Zoom lens and imaging apparatus

Abstract

To provide a zoom lens that has a high variable power ratio and high performance, is small-sized and easily manufactured, and is capable of high-speed zooming and high-speed focusing.SOLUTION: A zoom lens L0 has a first lens group LF1 not moving for zooming and having a negative refractive power, at least one object-side lens group LF2 moving for zooming, an intermediate lens group LM not moving for zooming, and at least one image-side lens group LR moving for zooming, which are arranged in order from an object side to an image side. In zooming, the interval between the adjacent lens groups changes. Of the at least one object-side lens group and the at least one image-side lens group, at least two lens groups move for focusing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Zoom lenses used in imaging are expected to be small and lightweight, and to have high optical performance with good correction of various aberrations such as chromatic aberration. They are also expected to have a wide angle of view, a high zoom ratio, be easy to manufacture, and be capable of high-speed zooming and focusing.

[0003] The zoom lens disclosed in Patent Document 1 is composed of, arranged in order from the object side to the image side, a negative first lens group that does not move for zooming, a positive second lens group and a positive third lens group that each move for zooming, a negative fourth lens group that does not move for zooming, a positive fifth lens group that moves for zooming, and a positive sixth lens group that does not move for zooming. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-173588 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] To enable high-speed zooming and focusing, it is important to reduce the mass and movement distance of the lens groups that move during zooming. However, reducing the mass and movement distance of the lens groups that move during zooming makes it difficult to achieve a high zoom ratio and high performance. Furthermore, reducing the number of lens groups that move during zooming to achieve compactness and ease of manufacturing makes it difficult to correct aberrations and reduces the degree of freedom in the zoom ratio. Reducing the mass and movement distance of the lens groups that move during focusing makes it difficult to correct aberrations at close distances.

[0006] The present invention provides a zoom lens that has a high zoom ratio, high performance, is small and easy to manufacture, and is capable of high-speed zooming and focusing. [Means for solving the problem]

[0007] A zoom lens according to one aspect of the present invention includes, arranged in order from the object side to the image side, a first lens group having negative refractive power that does not move for zooming, at least one object-side lens group that moves for zooming, an intermediate lens group that does not move for zooming, and at least one image-side lens group that moves for zooming. The spacing between adjacent lens groups changes during zooming. At least two of the at least one object-side lens group and the at least one image-side lens group move for focusing. An imaging device equipped with the zoom lens also constitutes another aspect of the present invention. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a zoom lens that has a high zoom ratio and high performance, is small in size and easy to manufacture, and is capable of high-speed zooming and focusing. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a zoom lens according to a first embodiment. [Figure 2] 4A to 4C are aberration diagrams of the zoom lens of Example 1 at the wide-angle end and the telephoto end and in the infinity-focused state. [Figure 3] 4A to 4C are aberration diagrams of the zoom lens of Example 1 at the wide-angle end and the telephoto end and in the closest focusing state. [Figure 4] FIG. 10 is a cross-sectional view of a zoom lens according to a second embodiment. [Figure 5] 10A to 10C are aberration diagrams of the zoom lens of Example 2 at the wide-angle end and the telephoto end and in the infinity-focused state. [Figure 6] 10A to 10C are aberration diagrams of the zoom lens of Example 2 at the wide-angle end and the telephoto end and in the closest focusing state. [Figure 7] FIG. 10 is a cross-sectional view of a zoom lens according to a third embodiment. [Figure 8] 10A to 10C are aberration diagrams of the zoom lens of Example 3 at the wide-angle end and the telephoto end and in the infinity-focused state. [Figure 9] 11A to 11C are aberration diagrams of the zoom lens of Example 3 at the wide-angle end and the telephoto end and in the closest focusing state. [Figure 10] FIG. 10 is a cross-sectional view of a zoom lens according to a fourth embodiment. [Figure 11] 10A to 10C are aberration diagrams of the zoom lens of Example 4 at the wide-angle end and the telephoto end and in the infinity focused state. [Figure 12] 10A to 10C are aberration diagrams of the zoom lens of Example 4 at the wide-angle end and the telephoto end and in the closest focusing state. [Figure 13] FIG. 10 is a cross-sectional view of a zoom lens according to a fifth embodiment. [Figure 14] 10A to 10C are aberration diagrams of the zoom lens of Example 5 at the wide-angle end and the telephoto end and in the infinity focused state. [Figure 15] 11A to 11C are aberration diagrams of the zoom lens of Example 5 at the wide-angle end and the telephoto end and in the closest focusing state. [Figure 16] FIG. 1 is a schematic diagram of an imaging device equipped with a zoom lens according to any one of Examples 1 to 5. DETAILED DESCRIPTION OF THE INVENTION

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

[0011] 1, 4, 7, 10, and 13 show cross sections of the zoom lens L0 of Examples 1 to 5 at the wide-angle end and in a state where the lens is focused on an object at infinity (hereinafter referred to as the infinity focused state). In each figure, the left side is the object side (front side), and the right side is the image side (rear side). The zoom lens L0 of each Example is used in various imaging devices such as digital still cameras, video cameras, surveillance cameras, and broadcast cameras.

[0012] The zoom lens L0 of each embodiment is composed of multiple lens groups. A lens group is a group of one or more lenses or optical elements that move together during zooming between the wide-angle end and the telephoto end, and during focusing between an infinity-focused state and a state focused on the closest object (hereinafter referred to as the closest-focused state). That is, the spacing between adjacent lens groups changes during zooming and focusing. The lens groups may include an aperture stop. The wide-angle end and the telephoto end refer to zoom states with the maximum angle of view (shortest focal length) and the minimum angle of view (maximum focal length), respectively, when the lens group that moves during zooming is located at both ends of the range of movement along the optical axis for mechanical or control reasons.

[0013] The aperture stop SP determines (limits) the light flux at the maximum aperture F-number. The image plane IP is where the imaging surface (light-receiving surface) of an imaging element such as a CCD sensor or CMOS sensor or the film surface (photosensitive surface) of a silver halide film is located. The zoom lens L0 in each embodiment also includes multiple focus lens groups that move for focusing, and the arrows in the figures indicate the direction of movement of the focus lens groups when focusing from infinity to the closest distance.

[0014] The zoom lens L0 in each embodiment has, arranged in order from the object side to the image side, a first lens unit LF1 with negative refractive power, at least one object-side lens unit LF2, an intermediate lens unit LM, and at least one image-side lens unit LR. The first lens unit LF1 does not move for zooming, while at least one object-side lens unit LF2 moves for zooming. The intermediate lens unit LM does not move for zooming, while at least one image-side lens unit LR moves for zooming. In each figure, arrows below the lens units that move during zooming indicate the movement locus of those lens units when zooming from the wide-angle end to the telephoto end.

[0015] By making the first lens unit LF1, which has a large lens diameter, stationary (unmovable) during zooming, and moving the object-side lens unit LF2 and the image-side lens unit LR, which each have relatively small lens diameters, during zooming, high-speed zooming becomes easier. Furthermore, by making the intermediate lens unit LM stationary during zooming, a high zoom ratio can be easily achieved, and the mechanism for driving the moving lens units can be simplified, making it easier to manufacture and miniaturize the zoom lens L0. It is also possible to position a lens unit that does not move during zooming closer to the image than the image-side lens unit LR.

[0016] Furthermore, in the zoom lens L0 of each embodiment, at least two of the at least one object-side lens group LF2 and the at least one image-side lens group LR move for focusing. In each figure, an arrow below the lens group that moves during focusing indicates the direction in which that lens group moves during focusing from an infinity-focused state to a minimum-focused state.

[0017] By moving one of the lens groups that moves for zooming also for focusing, the mechanism that drives that lens group can be shared for both zooming and focusing, facilitating the manufacture and miniaturization of the zoom lens L0. Furthermore, by moving at least two lens groups during focusing, aberration correction at close ranges becomes easier, enabling high performance (high image quality during imaging) to be achieved.

[0018] In the zoom lens L0 of each embodiment, it is preferable that at least three of the at least one object-side lens unit LF2 and at least one image-side lens unit LR move for zooming, which makes it easier to achieve a high zoom ratio and correct aberrations during zooming.

[0019] In the zoom lens L0 of each embodiment, it is preferable that the first lens unit LF1 does not move for focusing. By keeping the first lens unit LF1, which has a large lens diameter, stationary, high-speed focusing can be facilitated.

[0020] In the zoom lens L0 of each embodiment, it is preferable that the intermediate lens unit LM does not move for focusing, which simplifies the mechanism for driving the moving lens units and makes it easier to reduce the size of the zoom lens L0.

[0021] In the zoom lens L0 of each embodiment, it is preferable that each of the lens groups included in at least one image-side lens group LR is composed of five or fewer lenses, which makes it possible to reduce the mass of the lens groups that move during zooming or focusing, making it easier to achieve high-speed zooming or focusing.

[0022] It is also preferable that the zoom lens L0 of each embodiment satisfies at least one of the conditions of the following expressions (1) to (11).

[0023] 0.7≦|fLF1| / fw≦11.7 (1) 0.2≦|fLF1 / fLM|≦3.4 (2) 0.3≦BFw / fw≦3.1 (3) 1.0≦|fLF11| / fw≦7.6 (4) 0.7≦mZLF2 / mZLR≦4.9 (5) 1.0≦βLF2t / βLF2w≦5.3 (6) 0.5≦(βLMt×βLRt) / (βLRw×βLRw)≦2.3 (7) 0.01≦TLM / ft≦0.20 (8) 0.2≦LSPw / Lw≦0.8 (9) 0.01≦mF2t / mF1t≦0.99 (10) 0.5≦|fLFF| / fw≦5.3 (11) In equations (1) to (11), fLF1 is the focal length of the first lens unit LF1, fw is the focal length of the entire zoom lens L0 at the wide-angle end and focused at infinity, and fLM is the focal length of the middle lens unit LM. BFw is the air-equivalent distance on the optical axis from the surface of the zoom lens L0 closest to the image to the image plane IP at the wide-angle end and focused at infinity, and corresponds to the back focus. fLF11 is the focal length mZL of the lens LF11 closest to the object in the first lens unit LF1.

[0024] mZLF2 is the maximum amount of movement of at least one object-side lens unit LF2 during zooming from the wide-angle end to the telephoto end, and mZLR is the maximum amount of movement of at least one image-side lens unit LR during zooming from the wide-angle end to the telephoto end. Note that the amount of movement of a lens unit that moves during zooming is the difference between the position of that lens unit at the wide-angle end and the position of that lens unit at the telephoto end, and does not include the amount of reciprocating movement, and is considered positive when the lens unit is located closer to the object at the telephoto end than at the wide-angle end.

[0025] βLF2t is the composite lateral magnification of at least one object-side lens unit LF2 at the telephoto end and in a state focused at infinity, and βLF2w is the composite lateral magnification of at least one object-side lens unit LF2 at the wide-angle end and in a state focused at infinity. βLMt is the lateral magnification of the intermediate lens unit LM at the telephoto end and in a state focused at infinity. βLRt is the composite lateral magnification of the lens units subsequent to at least one image-side lens unit LR (the at least one image-side lens unit LR and the final lens unit further to the image side than it) at the telephoto end and in a state focused at infinity. βLMw is the lateral magnification of the intermediate lens unit LM at the wide-angle end and in a state focused at infinity. βLRw is the composite lateral magnification of the lens units subsequent to at least one image-side lens unit LR at the wide-angle end and in a state focused at infinity.

[0026] TLM is the optical axial distance from the lens surface in the intermediate lens unit LM closest to the object to the lens surface in the intermediate lens unit LM closest to the image. ft is the focal length of the entire zoom lens L0 at the telephoto end and focused at infinity. LSPw is the optical axial distance from the aperture stop SP to the image plane IP at the wide-angle end and focused at infinity, and Lw is the optical axial distance from the lens surface in the first lens unit LF1 closest to the object to the image plane IP at the wide-angle end and focused at infinity, which corresponds to the overall lens length.

[0027] mF1t is the absolute value of the largest absolute movement amount of the lens group among at least two lens groups that move for focusing when focusing from infinity to the closest distance at the telephoto end. mF2t is the absolute value of the second largest absolute movement amount of the lens group among at least two lens groups that move for focusing when focusing from infinity to the closest distance at the telephoto end. The movement amount of a lens group that moves during focusing is the difference between the position of that lens group when focused at infinity and the position of that lens group when focused at the closest distance, and does not include the amount of reciprocating movement. It is considered positive when the lens group is located closer to the object in the closest distance focused state than in the infinity focused state. fLFF is the focal length of the lens group with the smallest absolute focal length among at least two lens groups that move for focusing.

[0028] The condition of formula (1) indicates the appropriate relationship between the focal length of the first lens unit LF1 and the focal length of the entire zoom lens L0 at the wide-angle end. If the absolute value of the focal length of the first lens unit LF1 becomes large so that |fLF1| / fw exceeds the upper limit of formula (1), the diameter of the first lens unit LF1 becomes large, making it difficult to reduce the size of the zoom lens L0, which is undesirable. If the absolute value of the focal length of the first lens unit LF1 becomes small so that |fLF1| / fw falls below the lower limit of formula (1), it becomes difficult to correct various aberrations, particularly distortion at the wide-angle end, which is also undesirable.

[0029] The condition of formula (2) indicates the appropriate relationship between the focal lengths of the first lens group LF1 and the intermediate lens group LM. If the absolute value of the focal length of the intermediate lens group LM becomes small so that |fLF1 / fLM| exceeds the upper limit of formula (2), the divergence effect of light rays at the intermediate lens group LM increases, the diameter of the image-side lens group LR increases, and it becomes difficult to reduce the size of the zoom lens L0, which is undesirable. If the absolute value of the focal length of the intermediate lens group LM becomes large so that |fLF1 / fLM| falls below the lower limit of formula (2), the magnification effect of the intermediate lens group LM becomes insufficient, making it difficult to achieve a high zoom ratio, which is undesirable.

[0030] The condition of formula (3) indicates the appropriate relationship between the back focal length at the wide-angle end and the focal length of the entire zoom lens L0. If the back focal length increases so that BFw / fw exceeds the upper limit of formula (3), the zoom lens L0 becomes large, which is not preferable. If the back focal length decreases so that BFw / fw falls below the lower limit of formula (3), the diameter of the image-side lens unit LR becomes large, which is not preferable.

[0031] The condition of equation (4) expresses the relationship between the focal length of the lens LF11 in the first lens group LF1 closest to the object and the focal length of the entire zoom lens L0 at the wide-angle end. If the absolute value of the focal length of lens LF11 becomes large enough that |fLF11| / fw exceeds the upper limit of equation (4), the diameter of the first lens group LF1 becomes large, making it difficult to reduce the size of the zoom lens L0, which is undesirable. If the absolute value of the focal length of lens LF11 becomes small enough that |fLF11| / fw falls below the lower limit of equation (4), it becomes difficult to correct various aberrations, particularly distortion at the wide-angle end, which is also undesirable.

[0032] The condition of equation (5) indicates the appropriate relationship between the movement amounts of the object-side lens unit LF2 and the image-side lens unit LR during zooming. If the movement amount of the object-side lens unit LF2 becomes so large that mZLF2 / mZLR exceeds the upper limit of equation (5), it becomes difficult to correct aberrations generated in the object-side lens unit LF2. This undesirably results in difficulty in correcting various aberrations, particularly spherical aberration at the telephoto end. Furthermore, if the movement amount of the image-side lens unit LR becomes so large that mZLF2 / mZLR falls below the lower limit of equation (5), it becomes undesirably difficult to correct various aberrations generated in the image-side lens unit LR, particularly astigmatism at the wide-angle end.

[0033] The condition of equation (6) indicates an appropriate range for the zoom ratio of the object-side lens unit LF2. If the zoom ratio βLF2t / βLF2w exceeds the upper limit of equation (6), it becomes difficult to correct aberrations occurring in the object-side lens unit LF2. As a result, it becomes difficult to correct various aberrations, particularly spherical aberration at the telephoto end, which is undesirable. If βLF2t / βLF2w falls below the lower limit of equation (6), it becomes difficult to achieve a high zoom ratio for the zoom lens L0, which is also undesirable.

[0034] The condition of equation (7) indicates the appropriate relationship between the zoom ratio of the intermediate lens group LM and the image-side lens group LR. If a fixed lens group is positioned closer to the image side than the image-side lens group LR, the zoom ratio is calculated including the fixed lens group. If (βLMt×βLRt) / (βLRw×βLRw) exceeds the upper limit of equation (7), it becomes difficult to correct aberrations occurring in the intermediate lens group LM. This undesirably makes it difficult to correct various aberrations, particularly astigmatism at the telephoto end. Furthermore, if (βLMt×βLRt) / (βLRw×βLRw) falls below the lower limit of equation (7), it becomes undesirable to achieve a high zoom ratio for the zoom lens L0.

[0035] The condition of equation (8) indicates the appropriate relationship between the thickness of the intermediate lens unit LM and the focal length of the entire zoom lens L0 at the telephoto end. If the thickness of the intermediate lens unit LM increases so that TLM / ft exceeds the upper limit of equation (8), it becomes difficult to ensure the necessary movement amount of the lens units that move during zooming, making it difficult to achieve a high zoom ratio for the zoom lens L0, which is undesirable. If the thickness of the intermediate lens unit LM decreases so that TLM / ft falls below the lower limit of equation (8), the degree of freedom for aberration correction in the intermediate lens unit LM becomes insufficient, making it difficult to correct various aberrations, particularly astigmatism at the telephoto end, which is also undesirable.

[0036] The condition of equation (9) indicates the appropriate relationship between the position of the aperture stop SP at the wide-angle end and the overall length of the zoom lens L0. If the aperture stop SP is located on the object side so that LSPw / Lw exceeds the upper limit of equation (9), the exit pupil position will be farther from the image plane IP, and the image-side lens unit LR will have a larger diameter, which is undesirable. If the aperture stop SP is located on the image side so that LSPw / Lw falls below the lower limit of equation (9), the entrance pupil position will be farther from the first lens unit LF1, and the first lens unit LF1 will have a larger diameter, which is undesirable.

[0037] The condition of equation (10) indicates the appropriate relationship between the maximum and second-largest movement amounts of the lens groups that move during focusing. If mF2t / mF1t exceeds the upper limit of equation (10), the zoom lens L0 will become large, which is undesirable. If mF2t / mF1t falls below the lower limit of equation (10), it will become difficult to correct various aberrations, which is undesirable.

[0038] The condition of equation (11) indicates the appropriate relationship between the focal length of the lens group that moves during focusing and the focal length of the entire zoom lens L0 at the wide-angle end. If the absolute value of the focal length of the lens group becomes large so that |fLFF| / fw exceeds the upper limit of equation (11), the zoom lens L0 will become large, which is undesirable. If the absolute value of the focal length of the lens group becomes small so that |fLFF| / fw falls below the lower limit of equation (11), the fluctuations in aberrations that occur during focusing will become large, which is undesirable.

[0039] It is more preferable that the numerical ranges of the formulas (1) to (11) are as follows:

[0040] 1.01≦|fLF1| / fw≦8.76 (1a) 0.31≦|fLF1 / fLM|≦2.54 (2a) 0.43≦BFw / fw≦2.31 (3a) 1.52≦|fLF11| / fw≦5.69 (4a) 1.05≦mZLF2 / mZLR≦3.69 (5a) 1.46≦βLF2t / βLF2w≦3.98 (6a) 0.74≦(βLMt×βLRt) / (βLRw×βLRw)≦1.71 (7a) 0.03≦TLM / ft≦0.14 (8a) 0.33≦LSPw / Lw≦0.73 (9a) 0.04≦mF2t / mF1t≦0.96 (10a) 0.73≦|fLFF| / fw≦3.97 (11a) Furthermore, it is more preferable to set the numerical ranges of the formulas (1) to (11) as follows.

[0041] 1.16≦|fLF1| / fw≦7.29 (1b) 0.37≦|fLF1 / fLM|≦2.11 (2b) 0.49≦BFw / fw≦1.92 (3b) 1.78≦|fLF11| / fw≦4.73 (4b) 1.22≦mZLF2 / mZLR≦3.08 (5b) 1.69≦βLF2t / βLF2w≦3.32 (6b) 0.86≦(βLMt×βLRt) / (βLRw×βLRw)≦1.42 (7b) 0.04≦TLM / ft≦0.11 (8b) 0.40≦LSPw / Lw≦0.69 (9b) 0.06≦mF2t / mF1t≦0.94 (10b) 0.85≦|fLFF| / fw≦3.31 (11b) Next, the zoom lens L0 of each embodiment will be described in detail.

[0042] 1, the zoom lens L0 of Example 1 is composed of, arranged in order from the object side to the image side, a first lens group LF1 having negative refractive power, an object-side lens group (second lens group) LF2 having positive refractive power, an intermediate lens group (third lens group) LM having negative refractive power, an image-side lens group (fourth and fifth lens groups) LR, and a final lens group (sixth lens group) LRR having positive refractive power. The image-side lens group LR is composed of, arranged in order from the object side, a first image-side lens group (fourth lens group) LR1 having positive refractive power and a second image-side lens group (fifth lens group) LR2 having negative refractive power.

[0043] The first lens unit LF1, the intermediate lens unit LM, and the final lens unit LRR do not move during zooming or focusing. For zooming from the wide-angle end to the telephoto end, the object-side lens unit LF2, the first image-side lens unit LR1, and the second image-side lens unit LR2 each move toward the object. For focusing from infinity to a close distance, the object-side lens unit LF2 and the first image-side lens unit LR1 move. The aperture stop SP is located closest to the object in the intermediate lens unit LM, and does not move during zooming or focusing.

[0044] 4 shows a zoom lens L0 of Example 2, which is composed of, arranged in order from the object side to the image side, a first lens group LF1 having negative refractive power, an object-side lens group (second lens group) LF2 having positive refractive power, an intermediate lens group (third lens group) LM having negative refractive power, an image-side lens group (fourth and fifth lens groups) LR, and a final lens group (sixth lens group) LRR having positive refractive power. The image-side lens group LR is composed of, arranged in order from the object side, a first image-side lens group (fourth lens group) LR1 having positive refractive power and a second image-side lens group (fifth lens group) LR2 having negative refractive power.

[0045] The first lens unit LF1, the intermediate lens unit LM, and the final lens unit LRR do not move during zooming or focusing. For zooming from the wide-angle end to the telephoto end, the object-side lens unit LF2, the first image-side lens unit LR1, and the second image-side lens unit LR2 each move toward the object. For focusing from infinity to a close distance, the object-side lens unit LF2 and the first image-side lens unit LR2 move. The aperture stop SP is located closest to the object in the intermediate lens unit LM, and does not move during zooming or focusing.

[0046] 7, the zoom lens L0 of Example 3 is composed of, arranged in order from the object side to the image side, a first lens group LF1 having negative refractive power, an object-side lens group (second and third lens groups) LF2, an intermediate lens group (fourth lens group) LM having negative refractive power, and an image-side lens group (fifth lens group) LR having positive refractive power. The object-side lens group LF2 is composed of, arranged in order from the object side, a first object-side lens group (second lens group) LF21 having positive refractive power and a second object-side lens group (third lens group) LF22 having positive refractive power.

[0047] The first lens group LF1 and the intermediate lens group LM do not move during zooming or focusing. During zooming from the wide-angle end to the telephoto end, the first object-side lens group LF21 moves along a locus convex toward the image side, and the second object-side lens group LF22 and the image-side lens group LR move toward the object side. During focusing from infinity to a close distance, the first object-side lens group LF21 and the second object-side lens group LF22 move. The aperture stop SP is located closest to the image in the second object-side lens group LF22 and moves integrally with the second object-side lens group LF22 during zooming and focusing.

[0048] 10 shows a zoom lens L0 of Example 4, which is composed of, arranged in order from the object side to the image side, a first lens unit LF1 having negative refractive power, an object-side lens unit (second and third lens units) LF2, an intermediate lens unit (fourth lens unit) LM having negative refractive power, an image-side lens unit (fifth lens unit) LR having positive refractive power, and a final lens unit (sixth lens unit) LRR having positive refractive power. The object-side lens unit LF2 is composed of, arranged in order from the object side, a first object-side lens unit (second lens unit) LF21 having negative refractive power and a second object-side lens unit (third lens unit) LF22 having positive refractive power.

[0049] The first lens unit LF1, the intermediate lens unit LM, and the final lens unit LRR do not move during zooming or focusing. When zooming from the wide-angle end to the telephoto end, the first object-side lens unit LF21 moves along a locus convex toward the image side, and the second object-side lens unit LF22 and the image-side lens unit LR move toward the object side. When focusing from infinity to a close distance, the first object-side lens unit LF21 and the second object-side lens unit LF22 move. The aperture stop SP is located closest to the object in the intermediate lens unit LM and does not move during zooming or focusing.

[0050] 13 shows a zoom lens L0 of Example 5, which is composed of, arranged in order from the object side to the image side, a first lens group LF1 having negative refractive power, an object-side lens group (second and third lens groups) LF2, an intermediate lens group (fourth lens group) LM having negative refractive power, an image-side lens group (fifth and sixth lens groups) LR, and a final lens group (seventh lens group) LRR having positive refractive power. The object-side lens group LF2 is composed of, arranged in order from the object side, a first object-side lens group (second lens group) LF21 having negative refractive power and a second object-side lens group (third lens group) LF22 having positive refractive power. The image-side lens group LR is composed of, arranged in order from the object side, a first image-side lens group (fifth lens group) LR1 having positive refractive power and a second image-side lens group (sixth lens group) LR2 having negative refractive power.

[0051] The first lens unit LF1, the intermediate lens unit LM, and the final lens unit LRR do not move during zooming or focusing. When zooming from the wide-angle end to the telephoto end, the first object-side lens unit LF21 moves along a locus convex toward the image side, and the second object-side lens unit LF22, the first image-side lens unit LR1, and the second image-side lens unit LR2 each move toward the object side. When focusing from infinity to a close distance, the first object-side lens unit LF21 and the second object-side lens unit LF22 move. The aperture stop SP is located closest to the object in the intermediate lens unit LM, and does not move during zooming or focusing.

[0052] In the zoom lens L0 of each embodiment, all surfaces having refractive power are refractive surfaces, which are easier to manufacture than surfaces composed of diffractive optical elements or reflective surfaces, and can easily achieve optical performance equal to or better than that of surfaces composed of diffractive optical elements or reflective surfaces.

[0053] The zoom lens L0 in each embodiment does not include an optical element such as a prism that bends the optical path, since using such an optical element would increase the overall length of the zoom lens L0 and make it difficult to reduce its size, which is undesirable.

[0054] Numerical Examples 1 to 5 corresponding to Examples 1 to 5, respectively, are shown below. In each numerical example, surface number i indicates the order of the surface when counted from the object side. r is the radius of curvature (mm) of the ith surface from the object side, d is the distance on the optical axis (lens thickness) or air gap (mm) between the ith and (i+1)th surfaces, and nd is the refractive index at the d-line of the optical material between the ith and (i+1)th surfaces. νd is the Abbe number based on the d-line of the optical material between the ith and (i+1)th surfaces.

[0055] The Abbe number νd based on the d-line is expressed as νd=(Nd-1) / (NF-NC), where Nd, NF, and NC are the refractive indices at the Fraunhofer d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm).

[0056] In each numerical example, d, focal length (mm), F-number, and half angle of view (°) are all values ​​when the zoom lens L0 is focused at infinity. BF represents back focus (mm). As mentioned above, back focus is the air-equivalent value of the distance on the optical axis from the lens surface closest to the image (final surface) of the zoom lens to the paraxial image plane. The total lens length is the distance on the optical axis from the lens surface closest to the object (front surface) of the zoom lens to the final surface plus the back focus.

[0057] An asterisk (*) next to a surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following equation, where X is the displacement from the vertex of the surface in the optical axis direction, H is the height from the optical axis in a direction perpendicular to the optical axis, the direction of light propagation is positive, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, and A10 are aspherical coefficients.

[0058] X=(H 2 / R) / [1+√{1-(1+K)(H / R) 2}] +A4×h 4 +A6×h 6 +A8×h 8 +A10×h 10 +A12×h 12 The "e±x" of the conic constant and aspherical coefficient is x10 ±x means.

[0059] The values ​​corresponding to the above formulas (1) to (15) in Numerical Examples 1 to 5 are summarized in Table 1. The zoom lens L0 in each of the Numerical Examples satisfies all of the conditions in formulas (1) to (15).

[0060] Figures 2, 5, 8, 11, and 14 show the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lens L0 of Numerical Examples 1 to 5 at the wide-angle and telephoto ends and in infinity-focused states, respectively. Figures 3, 6, 9, 12, and 15 show the longitudinal aberrations of the zoom lens L0 of Numerical Examples 1 to 5 at the wide-angle and telephoto ends and in the closest-focused states, respectively. In the spherical aberration diagrams, Fno is the F-number, and the amount of spherical aberration for the d-line (wavelength 587.56 nm) and g-line (wavelength 435.8 nm) is shown. In the astigmatism diagrams, ΔS represents the amount of astigmatism on the sagittal image plane, and ΔM represents the amount of astigmatism on the meridional image plane. In the distortion diagrams, the amount of distortion for the d-line is shown. In the chromatic aberration diagrams, the amount of chromatic aberration for the g-line is shown. ω is the imaging half angle of view (°) calculated by paraxial calculation. [Numerical example 1] Unit: mm Surface Data Surface number rd nd νd 1 60.337 1.10 1.75500 52.3 2 22.205 5.60 3 95.041 1.00 1.49700 81.5 4 28.486 4.44 5 -324.438 0.90 1.49700 81.5 6 51.098 0.15 7 28.954 2.79 1.76634 35.8 8 46.660 (variable) 9* 81.260 3.37 1.58313 59.4 10* -49.728 1.80 11 -21.057 1.00 1.80610 33.3 12 -97.409 3.71 1.72916 54.7 13 -26.313 0.15 14 73.779 4.40 1.59282 68.6 15 -39.643 (variable) 16 (Aperture) ∞ 1.11 17 -233.167 0.80 1.74320 49.3 18 23.020 1.75 1.96300 24.1 19 43.048 (variable) 20 19.372 6.59 1.49700 81.5 21 -16.915 0.90 1.61340 44.3 22 109.044 0.56 23* 56.998 4.10 1.49700 81.5 24* -23.010 (variable) 25 31.088 0.80 1.91650 31.6 26 16.809 11.25 27 -15.640 1.00 1.59349 67.0 28 -50.311 (variable) 29 -180.000 6.81 1.83481 42.7 30 -34.600 (variable) Image plane ∞ Aspheric data 9th page K = 0.00000e+00 A 4=-2.13397e-05 A 6=-4.55477e-08 A 8= 1.44090e-10 Side 10 K = 0.00000e+00 A 4=-1.50301e-05 A 6=-3.69895e-08 A 8= 1.32301e-10 Page 23 K = 0.00000e+00 A 4=-6.30838e-05 A 6=-2.18050e-08 A 8=-2.66564e-09 A10= 3.25378e-11 Page 24 K = 0.00000e+00 A 4=-1.32427e-05 A 6= 5.35799e-08 A 8=-3.16386e-09 A10= 3.28481e-11 Various data Zoom ratio 2.35 Wide-angle Mid-range Telephoto Focal length 20.63 32.35 48.50 F-number 4.10 4.10 4.12 Half angle of view (°) 42.23 33.36 24.04 Image height 21.64 21.64 21.64 Lens length 118.10 118.10 118.10 BF 11.49 11.49 11.49 Infinity focus d 8 22.89 12.67 2.44 d15 0.99 11.22 21.44 d19 13.65 8.52 2.50 d24 2.00 0.99 2.78 d28 1.00 7.13 11.36 d30 11.49 11.49 11.49 Closest focus state (object distance -280) d 8 22.68 13.43 4.16 d15 1.20 10.46 19.72 d19 12.99 7.38 0.99 d24 2.66 2.13 4.29 d28 1.00 7.13 11.36 d30 11.49 11.49 11.49 Lens group data Group starting plane focal length 1 1 -27.15 2 9 30.47 3 16 -62.89 4 20 25.24 5 25 -17.60 6 29 50.24 [Numerical example 2] Unit: mm Surface Data Surface number rd nd νd 1 54.916 1.10 1.75500 52.3 2 22.685 5.51 3 85.052 1.00 1.49700 81.5 4 26.652 4.93 5 -269.955 0.90 1.49700 81.5 6 44.063 0.15 7 29.066 3.02 1.76634 35.8 8 50.770 (variable) 9* 78.235 3.17 1.58313 59.4 10* -58.756 1.99 11 -21.065 1.00 1.80610 33.3 12 -111.227 3.85 1.72916 54.7 13 -26.033 0.15 14 72.705 4.44 1.59282 68.6 15 -39.095 (variable) 16 (Aperture) ∞ 1.10 17 -276.378 0.80 1.74320 49.3 18 23.261 1.76 1.96300 24.1 19 43.586 (variable) 20 19.712 6.36 1.49700 81.5 21 -16.375 0.90 1.61340 44.3 22 82.477 0.91 23* 64.428 4.16 1.49700 81.5 24* -22.314 (variable) 25 28.097 0.80 1.91650 31.6 26 17.152 10.89 27 -15.904 1.00 1.59349 67.0 28 -50.411 (variable) 29 -180.000 6.12 1.83481 42.7 30 -37.091 (variable) Image plane ∞ Aspheric data 9th page K = 0.00000e+00 A 4=-2.16511e-05 A 6=-4.63449e-08 A 8= 1.68284e-10 Side 10 K = 0.00000e+00 A 4=-1.48854e-05 A 6=-3.69255e-08 A 8= 1.69435e-10 Page 23 K = 0.00000e+00 A 4=-5.91731e-05 A 6= 6.73379e-09 A 8=-2.84611e-09 A10= 3.44880e-11 Page 24 K = 0.00000e+00 A 4=-1.33415e-05 A 6= 4.68294e-08 A 8=-2.80005e-09 A10= 3.07743e-11 Various data Zoom ratio 2.35 Wide-angle Mid-range Telephoto Focal length 20.62 32.27 48.50 F-number 4.10 4.10 4.10 Half angle of view (°) 42.23 33.53 24.04 Image height 18.72 21.38 21.64 Lens length 118.10 118.10 118.10 BF 11.50 11.50 11.50 Infinity focus d 8 22.82 12.55 2.27 d15 1.00 11.27 21.54 d19 12.71 7.27 1.00 d24 2.18 1.00 2.86 d28 1.91 8.53 12.94 d30 11.50 11.50 11.50 Closest focus state (object distance -280) d 8 22.10 12.51 2.90 d15 1.72 11.31 20.91 d19 12.71 7.27 1.00 d24 3.09 2.64 5.52 d28 1.00 6.89 10.28 d30 11.50 11.50 11.50 Lens group data Group starting plane focal length 1 1 -27.67 2 9 31.07 3 16 -65.72 4 20 26.84 5 25 -19.85 6 29 54.89 [Numerical example 3] Unit: mm Surface Data Surface number rd nd νd 1 50.138 1.50 2.00100 29.1 2 22.570 7.45 3 116.355 1.30 1.59282 68.6 4 35.489 4.98 5 -173.357 1.20 1.49700 81.5 6 27.379 5.78 1.91082 35.2 7 103.647 (variable) 8 -67.008 1.00 1.85478 24.8 9 55.824 0.36 10 64.927 4.72 1.95375 32.3 11* -46.353 (variable) 12 30.945 1.00 1.90366 31.3 13 22.207 6.69 1.59522 67.7 14* -195.735 1.37 15 (Aperture) ∞ (Variable) 16* -31.517 0.80 1.61340 44.3 17 27.386 2.64 1.92286 20.9 18 80.449 (variable) 19 30.011 5.74 1.49700 81.5 20 -31.783 0.45 21 44.726 6.67 1.49700 81.5 22 -20.853 0.80 2.05090 26.9 23 -44.250 1.33 24* 70.402 1.20 1.88202 37.2 25* 27.013 (variable) Image plane ∞ Aspheric data Page 11 K = 0.00000e+00 A 4=-2.12988e-07 A 6=-1.38481e-09 A 8=-2.96618e-12 Side 14 K = 0.00000e+00 A 4= 2.70462e-08 A 6= 5.91799e-10 A 8= 6.68411e-12 Page 16 K = 0.00000e+00 A 4=-6.84993e-07 A 6=-1.21471e-08 A 8=-2.80284e-11 Page 24 K = 0.00000e+00 A 4=-3.85359e-05 A 6= 1.24853e-07 A 8=-2.07298e-10 Page 25 K =-9.43177e+00 A 4= 3.62160e-05 A 6=-1.14770e-07 A 8= 1.04700e-09 A10=-3.45970e-12 A12= 2.70504e-15 Various data Zoom ratio 1.88 Wide-angle Mid-range Telephoto Focal length 20.61 29.26 38.72 F-number 2.90 2.90 2.90 Half angle of view (°) 43.64 36.48 29.19 Image height 19.65 21.64 21.64 Lens total length 130.70 130.70 130.70 BF 31.45 36.15 40.28 Infinity focus d 7 21.33 7.98 3.07 d11 6.72 11.43 7.70 d15 4.29 12.93 21.57 d18 9.91 5.21 1.08 d25 31.45 36.15 40.28 Closest focus state (object distance -350) d 7 24.64 12.39 8.13 d11 2.41 5.70 1.12 d15 5.28 14.25 23.09 d18 9.91 5.21 1.08 d25 31.45 36.15 40.28 Lens group data Group starting plane focal length 1 1 -30.24 2 8 119.72 3 12 54.58 4 16 -50.60 5 19 37.67 [Numerical example 4] Unit: mm Surface Data Surface number rd nd νd 1 59.938 1.30 1.95375 32.3 2 25.884 7.13 3 312.374 1.20 1.59522 67.7 4 52.105 3.98 5 -147.385 1.10 1.49700 81.5 6 63.082 0.15 7 38.951 8.57 1.61340 44.3 8 -51.665 (variable) 9 -41.833 1.00 1.72916 54.7 10 41.634 2.38 1.96300 24.1 11 94.111 (variable) 12* 54.449 3.37 1.58313 59.4 13* -60.192 1.94 14 -24.575 1.00 1.77047 29.7 15 -465.875 3.57 1.72916 54.7 16 -32.059 0.15 17 86.730 4.68 1.59282 68.6 18 -32.624 (variable) 19 (Aperture) ∞ 1.00 20 5442.213 0.80 1.70154 41.2 21 22.921 1.67 1.92286 20.9 22 38.541 (variable) 23 23.488 6.52 1.49700 81.5 24 -14.407 0.90 1.61340 44.3 25 111.244 0.10 26* 36.779 4.45 1.58313 59.4 27* -29.223 1.14 28 33.867 0.80 1.90043 37.4 29 15.869 10.48 30 -12.902 1.00 1.77250 49.6 31 -23.591 (variable) 32 -180.000 4.90 1.85150 40.8 33 -42.638 (variable) Image plane ∞ Aspheric data Side 12 K = 0.00000e+00 A 4=-7.79404e-06 A 6= 3.79879e-09 A 8= 1.60442e-10 Page 13 K = 0.00000e+00 A 4= 6.75267e-06 A 6= 1.00295e-08 A 8= 2.37861e-10 Page 26 K = 0.00000e+00 A 4=-3.72159e-05 A 6=-1.83098e-07 A 8=-3.84074e-10 A10=-1.31048e-12 Page 27 K = 0.00000e+00 A 4=-2.50771e-05 A 6=-1.40119e-07 A 8=-4.59186e-11 A10=-3.67840e-12 Various data Zoom ratio 2.35 Wide-angle Mid-range Telephoto Focal length 20.61 33.59 48.51 F-number 4.10 4.10 4.10 Half angle of view (°) 42.25 32.78 24.04 Image height 18.72 21.64 21.64 Lens length 127.34 127.34 127.34 BF 11.50 11.50 11.50 d 8 3.60 7.90 4.64 d11 20.62 7.03 1.00 d18 1.00 10.29 19.57 d22 14.30 7.35 1.00 d31 1.06 8.01 14.36 d33 11.50 11.50 11.50 Closest focus state (object distance -280) d 8 1.00 4.40 1.06 d11 22.08 9.82 4.31 d18 2.14 11.00 19.84 d22 14.30 7.35 1.00 d31 1.06 8.01 14.36 d33 11.50 11.50 11.50 Lens group data Group starting plane focal length 1 1 -120.11 2 9 -44.97 3 12 28.00 4 19 -71.65 5 23 503.26 6 32 64.56 [Numerical example 5] Unit: mm Surface Data Surface number rd nd νd 1* 82.883 2.00 1.76450 49.1 2* 21.676 4.60 3 36.111 1.00 1.59522 67.7 4 20.589 7.63 5 -435.594 0.80 1.53775 74.7 6 31.474 0.09 7 24.949 6.34 1.61340 44.3 8 497.131 (variable) 9 -30.826 0.80 1.72916 54.7 10 29.303 2.25 1.85478 24.8 11 86.925 (variable) 12* 40.193 3.70 1.58313 59.4 13* -26.938 0.92 14 -18.871 0.80 1.77047 29.7 15 91.624 4.08 1.72916 54.7 16 -26.039 0.15 17 90.469 4.32 1.59282 68.6 18 -24.156 (variable) 19 (Aperture) ∞ 1.09 20 -157.792 0.60 1.76200 40.1 21 13.410 1.85 1.92286 20.9 22 26.871 (variable) 23 16.012 5.36 1.49700 81.5 24 -9.606 0.80 1.61340 44.3 25 -39.728 0.10 26* 54.831 3.04 1.49700 81.5 27* -21.438 (variable) 28 54.218 0.70 1.90043 37.4 29 18.190 3.15 30 -12.436 1.20 1.76450 49.1 31* -34.102 (variable) 32 -120.000 5.15 1.49700 81.5 33 -19.584 (variable) Image plane ∞ Aspheric data Front page K = 0.00000e+00 A 4= 6.62752e-06 A 6=-5.13427e-09 A 8= 4.79864e-12 2nd side K = 0.00000e+00 A 4=-1.32833e-06 A 6= 2.26342e-09 A 8=-2.04969e-11 Side 12 K = 0.00000e+00 A 4=-2.87774e-05 A 6= 1.54519e-08 A 8= 6.02875e-11 Page 13 K = 0.00000e+00 A 4= 1.62786e-05 A 6= 1.47150e-08 A 8= 6.52822e-10 Page 26 K = 0.00000e+00 A 4=-5.10980e-05 A 6=-1.31748e-06 A 8= 3.56355e-08 A10=-2.19583e-10 Page 27 K = 0.00000e+00 A 4=-8.84256e-05 A 6=-2.11073e-07 A 8= 1.05026e-08 A10= 9.17567e-11 Page 31 K = 0.00000e+00 A 4= 1.31434e-04 A 6= 4.76407e-07 A 8=-2.76898e-09 Various data Zoom ratio 2.85 Wide-angle Mid-range Telephoto Focal length 10.31 18.51 29.40 F-number 4.10 4.10 4.12 Half angle of view (°) 48.96 36.42 24.92 Image height 13.66 13.66 13.66 Lens total length 111.48 111.48 111.48 BF 11.62 11.62 11.62 Infinity focus d 8 9.89 10.43 3.31 d11 14.40 3.87 1.00 d18 1.00 10.99 20.98 d22 9.08 4.76 1.00 d27 1.00 1.15 1.10 d31 1.95 6.12 9.94 d33 11.62 11.62 11.62 Closest focus state (object distance -200) d 8 10.21 9.65 2.39 d11 14.07 5.07 2.77 d18 1.00 10.57 20.13 d22 9.08 4.76 1.00 d27 1.34 1.31 1.07 d31 1.61 5.96 9.97 d33 11.62 11.62 11.62 Lens group data Group starting plane focal length 1 1 -30.93 2 9 -33.91 3 12 19.81 4 19 -37.07 5 23 16.64 6 28 -13.53 7 32 46.30

[0061] [Table 1]

[0062] [Imaging device] 11 shows a digital camera 10 as an imaging device equipped with a zoom lens L0 according to any one of Examples 1 to 5. The digital camera 10 includes a camera body 13, an imaging optical system 11 configured with the zoom lens L0 according to any one of Examples 1 to 5, and an imaging element 12 that photoelectrically converts a subject image formed by the imaging optical system 11 (capturing the subject through the zoom lens). The imaging element 12 is a photoelectric conversion element such as a CCD sensor or a CMOS sensor. The imaging optical system 11 and the camera body 13 may be detachable or may be configured as an integrated unit.

[0063] By using the zoom lens L0 of Examples 1 to 5 as an imaging optical system, it is possible to realize a small, lightweight digital camera 10 capable of capturing high-quality images.

[0064] The imaging optical system 11 can be used in various imaging devices such as video cameras, broadcast cameras, surveillance cameras, and silver halide film cameras.

[0065] The above embodiment includes the following configurations.

[0066] (Configuration 1) the zoom lens has, arranged in order from the object side to the image side, a first lens group having negative refractive power that does not move for zooming, at least one object-side lens group that moves for zooming, an intermediate lens group that does not move for zooming, and at least one image-side lens group that moves for zooming, and the spacing between adjacent lens groups changes during zooming; A zoom lens, wherein at least two of the at least one object-side lens group and the at least one image-side lens group move for focusing. (Configuration 2) The zoom lens according to configuration 1, wherein at least three lens groups among the at least one object-side lens group and the at least one image-side lens group move for zooming. (Configuration 3) 3. The zoom lens according to configuration 1 or 2, wherein the first lens group does not move for focusing. (Configuration 4) 4. The zoom lens according to any one of configurations 1 to 3, wherein the intermediate lens group does not move for focusing. (Configuration 5) 5. The zoom lens according to any one of configurations 1 to 4, wherein each of the lens groups included in the at least one image-side lens group is made up of five or less lenses. (Configuration 6) 6. A zoom lens according to any one of configurations 1 to 5, further comprising a final lens group that is disposed closer to the image side than the image-side lens group and does not move for zooming or focusing. (Configuration 7) When the focal length of the first lens group is fLF1 and the focal length of the zoom lens at the wide-angle end and when focused on an object at infinity is fw, 0.7≦|fLF1| / fw≦11.7 7. The zoom lens according to any one of configurations 1 to 6, wherein the following condition is satisfied: (Configuration 8) When the focal length of the first lens group is fLF1 and the focal length of the intermediate lens group is fLM, 0.2≦|fLF1 / fLM|≦3.4 8. The zoom lens according to any one of configurations 1 to 7, wherein the following condition is satisfied: (Configuration 9) When the zoom lens is at the wide-angle end and focused on an object at infinity, the air-equivalent distance on the optical axis from the surface of the zoom lens closest to the image side to the image plane is BFw, and the focal length of the zoom lens when the zoom lens is at the wide-angle end and focused on an object at infinity is fw. 0.3≦BFw / fw≦3.1 9. The zoom lens according to any one of configurations 1 to 8, wherein the following condition is satisfied: (Configuration 10) Let fLF11 be the focal length of the lens closest to the object in the first lens group, and fw be the focal length of the zoom lens at the wide-angle end when focused on an object at infinity. 1.0≦|fLF11| / fw≦7.6 10. The zoom lens according to any one of configurations 1 to 9, wherein the following condition is satisfied: (Configuration 11) When a lens group that moves for zooming is positioned closer to the object at the telephoto end than at the wide-angle end, the amount of movement of the lens group is defined as positive, and the maximum amount of movement of the at least one object-side lens group during zooming from the wide-angle end to the telephoto end is defined as mZLF2, and the maximum amount of movement of the at least one image-side lens group during zooming from the wide-angle end to the telephoto end is defined as mZLR, 0.7≦mZLF2 / mZLR≦4.9 11. The zoom lens according to any one of configurations 1 to 10, wherein the following condition is satisfied: (Configuration 12) When the composite lateral magnification of the at least one object-side lens unit at the telephoto end and in a state where the lens is focused on an object at infinity is βLF2t, and when the composite lateral magnification of the at least one object-side lens unit at the wide-angle end and in a state where the lens is focused on an object at infinity is βLF2w, 1.0≦βLF2t / βLF2w≦5.3 12. The zoom lens according to any one of configurations 1 to 11, wherein the following condition is satisfied: (Configuration 13) When the lateral magnification of the intermediate lens group at the telephoto end and in a state where the lens is focused on an object at infinity is βLMt, the composite lateral magnification of the lens groups subsequent to the at least one image-side lens group at the telephoto end and in a state where the lens is focused on an object at infinity is βLRt, the lateral magnification of the intermediate lens group at the wide-angle end and in a state where the lens is focused on an object at infinity is βLMw, and the composite lateral magnification of the lens groups subsequent to the at least one image-side lens group at the wide-angle end and in a state where the lens is focused on an object at infinity is βLRw, 0.5≦(βLMt×βLRt) / (βLRw×βLRw)≦2.3 13. The zoom lens according to any one of configurations 1 to 12, wherein the following condition is satisfied: (Configuration 14) Let TLM be the distance on the optical axis from the lens surface in the intermediate lens group closest to the object side to the lens surface in the intermediate lens group closest to the image side, and ft be the focal length of the zoom lens at the telephoto end when focused on an object at infinity. 0.01≦TLM / ft≦0.20 14. The zoom lens according to any one of configurations 1 to 13, wherein the following condition is satisfied: (Configuration 15) having an aperture stop, When the distance on the optical axis from the aperture stop to the image plane at the wide-angle end and in a state where an object at infinity is focused is defined as LSPw, and the distance on the optical axis from the lens surface in the first lens group closest to the object to the image plane at the wide-angle end and in a state where an object at infinity is focused is defined as Lw, 0.2≦LSPw / Lw≦0.8 15. The zoom lens according to any one of configurations 1 to 14, wherein the following condition is satisfied: (Configuration 16) When the movement amount of a lens group that moves for focusing is positioned closer to the object when focused on the nearest object than when focused on an object at infinity, the movement amount is defined as positive, and when the lens group that moves for focusing has the largest and second largest absolute values ​​of the movement amount during focusing from the state focused on an object at infinity to the state focused on the nearest object, among the at least two lens groups that move for focusing, the absolute values ​​of the largest and second largest movement amounts are defined as mF1t and mF2t, respectively. 0.01≦mF2t / mF1t≦0.99 16. The zoom lens according to any one of configurations 1 to 15, wherein the following condition is satisfied: (Configuration 17) Let fLFF be the focal length of the lens group having the smallest absolute value of focal length among the at least two lens groups that move for focusing, and fw be the focal length of the zoom lens at the wide-angle end when focused on an object at infinity. 0.5≦|fLFF| / fw≦5.3 17. The zoom lens according to any one of configurations 1 to 16, wherein the following condition is satisfied: (Configuration 18) The zoom lens according to any one of configurations 1 to 17, characterized in that it comprises, arranged in order from the object side to the image side, the first lens group, the object-side lens group having positive refractive power, the intermediate lens group having negative refractive power, a first image-side lens group having positive refractive power, a second image-side lens group having negative refractive power, and a final lens group having positive refractive power. (Configuration 19) The zoom lens according to any one of configurations 1 to 17, characterized in that it is composed of, arranged in order from the object side to the image side, the first lens group, a first object-side lens group with positive refractive power, a second object-side lens group with positive refractive power, an intermediate lens group with negative refractive power, and an image-side lens group with positive refractive power. (Configuration 20) The zoom lens according to any one of configurations 1 to 17, characterized in that it comprises, arranged in order from the object side to the image side, the first lens group, a first object-side lens group with negative refractive power, a second object-side lens group with positive refractive power, the intermediate lens group with negative refractive power, an image-side lens group with positive refractive power, and a final lens group with positive refractive power. (Configuration 21) The zoom lens according to any one of configurations 1 to 17, characterized in that it comprises, arranged in order from the object side to the image side, the first lens group, a first object-side lens group with negative refractive power, a second object-side lens group with positive refractive power, the intermediate lens group with negative refractive power, a first image-side lens group with positive refractive power, a second image-side lens group with negative refractive power, and a final lens group with positive refractive power. (Configuration 22) the zoom lens according to any one of configurations 1 to 21; and an image sensor for capturing an image of a subject through the zoom lens.

[0067] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of symbols]

[0068] LF1 First lens group LF2 object-side lens group LM intermediate lens group LR image-side lens group LRR final lens group

Claims

1. the zoom lens has, arranged in order from the object side to the image side, a first lens group having negative refractive power that does not move for zooming, at least one object-side lens group that moves for zooming, an intermediate lens group that does not move for zooming, and at least one image-side lens group that moves for zooming, and the spacing between adjacent lens groups changes during zooming; A zoom lens, wherein at least two of the at least one object-side lens group and the at least one image-side lens group move for focusing.

2. 2. The zoom lens according to claim 1, wherein at least three lens groups among the at least one object-side lens group and the at least one image-side lens group move for zooming.

3. 2. The zoom lens according to claim 1, wherein the first lens group does not move for focusing.

4. 2. The zoom lens according to claim 1, wherein the intermediate lens group does not move for focusing.

5. 2. The zoom lens according to claim 1, wherein each of the lens groups included in the at least one image-side lens group is composed of five or less lenses.

6. 2. The zoom lens according to claim 1, further comprising a final lens group that is disposed closer to the image side than the image-side lens group and does not move for zooming or focusing.

7. When the focal length of the first lens group is fLF1 and the focal length of the zoom lens at the wide-angle end and in a state where the zoom lens is focused on an object at infinity is fw, 0.7≦|fLF1| / fw≦11.7 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

8. When the focal length of the first lens group is fLF1 and the focal length of the intermediate lens group is fLM, 0.2≦|fLF1 / fLM|≦3.4 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

9. When the zoom lens is at the wide-angle end and focused on an object at infinity, the air-equivalent distance on the optical axis from the surface of the zoom lens closest to the image side to the image plane is BFw, and the focal length of the zoom lens when the zoom lens is at the wide-angle end and focused on an object at infinity is fw. 0.3≦BFw / fw≦3.1 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

10. When the focal length of the lens closest to the object in the first lens group is fLF11 and the focal length of the zoom lens at the wide-angle end when focused on an object at infinity is fw, 1.0≦|fLF11| / fw≦7.6 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. When a lens group that moves for zooming is positioned closer to the object side at the telephoto end than at the wide-angle end, the amount of movement of the lens group is defined as positive, and the maximum amount of movement of the at least one object-side lens group during zooming from the wide-angle end to the telephoto end is defined as mZLF2, and the maximum amount of movement of the at least one image-side lens group during zooming from the wide-angle end to the telephoto end is defined as mZLR, 0.7≦mZLF2 / mZLR≦4.9 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. When the composite lateral magnification of the at least one object-side lens unit at the telephoto end and in a state where the lens is focused on an object at infinity is βLF2t, and the composite lateral magnification of the at least one object-side lens unit at the wide-angle end and in a state where the lens is focused on an object at infinity is βLF2w, 1.0≦βLF2t / βLF2w≦5.3 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

13. When the lateral magnification of the intermediate lens group at the telephoto end and in a state where the lens is focused on an object at infinity is βLMt, the combined lateral magnification of the lens groups subsequent to the at least one image-side lens group at the telephoto end and in a state where the lens is focused on an object at infinity is βLRt, the lateral magnification of the intermediate lens group at the wide-angle end and in a state where the lens is focused on an object at infinity is βLMw, and the combined lateral magnification of the lens groups subsequent to the at least one image-side lens group at the wide-angle end and in a state where the lens is focused on an object at infinity is βLRw, 0.5≦(βLMt×βLRt) / (βLRw×βLRw)≦2.3 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

14. Let TLM be the distance on the optical axis from the lens surface in the intermediate lens group closest to the object side to the lens surface in the intermediate lens group closest to the image side, and ft be the focal length of the zoom lens at the telephoto end when focused on an object at infinity. 0.01≦TLM / ft≦0.20 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

15. an aperture stop; When the distance on the optical axis from the aperture stop to the image plane at the wide-angle end and in a state where an object at infinity is focused is defined as LSPw, and the distance on the optical axis from the lens surface in the first lens group closest to the object to the image plane at the wide-angle end and in a state where an object at infinity is focused is defined as Lw, 0.2≦LSPw / Lw≦0.8 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

16. When the movement amount of a lens group that moves for focusing is positioned closer to the object when focused on the nearest object than when focused on an object at infinity is defined as positive, and when the lens group that moves for focusing has the largest and second largest absolute values ​​of the movement amount during focusing from the state focused on an object at infinity to the state focused on the nearest object among the at least two lens groups that move for focusing, the absolute values ​​of the largest and second largest movement amounts are defined as mF1t and mF2t, respectively. 0.01≦mF2t / mF1t≦0.99 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

17. Let f be the focal length of the lens group having the smallest absolute value of focal length among the at least two lens groups that move for focusing, and let f be the focal length of the zoom lens at the wide-angle end when focused on an object at infinity. 0.5≦|fLFF| / fw≦5.3 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

18. 2. The zoom lens according to claim 1, comprising, arranged in order from the object side to the image side, the first lens group, the object-side lens group having positive refractive power, the intermediate lens group having negative refractive power, a first image-side lens group having positive refractive power, a second image-side lens group having negative refractive power, and a final lens group having positive refractive power.

19. 2. The zoom lens according to claim 1, comprising, arranged in order from the object side to the image side, the first lens group, a first object-side lens group with positive refractive power, a second object-side lens group with positive refractive power, an intermediate lens group with negative refractive power, and an image-side lens group with positive refractive power.

20. 2. The zoom lens according to claim 1, comprising, arranged in order from the object side to the image side, the first lens group, a first object-side lens group having negative refractive power, a second object-side lens group having positive refractive power, the intermediate lens group having negative refractive power, an image-side lens group having positive refractive power, and a final lens group having positive refractive power.

21. 2. The zoom lens according to claim 1, comprising, arranged in order from the object side to the image side, the first lens group, a first object-side lens group having negative refractive power, a second object-side lens group having positive refractive power, the intermediate lens group having negative refractive power, a first image-side lens group having positive refractive power, a second image-side lens group having negative refractive power, and a final lens group having positive refractive power.

22. a zoom lens according to any one of claims 1 to 21; and an image sensor for capturing an image of a subject through the zoom lens.

Images