable lens group, is f2, -10.00 ≤ f1 / f2 ≤ -7.90 ···(4) It would be good if the following conditions were met.

[0022] Condition (4) specifies the ratio of the focal lengths of the first lens group and the second lens group. By satisfying condition (4), it is possible to achieve both compact size, light weight, high magnification ratio, and high optical performance. If the upper limit of condition (4) is not met, the focal length of the first lens group becomes excessively short, which is advantageous in terms of wide-angle, but makes it difficult to correct aberrations that occur in the first lens group at the telephoto end. If the lower limit of condition (4) is not met, the focal length of the first lens group becomes excessively long, making it difficult to widen the angle of view at the wide-angle end. In addition, the lens diameter of the first lens group becomes large, making it difficult to achieve a small and lightweight design.

[0023] Preferably, condition (4) should be set as follows: -9.50 ≤ f1 / f2 ≤ -8.00 ···(4a) More preferably, the condition (4a) should be set as follows: -9.00≦f1 / f2≦-8.00 (4b)

[0024] As a further embodiment of the zoom lens of the present invention, when the focal length of the N lens group, which is the negative refractive power lens group located furthest towards the image side among the moving lens group, is denoted as fN, -2.75 ≤ f1 / fN ≤ -1.00 ···(5) It would be good if the following conditions were met.

[0025] By satisfying condition (5), the lens achieves both compact size, light weight, high magnification ratio, and high optical performance. If the upper limit of condition (5) is not met, the refractive power of the N lens group becomes too weak compared to the refractive power of the first lens group, increasing the amount of movement of the N lens group during zooming, making it difficult to achieve a high magnification ratio and compact size. Alternatively, the refractive power of the first lens group becomes too strong compared to the refractive power of the N lens group, resulting in many aberrations such as chromatic aberration and distortion at the wide-angle end and spherical aberration at the telephoto end, making it difficult to correct these aberrations.

[0026] If the lower limit of condition (5) is not met, the refractive power of the N lens group becomes too strong compared to the refractive power of the first lens group, increasing the fluctuations of various aberrations such as spherical aberration and coma aberration during zooming, making it difficult to reduce these fluctuations. Also, the refractive power of the first lens group becomes too weak compared to the refractive power of the N lens group, increasing the lens diameter of the first lens group and making it difficult to make the first lens group small and lightweight.

[0027] Preferably, condition (5) should be set as follows: -2.70 ≤ f1 / fN ≤ -2.00 ···(5a) More preferably, the condition (5a) should be set as follows: -2.65≦f1 / fN≦-2.40 (5b)

[0028] As a further embodiment of the zoom lens of the present invention, the average Abbe number of the positive refractive power lenses included in the first lens group is ν1ave, 65.00 ≤ ν1ave ≤ 100.00 ···(6) It would be good if the following conditions were met.

[0029] By satisfying condition (6), a high magnification ratio and high optical performance are achieved. Materials that satisfy condition (6) have a relatively large partial dispersion ratio between the g-line and the F-line, which is effective in suppressing the second-order spectrum of axial chromatic aberration at the telephoto end. If the lower limit of condition (6) is not satisfied, the average partial dispersion ratio of the positive refractive power lenses included in the first lens group becomes excessively small, making it difficult to suppress the second-order spectrum of axial chromatic aberration at the telephoto end.

[0030] Preferably, condition (6) should be set as follows: 70.00 ≤ ν1ave ≤ 95.00 ···(6a) More preferably, the condition (6a) should be set as follows: 71.00≦ν1ave≦93.00 (6b)

[0031] As a further embodiment of the zoom lens of the present invention, the second lens group includes a first positive lens, and when the Abbe number with respect to the d line of the first positive lens is νp1 and the partial dispersion ratio between the g line and the F line is θgF1p, 0.65 ≤ θgFp1 + 0.0011 × νp1 ≤ 0.70 ···(7) It would be good if the following conditions were met.

[0032] Including a first positive lens that satisfies condition (7) in the second lens group is effective in suppressing chromatic aberration associated with widening the angle of view at the wide-angle end. If the upper limit of condition (7) is not met, the partial dispersion ratio of the first positive lens becomes too large, resulting in excessive correction of the second-order spectrum of chromatic aberration at the wide-angle end, which is undesirable. Also, with existing glass materials, the Abbe number becomes too small, making it difficult to correct the first-order chromatic aberration while correcting spherical aberration and coma aberration at the reference wavelength (d line), which is undesirable. If the lower limit of condition (7) is not met, the partial dispersion ratio of the first positive lens becomes too small, resulting in insufficient correction of the second-order spectrum of chromatic aberration at the wide-angle end, which is undesirable.

[0033] Preferably, condition (7) should be set as follows: 0.651≦θgFp1+0.0011×νp1≦0.693 ···(7a) More preferably, the condition (7a) is set as follows. 0.652≦θgFp1+0.0011×νp1≦0.686 (7b)

[0034] As a further embodiment of the zoom lens of the present invention, when the lateral magnification at the telephoto end of the second lens group is β2t, 4.00≦|β2t / β2w|≦600.00 ···(8) It would be good if the following conditions were met.

[0035] By satisfying condition (8), it is possible to effectively reduce aberration fluctuations associated with zooming, while also achieving a high amplification ratio and a compact, lightweight design. If the upper limit of condition (8) is not met, the magnification factor handled by the second lens group, which is the main magnification lens group, becomes too large, resulting in a strong negative refractive power of the second lens group, making it difficult to correct spherical aberration and axial chromatic aberration, especially at the telephoto end. If the lower limit of condition (8) is not met, the magnification factor handled by the second lens group, which is the main magnification lens group, becomes too small, making it difficult to achieve a high magnification ratio.

[0036] Preferably, condition (8) should be set as follows: 45.00≦|β2t / β2w|≦300.00 ···(8a) More preferably, the conditional expression (8a) should be set as follows: 50.00≦|β2t / β2w|≦100.00 ···(8b)

[0037] As a further embodiment of the zoom lens of the present invention, when LD1 is the distance along the optical axis from the lens surface closest to the object to the lens surface closest to the image in the first lens group, 1.00 ≤ f1 / LD1 ≤ 2.20 ···(9) It would be good if the following conditions were met.

[0038] By satisfying condition (9), it is possible to achieve a combination of small size, light weight, high magnification ratio, and high optical performance. If the upper limit of condition (9) is not met, the thickness of the first lens group becomes excessively thin, reducing the number of usable lenses and making it difficult to correct aberrations effectively. If the lower limit of condition (9) is not met, the thickness of the first lens group becomes excessively thick, increasing the lens diameter of the first lens group and making miniaturization difficult. Alternatively, the focal length of the first lens group becomes excessively small, making it difficult to correct aberrations effectively.

[0039] Preferably, condition (9) should be set as follows: 1.10≦f1 / LD1≦2.10 (9a) More preferably, the conditional expression (9a) should be set as follows: 1.20≦f1 / LD1≦2.00 (9b)

[0040] Further forms of the zoom lens of the present invention include: -0.76 ≤ bok1 / LD1 ≤ -0.20 ···(10) It would be good if the following conditions were met.

[0041] By satisfying condition (10), it is possible to achieve both small size, light weight, high magnification ratio, and high optical performance. If the upper limit of condition (10) is not met, the rear principal point of the first lens group will be positioned excessively towards the image, the absolute value of the lateral magnification of the second lens group at the wide-angle end will become excessively small, and the amount of movement of the second lens group will become large, resulting in an excessively large zoom lens. Alternatively, the focal length of the first lens group will become excessively short, making it difficult to keep aberrations within acceptable limits at the telephoto end.

[0042] If the lower limit of condition (10) is not met, the rear principal point of the first lens group will be positioned excessively towards the object, and the entrance pupil at the wide-angle end will be positioned excessively towards the image, resulting in the first lens group becoming excessively large. The focal length of the first lens group will become excessively long, the absolute value of the lateral magnification of the second lens group at the wide-angle end will become excessively small, and the amount of movement of the second lens group will become large, resulting in the zoom lens becoming excessively large.

[0043] Preferably, condition (10) should be set as follows: -0.75≦bok1 / LD1≦-0.50 (10a) More preferably, the conditional expression (10a) should be set as follows. -0.75≦bok1 / LD1≦-0.55 (10b)

[0044] A further form of the zoom lens of the present invention is characterized in that a part of the first lens group moves during focusing. By giving the first lens group, which is located closest to the object in the zoom lens, a focusing function can be maintained when changing magnification from the wide-angle end to the telephoto end, making it possible to realize a zoom lens suitable for video recording.

[0045] The zoom lens of the present invention is characterized in that the first lens group consists of 6 to 8 lenses, and the movable lens group includes at least two lens groups having negative refractive power.

[0046] Furthermore, the imaging device of the present invention is characterized by comprising a zoom lens of each embodiment and an image sensor having a predetermined effective imaging range for receiving the image formed by the zoom lens. The specific configurations of the zoom lenses of numerical examples 1 to 6, corresponding to examples 1 to 6 of the present invention, are described below. [Examples]

[0047] Figure 1 is a cross-sectional view of a zoom lens, which is Embodiment 1 of the present invention (Numerical Embodiment 1), when it is in focus at the wide-angle end and at infinity. Figure 2 shows the longitudinal aberration diagrams of Numerical Embodiment 1 at the wide-angle end (a), focal length 319.6 mm (b), and telephoto end (c). All of the aberration diagrams are longitudinal aberration diagrams when the lens is in focus at infinity. The focal length values ​​are the values ​​expressed in units (mm) of the Numerical Embodiments described later. This is the same for all the Numerical Embodiments described below.

[0048] The zoom lens of Example 1 has, in order from the object side to the image side, a first lens group U1 with a positive refractive index, a second lens group U2 with a negative refractive power, a third lens group U3 with a negative refractive power, and a fourth lens group U4 with a positive refractive power. The first lens group U1 does not move for magnification. The first lens group U1 also includes a sub-lens group that moves for focusing. The second lens group U2 moves toward the image side when magnification is changed from the wide-angle end to the telephoto end. The third lens group U3 moves nonlinearly along the optical axis in conjunction with the movement of the second lens group U2, correcting image plane fluctuations associated with magnification. The fourth lens group U4 does not move for magnification and has an imaging function.

[0049] In this embodiment, the second lens group U2 and the third lens group U3 constitute a variable magnification system, with the second and third lens groups U2 and U3 corresponding to the moving lens group. The fourth lens group U4 corresponds to the rear lens group. The aperture diaphragm SP is positioned adjacent to the object side of the fourth lens group U4. I represents the image plane. When used in the imaging optical system of broadcast television cameras, video cameras, and digital still cameras, it corresponds to the imaging surface of a solid-state image sensor (photoelectric conversion element) that receives light from the image formed by the zoom lens and converts it into photoelectric energy. When used in the imaging optical system of a film camera, it corresponds to the film surface to which the image formed by the zoom lens is exposed.

[0050] In the longitudinal aberration diagram, the solid line and dashed line in the spherical aberration diagram represent the d line and the g line, respectively. The dashed line and solid line in the astigmatism diagram represent the meridional image plane and the sagittal image plane, respectively, and the dashed line in the chromatic aberration diagram represents the g line. ω is the half-angle of view, and Fno is the F-number. In the longitudinal aberration diagram, spherical aberration is drawn on a scale of 0.4 mm, astigmatism on a scale of 0.4 mm, distortion on a scale of 5%, and chromatic aberration on a scale of 0.05 mm. In each of the following embodiments, the wide-angle end and telephoto end refer to the zoom position when the second lens group U2 for variable magnification is located at both ends of the movable range in the optical axis direction in the mechanism.

[0051] The first lens group U1 corresponds to the 1st to 13th surfaces. The second lens group U2 corresponds to the 14th to 22nd surfaces. The third lens group U3 corresponds to the 23rd to 25th surfaces. The fourth lens group U4 corresponds to the 26th to 44th surfaces. The aperture diaphragm SP corresponds to the 26th surface.

[0052] Numerical Example 1, corresponding to Example 1, will now be described. In all numerical examples, not just Numerical Example 1, i indicates the order of the surfaces (optical surfaces) from the object side, ri indicates the radius of curvature of the i-th surface from the object side, and di indicates the distance (on the optical axis) between the i-th surface and the (i+1)-th surface from the object side. Furthermore, ndi, νdi, and θgF represent the refractive index, Abbe number, and partial dispersion ratio of the medium (optical material) between the i-th surface and the (i+1)-th surface, and BF represents the back focus in air equivalent.

[0053] Here, the Abbe number νd and the partial dispersion ratio θgF are given by Ng, NF, Nd, and NC, respectively, when the refractive indices of the Fraunhofer lines g-line (wavelength 435.8 nm), F-line (wavelength 486.1 nm), d-line (wavelength 587.6 nm), and C-line (wavelength 656.3 nm) are Ng, NF, Nd, and NC. νd = (Nd-1) / (NF-NC) θgF = (Ng - NF) / (NF - NC) It is represented as follows.

[0054] The aspherical shape is represented by the following equation when the X-axis is in the optical axis direction, the H-axis is perpendicular to the optical axis, the direction of light propagation is positive, R is the paraxial curvature radius, k is the conic constant, and A3 to A16 are the aspherical coefficients respectively. Also, "e-Z" means "×10 9 ". X = (H 2 / R) / [1 + {1 - (1 + k)(H / R) 2}^ 1 / 2 + A4H ^ 4 + A6H 6 ^ 8 + A8H 10 ^ 12 + A10H 14 ^ 16 + A3H 3 ^ 5 + A5H 7 ^ 9 + A9H 11 ^ 13 + A11H 15 ···(11)

[0055] Table 1 shows the corresponding values of each conditional expression in this embodiment. This embodiment satisfies the conditional expressions (1) to (10), and by appropriately setting the configurations and paraxial quantities of both the first lens group and the second lens group, a zoom lens having high magnification ratio with small size and light weight, wide-angle angle of view widening at the wide-angle end, and high optical performance over the entire zoom range is achieved. However, for the zoom lens of the present invention, it is essential to satisfy the conditional expressions (1), (2), and (3), but it does not matter if the conditional expressions (4) to (10) are not satisfied. However, if at least one of the conditional expressions (4) to (10) is satisfied, better effects can be achieved. This is the same for other embodiments.

[0056] Figure 13 is a schematic diagram of an imaging device (television camera system) using the zoom lens of each example as an imaging optical system. <00003In Figure 13, 101 is a zoom lens from one of Examples 1 to 6. 124 is a camera. The zoom lens 101 is detachable from the camera 124. 125 is an imaging device configured by attaching the zoom lens 101 to the camera 124. The zoom lens 101 has a first lens group F, a magnification section LZ, and a rear group R for image formation. The first lens group F includes a focusing lens group. The magnification section LZ includes a second lens group that moves along the optical axis for magnification, and a third lens group that moves along the optical axis to correct image plane fluctuations associated with magnification. SP is an aperture diaphragm.

[0057] 114 and 115 are drive mechanisms such as helicoids and cams that drive the first lens group F and the magnification unit LZ in the optical axis direction, respectively. 116 to 118 are motors (driving means) that electrically drive the drive mechanisms 114 and 115 and the aperture diaphragm SP. 119 to 121 are detectors such as encoders, potentiometers, or photosensors for detecting the position of the first lens group F and the magnification unit LZ on the optical axis, and the aperture diameter of the aperture diaphragm SP. In camera 124, 109 is a glass block corresponding to the optical filter and color separation optical system within camera 124, and 110 is a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor that receives the subject image formed by the zoom lens 101. Also, 111 and 122 are CPUs that control various drives of the zoom lens 101 and camera 124.

[0058] In this way, by adapting the zoom lens of the present invention to television cameras, movie cameras, and digital still cameras, it is possible to realize an imaging device that is small and lightweight, has a high magnification ratio with a wide angle of view at the wide-angle end, and has high optical performance across the entire zoom range. [Examples]

[0059] Figure 3 is a cross-sectional view of the zoom lens, which is Embodiment 2 of the present invention (Numerical Embodiment 2), when it is in focus at infinity at the wide-angle end. Figure 4 shows the longitudinal aberration diagram of Numerical Embodiment 2 at the wide-angle end (a), focal length 303.3 mm (b), and telephoto end (c).

[0060] The zoom lens of Example 2 has, in order from the object side to the image side, a first lens group U1 with a positive refractive index, a second lens group U2 with a negative refractive power, a third lens group U3 with a negative refractive power, a fourth lens group U4 with a positive refractive power, and a fifth lens group U5 with a positive refractive power. The first lens group U1 does not move for magnification. The first lens group U1 also has a sub-lens group that moves for focusing. When magnification from the wide-angle end to the telephoto end, the second lens group U2 moves toward the image side, and the third lens group U3 also moves. The fourth lens group U4 moves nonlinearly along the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3, correcting image plane fluctuations associated with magnification. The fifth lens group U5 does not move for magnification and has an imaging function.

[0061] In this embodiment, the second lens group U2, the third lens group U3, and the fourth lens group U4 constitute the variable magnification system, with the second, third, and fourth lens groups U2, U3, and U4 corresponding to the moving lens groups. The fifth lens group U5 corresponds to the rear lens group. The aperture diaphragm SP is positioned between the fourth lens group U4 and the fifth lens group U5 and moves independently of the lens groups during magnification. I represents the image plane. When used in the imaging optical system of broadcast television cameras, video cameras, and digital still cameras, it corresponds to the imaging surface of a solid-state image sensor (photoelectric conversion element) that receives light from the image formed by the zoom lens and converts it into photoelectric energy. When used in the imaging optical system of a film camera, it corresponds to the film surface to which the image formed by the zoom lens is exposed.

[0062] The first lens group U1 corresponds to the 1st to 13th surfaces. The second lens group U2 corresponds to the 14th to 22nd surfaces. The third lens group U3 corresponds to the 23rd to 25th surfaces. The fourth lens group U4 corresponds to the 26th to 27th surfaces. The fifth lens group U5 corresponds to the 29th to 46th surfaces. The aperture diaphragm SP corresponds to the 28th surface.

[0063] Table 1 shows the corresponding values ​​for each conditional expression in this embodiment. This embodiment satisfies conditions (1) to (10), and by appropriately setting the configuration of the first and second lens groups and the paraxial amount, it achieves a zoom lens that is compact and lightweight, has a high magnification ratio with a wide angle of view at the wide-angle end, and has high optical performance across the entire zoom range. [Examples]

[0064] Figure 5 is a cross-sectional view of the zoom lens, which is Embodiment 3 of the present invention (Numerical Embodiment 3), when it is in focus at infinity at the wide-angle end. Figure 6 shows the longitudinal aberration diagram of Numerical Embodiment 3 at the wide-angle end (a), focal length 319.3 mm (b), and telephoto end (c).

[0065] The zoom lens of Example 3 has, in order from the object side to the image side, a first lens group U1 with a positive refractive index, a second lens group U2 with a negative refractive power, a third lens group U3 with a negative refractive power, and a fourth lens group U4 with a positive refractive power. The first lens group U1 does not move for magnification. The first lens group U1 also has a sub-lens group that moves for focusing. The second lens group U2 moves towards the image side when magnification changes from the wide-angle end to the telephoto end. The third lens group U3 moves nonlinearly along the optical axis in conjunction with the movement of the second lens group U2, correcting image plane fluctuations associated with magnification. The fourth lens group U4 does not move for magnification and has an imaging function.

[0066] In this embodiment, the second lens group U2 and the third lens group U3 constitute a variable magnification system, with the second lens group U2 and the third lens group U3 corresponding to the moving lens group. The fourth lens group U4 corresponds to the rear lens group. The aperture diaphragm SP is positioned adjacent to the object side of the fourth lens group U4. I represents the image plane. When used in the imaging optical system of broadcast television cameras, video cameras, and digital still cameras, it corresponds to the imaging surface of a solid-state image sensor (photoelectric conversion element) that receives light from the image formed by the zoom lens and converts it into photoelectric energy. When used in the imaging optical system of a film camera, it corresponds to the film surface to which the image formed by the zoom lens is exposed. The first lens group U1 corresponds to the 1st to 14th surfaces. The second lens group U2 corresponds to the 15th to 23rd surfaces. The third lens group U3 corresponds to the 24th to 26th surfaces. The fourth lens group U4 corresponds to the 28th to 45th surfaces. The aperture diaphragm SP corresponds to the 27th surface.

[0067] Table 1 shows the corresponding values ​​for each conditional expression in this embodiment. This embodiment satisfies conditions (1) to (10), and by appropriately setting the configuration of the first and second lens groups and the paraxial amount, it achieves a zoom lens that is compact and lightweight, has a high magnification ratio with a wide angle of view at the wide-angle end, and has high optical performance across the entire zoom range. [Examples]

[0068] Figure 7 is a cross-sectional view of the zoom lens, which is Embodiment 4 of the present invention (Numerical Embodiment 4), when it is in focus at infinity at the wide-angle end. Figure 8 shows the longitudinal aberration diagram of Numerical Embodiment 4 at the wide-angle end (a), focal length 319.6 mm (b), and telephoto end (c).

[0069] The zoom lens of Example 4 has, in order from the object side to the image side, a first lens group U1 with a positive refractive index, a second lens group U2 with a negative refractive power, a third lens group U3 with a negative refractive power, and a fourth lens group U4 with a positive refractive power. The first lens group U1 does not move for magnification. The first lens group U1 also has a sub-lens group that moves for focusing. The second lens group U2 moves towards the image side when magnification changes from the wide-angle end to the telephoto end. The third lens group U3 moves nonlinearly along the optical axis in conjunction with the movement of the second lens group U2, correcting image plane fluctuations associated with magnification. The fourth lens group U4 does not move for magnification and has an imaging function.

[0070] In this embodiment, the second lens group U2 and the third lens group U3 constitute a variable magnification system, with the second lens group U2 and the third lens group U3 corresponding to the moving lens group. The fourth lens group U4 corresponds to the rear lens group. The aperture diaphragm SP is positioned adjacent to the object side of the fourth lens group U4. I represents the image plane. When used in the imaging optical system of broadcast television cameras, video cameras, and digital still cameras, it corresponds to the imaging surface of a solid-state image sensor (photoelectric conversion element) that receives light from the image formed by the zoom lens and converts it into photoelectric energy. When used in the imaging optical system of a film camera, it corresponds to the film surface to which the image formed by the zoom lens is exposed. The first lens group U1 corresponds to the 1st to 13th surfaces. The second lens group U2 corresponds to the 14th to 22nd surfaces. The third lens group U3 corresponds to the 23rd to 25th surfaces. The fourth lens group U4 corresponds to the 27th to 50th surfaces. The aperture diaphragm SP corresponds to the 26th surface.

[0071] Table 1 shows the corresponding values ​​for each conditional expression in this embodiment. This embodiment satisfies conditions (1) to (10), and by appropriately setting the configuration of the first and second lens groups and the paraxial amount, it achieves a zoom lens that is compact and lightweight, has a high magnification ratio with a wide angle of view at the wide-angle end, and has high optical performance across the entire zoom range. [Examples]

[0072] Figure 9 is a cross-sectional view of the zoom lens, which is Embodiment 5 of the present invention (Numerical Embodiment 5), when it is in focus at infinity at the wide-angle end. Figure 10 shows the longitudinal aberration diagram of Numerical Embodiment 5 at the wide-angle end (a), focal length 295.7 mm (b), and telephoto end (c).

[0073] The zoom lens of Example 5 has, in order from the object side to the image side, a first lens group U1 with a positive refractive index, a second lens group U2 with a negative refractive power, a third lens group U3 with a negative refractive power, and a fourth lens group U4 with a positive refractive power. The first lens group U1 does not move for magnification. The first lens group U1 also has a sub-lens group that moves for focusing. The second lens group U2 moves towards the image side when magnification changes from the wide-angle end to the telephoto end. The third lens group U3 moves nonlinearly along the optical axis in conjunction with the movement of the second lens group U2, correcting image plane fluctuations associated with magnification. The fourth lens group U4 does not move for magnification and has an imaging function.

[0074] In this embodiment, the second lens group U2 and the third lens group U3 constitute a variable magnification system, with the second lens group U2 and the third lens group U3 corresponding to the moving lens group. The fourth lens group U4 corresponds to the rear lens group. The aperture diaphragm SP is positioned adjacent to the object side of the fourth lens group U4. I represents the image plane. When used in the imaging optical system of broadcast television cameras, video cameras, and digital still cameras, it corresponds to the imaging surface of a solid-state image sensor (photoelectric conversion element) that receives light from the image formed by the zoom lens and converts it into photoelectric energy. When used in the imaging optical system of a film camera, it corresponds to the film surface to which the image formed by the zoom lens is exposed. The first lens group U1 corresponds to the 1st to 14th surfaces. The second lens group U2 corresponds to the 15th to 23rd surfaces. The third lens group U3 corresponds to the 24th to 26th surfaces. The fourth lens group U4 corresponds to the 28th to 45th surfaces. The aperture diaphragm SP corresponds to the 27th surface.

[0075] Table 1 shows the corresponding values ​​for each conditional expression in this embodiment. This embodiment satisfies conditions (1) to (10), and by appropriately setting the configuration of the first and second lens groups and the paraxial amount, it achieves a zoom lens that is compact and lightweight, has a high magnification ratio with a wide angle of view at the wide-angle end, and has high optical performance across the entire zoom range. [Examples]

[0076] Figure 11 is a cross-sectional view of a zoom lens, which is Embodiment 6 of the present invention (Numerical Embodiment 6), when it is in focus at infinity at the wide-angle end. Figure 12 shows the longitudinal aberration diagram of Numerical Embodiment 6 at the wide-angle end (a), focal length 318.9 mm (b), and telephoto end (c).

[0077] The zoom lens of Example 6 has, in order from the object side to the image side, a first lens group U1 with a positive refractive index, a second lens group U2 with a negative refractive power, a third lens group U3 with a negative refractive power, a fourth lens group U4 with a negative refractive power, and a fifth lens group U5 with a positive refractive power. The first lens group U1 does not move for magnification. The first lens group U1 also has a sub-lens group that moves for focusing. The second lens group U2 moves towards the image side when magnification is changed from the wide-angle end to the telephoto end. The third lens group U3 moves during magnification. The fourth lens group U4 moves nonlinearly along the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3, correcting image plane fluctuations associated with magnification. The fifth lens group U5 does not move for magnification and has an imaging function.

[0078] In this embodiment, the second lens group U2, the third lens group U3, and the fourth lens group U4 constitute the variable magnification system, with the second, third, and fourth lens groups U2, U3, and U4 corresponding to the moving lens groups. The fifth lens group U5 corresponds to the rear lens group. The aperture diaphragm SP does not move for the purpose of magnification and is positioned adjacent to the object side of the fifth lens group U5. I represents the image plane. When used in the imaging optical system of broadcast television cameras, video cameras, and digital still cameras, it corresponds to the imaging surface of a solid-state image sensor (photoelectric conversion element) that receives light from the image formed by the zoom lens and converts it into photoelectric energy. When used in the imaging optical system of a film camera, it corresponds to the film surface to which the image formed by the zoom lens is exposed.

[0079] The first lens group U1 corresponds to the 1st to 12th surfaces. The second lens group U2 corresponds to the 13th to 17th surfaces. The third lens group U3 corresponds to the 18th to 21st surfaces. The fourth lens group U4 corresponds to the 22nd to 24th surfaces. The fifth lens group U5 corresponds to the 26th to 43rd surfaces. The aperture diaphragm SP corresponds to the 25th surface.

[0080] Table 1 shows the corresponding values ​​for each conditional expression in this embodiment. This embodiment satisfies conditions (1) to (10), and by appropriately setting the configuration of the first and second lens groups and the paraxial amount, it achieves a zoom lens that is compact and lightweight, has a high magnification ratio with a wide angle of view at the wide-angle end, and has high optical performance across the entire zoom range.

[0081] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist. A feature of the present invention is the appropriate setting of the configuration and paraxial amount of the first lens group and the second lens group, and the effects of the present invention can be achieved even if the moving lens group and the rear lens group are configured other than those of numerical examples 1 to 6.

[0082] [Numerical Example 1] Unit: mm Surface data Face number rd nd vd θgF 1 207.412 9.43 1.48749 70.2 0.5300 2 ∞ 0.20 3 116.032 11.24 1.43387 95.1 0.5373 4 384.963 30.59 5 92.031 8.22 1.43875 94.7 0.5340 6 223.420 2.50 1.83481 42.7 0.5648 7 64.299 9.07 8 64.957 12.26 1.43387 95.1 0.5373 9 598.818 0.19 10 72.155 7.08 1.49700 81.5 0.5375 11 174.022 1.46 12 160.528 2.50 1.65160 58.5 0.5390 13 102.934 (variable) 14 69.712 0.90 2.05090 26.9 0.6054 15 28.900 3.74 16 32.088 5.67 1.89286 20.4 0.6393 17 -73.872 0.80 1.88300 40.8 0.5667 18 19.717 2.49 19 214.165 3.21 1.80810 22.8 0.6307 20 -79.689 1.58 21 -20.801 0.80 1.88300 40.8 0.5667 22* -59.037 (variable) 23 -40.519 0.80 1.77250 49.6 0.5520 24 69.322 2.21 1.84666 23.8 0.6205 25 -797.480 (variable) 26 (aperture) ∞ 1.92 27 1696.452 3.36 1.49700 81.5 0.5375 28 -59.000 0.19 29 215.537 2.89 1.43875 94.7 0.5340 30 -125.881 0.19 31 94.438 5.29 1.43875 94.7 0.5340 32 -44.360 0.90 1.85478 24.8 0.6122 33 -85.726 33.38 34 21.528 6.64 1.43875 94.7 0.5340 35 -776.921 0.20 36 38.067 4.51 1.62004 36.3 0.5879 37 -114.531 0.80 1.75500 52.3 0.5474 38 53.839 5.74 39 -171.891 0.80 1.88300 40.8 0.5667 40 14.847 4.86 1.56732 42.8 0.5731 41 -33.777 0.20 42 162.112 3.36 1.56732 42.8 0.5731 43 -15.792 0.80 1.88300 40.8 0.5667 44 -295.346 5.00 45 ∞ 33.00 1.60859 46.4 0.5664 46 ∞ 13.20 1.51680 64.2 0.5347 47 ∞ 7.40 Image plane ∞ Aspherical data Page 22 K = 0.00000e+00 A 4=-1.22385e-05 A 6=-2.00160e-08 A 8= 3.04799e-10 A10=-1.69032e-12 Various data Zoom ratio 22.00 Wide-angle, Medium, Telephoto Focal length 25.05 319.58 551.03 F-number 2.90 2.91 5.01 Half-angle (°): 12.38 0.99 0.57 Image height 5.50 5.50 5.50 Lens length 331.14 331.14 331.14 BF 7.40 7.40 7.40 d13 0.57 60.61 64.51 d22 63.57 3.68 13.71 d25 15.44 15.29 1.35 Zoom lens group data Group starting plane focal length 1 1 154.26 2 14 -18.30 3 23 -59.20 4 26 34.47

[0083] [Numerical Example 2] Unit: mm Surface data Face number rd nd vd θgF 1 202.661 9.74 1.48749 70.2 0.5300 2 -6658.305 1.87 3 113.881 11.31 1.43387 95.1 0.5373 4 391.479 26.72 5 91.432 9.88 1.43387 95.1 0.5373 6 246.011 2.50 1.83481 42.7 0.5648 7 64.173 9.40 8 65.427 11.74 1.43387 95.1 0.5373 9 583.839 0.18 10 70.658 9.09 1.43875 94.7 0.5340 11 202.100 1.50 12 171.731 2.50 1.65160 58.5 0.5390 13 105.863 (variable) 14 69.721 0.90 2.00330 28.3 0.5980 15 29.269 1.12 16 32.496 4.14 1.89286 20.4 0.6393 17 -63.498 0.80 1.88300 40.8 0.5667 18 17.172 2.72 19 176.734 2.13 1.80810 22.8 0.6307 20 -66.005 1.80 21 -17.900 0.80 1.88300 40.8 0.5667 22* -43.402 (variable) 23 -38.908 0.80 1.77250 49.6 0.5520 24 66.885 2.31 1.84666 23.8 0.6205 25 -449.582 (variable) 26 105.883 4.04 1.77250 49.6 0.5520 27* -57.941 (variable) 28 (aperture) ∞ (variable) 29 64.350 3.24 1.49700 81.5 0.5375 30 -372.245 0.54 31 -291.111 2.12 1.43875 94.7 0.5340 32 -96.965 0.26 33 -12625.331 3.12 1.43875 94.7 0.5340 34 -52.774 0.90 1.85478 24.8 0.6122 35 282.924 34.64 36 19.754 6.43 1.43875 94.7 0.5340 37 -74.160 0.20 38 56.639 4.84 1.62004 36.3 0.5879 39 -28.771 0.80 1.75500 52.3 0.5474 40 20.568 3.25 41 -47.750 0.80 1.88300 40.8 0.5667 42 21.763 3.66 1.56732 42.8 0.5731 43 -37.181 0.20 44 26.353 4.87 1.56732 42.8 0.5731 45 -16.938 0.80 1.88300 40.8 0.5667 46 -43.402 5.00 47 ∞ 33.00 1.60859 46.4 0.5664 48 ∞ 13.20 1.51680 64.2 0.5347 49 ∞ 9.46 Image plane ∞ Aspherical data Page 22 K = 0.00000e+00 A 4=-1.90246e-05 A 6=-5.80323e-08 A 8= 7.71299e-10 A10=-4.09310e-12 Page 27 K = 7.32611e-01 A 4= 1.36936e-06 A 6=-5.11362e-09 A 8= 1.46932e-10 A10= 8.87259e-13 A12=-3.22991e-15 A14= 4.90052e-18 A16=-4.88816e-20 A 3= 3.90648e-07 A 5= 1.45571e-07 A 7=-1.62940e-09 A 9=-2.64921e-12 A11=-7.28730e-14 A13= 2.03419e-16 A15= 7.02199e-19 Various data Zoom ratio 25.49 Wide-angle, Medium, Telephoto Focal length 24.06 303.26 613.19 F-numbers: 2.91, 2.90, 5.63 Half-angle (°): 12.88 1.04 0.51 Image height 5.50 5.50 5.50 Lens length 331.17 331.17 331.17 BF 9.46 9.46 9.46 d13 0.59 59.80 64.59 d22 66.27 1.86 5.98 d25 13.74 16.74 -0.21 d27 0.71 0.67 7.04 d28 0.51 2.76 4.42 Zoom lens group data Group starting plane focal length 1 1 153.63 2 14 -17.39 3 23 -59.55 4 26 49.00 5 29 85.46

[0084] [Numerical Example 3] Unit: mm Surface data Face number rd nd vd θgF 1 165.227 8.00 1.48749 70.2 0.5300 2 441.488 0.50 3 114.618 4.00 1.72047 34.7 0.5834 4 89.067 3.00 5 92.626 17.00 1.43387 95.1 0.5373 6 1816.739 10.14 7 121.479 10.00 1.43387 95.1 0.5373 8 5733.931 0.20 9 99.789 11.50 1.49700 81.5 0.5375 10 1192.254 2.50 1.72047 34.7 0.5834 11 148.945 5.72 12 595.542 5.40 1.80810 22.8 0.6307 13 -371.321 2.20 1.72047 34.7 0.5834 14 153.994 (variable) 15 69.712 0.90 2.05090 26.9 0.6054 16 28.900 3.74 17 32.088 5.67 1.89286 20.4 0.6393 18 -73.872 0.80 1.88300 40.8 0.5667 19 19.717 2.49 20 214.165 3.21 1.80810 22.8 0.6307 21 -79.689 1.58 22 -20.801 0.80 1.88300 40.8 0.5667 23* -59.037 (variable) 24 -40.519 0.80 1.77250 49.6 0.5520 25 69.322 2.21 1.84666 23.8 0.6205 26 -797.480 (variable) 27 (aperture) ∞ 1.92 28 1696.452 3.36 1.49700 81.5 0.5375 29 -59.000 0.19 30 215.537 2.89 1.43875 94.7 0.5340 31 -125.881 0.19 32 94.438 5.29 1.43875 94.7 0.5340 33 -44.360 0.90 1.85478 24.8 0.6122 34 -85.726 33.38 35 21.528 6.64 1.43875 94.7 0.5340 36 -776.921 0.20 37 38.067 4.51 1.62004 36.3 0.5879 38 -114.531 0.80 1.75500 52.3 0.5474 39 53.839 5.74 40 -171.891 0.80 1.88300 40.8 0.5667 41 14.847 4.86 1.56732 42.8 0.5731 42 -33.777 0.20 43 162.112 3.36 1.56732 42.8 0.5731 44 -15.792 0.80 1.88300 40.8 0.5667 45 -295.346 5.00 46 ∞ 33.00 1.60859 46.4 0.5664 47 ∞ 13.20 1.51680 64.2 0.5347 48 ∞ 7.40 Image plane ∞ Aspherical data Page 23 K = 0.00000e+00 A 4=-1.25694e-05 A 6=-1.38049e-08 A 8= 2.19338e-10 A10=-1.23102e-12 Various data Zoom ratio 22.00 Wide-angle, Medium, Telephoto Focal length 25.04 319.32 550.78 F-number 2.90 2.91 5.01 Half-angle (°): 12.39 0.99 0.57 Image height 5.50 5.50 5.50 Lens length 319.25 319.25 319.25 BF 7.40 7.40 7.40 d14 3.26 63.34 67.25 d23 63.57 3.59 13.63 d26 15.44 15.33 1.38 Zoom lens group data Group starting plane focal length 1 1 154.32 2 15 -18.30 3 24 -59.20 4 27 34.47

[0085] [Numerical Example 4] Unit: mm Surface data Face number rd nd vd θgF 1 207.412 9.43 1.48749 70.2 0.5300 2 ∞ 0.20 3 116.032 11.24 1.43387 95.1 0.5373 4 384.963 30.59 5 92.031 8.22 1.43875 94.7 0.5340 6 223.420 2.50 1.83481 42.7 0.5648 7 64.299 9.07 8 64.957 12.26 1.43387 95.1 0.5373 9 598.818 0.19 10 72.155 7.08 1.49700 81.5 0.5375 11 174.022 1.46 12 160.528 2.50 1.65160 58.5 0.5390 13 102.934 (variable) 14 69.712 0.90 2.05090 26.9 0.6054 15 28.900 3.74 16 32.088 5.67 1.89286 20.4 0.6393 17 -73.872 0.80 1.88300 40.8 0.5667 18 19.717 2.49 19 214.165 3.21 1.80810 22.8 0.6307 20 -79.689 1.58 21 -20.801 0.80 1.88300 40.8 0.5667 22* -59.037 (variable) 23 -40.519 0.80 1.77250 49.6 0.5520 24 69.322 2.21 1.84666 23.8 0.6205 25 -797.480 (variable) 26 (aperture) ∞ 0.94 27 97.228 4.73 1.65160 58.5 0.5425 28 -48.412 0.20 29 360.351 2.73 1.61800 63.3 0.5441 30 -106.301 0.20 31 82.831 5.25 1.43875 94.7 0.5340 32 -37.631 0.90 1.84666 23.8 0.6205 33 -107.868 3.26 34 -77.618 0.85 1.88300 40.8 0.5667 35 353.288 0.20 36 37.068 2.20 1.84666 23.8 0.6205 37 63.502 1.50 38 395.280 0.85 1.85150 40.8 0.5695 39 70.102 33.25 40 23.662 5.91 1.53775 74.7 0.5392 41 -89.214 0.20 42 171.242 3.25 1.62004 36.3 0.5879 43 -58.483 0.80 1.75500 52.3 0.5474 44 53.648 1.43 45 88.101 0.80 1.88300 40.8 0.5667 46 18.601 4.46 1.56732 42.8 0.5731 47 -83.013 0.20 48 38.411 4.49 1.56732 42.8 0.5731 49 -18.944 0.80 1.88300 40.8 0.5667 50 179.306 5.00 51 ∞ 33.00 1.60859 46.4 0.5664 52 ∞ 13.20 1.51680 64.2 0.5347 53 ∞ 12.97 Image plane ∞ Aspherical data Page 22 K = 0.00000e+00 A 4=-1.22385e-05 A 6=-2.00160e-08 A 8= 3.04799e-10 A10=-1.69032e-12 Various data Zoom ratio 22.00 Wide-angle, Medium, Telephoto Focal length 25.05 319.60 551.06 F-number 2.90 2.91 5.02 Half-angle (°): 12.38 0.99 0.57 Image height 5.50 5.50 5.50 Lens length 340.07 340.07 340.07 BF 12.97 12.97 12.97 d13 0.57 60.61 64.51 d22 63.57 3.68 13.71 d25 15.44 15.29 1.35 Zoom lens group data Group starting plane focal length 1 1 154.26 2 14 -18.30 3 23 -59.20 4 26 42.72

[0086] [Numerical Example 5] Unit: mm Surface data Face number rd nd vd θgF 1 125.695 9.78 1.48749 70.2 0.5300 2 426.688 0.41 3 133.026 3.00 1.72047 34.7 0.5834 4 83.991 2.45 5 84.045 15.10 1.43387 95.1 0.5373 6 659.122 9.12 7 147.679 7.74 1.43387 95.1 0.5373 8 949.778 0.19 9 111.561 10.05 1.52841 76.5 0.5396 10 -1201.449 2.50 1.72047 34.7 0.5834 11 284.187 3.67 12 2693.234 4.40 1.80810 22.8 0.6307 13 -272.821 2.20 1.72047 34.7 0.5834 14 398.569 (variable) 15 204.617 0.90 2.00330 28.3 0.5980 16 38.562 11.24 17 45.892 5.43 1.89286 20.4 0.6393 18 -56.349 0.80 1.88300 40.8 0.5667 19 22.336 3.05 20 -112.870 2.34 1.80810 22.8 0.6307 21 -34.115 3.92 22 -21.398 0.80 1.88300 40.8 0.5667 23* -59.037 (variable) 24 -39.007 0.80 1.77250 49.6 0.5520 25 54.506 2.34 1.84666 23.8 0.6205 26 -3621.839 (variable) 27 (aperture) ∞ 2.33 28 -287.363 3.18 1.49700 81.5 0.5375 29 -52.249 0.19 30 203.712 3.07 1.43875 94.7 0.5340 31 -108.770 0.20 32 75.596 7.19 1.43875 94.7 0.5340 33 -68.169 0.90 1.85478 24.8 0.6122 34 -138.978 37.20 35 19.251 8.57 1.43875 94.7 0.5340 36 -61.667 2.15 37 -49.588 2.57 1.62004 36.3 0.5879 38 -30.807 0.80 1.75500 52.3 0.5474 39 173.515 2.84 40 31.730 0.80 1.88300 40.8 0.5667 41 12.595 5.54 1.56732 42.8 0.5731 42 -89.922 0.20 43 22.651 3.64 1.56732 42.8 0.5731 44 -35.915 0.80 1.88300 40.8 0.5667 45 24.220 5.00 46 ∞ 33.00 1.60859 46.4 0.5664 47 ∞ 13.20 1.51680 64.2 0.5347 48 ∞ 7.39 Image plane ∞ Aspherical data Page 23 K = 0.00000e+00 A 4=-1.08780e-05 A 6=-1.24306e-09 A 8=-2.57992e-10 A10= 1.84301e-12 Various data Zoom ratio 26.00 Wide-angle, Medium, Telephoto Focal length 20.00 295.69 520.01 F-number 2.90 2.90 5.10 Half-angle (°): 15.38 1.07 0.61 Image height 5.50 5.50 5.50 Lens length 321.29 321.29 321.29 BF 7.39 7.39 7.39 d14 1.99 61.25 64.62 d23 61.96 2.78 12.23 d26 14.36 14.28 1.47 Zoom lens group data Group starting plane focal length 1 1 134.03 2 15 -16.56 3 24 -54.98 4 27 33.87

[0087] [Numerical Example 6] Unit: mm Surface data Face number rd nd vd θgF 1 132.083 7.50 1.48749 70.2 0.5300 2 233.784 0.19 3 78.446 16.20 1.43387 95.1 0.5373 4 196.529 18.60 5 77.999 11.89 1.43387 95.1 0.5373 6 260.591 0.50 7 212.148 2.50 1.81600 46.6 0.5568 8 53.772 10.66 9 53.628 10.91 1.43387 95.1 0.5373 10* 121.203 7.46 11 72.901 12.14 1.43387 95.1 0.5373 12 -605.425 (variable) 13 35.554 0.90 2.00330 28.3 0.5980 14 16.172 5.18 15 -78.133 5.48 1.89286 20.4 0.6393 16 -19.709 0.80 1.88300 40.8 0.5667 17 56.554 (Variable) 18 29.601 4.16 1.80810 22.8 0.6307 19 637.276 1.44 20 -36.538 1.20 1.88300 40.8 0.5667 21 163.683 (variable) 22 -31.862 0.80 1.77250 49.6 0.5520 23 51.536 2.57 1.84666 23.8 0.6205 24 -382.313 (variable) 25 (aperture) ∞ 0.50 26 61.254 6.59 1.52841 76.5 0.5396 27* -50.831 0.20 28 82.026 5.99 1.43875 94.7 0.5340 29 -44.256 1.22 30 -42.309 1.42 1.43875 94.7 0.5340 31 -43.006 0.90 1.85478 24.8 0.6122 32 -89.080 33.37 33 18.458 7.30 1.43875 94.7 0.5340 34 -330.624 5.16 35 349.673 3.19 1.62004 36.3 0.5879 36 -26.336 0.80 1.75500 52.3 0.5474 37 257.888 1.67 38 -67.939 0.80 1.88300 40.8 0.5667 39 14.248 3.90 1.56732 42.8 0.5731 40 -122.138 0.10 41 35.204 4.18 1.60562 43.7 0.5721 42 -15.787 0.80 1.88300 40.8 0.5667 43 -77.921 5.00 44 ∞ 33.00 1.60859 46.4 0.5664 45 ∞ 13.20 1.51680 64.2 0.5347 46 ∞ 7.40 Image plane ∞ Aspherical data Side 10 K = 0.00000e+00 A 4= 6.17944e-07 A 6= 7.54439e-11 A 8= 3.64497e-14 A10=-1.00803e-17 A12= 6.02968e-21 Page 27 K = 0.00000e+00 A 4= 2.55252e-06 A 6= 1.88150e-09 A 8=-6.07966e-12 A10= 9.79064e-15 Various data Zoom ratio 21.95 Wide-angle, Medium, Telephoto Focal length 30.03 318.92 659.13 F-number 2.90 2.90 6.00 Half-angle (°): 10.38 0.99 0.48 Image height 5.50 5.50 5.50 Overall lens length 331.07 331.07 331.07 BF 7.40 7.40 7.40 d12 10.99 49.33 52.58 d17 2.00 5.12 3.70 d21 45.45 4.70 16.17 d24 14.87 14.17 0.86 Zoom lens group data Group Starting surface Focal length 1 1 126.77 2 13 -15.13 3 18 -2122.54 4 22 -48.83 5 25 32.36

[0088] Table 1 shows various numerical values in each numerical example corresponding to conditional expressions (1) to (10). [Table 1]

[0089] The disclosure of this embodiment includes the following configurations. (Configuration 1) From the object side to the image side in order, it has a first lens group with a positive refractive power that does not move for zooming, two or more moving lens groups that move for zooming, and a rear lens group with a positive refractive power that does not move for zooming, The distance between adjacent lens groups all changes for zooming, [[ID=4E]]When the focal length at the telephoto end is ft, the focal length of the first lens group is f1, the length on the optical axis from the final surface of the first lens group when focused at infinity to the rear principal point of the first lens group is bok1, and the lateral magnification at the wide-angle end of the second lens group, which is the lens group with a negative refractive power located closest to the object side among the moving lens groups, is β2w, 3.50 ≦ ft / f1 ≦ 7.00 0.10 ≦ (f1 + bok1) / f1 ≦ 0.69 -0.36 ≦ β2w ≦ -0.10 A zoom lens characterized by satisfying the following conditions. (Configuration 2) When the focal length of the second lens group is f2, -10.00 ≤ f1 / f2 ≤ -7.90 A zoom lens according to configuration 1, characterized by satisfying the following conditions. (Composition 3) When fN is the focal length of the N lens group, which is the negative refractive power lens group located closest to the image among the two or more moving lens groups, -2.75 ≤ f1 / fN ≤ -1.00 A zoom lens according to configuration 1 or 2, characterized by satisfying the following conditions. (Composition 4) When the average Abbe number of the positive refractive power lenses included in the first lens group is denoted as ν1ave, 65.00 ≤ ν1ave ≤ 100.00 A zoom lens according to any one of configurations 1 to 3, characterized by satisfying the following conditions. (Composition 5) The second lens group includes a first positive lens with positive refractive power, When the Abbe number with respect to the d line of the first positive lens is νp1, and the partial dispersion ratio between the g line and the F line of the first positive lens is θgF1p, 0.65 ≤ θgFp1 + 0.0011 × νp1 ≤ 0.70 A zoom lens according to any one of configurations 1 to 4, characterized by satisfying the following conditions. (Composition 6) When the lateral magnification at the telephoto end of the second lens group is β2t, 4.00 ≤ |β2t / β2w| ≤ 600.00 A zoom lens according to any one of configurations 1 to 5, characterized by satisfying the following conditions. (Composition 7) When LD1 is the distance along the optical axis from the lens surface closest to the object to the lens surface closest to the image of the first lens group, 1.00 ≤ f1 / LD1 ≤ 2.20 A zoom lens according to any one of configurations 1 to 6, characterized by satisfying the following conditions. (Composition 8) When LD1 is the distance along the optical axis from the lens surface closest to the object to the lens surface closest to the image of the first lens group, -0.76 ≤ bok1 / LD1 ≤ -0.20 A zoom lens according to any one of configurations 1 to 7, characterized by satisfying the following conditional expression. (Composition 9) The zoom lens according to any one of configurations 1 to 8, characterized in that the first lens group consists of 6 to 8 lenses. (Composition 10) The zoom lens according to any one of configurations 1 to 9, characterized in that the first lens group includes a sub-lens group that moves for focusing. (Composition 11) The zoom lens according to any one of configurations 1 to 10, characterized in that the two or more moving lens groups include at least two lens groups having negative refractive power. (Composition 12) The lens system has, in order from the object side to the image side, a first lens group with positive refractive power that does not move for magnification, two or more moving lens groups that move for magnification, and a rear lens group with positive refractive power that does not move for magnification. The spacing between adjacent lens groups changes due to the variable magnification. When the focal length of the first lens group is f1, and the length along the optical axis from the final surface of the first lens group at infinity focus to the rear principal point of the first lens group is bok1, 0.10 ≤ (f1 + bok1) / f1 ≤ 0.69 A zoom lens characterized by satisfying the following conditions. (Composition 13) An imaging device characterized by having a zoom lens according to any of configurations 1 to 12, and an image sensor that receives an image formed by the zoom lens. [Explanation of Symbols]

[0090] U1 First Lens Group U2, the second lens group U3, the third lens group U4, the fourth lens group U5, the fifth lens group

Claims

1. The lens has, in order from the object side to the image side, a first lens group with positive refractive power that does not move for magnification, two or more moving lens groups that move for magnification, and a rear lens group with positive refractive power that does not move for magnification. The spacing between adjacent lens groups changes due to the variable magnification. When ft is the focal length at the telephoto end, f1 is the focal length of the first lens group, bok1 is the distance along the optical axis from the final surface of the first lens group when it is in focus at infinity to the rear principal point of the first lens group, and β2w is the lateral magnification at the wide-angle end of the second lens group, which is the negative refractive power lens group located closest to the object among the two or more movable lens groups, 3.50 ≤ ft / f1 ≤ 7.00 0.10≦(f1+bok1) / f1≦0.69 -0.36 ≤ β2w ≤ -0.10 A zoom lens characterized by satisfying the following conditions.

2. When the focal length of the second lens group is f2, -10.00 ≤ f1 / f2 ≤ -7.90 The zoom lens according to claim 1, characterized by satisfying the following conditions.

3. When the focal length of the N lens group, which is the negative refractive power lens group located closest to the image among the two or more moving lens groups, is denoted as fN, -2.75 ≤ f1 / fN ≤ -1.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

4. When the average Abbe number of the positive refractive power lenses included in the first lens group is denoted as ν1ave, 65.00 ≤ ν1ave ≤ 100.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

5. The second lens group includes a first positive lens with positive refractive power, When the Abbe number with respect to the d line of the first positive lens is νp1, and the partial dispersion ratio between the g line and the F line of the first positive lens is θgF1p, 0.65 ≤ θ gFp1 + 0.0011 × νp1 ≤ 0.70 The zoom lens according to claim 1, characterized by satisfying the following conditions.

6. When the lateral magnification at the telephoto end of the second lens group is β2t, 4.00≦|β2t / β2w|≦600.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

7. When LD1 is defined as the distance along the optical axis from the lens surface closest to the object to the lens surface closest to the image of the first lens group, 1.00 ≤ f1 / LD1 ≤ 2.20 The zoom lens according to claim 1, characterized by satisfying the following conditions.

8. When LD1 is defined as the distance along the optical axis from the lens surface closest to the object to the lens surface closest to the image of the first lens group, -0.76 ≤ bok1 / LD1 ≤ -0.20 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

9. The zoom lens according to claim 1, characterized in that the first lens group consists of six to eight lenses.

10. The zoom lens according to claim 1, characterized in that the first lens group includes a sub-lens group that moves for focusing.

11. The zoom lens according to claim 1, characterized in that the two or more movable lens groups include at least two lens groups having negative refractive power.

12. The lens has, in order from the object side to the image side, a first lens group with positive refractive power that does not move for magnification, two or more moving lens groups that move for magnification, and a rear lens group with positive refractive power that does not move for magnification. The spacing between adjacent lens groups changes due to the magnification. When the focal length of the first lens group is f1, and the distance along the optical axis from the final surface of the first lens group at infinity focus to the rear principal point of the first lens group is bok1, 0.10≦(f1+bok1) / f1≦0.69 A zoom lens characterized by satisfying the following conditions.

13. An imaging device characterized by having a zoom lens according to any one of claims 1 to 12, and an image sensor that receives an image formed by the zoom lens.

Images