Zoom lens and imaging device

Abstract

To provide a zoom lens which is advantageous in terms of a wide angle of view, compactness, light weight, and high optical performance.SOLUTION: A zoom lens is comprised of a first lens group U1 having positive refractive power and a succeeding group including a plurality of lens groups U2-U5, arranged in order from the object side to the image side, and is configured to zoom in and out by changing distances between adjacent lens groups. The first lens group is stationary while zooming. The succeeding group includes, in order from the image side to the object side, a final lens group with positive refractive power and configured to be stationary while zooming, a final movable positive lens group with positive refractive power, comprised of one or two lenses and moving while zooming, and an aperture stop configured to move while zooming. The aperture stop is located further on the object side at the wide-angle end of the zoom lens than at the telephoto end. The zoom lens satisfies a condition expressed as: 0.01≤Lwt / Td≤0.25, where Lwt represents an optical axial distance between a position of the aperture stop at the wide-angle end and a position of the aperture stop at the telephoto end, and Td represents an optical axial distance from a most object-side surface of the zoom lens at the wide-angle end to the image plane.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a zoom lens and an imaging apparatus. [Background technology]

[0002] As a zoom lens with a wide angle of view and a high zoom ratio, a positive lead type zoom lens in which a first lens group with positive refractive power is arranged closest to the object side is known. Patent Document 1 discloses a zoom lens with a variable magnification ratio of about 7, which is composed of, in order from the object side to the image side, a first lens group with positive refractive power, a second lens group to a fifth lens group that move when changing magnification, and a sixth lens group. The fifth lens group includes an aperture. Patent Document 2 discloses a zoom lens with a wide angle of view and compatible with a full-size image sensor, which is composed of, in order from the object side to the image side, a first lens group with positive refractive power, a second lens group to a fourth lens group that move when changing magnification, and a fifth lens group, which includes an aperture. The fourth lens group includes an aperture. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-173481 A [Patent Document 2] JP 2020-160262 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to achieve high optical performance, a wide angle of view, and compact size in a positive-lead zoom lens, it is important to appropriately set the position of the aperture and the focal length of each lens group. To further widen the angle of view, the lens diameter of the first lens group, which is determined by the height of the off-axis light rays at the wide-angle end, increases, making the zoom lens larger, or it becomes difficult to achieve good optical performance (image performance) from the center to the periphery because it is necessary to shorten the focal length of the first lens group.

[0005] In the zoom lens of Patent Document 1, the amount of movement of the lens group including the aperture is small, and the lens diameter of the first lens group increases when the angle of view is widened. Also, in the zoom lens of Patent Document 2, the lens group including the aperture is composed of three or more lenses, which is disadvantageous in achieving both a bright aperture ratio and a compact and lightweight design.

[0006] The present invention provides a zoom lens that is advantageous in terms of, for example, a wide angle of view, small size and light weight, and high optical performance over the entire zoom range. [Means for solving the problem]

[0007] A zoom lens according to one aspect of the present invention comprises, in order from the object side to the image side, a first lens group having positive refractive power and a subsequent group including a plurality of lens groups, and performs magnification change by changing the spacing between adjacent lens groups. The first lens group does not move during magnification change. The subsequent group comprises, in order from the image side to the object side, a final lens group having positive refractive power that does not move during magnification change, a final movable positive lens group having positive refractive power that is composed of one or two lenses and moves during magnification change, and The zoom lens system comprises a final movable negative lens group having a negative refractive power that moves during zooming, and one or two movable lens groups having a negative refractive power that move during zooming, the subsequent lens group being located closer to the object side than the final movable positive lens group, The aperture diaphragm is movable during zooming. Edge If the distance on the optical axis between the position of the aperture stop at the wide-angle end and the position of the aperture stop at the telephoto end is Lwt, and the distance on the optical axis from the surface of the zoom lens closest to the object at the wide-angle end to the image plane is Td, then 0.01≦Lwt / Td≦0.25 The present invention is characterized in that the above conditions are satisfied. An image pickup apparatus including the above zoom lens also constitutes another aspect of the present invention. Effect of the Invention

[0008] According to the present invention, for example, it is possible to provide a zoom lens that is advantageous in terms of a wide angle of view, a small size and light weight, and high optical performance over the entire zoom range. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a zoom lens according to a first embodiment. [Diagram 2] 5A and 5B are aberration diagrams of the zoom lens of Example 1 at the wide-angle end and an intermediate zoom position, respectively. [Diagram 3] 5A to 5C are aberration diagrams at the telephoto end of the zoom lens of the first embodiment. [Figure 4] FIG. 11 is a cross-sectional view of a zoom lens according to a second embodiment. [Diagram 5] 11A and 11B are aberration diagrams of the zoom lens of Example 2 at the wide-angle end and an intermediate zoom position, respectively. [Figure 6] 8A to 8C are aberration diagrams at the telephoto end of the zoom lens of Example 2. [Figure 7] FIG. 11 is a cross-sectional view of a zoom lens according to a third embodiment. [Figure 8] 11A and 11B are aberration diagrams of the zoom lens of Example 3 at the wide-angle end and an intermediate zoom position, respectively. [Figure 9] 11A to 11C are aberration diagrams at the telephoto end of the zoom lens of Example 3. [Figure 10] FIG. 11 is a cross-sectional view of a zoom lens according to a fourth embodiment. [Figure 11] 11A and 11B are aberration diagrams of the zoom lens of Example 4 at the wide-angle end and an intermediate zoom position, respectively. [Figure 12] 13A to 13C are aberration diagrams at the telephoto end of the zoom lens of Example 4. [Figure 13] FIG. 13 is a cross-sectional view of a zoom lens according to a fifth embodiment. [Figure 14] 13A and 13B are aberration diagrams of the zoom lens of Example 5 at the wide-angle end and an intermediate zoom position, respectively. [Figure 15] 13A to 13C are aberration diagrams at the telephoto end of the zoom lens of Example 5. [Figure 16] FIG. 13 is a cross-sectional view of a zoom lens according to a sixth embodiment. [Figure 17] 13A and 13B are aberration diagrams of the zoom lens of Example 6 at the wide-angle end and an intermediate zoom position, respectively. [Figure 18] 13A to 13C are aberration diagrams at the telephoto end of the zoom lens of Example 6. [Figure 19] 3A and 3B are optical path diagrams at the wide-angle end and the telephoto end of the zoom lens of the first embodiment. [Figure 20] FIG. [Figure 21] FIG. 1 is a diagram showing an image pickup apparatus equipped with a zoom lens according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] 1, 4, 7, 10, 13 and 16 show cross sections of the zoom lenses of Examples 1 to 6 in a state where the zoom lenses are focused on an object at infinity at the wide-angle end (hereinafter referred to as an infinity focused state). The wide-angle end and the telephoto end respectively show the zoom states of the maximum angle of view (shortest focal length) and the minimum angle of view (maximum focal length) when the lens group moving during magnification is located at both ends of the range in which the lens group can move mechanically or controllably on the optical axis. The zoom lenses of the Examples are used as imaging optical systems for broadcast television cameras, video cameras, digital still cameras and cameras for silver halide film. In each figure, Un (n=1 to 6) is a lens group, SP is an aperture stop and IP is an image plane. The imaging surface of an imaging element (photoelectric conversion element) or the photosensitive surface of a silver halide film is disposed on the image plane IP.

[0012] Prior to describing specific Examples 1 to 6, we will describe matters common to each of the Examples. The zoom lens of each Example has a wide angle of view (total angle of view 2ω=about 54 to 100°) and a magnification ratio (zoom ratio) of about 2 to 13, and in order to obtain high optical performance over the entire zoom range while being small and lightweight, the movement amount of the aperture diaphragm relative to the total length and the configuration of the lens group that moves during magnification are appropriately set.

[0013] The zoom lens of each embodiment is composed of, in order from the object side to the image side, a first lens group (U1) with positive refractive power and a subsequent group including multiple lens groups (U2 to U5 or U6). The zoom lens of each embodiment is a positive-lead type zoom lens in which a lens group with positive refractive power is arranged closest to the object side.

[0014] The zoom lens of each embodiment changes the spacing between adjacent lens groups to change the magnification. The first lens group does not move (is stationary) during magnification. The subsequent groups include, in order from the image side to the object side, a final lens group with a positive refractive index that does not move during magnification, and a final movable positive lens group with a positive refractive power that is composed of one or two lenses and moves during magnification. In each embodiment, one lens means a single lens, and a cemented lens in which two lenses are cemented together is counted as two lenses. This is because a cemented lens and two lenses that are not cemented can exhibit the same chromatic aberration correction effect.

[0015] The subsequent group also includes an aperture stop (SP) that moves during magnification variation.

[0016] A focal length changing optical system having a lens group that can be inserted or removed or detached before or after the final lens group to change the focal length of the entire zoom lens system may be arranged. Also, a drive mechanism may be provided that moves all or part of the final lens group slightly along the optical axis to suppress focus shift during magnification change over the entire zoom range.

[0017] In the zoom lens of each embodiment, the aperture stop is located closer to the object side at the wide-angle end than at the telephoto end. When the distance between the positions of the aperture stop at the wide-angle end and the telephoto end is Lwt and the distance on the optical axis from the surface of the first lens group (i.e., the zoom lens) closest to the object side at the wide-angle end to the image plane is Td, the condition shown in the following formula (1) is satisfied.

[0018] 0.01≦Lwt / Td≦0.25 (1) Note that the distance Lwt corresponds to the amount of movement of the aperture stop when changing magnification from the wide-angle end to the telephoto end, with the direction in which the aperture stop moves from the wide-angle end toward the image side at the telephoto end being defined as positive, and is determined only from the positions at the wide-angle end and telephoto end even when the direction of movement of the aperture stop changes during magnification change.

[0019] The relationship between the movement amount of the aperture stop and the first lens group will be described. The upper and lower diagrams in FIG. 19 respectively show the optical paths in the zoom lens of Example 1 (Numerical Example 1 described later) at the wide-angle end and the telephoto end in the infinity focus state. As can be seen from these diagrams, the lens diameter of the lens closest to the object, which has the largest lens diameter in the first lens group U1, is determined by the height of the off-axis light ray in the infinity focus state at the wide-angle end. Therefore, the lens diameter of the lens closest to the object increases as the angle of view becomes wider. In each embodiment, the aperture stop is positioned closer to the object at the wide-angle end than the telephoto end, so that the entrance pupil at the wide-angle end of the zoom lens is positioned closer to the object than the telephoto end (pushed out), thereby suppressing the increase in the lens diameter of the lens closest to the object that accompanies the wide-angle view.

[0020] Equation (1) shows the condition regarding the relationship between the amount of movement of the aperture stop arranged in the succeeding group on the optical axis during magnification change from the telephoto end to the wide-angle end and the distance on the optical axis from the surface closest to the object at the wide-angle end to the image plane (total lens length). The zoom lens is made compact by satisfying the condition of Lwt / Td in equation (1). If Lwt / Td exceeds the upper limit of equation (1), the space for magnification change in the succeeding group becomes long, which is undesirable because it makes it difficult to make the zoom lens compact. If Lwt / Td falls below the lower limit of equation (1), the effect of the aperture stop at the wide-angle end in pushing the entrance pupil toward the object side becomes small, which is undesirable because it makes it difficult to make the zoom lens compact.

[0021] It is more preferable to set the numerical range of formula (1) as follows:

[0022] 0.02≦Lwt / Td≦0.20 (1a) It is more preferable to set the numerical range of formula (1) as follows:

[0023] 0.03≦Lwt / Td≦0.15 (1b) It is even more preferable to set the numerical range of formula (1) as follows:

[0024] 0.04≦Lwt / Td≦0.07 (1c) It is desirable for the zoom lens of each embodiment to satisfy at least one of the conditions of the following expressions (2) to (13), in addition to the condition of expression (1).

[0025] The subsequent group of the zoom lens in each embodiment includes the above-mentioned final lens group (hereinafter, r is attached) and the final moving positive lens group (hereinafter, m1 is attached), as well as the final moving negative lens group m2, which is composed of one or two lenses and has a negative refractive power and moves during magnification. The average value of the Abbe number based on the d-line of the optical material of all the positive lenses included in the final moving positive lens group is νm1, and the average value of the partial dispersion ratio for the g-line and the F-line is θm1. The average value of the Abbe number based on the d-line of the optical material of all the negative lenses included in the final moving negative lens group is νm2, and the average value of the partial dispersion ratio for the g-line and the F-line is θm2. In this case, it is desirable to satisfy the condition shown in the following formula (2). -2.0×10 -3 ≦(θm1-θm2) / (νm2-νm1)≦2.5×10 -3 (2) The final moving positive lens group m1 is adjacent to the final lens group r, and the smaller (brighter) the aperture ratio of the zoom lens, the larger the lens diameter of the final moving positive lens group m1. In order to reduce the size and weight of the lens group that moves during magnification, it is effective to reduce the number of lenses that make up the lens group. For this reason, in each embodiment, the final moving positive lens group m1 is composed of one or two lenses. In addition, by arranging the final moving positive lens group m1 and the final moving negative lens group m2 closely to each other and using the relationship in the characteristics of the glass materials between the moving lens groups to perform chromatic aberration correction, it is possible to correct chromatic aberration well over the entire zoom range.

[0026] The Abbe number νd(νm1,νm2) of the optical material based on the d-line in formula (2) and the partial dispersion ratio θgF(θm1,θm2) for the g-line and F-line are respectively expressed by the following formulas (a) and (b). In each formula, the refractive indexes of the optical material for 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 respectively denoted as Ng, NF, Nd, and NC.

[0027] νd=(Nd-1) / (NF-NC) (a) θgF=(Ng-NF) / (NF-NC) (b) The relationship between the final moving positive lens group m1 and the final moving negative lens group m2 in terms of chromatic aberration correction will be described. As shown in FIG. 20, the partial dispersion ratio θgF of existing optical materials is distributed in a narrow range with respect to the Abbe number νd, and the smaller νd is, the larger θgF tends to be. Two lenses Gp and Gn have positive and negative refractive powers Φp and Φn, respectively, and Abbe numbers νp and νn, and the incidence height of the axial paraxial ray of each lens is h, and the incidence height of the pupil paraxial ray is H. In this case, the axial chromatic aberration coefficient L and the magnification chromatic aberration coefficient T of the thin close contact system constituted by the lenses Gp and Gn are expressed by the following formulas (c) and (d).

[0028] L = h × h × (Φp / νp + Φn / νn) (c) T = h × H × (Φp / νp + Φn / νn) (d) In addition, Φp+Φn=Φ(e) Furthermore, the axial paraxial ray and pupil paraxial ray are rays defined as follows. An axial paraxial ray is a paraxial ray that is incident on a zoom lens parallel to the optical axis with an entrance height of 1, with the focal length at the wide-angle end of the entire zoom lens system normalized to 1. A pupil paraxial ray is a paraxial ray that is incident on the zoom lens at the maximum image height on the imaging surface, with the focal length at the wide-angle end of the entire zoom lens system normalized to 1, and that passes through the intersection of the entrance pupil of the zoom lens and the optical axis.

[0029] The refractive power of each lens in formulas (c) and (d) is normalized so that Φ = 1 in formula (e). The same applies to three or more lenses. When L = 0 and T = 0 in formulas (c) and (d), the imaging positions of the C-line and F-line coincide on the axis and on the image plane. Correcting chromatic aberration for two specific wavelengths in this way is generally called dual-wavelength achromatism (first-order spectrum correction). In particular, in high-magnification zoom lenses, the chromatic aberration of each lens group, i.e., L and T, are corrected to be close to 0 in order to suppress chromatic aberration fluctuations that occur when changing magnification.

[0030] In a state where the focus is at infinity, that is, when a light beam is incident on a zoom lens with the object distance at infinity, the amount of deviation of the axial chromatic aberration for the g-line relative to the F-line and the amount of deviation of the lateral chromatic aberration are respectively defined as the secondary spectral amount of axial chromatic aberration Δs and the secondary spectral amount of lateral chromatic aberration Δy. These are expressed by the following equations (f) and (g), where f is the focal length of the entire zoom lens system and Y is the image height.

[0031] Δs=-h×h×(θp-θn) / (νp-νn)×f (f) Δy=-h×H×(θp-θn) / (νp-νn)×Y (g) In this way, correcting chromatic aberration for three specific wavelengths by adding another specific wavelength to the above two wavelengths is generally called three-wavelength achromatization (second-order spectrum correction).

[0032] As the magnification ratio of a zoom lens increases, the focal length f in formula (f) increases, making it difficult to reduce the secondary spectrum of axial chromatic aberration. Also, as the angle of a zoom lens increases, the pupil paraxial ray H in formula (g) increases, making it difficult to reduce the secondary spectrum of lateral chromatic aberration at the wide-angle end. In each embodiment, the zoom lens is particularly designed to widen its angle, while providing excellent correction for the primary and secondary spectra of lateral chromatic aberration and axial chromatic aberration over the entire zoom range. By satisfying the condition of formula (2), it is possible to provide an appropriate difference between the Abbe number and the partial dispersion ratio in the final moving positive lens group m1 and the final moving negative lens group m2, which is more advantageous for chromatic aberration correction in the entire zoom range. If (θm1-θm2) / (νm2-νm1) exceeds the upper limit or falls below the lower limit of formula (2), it becomes difficult to provide the final moving positive lens group m1 and the final moving negative lens group m2 with appropriate chromatic aberration correction power. Moreover, it becomes difficult to achieve good optical performance in the entire zoom range, which is undesirable.

[0033] It is more preferable to set the numerical range of formula (2) as follows: -1.0×10 -3 ≦(θm1-θm2) / (νm2-νm1)≦2.2×10 -3 (2a) It is more preferable to set the numerical range of formula (2) as follows: -0.5×10 -3 ≦(θm1-θm2) / (νm2-νm1)≦1.9×10 -3 (2b) It is more preferable to set the numerical range of formula (2) as follows:

[0034] 0≦(θm1-θm2) / (νm2-νm1)≦1.9×10 -3 (2c) It is even more preferable to set the numerical range of formula (2) as follows: 0.2×10 -3 ≦(θm1-θm2) / (νm2-νm1)≦1.5×10 -3 (2d) It is even more preferable to set the numerical range of formula (2) as follows: 0.5×10 -3 ≦(θm1-θm2) / (νm2-νm1)≦1.3×10 -3 (2e) In addition, it is desirable that the zoom lens of each embodiment satisfies the condition shown in the following formula (3), where the maximum air gap between the final moving positive lens group m1 and the final moving negative lens group m2 in the entire zoom range from the wide-angle end to the telephoto end is Dm12 and the focal length of the final moving positive lens group m1 is fm1. 0.01≦Dm12 / fm1≦0.50 (3) In the zoom lens of each embodiment, in order to reduce the weight of the final moving positive lens group m1 and the final moving negative lens group m2, it is not necessary to perform chromatic aberration correction by positive and negative lenses in each lens group. Therefore, it is desirable to properly select the optical material of the lenses of the final moving positive lens group m1 and the final moving negative lens group m2 adjacent thereto to perform chromatic aberration correction between the lens groups, thereby correcting chromatic aberration well in the entire zoom range. In the zoom lens of each embodiment, the final moving positive lens group m1 and the final moving negative lens group m2 are moved to draw different movement loci during magnification, thereby improving the aberration correction ability in the intermediate zoom range. However, since the chromatic aberration correction ability changes at the same time, it is basically necessary for the final moving positive lens group m1 and the final moving negative lens group m2 to maintain a relationship close to each other in the entire zoom range.

[0035] Equation (3) shows the condition regarding the relationship between the maximum air gap between the final moving positive lens group m1 and the final moving negative lens group m2 during magnification change and the focal length fm1 of the final moving positive lens group m1. By satisfying the condition of Equation (3), the final moving positive lens group m1 and the final moving negative lens group m2 can be appropriately close to each other in the entire zoom range, and it is possible to effectively suppress the fluctuation of the chromatic aberration correction ability in the entire zoom range. If Dm12 / fm1 exceeds the upper limit of Equation (3), the final moving positive lens group m1 and the final moving negative lens group m2 are relatively far apart, which is not preferable because it is difficult to effectively correct chromatic aberration in the entire zoom range. If Dm12 / fm1 falls below the lower limit of Equation (3), there is almost no fluctuation in the distance between the final moving positive lens group m1 and the final moving negative lens group m2, which is not preferable because it is difficult to divide the lens groups and use them to correct aberrations other than chromatic aberration.

[0036] It is more preferable to set the numerical range of formula (3) as follows: 02≦Dm12 / fm1≦0.45 (3a) It is more preferable to set the numerical range of the formula (3) as follows: 0.03≦Dm12 / fm1≦0.40 (3b) It is more preferable to set the numerical range of the formula (3) as follows: 0.04≦Dm12 / fm1≦0.35 (3c) It is even more preferable to set the numerical range of formula (3) as follows: 0.05≦Dm12 / fm1≦0.30 (3d) Furthermore, it is desirable that the zoom lens of each embodiment satisfies the condition shown in the following formula (4), where the focal length of the final moving positive lens unit m1 is fm1 and the focal length of the final moving negative lens unit m2 is fm2. -5.0≦fm2 / fm1≦-0.7 (4) By satisfying the conditional expression (4), the zoom lens can be made even more compact. If fm2 / fm1 exceeds the upper limit of expression (4), the refractive power of the final moving negative lens group m2 becomes strong, the lens diameter of the subsequent group becomes large, and it becomes difficult to make the zoom lens compact, which is not preferable. If fm2 / fm1 falls below the lower limit of expression (4), the refractive power of the final moving negative lens group m2 becomes weak, the amount of movement of the final moving negative lens group m2 during magnification change becomes large, and it becomes difficult to make the zoom lens compact, which is not preferable.

[0037] It is more preferable to set the numerical range of the formula (4) as follows: -4.7≦fm2 / fm1≦-0.8 (4a) It is more preferable to set the numerical range of the formula (4) as follows: -3.2≦fm2 / fm1≦-0.9 (4b) It is more preferable to set the numerical range of the formula (4) as follows: -2.4≦fm2 / fm1≦-1.0 (4c) In the zoom lens of each embodiment, the final moving positive lens group m1 is composed of one positive lens, and when the Abbe number of the optical material of the positive lens with respect to the d-line is denoted by νm1u and the partial dispersion ratio with respect to the g-line and F-line is denoted by θm1u, it is desirable to satisfy the conditions shown in the following expressions (5) and (6). 28≦νm1u≦60 (5) 0.540≦θm1u≦0.600 (6) By satisfying formulas (5) and (6), the zoom lens can be made smaller and have high optical performance. Formulas (5) and (6) show the conditions for the range of dispersion (Abbe number) and partial dispersion ratio to favorably correct lateral chromatic aberration, which tends to increase with increasing angle, when the final moving positive lens group m1 is composed of one positive lens. If νm1u is below the lower limit of formula (5) or θm1u is above the upper limit of formula (6), the positive lens using existing optical materials will have excessively high dispersion and high partial dispersion ratio, making it difficult to achieve good optical performance over the entire zoom range, which is not preferable. If νm1u is above the upper limit of formula (5) or θm1u is below the lower limit of formula (6), the positive lens will have excessively high partial dispersion ratio, making it difficult to achieve good optical performance over the entire zoom range, which is also not preferable.

[0038] It is more preferable to set the numerical ranges of the expressions (5) and (6) as follows: 29≦νm1u≦59 (5a) 0.542≦θm1u≦0.595 (6a) It is more preferable to set the numerical ranges of the formulas (5) and (6) as follows: 31≦νm1u≦56 (5b) 0.543≦θm1u≦0.590 (6b) It is more preferable to set the numerical ranges of the expressions (5) and (6) as follows: 33≦νm1u≦50 (5c) 0.550≦θm1u≦0.585 (6c) In addition, in the zoom lens of each embodiment, the final movable negative lens group m2 is composed of one negative lens, and when the Abbe number of the optical material of the negative lens with respect to the d-line is denoted by νm2u and the partial dispersion ratio with respect to the g-line and F-line is denoted by θm2u, it is desirable to satisfy the conditions shown in the following expressions (7) and (8). 60≦νm2u≦110 (7) 0.520≦θm2u≦0.550 (8) By satisfying the conditions of formulas (7) and (8), the zoom lens can be made smaller and high optical performance can be achieved. Formulas (7) and (8) show the conditions for establishing an appropriate chromatic aberration correction relationship with the final moving positive lens group m1 when the final moving negative lens group m2 is composed of one negative lens. By satisfying these conditions, it is advantageous to correct lateral chromatic aberration, which tends to increase with a wider angle. If νm2u falls below the lower limit of formula (7), the fluctuation of first-order chromatic aberration due to the movement of the final moving negative lens group m2 accompanying the magnification change becomes large, which is not preferable because it becomes difficult to achieve good optical performance in the entire zoom range. If θm2u exceeds the upper limit of formula (8), the fluctuation of second-order chromatic aberration due to the movement of the final moving negative lens group m2 accompanying the magnification change becomes large, which is not preferable because it becomes difficult to achieve good optical performance in the entire zoom range.

[0039] It is more preferable to set the numerical ranges of the expressions (7) and (8) as follows: 63≦νm2u≦107 (7a) 0.522≦θm2u≦0.545 (8a) It is more preferable to set the numerical ranges of the expressions (7) and (8) as follows: 70≦νm2u≦102 (7b) 0.524≦θm2u≦0.543 (8b) It is more preferable to set the numerical ranges of the expressions (7) and (8) as follows: 74≦νm2u≦97 (7c) 0.526≦θm2u≦0.540 (8c) It is even more preferable to set the numerical ranges of the expressions (7) and (8) as follows: 80≦νm2u≦95 (7d) 0.528≦θmu2≦0.538 (8d) Furthermore, when the lateral magnification of the final moving positive lens unit m1 at the wide-angle end in the infinity focused state is βm1, it is desirable for the zoom lens of each embodiment to satisfy the condition shown in the following formula (9).

[0040] |1 / βm1|≦0.2 (9) By satisfying the condition of formula (9), the light rays emerging from the final moving positive lens group m1 are made closer to parallel, reducing the change in the aperture diameter during magnification change, and the control mechanism for controlling the aperture diameter can be simplified. If |1 / βm1| exceeds the upper limit of formula (9), the light rays emerging from the final moving positive lens group m1 have an angle, causing a large change in the aperture diameter during magnification change and complicating the control mechanism, which is not preferable.

[0041] It is more preferable to set the numerical range of the formula (9) as follows: |1 / βm1|≦0.15 (9a) It is more preferable to set the numerical range of the formula (9) as follows: |1 / βm1|≦0.13 (9b) It is more preferable to set the numerical range of the formula (9) as follows: |1 / βm1|≦0.11 (9c) It is even more preferable to set the numerical range of the formula (9) as follows: |1 / βm1|≦0.04 (9d) In addition, one or two n-th moving lens groups that move during magnification in the subsequent groups of the zoom lens in each embodiment include a lens group with negative refractive power (negative lens group).When the composite focal length of the one or two n-th moving lens groups in the infinity focus state at the wide-angle end is fn and the focal length of the first lens group is f1, it is desirable to satisfy the conditions shown in the following expressions (10) and (11). -5.0≦f1 / fn≦-0.8 (10) -2.5≦fm1 / fn≦-1.2 (11) Equations (10) and (11) show the conditions for the power arrangement of the lens groups to achieve further miniaturization and high performance of the zoom lens. The focal length of the zoom lens is the product of the focal length of the first lens group and the lateral magnification of the succeeding lens group. Therefore, in order to achieve a wide angle of view, it is necessary to set the focal length of the first lens group appropriately. If f1 / fn exceeds the upper limit of equation (10), the refractive power of the first lens group becomes strong, making it difficult to correct aberration fluctuations, which is not preferable. In addition, the refractive power of the nth moving lens group is insufficient relative to the first lens group, which is disadvantageous in making the zoom lens small and lightweight. If f1 / fn falls below the lower limit of equation (10), the refractive power of the first lens group becomes insufficient, making it difficult to achieve a wide angle of view and a small and lightweight zoom lens, which is not preferable.

[0042] It is more preferable to set the numerical range of the formula (10) as follows: -4.0≦f1 / fn≦-0.9 (10a) It is more preferable to set the numerical range of the formula (10) as follows: -3.5≦f1 / fn≦-1.0 (10b) It is more preferable to set the numerical range of the formula (10) as follows: -3.0≦f1 / fn≦-1.3 (10c) Moreover, by satisfying the condition of formula (11), the zoom lens can be made even more compact. If fm1 / fn exceeds the upper limit of formula (11), the refractive power of the negative lens group in the subsequent group becomes weak, the amount of movement of the negative lens group during magnification change becomes large, and it becomes difficult to make the zoom lens compact, which is not preferable. If fm1 / fn falls below the lower limit of formula (11), the refractive power of the positive lens group in the subsequent group becomes weak, the lens diameter of the subsequent group becomes large, and it becomes difficult to make the zoom lens compact, which is not preferable.

[0043] It is more preferable to set the numerical range of the formula (11) as follows: -2.4≦fm1 / fn≦-1.3 (11a) It is more preferable to set the numerical range of the formula (11) as follows: -2.3≦fm1 / fn≦-1.4 (11b) It is more preferable to set the numerical range of the formula (11) as follows: -2.1≦fm1 / fn≦-1.5 (11c) In addition, it is desirable that the zoom lens of each embodiment satisfy the condition shown in the following equation (12), where the lateral magnifications of the nth moving lens group at the wide-angle end and the telephoto end are βnw and βnt, respectively, and the magnification ratio from the wide-angle end to the telephoto end of the entire zoom lens system is Zwt. 0.6≦(βtn / βwn) / Zwt≦4.0 (12) The condition of formula (12) indicates the condition regarding the ratio of the zoom ratio from the wide-angle end to the telephoto end that is shared by the nth moving lens group. By satisfying the condition of formula (12), appropriate sharing of the zoom ratio is possible, which is further advantageous for miniaturization and high performance of the zoom lens. If (βtn / βwn) / Zwt exceeds the upper limit of formula (12), the share of the nth moving lens group in the zoom ratio becomes too large, which is undesirable because it becomes difficult to suppress aberration fluctuations due to the movement of the nth lens group. If (βtn / βwn) / Zwt falls below the lower limit of formula (12), the share of the zoom ratio of the lens groups after the nth moving lens group, which have a relatively simple configuration, increases, which is undesirable because it becomes difficult to improve performance.

[0044] It is more preferable to set the numerical range of the formula (12) as follows: 0.7≦(βtn / βwn) / Zwt≦3.1 (12a) It is more preferable to set the numerical range of the formula (12) as follows: 0.8≦(βtn / βwn) / Zwt≦2.0 (12b) It is more preferable to set the numerical range of the formula (12) as follows: 0.9≦(βtn / βwn) / Zwt≦1.4 (12c) It is even more preferable to set the numerical range of the formula (12) as follows: 0.9≦(βtn / βwn) / Zwt≦1.2 (12d) Furthermore, in the zoom lens of each embodiment, when the average values ​​of the Abbe numbers based on the d-line of the optical materials of all the positive lenses and all the negative lenses in the negative lens group included in the nth moving lens group are respectively νnp and νnn, and the average values ​​of the partial dispersion ratios for the g-line and the F-line are respectively θnp and θnn, it is desirable to satisfy the condition shown in the following equation (13). -1.0×10 -3 ≦(θnp-θnn) / (νnn-νnp)≦3.0×10 -3 (13) By satisfying the condition of formula (13), it is possible to provide a difference in Abbe number and partial dispersion ratio that is advantageous for correcting chromatic aberration in the negative lens group, particularly lateral chromatic aberration that tends to increase as the angle of view becomes wider. If (θnp-θnn) / (νnn-νnp) exceeds the upper limit of formula (13), the correction of chromatic aberration in the negative lens group becomes insufficient, making it difficult to achieve good optical performance, which is not preferable.

[0045] It is more preferable to set the numerical range of the formula (13) as follows: -0.5×10 -3 ≦(θnp-θnn) / (νnn-νnp)≦2.7×10 -3 (13a) It is more preferable to set the numerical range of the formula (13) as follows: 0≦(θnp-θnn) / (νnn-νnp)≦2.5×10 -3 (13b) It is more preferable to set the numerical range of the formula (13) as follows: 0≦(θnp-θnn) / (νnn-νnp)≦2.4×10 -3 (13c) It is even more preferable to set the numerical range of the formula (13) as follows: 0.5×10 -3 ≦(θnp-θnn) / (νnn-νnp)≦2.2×10 -3 (13d) It is even more preferable to set the numerical range of the formula (13) as follows:

[0046] 1.0×10 -3 ≦(θnp-θnn) / (νnn-νnp)≦2.1×10 -3 (13d) Examples 1 to 6 and corresponding Numerical Examples 1 to 6 will be described below. EXAMPLES

[0047] The zoom lens of Example 1 (Numerical Example 1) shown in FIG. 1 has a first lens group U1 with positive refractive power, which is fixed during magnification change and moves during focus adjustment, located closest to the object side. In addition, as a subsequent group, the following lens group is provided, in order from the object side to the image side, with a second lens group U2 with negative refractive power, which moves toward the image side during magnification change from the wide-angle end to the telephoto end, and a third lens group U3 with negative refractive power and a fourth lens group U4 with positive refractive power, which move during magnification change. The fourth lens group U4 moves nonlinearly on the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3 in order to correct image plane fluctuations accompanying magnification change. Furthermore, the subsequent group includes a fifth lens group U5 with positive refractive power, which is located closest to the image side and does not move during magnification change.

[0048] In this embodiment, the second lens group U2 corresponds to the n-th moving lens group, the third lens group U3 corresponds to the final moving negative lens group m2, the fourth lens group U4 corresponds to the final moving positive lens group m1, and the fifth lens group U5 corresponds to the final lens group r. The aperture stop SP is included in the fourth lens group U4 and is disposed closest to the object in the fourth lens group U4. In Numerical Example 1, surface number i indicates the order of the surface when counted from the object side. r is the radius of curvature (mm) of the i-th surface from the object side, d is the lens thickness or air gap (mm) on the optical axis between the i-th and (i+1)-th surfaces, and nd is the refractive index at the d-line of the optical material between the i-th and (i+1)-th surfaces. νd is the Abbe number based on the d-line of the optical material between the i-th and (i+1)-th surfaces. Furthermore, θgF is the partial dispersion ratio for the g-line and F-line of the optical material between the i-th and (i+1)-th surfaces. Numerical Example 1 also shows the effective diameter (mm) and focal length (mm) of each surface.

[0049] BF stands for back focus (mm). Back focus is the distance on the optical axis from the final surface of a zoom lens (the lens surface closest to the image) to the paraxial image plane, expressed as an air-equivalent length. The total lens length is the distance on the optical axis from the foreground surface of a zoom lens (the lens surface closest to the object) to the final surface plus the back focus, and the total lens length at the wide-angle end corresponds to the distance Td in formula (1).

[0050] An "*" next to a surface number means that the surface has an aspheric shape. The aspheric shape is expressed by the following formula, where the optical axis direction is the X-axis, the direction perpendicular to the optical axis is the H-axis, the light traveling direction is positive, R is the paraxial radius of curvature, K is the conic constant, and A3 to A16 are aspheric coefficients. "eZ" is "×10 -Z " means.

[0051]

number

[0052] It should be noted that these explanations regarding the numerical examples also apply to other numerical examples described later.

[0053] In Numerical Example 1, the first lens group U1 corresponds to surfaces 1 to 16. The second lens group U2 corresponds to surfaces 17 to 23. The third lens group U3 corresponds to surfaces 24 to 25. The fourth lens group U4 corresponds to surfaces 26 to 28. The fifth lens group U5 corresponds to surfaces 29 to 41.

[0054] The first lens group U1 is composed of a first sub-lens group (surfaces 1 to 7) with negative refractive power that does not move during focus adjustment, a second sub-lens group (surfaces 8 to 9) with positive refractive power that moves toward the image side during focus adjustment from the infinity side to the close distance side, and a third sub-lens group (surfaces 10 to 16) with positive refractive power that does not move during focus adjustment. In Numerical Example 1, the maximum air spacing mD12 between the third lens group U3 and the fourth lens group U4 is the spacing at a focal length of 35 mm.

[0055] 2A and 2B respectively show longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lens of Example 1 (Numerical Example 1) at the wide-angle end and at the intermediate zoom position (focal length 35 mm) in the infinity focused state. FIG. 3 shows longitudinal aberrations of the zoom lens of Example 1 at the telephoto end in the infinity focused state. In each spherical aberration diagram, Fno indicates the F-number, and the solid line, the two-dot chain line, and the one-dot chain line indicate the spherical aberrations for the e-line (wavelength 546.1 nm), the g-line, and the C-line, respectively. In the astigmatism diagram, ω indicates the half angle of view (°), the solid line S indicates the sagittal image plane, and the dashed line M indicates the meridional image plane. Distortion is shown for the g-line. In the chromatic aberration diagram, the two-dot chain line and the one-dot chain line indicate the lateral chromatic aberration for the g-line and the C-line, respectively. The spherical aberration diagram is drawn on a scale of 0.4 mm, the astigmatism diagram is drawn on a scale of 0.4 mm, the distortion diagram is drawn on a scale of 10%, and the chromatic aberration diagram is drawn on a scale of 0.1 mm. The explanations for these longitudinal aberration diagrams are the same as those for the longitudinal aberration diagrams of other examples described later.

[0056] Table 1 shows the values ​​of the conditions of the above-mentioned expressions (1) to (13) in Example 1 (Numerical Example 1). The zoom lens of Example 1 satisfies each of the conditions, and has high optical performance over the entire zoom range while having a wide angle of view and being small and lightweight. In particular, in this example, the third lens group U3 is composed of one negative lens, and the fourth lens group U4 is composed of one positive lens, thereby achieving a wide angle, a small size and a lightweight zoom lens, while also achieving a bright aperture ratio and high optical performance. EXAMPLES

[0057] The zoom lens of Example 2 (Numerical Example 2) shown in FIG. 4 has a first lens group U1 with positive refractive power, which is fixed during magnification change, and moves during focus adjustment, located closest to the object side. In addition, as a subsequent group, the following lens group is provided, in order from the object side to the image side, with a second lens group U2 with negative refractive power, which moves toward the image side during magnification change from the wide-angle end to the telephoto end, and a third lens group U3 with negative refractive power and a fourth lens group U4 with positive refractive power, which move during magnification change. The fourth lens group U4 moves nonlinearly on the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3 in order to correct image plane fluctuations accompanying magnification change. Furthermore, the subsequent group includes a fifth lens group U5 with positive refractive power, which is located closest to the image side and does not move during magnification change, and which is fixed during magnification change.

[0058] In this embodiment, the second lens group U2 corresponds to the n-th moving lens group, the third lens group U3 corresponds to the final moving negative lens group m2, the fourth lens group U4 corresponds to the final moving positive lens group m1, and the fifth lens group U5 corresponds to the final lens group r. The aperture stop SP is included in the fourth lens group U4 and is disposed closest to the object in the fourth lens group U4.

[0059] In Numerical Example 2, the first lens group U1 corresponds to surfaces 1 to 14. The second lens group U2 corresponds to surfaces 15 to 21. The third lens group U3 corresponds to surfaces 22 to 23. The fourth lens group U4 corresponds to surfaces 24 to 26. The fifth lens group U5 corresponds to surfaces 27 to 39.

[0060] The first lens group U1 is composed of a first sub-lens group (surfaces 1 to 4) with negative refractive power that does not move during focus adjustment, a second sub-lens group (surfaces 5 to 7) with negative refractive power that moves toward the image side during focus adjustment from the infinity side to the close distance side, and a third sub-lens group (surfaces 8 to 14) with positive refractive power that does not move during focus adjustment. In Numerical Example 2, the maximum air spacing mD12 between the third lens group U3 and the fourth lens group U4 is the spacing at a focal length of 67 mm.

[0061] 5A and 5B respectively show longitudinal aberrations of the zoom lens of Example 2 (Numerical Example 2) at the wide-angle end and at the intermediate zoom position (focal length 90 mm) when focused on infinity. Fig. 6 shows longitudinal aberrations of the zoom lens of Example 2 at the telephoto end when focused on infinity.

[0062] Table 1 shows the values ​​of the conditions of the above-mentioned expressions (1) to (13) in Example 2 (Numerical Example 2) all together. The zoom lens of Example 2 satisfies each of the conditions, and has high optical performance over the entire zoom range while having a wide angle of view and being small and lightweight. In particular, in this Example, the third lens group U3 is composed of one negative lens, and the fourth lens group U4 is composed of one positive lens, thereby achieving a wide angle, a small size and a lightweight zoom lens, while also achieving a bright aperture ratio and high optical performance. EXAMPLES

[0063] The zoom lens of Example 3 (Numerical Example 3) shown in FIG. 7 has a first lens group U1 with positive refractive power, which is fixed during magnification change, and moves during focus adjustment, located closest to the object side. In addition, as a subsequent group, the zoom lens has, in order from the object side to the image side, a second lens group U2 with negative refractive power, which moves toward the image side during magnification change from the wide-angle end to the telephoto end, a third lens group U3 with negative refractive power, and a fourth lens group U4 with positive refractive power, which move during magnification change. The fourth lens group U4 moves nonlinearly on the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3 in order to correct image plane fluctuations accompanying magnification change. The subsequent group further includes a fifth lens group U5 with positive refractive power, which is disposed closest to the image side and does not move during magnification change. DG is dummy glass corresponding to the color separation optical system light, etc., included in the imaging device.

[0064] In this embodiment, the second lens group U2 corresponds to the n-th moving lens group, the third lens group U3 corresponds to the final moving negative lens group m2, the fourth lens group U4 corresponds to the final moving positive lens group m1, and the fifth lens group U5 corresponds to the final lens group r. The aperture stop SP is included in the fourth lens group U4 and is disposed closest to the object in the fourth lens group U4.

[0065] In Numerical Example 3, the first lens group U1 corresponds to surfaces 1 to 21. The second lens group U2 corresponds to surfaces 22 to 30. The third lens group U3 corresponds to surfaces 31 to 33. The fourth lens group U4 corresponds to surfaces 34 to 38. The fifth lens group U5 corresponds to surfaces 39 to 48. The dummy glass DG corresponds to surfaces 49 to 51.

[0066] The first lens group U1 is composed of a first sub-lens group (surfaces 1 to 8) with negative refractive power that does not move during focus adjustment, a second sub-lens group (surfaces 9 to 10) with negative refractive power that moves toward the image side during focus adjustment from the infinity side to the close distance side, and a third sub-lens group (surfaces 11 to 21) with positive refractive power that does not move during focus adjustment. In Numerical Example 3, the maximum air spacing mD12 between the third lens group U3 and the fourth lens group U4 is the spacing at a focal length of 16 mm.

[0067] 8A and 8B respectively show longitudinal aberrations of the zoom lens of Example 3 (Numerical Example 3) at the wide-angle end and at the intermediate zoom position (focal length 16 mm) when focused on infinity. Fig. 9 shows longitudinal aberrations of the zoom lens of Example 3 at the telephoto end when focused on infinity.

[0068] Table 1 shows the values ​​of the conditions of the above-mentioned expressions (1) to (13) in Example 3 (Numerical Example 3). The zoom lens of Example 3 satisfies each of the conditions, and has high optical performance over the entire zoom range while being compact and lightweight with a wide angle of view. In particular, in this example, the third lens group U3 is composed of two lenses, one negative lens and one positive lens, and the fourth lens group U4 is composed of two positive lenses, thereby achieving a wide angle and a compact and lightweight zoom lens while simultaneously achieving a bright aperture ratio and high optical performance. EXAMPLES

[0069] The zoom lens of Example 4 (Numerical Example 4) shown in FIG. 10 has a first lens group U1 with positive refractive power that is fixed during magnification and moves during focus adjustment, located closest to the object side. In addition, as a subsequent group, the lens group U2 with negative refractive power that moves to the image side during magnification from the wide-angle end to the telephoto end, a third lens group U3 with negative refractive power, a fourth lens group U4 with negative refractive power, and a fifth lens group U5 with positive refractive power that move during magnification, in that order from the object side to the image side. The fifth lens group U5 moves nonlinearly on the optical axis in conjunction with the movements of the second lens group U2, the third lens group U3, and the fourth lens group U4 in order to correct image plane fluctuations accompanying magnification. The subsequent group further includes a sixth lens group U6 with positive refractive power that is located closest to the image side and does not move during magnification.

[0070] In this embodiment, the second lens group U2 and the third lens group U3 correspond to the n-th moving lens group, the fourth lens group U4 corresponds to the final moving negative lens group m2, the fifth lens group U5 corresponds to the final moving positive lens group m1, and the sixth lens group U6 corresponds to the final lens group r. The aperture stop SP is included in the third lens group U3 and is disposed closest to the image side in the third lens group U3.

[0071] In Numerical Example 4, the first lens group U1 corresponds to surfaces 1 to 16. The second lens group U2 corresponds to surfaces 17 to 22. The third lens group U3 corresponds to surfaces 23 to 25. The fourth lens group U4 corresponds to surfaces 26 to 28. The fifth lens group U5 corresponds to surfaces 29 to 30. The sixth lens group U6 corresponds to surfaces 31 to 43.

[0072] The first lens group U1 is composed of a first sub-lens group (surfaces 1 to 6) with negative refractive power that does not move during focus adjustment, a second sub-lens group (surfaces 7 to 8) with negative refractive power that moves toward the image side during focus adjustment from the infinity side to the close distance side, and a third sub-lens group (surfaces 9 to 16) with positive refractive power that does not move during focus adjustment. In Numerical Example 4, the maximum air spacing mD12 between the fourth lens group U4 and the fifth lens group U5 is the spacing at a focal length of 22.6 mm.

[0073] 11A and 11B respectively show longitudinal aberrations of the zoom lens of Example 4 (Numerical Example 4) at the wide-angle end and at the intermediate zoom position (focal length 22.6 mm) when focused on infinity. Fig. 12 shows longitudinal aberrations of the zoom lens of Example 4 at the telephoto end when focused on infinity.

[0074] Table 1 shows the values ​​of the conditions of the above-mentioned expressions (1) to (13) in Example 4 (Numerical Example 3) all together. The zoom lens of Example 4 satisfies each of the conditions, and has high optical performance over the entire zoom range while being compact and lightweight with a wide angle of view. In particular, in this Example, the third lens group U3 is composed of two lenses, one negative lens and one positive lens, and the fourth lens group U4 is composed of one positive lens, thereby achieving a wide angle and a compact and lightweight zoom lens while simultaneously achieving a bright aperture ratio and high optical performance. EXAMPLES

[0075] The zoom lens of Example 5 (Numerical Example 5) shown in FIG. 13 has a first lens group U1 with positive refractive power, which is fixed during magnification change and moves during focus adjustment, located closest to the object side. In addition, as a subsequent group, the following lens group is provided, in order from the object side to the image side, with a second lens group U2 with negative refractive power, which moves toward the image side during magnification change from the wide-angle end to the telephoto end, and a third lens group U3 with negative refractive power and a fourth lens group U4 with positive refractive power, which move during magnification change. The fourth lens group U4 moves nonlinearly on the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3 in order to correct image plane fluctuations accompanying magnification change. In addition, the subsequent group includes a fifth lens group U5 with positive refractive power, which is located closest to the image side and does not move during magnification change, located closest to the image side.

[0076] In this embodiment, the second lens group U2 corresponds to the n-th moving lens group, the third lens group U3 corresponds to the final moving negative lens group m2, the fourth lens group U4 corresponds to the final moving positive lens group m1, and the fifth lens group U5 corresponds to the final lens group r. The aperture diaphragm SP is disposed between the third lens group U3 and the fourth lens group U4, and moves independently during magnification.

[0077] In Numerical Example 5, the first lens group U1 corresponds to surfaces 1 to 18. The second lens group U2 corresponds to surfaces 19 to 25. The third lens group U3 corresponds to surfaces 26 to 28. The aperture stop SP corresponds to surface 29. The fourth lens group U4 corresponds to surfaces 30 to 31. The fifth lens group U5 corresponds to surfaces 32 to 48.

[0078] The first lens group U1 is composed of a first sub-lens group (surfaces 1 to 6) with negative refractive power that does not move during focus adjustment, a second sub-lens group (surfaces 7 to 8) with negative refractive power that moves toward the image side during focus adjustment from the infinity side to the close distance side, and a third sub-lens group (surfaces 9 to 18) with positive refractive power that does not move during focus adjustment. In Numerical Example 5, the maximum air spacing mD12 between the third lens group U3 and the fourth lens group U4 is the spacing at a focal length of 28.5 mm.

[0079] 14A and 14B respectively show longitudinal aberrations of the zoom lens of Example 5 (Numerical Example 5) at the wide-angle end and at the intermediate zoom position (focal length 50 mm) when focused on infinity. Fig. 15 shows longitudinal aberrations of the zoom lens of Example 5 at the telephoto end when focused on infinity. Table 1 shows the values ​​of the conditions of the above-mentioned expressions (1) to (13) in Example 5 (Numerical Example 5). The zoom lens of Example 5 satisfies each of the conditions, and has high optical performance over the entire zoom range while being compact and lightweight with a wide angle of view. In particular, in this example, the fourth lens group U4 is composed of two lenses, one negative lens and one positive lens, and the fifth lens group U5 is composed of one positive lens, thereby achieving a wide angle and a compact and lightweight zoom lens while simultaneously achieving a bright aperture ratio and high optical performance. Furthermore, the aperture stop SP is moved independently of the other lens groups, thereby further increasing the degree of freedom in compactness and weight reduction of the zoom lens and aberration correction. EXAMPLES

[0080] The zoom lens of Example 6 (Numerical Example 6) shown in FIG. 16 has a first lens group U1 with positive refractive power, which is fixed during magnification change and moves during focus adjustment, located closest to the object side. In addition, as a subsequent group, the following lens group is provided, in order from the object side to the image side, with a second lens group U2 with negative refractive power, which moves toward the image side during magnification change from the wide-angle end to the telephoto end, and a third lens group U3 with negative refractive power and a fourth lens group U4 with positive refractive power, which move during magnification change. The fourth lens group U4 moves nonlinearly on the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3 in order to correct image plane fluctuations accompanying magnification change. Furthermore, the subsequent group includes a fifth lens group U5 with positive refractive power, which is located closest to the image side and does not move during magnification change.

[0081] In this embodiment, the second lens group U2 corresponds to the n-th moving lens group, the third lens group U3 corresponds to the final moving negative lens group m2, the fourth lens group U4 corresponds to the final moving positive lens group m1, and the fifth lens group U5 corresponds to the final lens group r. The aperture diaphragm SP is disposed between the second lens group U2 and the third lens group U3, and moves independently during magnification.

[0082] In Numerical Example 6, the first lens group U1 corresponds to surfaces 1 to 13. The second lens group U2 corresponds to surfaces 14 to 20. The aperture stop SP corresponds to surface 21. The third lens group U3 corresponds to surfaces 22 to 23. The fourth lens group U4 corresponds to surfaces 24 to 26. The fifth lens group U5 corresponds to surfaces 27 to 38.

[0083] The first lens group U1 is composed of a first sub-lens group (surfaces 1 to 6) with negative refractive power that does not move during focus adjustment, a second sub-lens group (surfaces 7 to 8) with negative refractive power that moves toward the image side during focus adjustment from the infinity side to the close distance side, and a third sub-lens group (surfaces 9 to 13) with positive refractive power that does not move during focus adjustment. In Numerical Example 6, the maximum air spacing mD12 between the third lens group U3 and the fourth lens group U4 is the spacing at a focal length of 27 mm.

[0084] 17A and 17B respectively show longitudinal aberrations of the zoom lens of Example 6 (Numerical Example 6) at the wide-angle end and at the intermediate zoom position (focal length 37.5 mm) when focused on infinity. Fig. 18 shows longitudinal aberrations of the zoom lens of Example 6 at the telephoto end when focused on infinity.

[0085] Table 1 shows the values ​​of the conditions of the above-mentioned expressions (1) to (13) in Example 6 (Numerical Example 6). The zoom lens of Example 6 satisfies each of the conditions, and has high optical performance over the entire zoom range while being compact and lightweight with a wide angle of view. In particular, in this example, the third lens group U3 is composed of one negative lens, and the fourth lens group U5 is composed of two lenses, one negative lens and one positive lens, thereby achieving a wide angle, compactness and light weight of the zoom lens, while achieving both a bright aperture ratio and high optical performance. Furthermore, the aperture stop SP is moved independently of the other lens groups, thereby further increasing the degree of freedom in compactness and light weight of the zoom lens and correction of aberrations. (Numerical example 1) Unit: mm Surface number rd nd νd θgF Effective diameter Focal length 1* 312.09871 2.50000 1.804000 46.53 0.5577 90.176 -49.629 2 35.41165 27.44337 1.000000 0.00 0.0000 64.430 0.000 3 -123.76796 1.50000 1.763850 48.49 0.5589 63.015 -116.254 4 321.52157 6.91091 1.000000 0.00 0.0000 62.906 0.000 5 217.21964 1.50000 1.763850 48.49 0.5589 64.606 -178.164 6 83.67057 9.23784 1.846660 23.78 0.6205 64.757 100.343 7 3203.73917 7.40933 1.000000 0.00 0.0000 64.754 0.000 8* 83.80576 14.34011 1.603001 65.44 0.5401 65.507 80.546 9 -109.00708 6.19099 1.000000 0.00 0.0000 64.910 0.000 10 -1034.45742 1.50000 1.805181 25.42 0.6161 58.153 -71.011 11 61.15588 8.17606 1.438750 94.66 0.5340 55.800 140.823 12 4621.73607 0.20000 1.000000 0.00 0.0000 55.752 0.000 13 122.00000 6.57256 1.755000 52.32 0.5474 55.738 102.307 14 -208.22314 0.20000 1.000000 0.00 0.0000 55.765 0.000 15 -497.04040 4.98914 1.712995 53.87 0.5459 55.542 182.160 16 -103.76583 (Variable) 1.000000 0.00 0.0000 55.437 0.000 17 -530.46608 1.25000 1.537750 74.70 0.5392 32.363 -67.034 18 38.84025 5.22554 1.000000 0.00 0.0000 30.905 0.000 19 -117.12242 1.25000 1.834810 42.74 0.5648 30.886 -35.726 20 40.50865 5.25419 1.858956 22.73 0.6284 31.490 51.468 21 408.99391 3.47521 1.000000 0.00 0.0000 31.718 0.000 22 -60.05260 1.25000 1.804000 46.53 0.5577 31.967 -220.375 23 -91.44834 (Variable) 1.000000 0.00 0.0000 32.710 0.000 24 -96.04104 1.40000 1.496999 81.54 0.5375 33.650 -159.776 25 468.65371 (Variable) 1.000000 0.00 0.0000 34.882 0.000 26 (Aperture) 6.64159 1.000000 0.00 0.0000 36.448 0.000 27 54.99081 6.45651 1.804000 46.58 0.5573 43.526 68.664 28* 5820.92432 (variable) 1.000000 0.00 0.0000 43.349 0.000 29 34.67248 8.39358 1.487490 70.23 0.5300 43.443 102.958 30 102.44709 5.19167 1.000000 0.00 0.0000 42.007 0.000 31 72.35771 1.30000 2.001000 29.14 0.5997 39.006 -51.266 32 29.89349 11.31360 1.438750 94.66 0.5340 36.397 51.585 33 -83.27147 0.49811 1.000000 0.00 0.0000 35.778 0.000 34 67.21711 11.67354 1.858956 22.73 0.6284 33.515 24.203 35 -28.08537 1.20000 2.050900 26.94 0.6054 31.058 -30.300 36 -228.46114 0.43589 1.000000 0.00 0.0000 29.548 0.000 37 191.16657 1.10000 2.050900 26.94 0.6054 29.354 -29.208 38 26.56866 8.67028 1.589130 61.14 0.5407 28.676 49.991 39 230.28715 0.31516 1.000000 0.00 0.0000 29.644 0.000 40 48.39839 3.51047 1.487490 70.23 0.5300 30.558 266.078 41 75.21484 0.00000 1.000000 0.00 0.0000 30.645 0.000 Image plane ∞ Aspheric Data Front page K = 0.00000e+000 A 4= 1.91539e-006 A 6=-9.04805e-010 A 8= 8.48122e-013 A10=-7.22790e-016 A12= 4.05143e-019 A14=-1.23037e-022 A16= 1.54023e-026 Side 8 K = 0.00000e+000 A 4=-1.44627e-006 A 6= 5.00529e-010 A 8=-7.74823e-013 A10= 1.05228e-015 A12=-7.56855e-019 A14= 2.69751e-022 A16=-3.23896e-026 Page 28 K = 0.00000e+000 A 4= 2.08152e-006 A 6= 8.75490e-010 A 8=-9.88539e-012 A10= 5.49901e-014 A12=-1.65657e-016 A14= 2.49322e-019 A16=-1.47945e-022 Various data Zoom ratio 2.50 Focal length 20.00 35.00 50.00 F-number 2.20 2.20 2.20 Half angle of view (°) 47.25 31.72 23.40 Lens total length 284.12 284.12 284.12 BF 50.30 50.30 50.30 d16 1.19 27.56 40.67 d23 26.78 4.68 2.37 d25 3.17 7.88 2.70 d28 18.19 9.22 3.60 Lens Group Data Group starting plane focal length 1 1 46.01 2 17 -33.54 3 24 -159.78 4 26 68.66 5 29 85.16 (Numerical example 2) Unit: mm Surface Data Surface number rd nd νd θgF Effective diameter Focal length 1 565.31342 8.39049 1.517417 52.43 0.5564 96.986 328.873 2 -243.78309 0.20000 1.000000 0.00 0.0000 95.873 0.000 3 -496.37641 3.00000 1.639999 60.08 0.5370 90.984 -154.244 4 124.12575 29.25722 1.000000 0.00 0.0000 81.947 0.000 5 -333.77782 2.40000 1.639999 60.08 0.5370 72.355 -154.035 6 141.08884 2.70809 1.846660 23.78 0.6205 69.103 678.773 7 184.75390 3.01070 1.000000 0.00 0.0000 68.544 0.000 8 209.32519 7.09849 1.595220 67.74 0.5442 69.149 194.445 9 -257.60768 0.29722 1.000000 0.00 0.0000 69.567 0.000 10 140.25260 2.50000 1.846660 23.78 0.6205 70.979 -265.373 11 85.96457 11.75989 1.438750 94.66 0.5340 70.236 146.472 12 -246.40158 0.27182 1.000000 0.00 0.0000 70.376 0.000 13 73.94018 8.56360 1.712995 53.87 0.5459 70.251 131.702 14 325.68155 (Variable) 1.000000 0.00 0.0000 69.566 0.000 15 199.86035 1.50000 1.537750 74.70 0.5392 38.701 -86.236 16 37.63806 5.72326 1.000000 0.00 0.0000 36.292 0.000 17 -290.51681 1.50000 1.654115 39.68 0.5737 36.224 -57.241 18 43.36578 4.14379 1.846660 23.78 0.6205 36.022 70.125 19 149.79522 4.74070 1.000000 0.00 0.0000 35.858 0.000 20 -53.78699 1.50000 1.743997 44.78 0.5655 35.841 -106.216 21 -168.53308 (Variable) 1.000000 0.00 0.0000 36.848 0.000 22 -60.30318 1.50000 1.438750 94.66 0.5340 37.769 -123.263 23 541.39520 (Variable) 1.000000 0.00 0.0000 39.869 0.000 24 (Aperture) 1.47190 1.000000 0.00 0.0000 41.604 0.000 25 76.20576 5.83517 2.001000 29.14 0.5997 44.862 64.166 26* -414.18737 (variable) 1.000000 0.00 0.0000 44.843 0.000 27 112.60564 7.25699 1.487490 70.23 0.5300 44.815 108.716 28 -98.63129 4.21449 1.000000 0.00 0.0000 44.477 0.000 29 254.35708 1.50000 1.854780 24.80 0.6122 41.062 -38.968 30 29.61810 11.48226 1.618000 63.33 0.5441 38.600 41.362 31 -163.41664 5.01834 1.000000 0.00 0.0000 38.210 0.000 32 116.26650 7.59835 1.806100 40.93 0.5713 35.578 37.990 33 -40.67631 1.10000 1.854780 24.80 0.6122 34.822 -37.737 34 165.31961 6.80980 1.000000 0.00 0.0000 34.968 0.000 35 154.24702 12.35412 1.892860 20.36 0.6393 36.588 30.030 36 -31.65728 1.10000 1.800999 34.97 0.5864 36.627 -23.247 37 46.68041 0.59421 1.000000 0.00 0.0000 35.897 0.000 38 64.70769 6.80513 1.539956 59.46 0.5441 35.593 101.725 39 -359.44654 0.00000 1.000000 0.00 0.0000 36.219 0.000 Image plane ∞ Aspheric Data Page 26 K = 0.00000e+000 A 4= 1.36315e-006 A 6=-3.51991e-011 A 8=-4.35765e-014 A10 = 1.49816e-017 Various data Zoom ratio 3.00 Focal length 45.00 67.00 90.00 135.00 F-number 2.20 2.20 2.20 2.20 Half angle of view (°) 27.27 19.10 14.44 9.75 Lens total length 285.78 285.78 285.78 285.78 BF 52.00 52.00 52.00 52.00 d14 1.13 21.68 36.34 51.33 d21 29.42 7.94 4.52 4.51 d23 9.25 13.87 11.12 2.92 d26 20.94 17.25 8.76 1.99 Lens Group Data Group starting plane focal length 1 1 106.54 2 15 -37.98 3 22 -123.26 4 24 64.17 5 27 95.60 (Numerical example 3) Unit: mm Surface Data Surface number rd nd νd θgF Effective diameter Focal length 1* 963.48779 2.50000 1.834810 42.74 0.5648 79.927 -39.756 2 32.21778 16.56896 1.000000 0.00 0.0000 56.513 0.000 3* 176.21722 2.00000 1.816000 46.62 0.5568 55.665 -216.003 4 87.89143 9.46327 1.000000 0.00 0.0000 53.246 0.000 5 -92.63298 1.80000 1.882997 40.76 0.5667 52.755 -111.739 6 -1404.04903 0.15000 1.000000 0.00 0.0000 53.355 0.000 7 101.56945 4.35199 1.922860 18.90 0.6495 54.075 139.918 8 445.99650 3.28870 1.000000 0.00 0.0000 53.812 0.000 9 211.03669 7.04881 1.595220 67.74 0.5442 52.875 118.909 10* -105.72030 4.45598 1.000000 0.00 0.0000 52.419 0.000 11 -1118.38500 8.36306 1.433870 95.10 0.5373 51.267 133.670 12 -55.39308 0.29743 1.000000 0.00 0.0000 51.911 0.000 13 -55.40012 1.70000 1.800000 29.84 0.6017 51.902 -146.757 14 -105.59441 0.18000 1.000000 0.00 0.0000 53.959 0.000 15 154.10268 1.70000 1.916500 31.60 0.5911 56.307 -103.302 16 58.60506 13.06047 1.438750 94.66 0.5340 56.367 94.291 17 -132.22982 0.40000 1.000000 0.00 0.0000 57.470 0.000 18 1432.31631 8.96363 1.433870 95.10 0.5373 59.006 151.279 19 -68.83776 0.40000 1.000000 0.00 0.0000 59.501 0.000 20 116.03285 7.88147 1.763850 48.49 0.5589 59.128 95.318 21 -192.20285 (Variable) 1.000000 0.00 0.0000 58.686 0.000 22 182.45216 0.70000 2.001000 29.14 0.5997 22.265 -23.163 23 20.67952 3.78836 1.000000 0.00 0.0000 20.084 0.000 24 -67.41255 0.70000 1.438750 94.66 0.5340 19.908 -67.266 25 52.89819 2.45901 1.000000 0.00 0.0000 19.501 0.000 26 -184.88863 5.09230 1.854780 24.80 0.6122 19.390 19.629 27 -15.71421 0.70000 1.882997 40.76 0.5667 19.395 -15.994 28 151.05341 0.24382 1.000000 0.00 0.0000 19.498 0.000 29 41.93140 2.78127 1.647689 33.79 0.5938 19.674 54.414 30 -224.97708 (Variable) 1.000000 0.00 0.0000 19.542 0.000 31 -34.77729 0.80000 1.729157 54.68 0.5444 18.699 -26.093 32 42.82558 2.38385 1.846660 23.78 0.6205 19.783 58.388 33 293.47891 (Variable) 1.000000 0.00 0.0000 20.172 0.000 34 (Aperture) 1.00000 1.000000 0.00 0.0000 26.100 0.000 35* 69.10287 5.05113 1.589130 61.14 0.5407 27.442 71.819 36 -107.23910 0.50000 1.000000 0.00 0.0000 28.140 0.000 37 66.08017 4.22964 1.487490 70.23 0.5300 28.822 120.623 38 -539.28698 (Variable) 1.000000 0.00 0.0000 28.827 0.000 39 74.09824 5.00000 1.639799 34.46 0.5922 27.876 55.182 40 -66.52059 5.47385 1.000000 0.00 0.0000 27.511 0.000 41 -112.12205 0.90000 1.882997 40.76 0.5667 23.895 -19.734 42 20.85216 6.79806 1.487490 70.23 0.5300 22.949 38.664 43 -181.51707 0.50000 1.000000 0.00 0.0000 23.271 0.000 44 45.98850 8.01769 1.438750 94.66 0.5340 23.507 35.367 45 -22.25685 0.90000 2.001000 29.14 0.5997 23.517 -42.451 46 -47.26612 0.50000 1.000000 0.00 0.0000 24.566 0.000 47 99.45872 5.89156 1.487490 70.23 0.5300 25.327 48.495 48 -30.54482 4.00000 1.000000 0.00 0.0000 25.527 0.000 49 ∞ 33.00000 1.608590 46.44 0.5664 40.000 0.000 50 ∞ 13.20000 1.516800 64.17 0.5347 40.000 0.000 51 ∞ 0.00000 1.000000 0.00 0.0000 40.000 0.000 Image plane ∞ Aspheric Data Front page K = 0.00000e+000 A 4= 3.44812e-006 A 6= 1.07704e-008 A 8= 7.67357e-012 A10= 9.50640e-014 A12= 1.11173e-016 A14= 1.84902e-020 A16=-4.54134e-026 A 3= 1.18753e-005 A 5=-1.35919e-007 A 7=-3.25626e-010 A 9=-1.17107e-012 A11=-4.11261e-015 A13=-1.90081e-018 A15=-7.34375e-023 Page 3 K = 0.00000e+000 A 4=-2.23245e-006 A 6=-7.25846e-008 A 8=-7.12638e-010 A10=-3.22136e-013 A12= 1.59835e-015 A14=-6.53534e-019 A16=-2.01913e-022 A 3=-8.59491e-006 A 5= 3.82988e-007 A 7= 9.13105e-009 A 9= 3.03033e-011 A11=-3.27032e-014 A13=-1.78607e-017 A15= 2.22630e-020 Page 10 K = 0.00000e+000 A 4= 9.40059e-007 A 6= 1.41016e-008 A 8= 2.70921e-010 A10= 2.08488e-013 A12=-7.69021e-016 A14= 1.05318e-018 A16= 2.20512e-022 A 3=-1.65554e-006 A 5=-2.41420e-008 A 7=-2.66426e-009 A 9=-1.44061e-011 A11= 1.68272e-014 A13=-4.84134e-018 A15=-2.64586e-020 Page 35 K =-9.88912e+000 A 4=-7.04883e-007 A 6=-1.40259e-009 A 8=-1.03348e-012 Various data Zoom ratio 13.64 Focal length 4.40 16.00 60.00 F-number 1.85 1.85 2.74 Half angle of view (°) 51.34 18.97 5.24 Lens total length 307.65 307.65 307.65 BF 7.45 7.45 7.45 d21 0.65 39.52 57.72 d30 38.78 1.50 6.83 d33 12.81 16.79 1.20 d38 38.77 33.20 25.27 Lens Group Data Group starting plane focal length 1 1 31.68 2 22 -20.30 3 31 -47.23 4 34 45.67 5 39 50.32 (Numerical example 4) Unit: mm Surface Data Surface number rd nd νd θgF Effective diameter Focal length 1* 107.58786 2.40000 1.763850 48.49 0.5589 73.044 -46.128 2 26.38228 25.82333 1.000000 0.00 0.0000 50.774 0.000 3 -80.19301 1.64503 1.763850 48.49 0.5589 48.067 -44.969 4 61.14574 3.11155 1.000000 0.00 0.0000 46.370 0.000 5 65.03455 6.75280 1.854780 24.80 0.6122 47.389 70.937 6 -991.28086 2.10705 1.000000 0.00 0.0000 47.014 0.000 7 2435.96345 5.33796 1.537750 74.70 0.5392 46.071 192.449 8* -108.35892 5.86909 1.000000 0.00 0.0000 46.283 0.000 9 -77.53096 1.50000 1.800000 29.84 0.6017 45.577 -53.979 10 100.09169 10.19852 1.496999 81.54 0.5375 47.085 74.030 11 -56.46737 0.26908 1.000000 0.00 0.0000 47.798 0.000 12 59.42574 1.50000 1.834000 37.16 0.5776 48.441 -91.650 13 33.13983 12.18992 1.589130 61.14 0.5407 46.324 51.800 14 -350.03933 0.20000 1.000000 0.00 0.0000 46.036 0.000 15 65.72328 6.50682 1.763850 48.49 0.5589 44.526 73.309 16 -374.47003 (Variable) 1.000000 0.00 0.0000 43.561 0.000 17 456.78250 1.10000 1.834810 42.74 0.5648 26.293 -33.078 18 26.14735 5.69692 1.000000 0.00 0.0000 25.108 0.000 19 -60.59851 1.00000 1.496999 81.54 0.5375 25.562 -56.691 20 53.23977 0.19937 1.000000 0.00 0.0000 27.273 0.000 21 43.65730 4.86019 2.001000 29.14 0.5997 28.026 35.526 22 -189.27119 (Variable) 1.000000 0.00 0.0000 28.182 0.000 23 -47.87285 1.20000 1.763850 48.49 0.5589 28.190 -69.454 24 -474.24532 2.30134 1.000000 0.00 0.0000 29.018 0.000 25 (Aperture) (Variable) 1.000000 0.00 0.0000 30.104 0.000 26 504.53903 1.20000 1.891900 37.13 0.5780 30.748 -144.140 27 102.85825 1.61908 1.717362 29.52 0.6047 31.164 275.425 28 211.31465 (Variable) 1.000000 0.00 0.0000 31.414 0.000 29* 45.86226 5.55563 1.696797 55.53 0.5434 34.434 57.172 30 -297.80366 (Variable) 1.000000 0.00 0.0000 34.491 0.000 31 -1075.02325 3.84064 1.763850 48.49 0.5589 34.000 103.125 32 -73.84411 8.02428 1.000000 0.00 0.0000 33.991 0.000 33 37.26529 5.92550 1.517417 52.43 0.5564 28.983 53.571 34 -104.15074 1.20000 2.000690 25.46 0.6136 28.655 -26.075 35 35.45085 0.19760 1.000000 0.00 0.0000 28.372 0.000 36 24.91782 8.74590 1.595220 67.74 0.5442 30.792 32.989 37 -81.82293 0.53816 1.000000 0.00 0.0000 30.508 0.000 38 -2269.28963 1.20000 2.000690 25.46 0.6136 29.590 -18.188 39 18.52406 8.67501 1.922860 18.90 0.6495 27.881 18.803 40 -263.21728 1.99878 1.000000 0.00 0.0000 27.578 0.000 41 285.65324 8.95213 1.496999 81.54 0.5375 26.508 31.640 42 -16.51890 1.10000 2.003300 28.27 0.5980 25.779 -20.674 43 -81.21906 0.00000 1.000000 0.00 0.0000 28.187 0.000 Image plane ∞ Aspheric Data Front page K = 0.00000e+000 A 4= 3.70534e-006 A 6=-1.65787e-009 A 8= 1.42981e-012 A10=-7.28306e-016 A12= 3.41473e-019 A14=-9.69561e-023 A16= 1.48551e-026 Side 8 K = 0.00000e+000 A 4= 7.06974e-007 A 6=-1.72530e-009 A 8= 7.19872e-013 A10=-6.21181e-016 A12= 7.56517e-020 Page 29 K = 0.00000e+000 A 4=-3.37197e-006 A 6=-2.04690e-010 A 8=-7.48146e-013 Various data Zoom ratio 2.00 Focal length 18.00 22.60 36.00 F-number 2.40 2.40 2.40 Half angle of view (°) 50.24 43.80 31.00 Lens total length 230.26 230.26 230.26 BF 32.80 32.80 32.80 d16 0.99 12.00 28.52 d22 3.27 3.10 3.33 d25 11.70 6.62 1.26 d28 5.90 6.72 2.31 d30 15.06 8.48 1.50 Lens Group Data Group starting plane focal length 1 1 33.50 2 17 -60.90 3 23 -69.45 4 26 -300.00 5 29 57.17 6 31 87.59 (Numerical example 5) Unit: mm Surface Data Surface number rd nd νd θgF Effective diameter Focal length 1* 179.28818 2.58020 1.800999 34.97 0.5864 88.384 -65.453 2 40.51580 28.15343 1.000000 0.00 0.0000 68.427 0.000 3 -84.81243 1.64503 1.639999 60.08 0.5370 67.003 -105.635 4 342.44067 0.17808 1.000000 0.00 0.0000 67.172 0.000 5 142.27010 6.36004 1.959060 17.47 0.6598 67.574 136.595 6 -1941.09474 1.48371 1.000000 0.00 0.0000 67.250 0.000 7 215.87053 9.55363 1.537750 74.70 0.5392 65.711 140.386 8* -114.85361 6.55908 1.000000 0.00 0.0000 65.655 0.000 9 -614.33686 8.00749 1.487490 70.23 0.5300 67.083 190.144 10 -81.12458 2.00000 1.850250 30.05 0.5979 67.301 -253.819 11 -130.85190 0.17660 1.000000 0.00 0.0000 68.643 0.000 12 166.94003 1.84300 1.846660 23.78 0.6205 69.198 -120.436 13 63.36609 13.93587 1.438750 94.66 0.5340 68.495 118.498 14 -274.01084 0.18430 1.000000 0.00 0.0000 68.962 0.000 15 235.61253 5.36965 1.537750 74.70 0.5392 70.377 309.585 16 -569.02578 0.18430 1.000000 0.00 0.0000 70.499 0.000 17 1629.47679 8.33649 1.763850 48.49 0.5589 70.577 124.954 18 -101.68731 (Variable) 1.000000 0.00 0.0000 70.591 0.000 19* -115.10910 1.19795 1.595220 67.74 0.5442 30.642 -48.039 20 38.37112 4.14288 1.000000 0.00 0.0000 27.108 0.000 21 -92.99580 0.82935 1.537750 74.70 0.5392 26.542 -89.867 22 101.59645 1.76664 1.000000 0.00 0.0000 25.573 0.000 23 -105.92074 2.39760 1.800000 29.84 0.6017 25.489 103.425 24 -47.13037 0.82935 1.595220 67.74 0.5442 25.306 -123.677 25 -131.04411 (Variable) 1.000000 0.00 0.0000 24.872 0.000 26 -48.70990 0.82935 1.804000 46.53 0.5577 24.475 -32.026 27 55.64235 2.17206 1.892860 20.36 0.6393 25.718 79.883 28 238.73317 (Variable) 1.000000 0.00 0.0000 26.001 0.000 29 (Aperture) (Variable) 1.000000 0.00 0.0000 26.750 0.000 30* 58.64939 5.22236 1.651597 58.55 0.5425 34.735 59.634 31 -112.43994 (Variable) 1.000000 0.00 0.0000 34.993 0.000 32 97.47026 6.17264 1.589130 61.14 0.5407 40.750 76.715 33 -82.88656 0.18430 1.000000 0.00 0.0000 40.841 0.000 34 98.28048 9.16148 1.487490 70.23 0.5300 39.862 61.841 35 -42.36176 1.10580 2.000690 25.46 0.6136 39.233 -66.298 36 -116.83120 0.18430 1.000000 0.00 0.0000 39.558 0.000 37 71.96735 9.16590 1.518229 58.90 0.5457 38.677 66.389 38 -63.53394 1.01365 1.799516 42.22 0.5672 37.507 -32.539 39 44.79204 11.24992 1.000000 0.00 0.0000 36.255 0.000 40 123.08263 10.52827 1.487490 70.23 0.5300 40.293 58.517 41 -36.24874 0.36860 1.000000 0.00 0.0000 40.758 0.000 42 1390.32998 7.58399 1.922860 18.90 0.6495 37.839 34.512 43 -32.92256 0.82935 1.882997 40.76 0.5667 37.466 -35.829 44 962.30499 1.99586 1.000000 0.00 0.0000 35.571 0.000 45 60.62112 8.40348 1.438750 94.66 0.5340 33.479 49.322 46 -32.35520 0.92150 2.000690 25.46 0.6136 32.626 -21.660 47 68.50387 0.64505 1.000000 0.00 0.0000 32.599 0.000 48 61.62245 5.48371 1.589130 61.14 0.5407 33.088 60.474 49 -82.42064 0.00000 1.000000 0.00 0.0000 33.239 0.000 Image plane ∞ Aspheric Data Front page K = 0.00000e+000 A 4= 3.26965e-007 A 6= 3.49556e-010 A 8=-2.18678e-013 A10=7.29562e-017 A12=-9.64672e-021 Side 8 K = 0.00000e+000 A 4= 6.44973e-007 A 6=-1.23889e-012 A 8= 8.79826e-014 A10=-1.25104e-016 A12= 4.19714e-020 Page 19 K = 0.00000e+000 A 4= 3.54713e-006 A 6=-4.63834e-009 A 8= 7.10201e-012 A10=-2.64552e-014 A12= 5.17715e-017 Page 30 K = 0.00000e+000 A 4=-3.30420e-006 A 6= 1.56947e-009 A 8=-1.01392e-012 Various data Zoom ratio 8.40 Focal length 15.50 28.50 50.00 130.20 F-number 2.40 2.44 2.51 3.56 Half angle of view (°) 43.68 27.43 16.49 6.50 Image height 14.80 14.80 14.80 14.80 Lens total length 315.01 315.01 315.01 315.01 BF 39.85 39.85 39.85 39.85 d18 0.69 29.65 51.38 73.10 d25 32.71 9.77 2.50 6.65 d28 3.00 3.46 2.13 1.50 d29 13.45 15.41 14.88 1.48 d31 34.38 25.93 13.33 1.49 Lens Group Data Group starting plane focal length 1 1 61.70 2 19 -32.45 3 26 -53.35 4 29 (Aperture) 5 30 59.63 6 32 73.74 (Numerical Example 6) Unit: mm Surface Data Surface number rd nd νd θgF Effective diameter Focal length 1* 331.42801 2.50000 1.905250 35.04 0.5848 55.948 -38.742 2 31.79439 15.85559 1.000000 0.00 0.0000 45.633 0.000 3 -71.80452 2.00000 1.905250 35.04 0.5848 45.724 -105.943 4 -283.85406 3.58328 1.000000 0.00 0.0000 47.807 0.000 5 348.54019 6.01156 1.846660 23.78 0.6205 51.729 120.439 6 -145.00543 2.39757 1.000000 0.00 0.0000 52.500 0.000 7* 477.99140 4.33759 1.603001 65.44 0.5401 53.705 205.487 8 -167.51918 8.15174 1.000000 0.00 0.0000 53.862 0.000 9 126.04168 1.50000 1.805181 25.42 0.6161 54.169 -120.586 10 54.83663 10.33425 1.438750 94.66 0.5340 53.726 103.278 11 -249.50526 0.20000 1.000000 0.00 0.0000 54.086 0.000 12 117.75694 10.33425 1.755000 52.32 0.5474 55.006 74.961 13* -105.76402 (variable) 1.000000 0.00 0.0000 55.013 0.000 14 -720.39137 1.25000 1.537750 74.70 0.5392 27.212 -65.731 15 37.31836 5.08509 1.000000 0.00 0.0000 25.235 0.000 16 -39.74822 1.25000 1.834810 42.74 0.5648 25.244 -52.280 17 -427.60077 0.15124 1.000000 0.00 0.0000 26.200 0.000 18 469.47906 3.02721 1.858956 22.73 0.6284 26.482 67.126 19 -66.30713 1.25000 1.804000 46.53 0.5577 26.844 -305.237 20 -91.44834 (Variable) 1.000000 0.00 0.0000 27.230 0.000 21 (Aperture) (Variable) 1.000000 0.00 0.0000 27.795 0.000 22 -126.38159 1.40000 1.487490 70.23 0.5300 28.028 -143.424 23 158.26586 (Variable) 1.000000 0.00 0.0000 28.601 0.000 24 50.88588 1.30000 1.720467 34.71 0.5834 32.054 -209.131 25 37.69504 5.55747 1.639999 60.08 0.5370 31.951 49.749 26* -198.19327 (variable) 1.000000 0.00 0.0000 31.949 0.000 27 126.14835 5.36134 1.496999 81.54 0.5375 35.539 91.179 28 -70.04065 0.16580 1.000000 0.00 0.0000 35.787 0.000 29 33.31496 1.30000 2.001000 29.14 0.5997 35.384 -236.366 30 28.65911 8.31543 1.438750 94.66 0.5340 34.206 69.535 31 414.66565 5.78064 1.000000 0.00 0.0000 33.228 0.000 32 59.92686 4.00000 2.050900 26.94 0.6054 29.994 93.160 33 147.17020 3.05378 1.000000 0.00 0.0000 28.655 0.000 34 -74.05040 1.10000 2.050900 26.94 0.6054 27.817 -17.967 35 25.83934 3.27150 1.589130 61.14 0.5407 26.857 144.982 36 35.24419 1.81511 1.000000 0.00 0.0000 27.210 0.000 37 34.12369 7.78305 1.487490 70.23 0.5300 29.344 44.064 38 -54.12850 0.00000 1.000000 0.00 0.0000 29.779 0.000 Image plane ∞ Aspheric Data Front page K = 0.00000e+000 A 4= 2.53228e-006 A 6= 3.11085e-009 A 8=-1.92875e-011 A10= 5.08445e-014 A12=-7.31505e-017 A14= 5.42530e-020 A16=-1.61062e-023 Side 7 K = 0.00000e+000 A 4=-7.36262e-007 A 6= 6.95119e-010 A 8=-5.95349e-012 A10= 3.05751e-014 A12=-6.95113e-017 A14= 7.57961e-020 A16=-3.17589e-023 Page 13 K = 0.00000e+000 A 4=-1.58900e-007 A 6=-5.27979e-011 A 8= 3.76780e-013 A10=-8.86857e-016 A12= 1.69703e-018 A14=-1.97977e-021 A16= 9.44234e-025 Page 26 K = 0.00000e+000 A 4= 2.65410e-006 A 6=-8.03548e-009 A 8= 2.30353e-010 A10=-2.89085e-012 A12= 1.81329e-014 A14=-5.51462e-017 A16= 6.46489e-020 Various data Zoom ratio 3.00 Focal length 18.00 27.00 37.50 53.99 F-number 2.20 2.20 2.20 2.20 Half angle of view (°) 39.43 28.69 21.50 15.33 Lens total length 232.60 232.60 232.60 232.60 BF 25.00 25.00 25.00 25.00 d13 0.97 34.34 53.74 69.45 d20 14.39 2.07 1.98 1.91 d21 1.54 1.89 2.00 1.99 d23 17.88 17.96 12.11 1.88 d26 43.41 21.91 8.35 2.94 Lens Group Data Group starting plane focal length 1 1 66.05 2 14 -44.99 3 21 (Aperture) 4 22 -143.42 5 24 65.98 6 27 72.49

[0086] [Table 1]

[0087] Fig. 21 shows the configuration of an imaging device (television camera system) 125 that uses any one of the zoom lenses according to the above-mentioned embodiments 1 to 6 as an imaging optical system. In Fig. 21, 101 is any one of the zoom lenses according to the embodiments 1 to 6. 124 is a camera. The zoom lens 101 is detachable from the camera 124.

[0088] The zoom lens 101 has a first lens group F, a magnification change section LZ included in the subsequent group, and a rear group R for imaging. The first lens group F is a lens group that moves during focus adjustment. The magnification change section LZ includes a plurality of lens groups that move during magnification change. An aperture stop SP moves in conjunction with magnification change. Reference numerals 114 and 115 denote driving mechanisms such as helicoids and cams that drive the first lens group F and the lens groups included in the magnification change section LZ in the optical axis direction, respectively.

[0089] Reference numerals 116 to 118 denote motors that drive the drive mechanisms 114 and 115 and the aperture diaphragm SP. Reference numerals 119 to 121 denote detectors such as encoders, potentiometers, or photosensors for detecting the positions of the first lens group F, the magnification variable section LZ, and the aperture diaphragm SP in the optical axis direction, and the aperture diameter of the aperture diaphragm SP.

[0090] In the camera 124, reference numeral 109 denotes a glass block corresponding to an optical filter or a color separation optical system, and reference numeral 110 denotes an imaging element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor that receives a subject image formed by the zoom lens 101. Reference numerals 111 and 122 denote CPUs that control the camera 124 and the zoom lens 101.

[0091] In this way, by using the zoom lens of each embodiment, it is possible to realize an imaging device having high optical performance.

[0092] The embodiments described above are merely representative examples, and various modifications and alterations are possible for each embodiment when implementing the present invention. [Explanation of symbols]

[0093] U1 First lens group U2 2nd lens group U3 Third lens group U4 4th lens group U5 Fifth lens group U6 6th lens group SP aperture stop IP image plane

Claims

1. A zoom lens comprising a first lens group having a positive refractive power and a subsequent group including a plurality of lens groups, which are arranged in order from an object side to an image side, and which performs magnification change by changing an interval between adjacent lens groups, The first lens group does not move during magnification change, The subsequent lens group comprises, in order from the image side to the object side, a final lens group having positive refractive power that does not move during magnification variation, a final movable positive lens group having positive refractive power that is composed of one or two lenses and moves during magnification variation, a final movable negative lens group having negative refractive power that moves during magnification variation, and one or two movable lens groups having negative refractive power that move during magnification variation. the subsequent lens group includes an aperture stop that is located closer to the object side than the final moving positive lens group and that moves during magnification variation, the aperture diaphragm is located closer to the object side at a wide-angle end of the zoom lens than at a telephoto end, Let Lwt be the distance on the optical axis between the position of the aperture stop at the wide-angle end and the position of the aperture stop at the telephoto end, and Td be the distance on the optical axis from the surface of the zoom lens closest to the object side to the image plane at the wide-angle end. 0.01≦Lwt / Td≦0.25 A zoom lens characterized by satisfying the following conditions.

2. the subsequent lens group has a final movable negative lens group having negative refractive power and consisting of one or two lenses, the final movable negative lens group being located closer to the object side than the final movable positive lens group; When the average value of the Abbe numbers of the optical materials of all the positive lenses included in the final moving positive lens group based on the d-line is denoted as νm1, the average value of the partial dispersion ratios of the optical materials of all the positive lenses based on the g-line and the F-line is denoted as θm1, the average value of the Abbe numbers of the optical materials of all the negative lenses included in the final moving negative lens group based on the d-line is denoted as νm2, and the average value of the partial dispersion ratios of the optical materials of all the negative lenses based on the g-line and the F-line is denoted as θm2, -2.0×10 －３ ≦(θ1-θ2) / (ν2-ν1)≦2.5×10 －３ 2. The zoom lens according to claim 1, which satisfies the following condition:

3. When the maximum air gap between the final moving positive lens unit and the final moving negative lens unit in the zoom range from the wide-angle end to the telephoto end is Dm12 and the focal length of the final moving positive lens unit is fm1, 0.01≦Dm12 / fm1≦0.50 3. The zoom lens according to claim 2, which satisfies the following condition:

4. When the focal length of the final moving positive lens unit is fm1 and the focal length of the final moving negative lens unit is fm2, -5.0≦fm2 / fm1≦-0.7 4. The zoom lens according to claim 2, wherein the following condition is satisfied:

5. The final moving negative lens group is composed of one negative lens, and when the Abbe number of the optical material of the negative lens with respect to the d-line is denoted by νm2u and the partial dispersion ratio of the optical material of the negative lens with respect to the g-line and the F-line is denoted by θm2u, then: 60≦νm2u≦110 0.520≦θm2u≦0.550 5. The zoom lens according to claim 2, which satisfies the following condition:

6. The final moving positive lens group is composed of one positive lens, and when the Abbe number of the optical material of the positive lens with respect to the d-line is denoted by νm1u and the partial dispersion ratio of the optical material of the positive lens with respect to the g-line and the F-line is denoted by θm1u, then: 28≦νm1u≦60 0.540≦θm1u≦0.600 6. The zoom lens according to claim 1, which satisfies the following condition:

7. When the lateral magnification of the final moving positive lens unit at the wide-angle end and in the infinity focused state is βm1, |1 / βm1|≦0.2 7. The zoom lens according to claim 1, which satisfies the following condition:

8. the subsequent group includes one or two moving lens groups that move during magnification change, the one or two moving lens groups including a negative lens group; When the composite focal length of the one or two moving lens groups at the wide-angle end and in a state of focusing at infinity is fn, the focal length of the first lens group is f1, and the focal length of the final moving positive lens group is fm1, -5.0≦f1 / fn≦-0.8 -2.5≦fm1 / fn≦-1.2 8. The zoom lens according to claim 1, which satisfies the following condition:

9. When the lateral magnifications of the one or two moving lens groups at the wide-angle end and the telephoto end are βnw and βnt, respectively, and the zoom ratio of the zoom lens is Zwt, 0.6≦(βnt / βnw) / Zwt≦4.0 9. The zoom lens according to claim 8, which satisfies the following condition:

10. When the average value of the Abbe numbers based on the d-line of the optical materials of all the positive lenses in the negative lens group included in the one or two moving lens groups is vnp, the average value of the Abbe numbers based on the d-line of the optical materials of all the negative lenses in the negative lens group included in the one or two moving lens groups is vnn, the average value of the partial dispersion ratios for the g-line and the F-line of the optical materials of all the positive lenses in the negative lens group included in the one or two moving lens groups is θnp, and the average value of the partial dispersion ratios for the g-line and the F-line of the optical materials of all the negative lenses in the negative lens group included in the one or two moving lens groups is θnn, -1.0×10 －３ ≦(θnp-θnn) / (νnn-νnp)≦3.0×10 －３ 10. The zoom lens according to claim 8, which satisfies the following condition:

11. 11. The zoom lens according to claim 1, wherein the aperture stop is included in the final moving positive lens group.

12. 11. The zoom lens according to claim 1, wherein the aperture stop is disposed closer to the object side than the final moving positive lens unit, and moves during magnification variation.

13. 13. The zoom lens according to claim 12, wherein the aperture stop is included in a lens group that is arranged closer to the object side than the final moving positive lens group and that moves during magnification variation.

14. A zoom lens according to any one of claims 1 to 13; and an image sensor for capturing an image formed by the zoom lens.

Images