Zoom lens, image capturing device having the same, and image capturing system

Abstract

To provide a negative lead-type, wide-angle zoom lens which is compact and light-weight, and yet offers superior optical performance over an entire zoom range.SOLUTION: A zoom lens provided herein comprises a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group L4 having positive refractive power. The first lens group consists of three or more lenses. When zooming from the wide-angle end to the telephoto end, the first lens group is stationary relative to the image plane. A focal length f1 of the first lens group, a focal length f2 of the second lens group, a focal length f4 of the fourth lens group, a distance LD1 along an optical axis from an object-side lens surface of a lens located on the most object side in the first lens group to an image-side lens surface of a lens located on the most image side in the first lens group, and a total length TTL of the zoom lens at the wide-angle end satisfy predetermined conditional expressions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a zoom lens, which is suitable for imaging devices such as digital still cameras, digital video cameras, broadcast cameras, surveillance cameras, vehicle-mounted cameras, and cameras for silver halide film. [Background technology]

[0002] In recent years, imaging optical systems used in imaging devices are desirably compact zoom lenses that have a wide angle of view and high optical performance over the entire zoom range.

[0003] Patent Document 1 proposes a negative-lead wide-angle zoom lens in which a first lens group with negative refractive power is disposed closest to the object side, as a zoom lens that is small in overall system size and can easily achieve a wide angle of view.

[0004] The negative-lead wide-angle zoom lens proposed in Patent Document 1 achieves a wide angle of view and high optical performance by moving the first lens group with negative refractive power when zooming from the wide-angle end to the telephoto end. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2020-101750 Summary of the Invention [Problem to be solved by the invention]

[0006] However, a configuration in which a large and heavy first lens group is moved, as in the wide-angle zoom lens described in Patent Document 1, complicates the movement mechanism, which is disadvantageous in terms of miniaturization and weight reduction.

[0007] The present invention provides a negative-lead type wide-angle zoom lens that is compact and lightweight yet has high optical performance over the entire zoom range. [Means for solving the problem]

[0008] 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 negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group L4 having positive refractive power, the distance between adjacent lens groups changing during zooming from the wide-angle end to the telephoto end, the first lens group being composed of three or more lenses, the first lens group being fixed with respect to an image plane during zooming from the wide-angle end to the telephoto end, and when a focal length of the first lens group is f1, a focal length of the second lens group is f2, a focal length of the fourth lens group is f4, a distance on the optical axis from an object-side lens surface of a lens arranged closest to the object in the first lens group to an image-side lens surface of a lens arranged closest to the image in the first lens group is LD1, and an air-equivalent length of the distance on the optical axis from the object-side lens surface of the lens arranged closest to the object in the zoom lens at the wide-angle end to the image plane is TTL, 0.85<(-f1) / f2<2.00 0.00<(-f1) / f4<0.55 0.00 <LD1 / TTL<0.27 The present invention is characterized in that the following conditional expression is satisfied:

[0009] Other objects and features of the present invention will be described in the following embodiments. Effect of the Invention

[0010] According to the present invention, it is possible to provide a negative-lead type wide-angle zoom lens that is small and lightweight, yet has high optical performance over the entire zoom range. [Brief description of the drawings]

[0011] [Figure 1] 3A to 3C are lens sectional views of the first embodiment when focusing on an object at infinity at the wide-angle end and the telephoto end. [Diagram 2]4A and 4B are longitudinal aberration diagrams of Example 1 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Diagram 3] 11A to 11C are lens sectional views of Example 2 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 4] 11A and 11B are longitudinal aberration diagrams of Example 2 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Diagram 5] 11A to 11C are lens sectional views of Example 3 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 6] 11A and 11B are longitudinal aberration diagrams of Example 3 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 7] 11A to 11C are lens sectional views of Example 4 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 8] 13A and 13B are longitudinal aberration diagrams of Example 4 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 9] 13A to 13C are lens sectional views of Example 5 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 10] 13A and 13B are longitudinal aberration diagrams of Example 5 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 11] 13A to 13C are lens sectional views of Example 6 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 12] 13A and 13B are longitudinal aberration diagrams of Example 6 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 13] 13A to 13C are lens sectional views of Example 7 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 14] 13A and 13B are longitudinal aberration diagrams of Example 7 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 15] 13A to 13C are lens sectional views of Example 8 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 16] 13A and 13B are longitudinal aberration diagrams of Example 8 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 17]13A to 13C are lens sectional views of Example 9 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 18] 13A and 13B are longitudinal aberration diagrams of Example 9 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 19] 23A to 23C are lens sectional views of Example 10 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 20] 23A and 23B are longitudinal aberration diagrams of Example 10 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 21] 21A to 21C are lens sectional views of Example 11 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 22] 13A and 13B are longitudinal aberration diagrams of Example 11 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Diagram 23] 23A to 23C are lens sectional views of Example 12 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 24] 23A and 23B are longitudinal aberration diagrams of Example 12 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Diagram 25] 23A to 23C are lens sectional views of Example 13 when focusing on an object at infinity at the wide-angle end and the telephoto end. [Figure 26] 23A and 23B are longitudinal aberration diagrams of Example 13 when focusing on an object at infinity at the wide-angle end and the telephoto end, respectively. [Figure 27] FIG. 1 is a schematic diagram of an imaging device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a zoom lens, an image pickup apparatus having the same, and an image pickup system according to the present invention will be described with reference to the accompanying drawings.

[0013] 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, and 25 are lens cross-sectional views of the zoom lenses of Examples 1 to 13 when focused on infinity at the wide-angle end (WIDE) / telephoto end (TELE), respectively. The zoom lenses of the respective Examples are zoom lenses used in imaging devices such as digital still cameras, silver halide film cameras, digital video cameras, surveillance cameras, broadcast cameras, and vehicle-mounted cameras.

[0014] In each lens cross-sectional view, the left side is the object side (front) and the right side is the image side (rear). The zoom lens of each embodiment is configured to have multiple lens groups. In this specification, a lens group is a group of lenses that move or stand still as a unit during zooming. That is, in the zoom lens of each embodiment, the distance between adjacent lens groups changes during zooming from the wide-angle end to the telephoto end. Note that the lens group may be composed of one lens or multiple lenses. The lens group may also include an aperture stop.

[0015] In each lens cross-sectional view, Li represents the i-th lens group (i is a natural number) counted from the object side in the zoom lens.

[0016] Also, SP is an aperture stop. The aperture stop SP determines (limits) the light flux of the open F-number (Fno). IP is an image plane, and when the zoom lens of each embodiment is used as the photographing optical system of a digital still camera or video camera, the imaging surface of a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor is disposed thereon. When the zoom lens of each embodiment is used as the photographing optical system of a silver halide film camera, a photosensitive surface equivalent to the film surface is disposed on the image plane IP.

[0017] The arrow in the optical axis direction indicates the movement direction of the focus lens group that moves when focusing from infinity to a close distance. The solid arrow below each lens group indicates the movement trajectory of each lens group when zooming from the wide-angle end to the telephoto end. The vertical dashed line below each lens group indicates that each lens group is fixed with respect to the image plane when zooming from the wide-angle end to the telephoto end. The double-headed arrow perpendicular to the optical axis indicates the movement of the lens group when image stabilization (image stabilization) is performed.

[0018] In the following embodiments, the wide-angle end and the telephoto end refer to zoom positions when the zooming lens group is located at both ends of a range in which it can mechanically move on the optical axis.

[0019] 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, and 26 are aberration diagrams at infinity focus for the zoom lenses of Examples 1 to 13. (a) shows the aberration diagram at the wide-angle end, and (b) shows the aberration diagram at the telephoto end.

[0020] In the spherical aberration diagram, Fno is the F-number, and shows the amount of spherical aberration for the d-line (wavelength 587.56 nm) and g-line (wavelength 435.84 nm). In the astigmatism diagram, S shows the amount of astigmatism at the sagittal image plane for the d-line, and M shows the amount of astigmatism at the meridional image plane for the d-line. In the distortion diagram, the amount of distortion for the d-line is shown. In the chromatic aberration diagram, the amount of chromatic aberration for the g-line is shown. ω is the imaging half angle of view (°) (angle of view in paraxial calculation), and shows the angle of view calculated by ray tracing.

[0021] Next, the characteristic configuration of the zoom lens of each embodiment will be described.

[0022] The zoom lens of each embodiment is composed of, arranged in order from the object side to the image side, a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power. In the zoom lens of each embodiment, the spacing between adjacent lens groups changes when zooming from the wide-angle end to the telephoto end.

[0023] The first lens group L1 is composed of three or more lenses. During zooming from the wide-angle end to the telephoto end, the first lens group L1 is fixed with respect to the image plane IP.

[0024] Furthermore, the zoom lens of each embodiment satisfies the following conditional expressions (1) to (3). Here, the focal length of the first lens group L1 is f1, the focal length of the second lens group L2 is f2, and the focal length of the fourth lens group L4 is f4. The distance on the optical axis from the object side lens surface of the lens arranged closest to the object in the first lens group L1 to the image side lens surface of the lens arranged closest to the image in the first lens group L1 is LD1. The air conversion length (total length when a parallel plate such as a filter is removed) (total lens length) of the distance on the optical axis from the object side lens surface of the lens arranged closest to the object in the zoom lens at the wide-angle end to the image plane IP is TTL.

[0025] 0.85<(-f1) / f2<2.00 (1) 0.00<(-f1) / f4<0.55 (2) 0.00 <LD1 / TTL<0.27 ···(3) Conditional formula (1) defines the ratio between the focal length f1 of the first lens group L1 and the focal length f2 of the second lens group L2. If the refractive power of the second lens group L2 is strong enough to exceed the upper limit of conditional formula (1), it becomes difficult to correct aberrations. If the refractive power of the second lens group L2 is weak enough to fall below the lower limit of conditional formula (1), the amount of movement of the second lens group L2 during zooming increases, resulting in an increase in the size of the zoom lens.

[0026] Conditional formula (2) specifies the ratio between the focal length f1 of the first lens group L1 and the focal length f4 of the fourth lens group L4. By satisfying the numerical range of conditional formula (2), it is possible to reduce the size of the zoom lens while ensuring telecentricity. If the refractive power of the fourth lens group L4 becomes strong enough to exceed the upper limit of conditional formula (2), the telecentricity will be improved, but this will be detrimental to reducing the size of the zoom lens. Note that the lower limit of conditional formula (2) will not be exceeded.

[0027] Conditional formula (3) specifies the ratio of the distance LD1 on the optical axis from the object side surface of the lens arranged closest to the object in the first lens group L1 to the image side surface of the lens arranged closest to the image in the first lens group L1 to the total lens length TTL of the zoom lens at the wide-angle end. By satisfying the numerical range of conditional formula (3), it is possible to reduce the weight of the zoom lens. If the upper limit of conditional formula (3) is exceeded, the distance LD1 becomes too large, and the first lens group L1 becomes large. Note that the lower limit of conditional formula (3) cannot be exceeded.

[0028] It is more preferable that the numerical ranges of the conditional expressions (1) to (3) be within the ranges of the following conditional expressions (1a) to (3a).

[0029] 0.88<(-f1) / f2<1.70 (1a) 0.09<(-f1) / f4<0.52 (2a) 0.07 <LD1 / TTL<0.25 ···(3a) It is more preferable that the numerical ranges of the conditional expressions (1) to (3) be within the numerical ranges of the following conditional expressions (1b) to (3b).

[0030] 0.89<(-f1) / f2<1.41 (1b) 0.16<(-f1) / f4<0.50 (2b) 0.13 <LD1 / TTL<0.24 ···(3b) As described above, the zoom lens of each embodiment is configured to satisfy conditional expressions (1) to (3), making it possible to provide a negative-lead type wide-angle zoom lens that is small and lightweight yet has high optical performance over the entire zoom range.

[0031] Next, a description will be given of configurations that are preferably satisfied in the zoom lens according to each embodiment.

[0032] In the zoom lens of each embodiment, it is preferable that the first lens group L1 is composed only of lenses having refractive power, which makes it possible to correct aberrations occurring in the first lens group L1 to a good level, and is advantageous for making the zoom lens more compact.

[0033] In the zoom lens of each embodiment, it is preferable that the second lens group L2 includes an aperture stop SP. It is also preferable that the third lens group L3 is a focus lens group that moves during focusing. This allows high optical performance to be achieved from focusing on close objects to focusing on long objects.

[0034] Next, conditions that the zoom lens of each embodiment should preferably satisfy will be described. The zoom lens of each embodiment should preferably satisfy one or more of the following conditional expressions (4) to (17).

[0035] Here, the air equivalent of the distance on the optical axis from the lens surface on the image side of the lens arranged closest to the image side in the zoom lens at the wide-angle end to the image plane IP when focusing on an object at infinity (the distance when a parallel plate such as a filter is removed) (back focus) is BFw. The focal length of the zoom lens at the wide-angle end is fw. The focal length of the third lens group L3 is f3. The focal length of the zoom lens at the telephoto end is ft. The lateral magnification of the second lens group L2 at the telephoto end when focusing on an object at infinity is β2t, and the lateral magnification of the second lens group L2 at the wide-angle end when focusing on an object at infinity is β2w. The lateral magnification of the third lens group L3 at the telephoto end when focusing on an object at infinity is β3t, and the lateral magnification of the third lens group L3 at the wide-angle end when focusing on an object at infinity is β3w. The focal length of the first negative lens in the first lens group L1 is fn1. The focal length of the second negative lens in the first lens group L1 is fn2. The focal length of the first positive lens in the first lens unit L1 is denoted as fp1.

[0036] 0.30 <BFw / (-f1)<1.50 ···(4) 0.07 <BFw / TTL<0.30 ···(5) 2.0 <TTL / (-f1)<6.0 ···(6) 3.0 <TTL / fw<7.5 ···(7) 0.1 <f2 / (-f3)<1.5 ···(8) 0.05 <f2 / f4<0.80 ···(9) 0.1<(-f3) / f4<2.0 (10) 0.5<(-f1) / fw<2.5 (11) 0.2<(-f1) / ft<1.4 (12) 0.5<β2t / β2w<3.0 (13) 0.5<β3t / β3w<2.0 (14) 0.5 <fn1 / f1<2.0 ···(15) 0.5 <fn2 / f1<10.0 ···(16) 0.5 <fp1 / (-f1)<5.0 ···(17) Conditional formula (4) specifies the ratio between the back focal length BFw of the zoom lens at the wide-angle end when focusing on an object at infinity and the focal length f1 of the first lens group L1. If the refractive power of the first lens group L1 is strong enough to exceed the upper limit of conditional formula (4), it becomes difficult to correct aberrations, which is undesirable. If the refractive power of the first lens group L1 is weak enough to fall below the lower limit of conditional formula (4), it becomes undesirable because the zoom lens becomes large.

[0037] Conditional formula (5) specifies the ratio between the back focal length BFw of the zoom lens at the wide-angle end when focusing on an object at infinity and the total lens length TTL of the zoom lens at the wide-angle end. By satisfying the numerical range of conditional formula (5), it is possible to reduce the size of the zoom lens while ensuring telecentricity. If the upper limit of conditional formula (5) is exceeded, the zoom lens becomes large, which is undesirable. If the lower limit of conditional formula (5) is exceeded, the back focal length BFw becomes too short, which makes it difficult to ensure telecentricity, which is undesirable.

[0038] Conditional formula (6) specifies the ratio between the total lens length TTL of the zoom lens at the wide-angle end and the focal length f1 of the first lens group L1. If the refractive power of the first lens group L1 becomes strong enough to exceed the upper limit of conditional formula (6), it becomes difficult to correct aberrations, which is undesirable. If the refractive power of the first lens group L1 becomes weak enough to fall below the lower limit of conditional formula (6), it becomes undesirable because the zoom lens becomes large.

[0039] Conditional formula (7) defines the ratio between the total lens length TTL of the zoom lens at the wide-angle end and the focal length fw of the zoom lens at the wide-angle end. If the upper limit of conditional formula (7) is exceeded, the zoom lens will become larger, which is undesirable. If the lower limit of conditional formula (7) is exceeded, it will become difficult to correct aberrations, which is undesirable.

[0040] Conditional formula (8) defines the ratio of the focal length f2 of the second lens group L2 to the focal length f3 of the third lens group L3. If the refractive power of the second lens group L2 becomes weaker as the upper limit of conditional formula (8) is exceeded, the zoom lens becomes larger, which is not preferable. If the refractive power of the second lens group L2 becomes strong as the lower limit of conditional formula (8) is exceeded, it becomes difficult to correct aberrations, which is not preferable.

[0041] Conditional formula (9) defines the ratio of the focal length f2 of the second lens group L2 to the focal length f4 of the fourth lens group L4. If the refractive power of the second lens group L2 becomes weak enough to exceed the upper limit of conditional formula (9), the zoom lens will become large, which is not preferable. If the refractive power of the second lens group L2 becomes strong enough to fall below the lower limit of conditional formula (9), it will become difficult to correct aberrations, which is not preferable.

[0042] Conditional expression (10) defines the ratio between the focal length f3 of the third lens group L3 and the focal length f4 of the fourth lens group L4. If the refractive power of the third lens group L3 becomes weak enough to exceed the upper limit of conditional expression (10), the zoom lens will become large, which is not preferable. If the refractive power of the third lens group L3 becomes strong enough to fall below the lower limit of conditional expression (10), it will become difficult to correct aberrations, which is not preferable.

[0043] Conditional expression (11) defines the ratio between the focal length f1 of the first lens group L1 and the focal length fw of the zoom lens at the wide-angle end. If the refractive power of the first lens group L1 becomes weak enough to exceed the upper limit of conditional expression (11), the zoom lens will become large, which is undesirable. If the refractive power of the first lens group L1 becomes strong enough to fall below the lower limit of conditional expression (11), it will become difficult to correct aberrations, which is undesirable.

[0044] Conditional expression (12) specifies the ratio between the focal length f1 of the first lens group L1 and the focal length ft of the zoom lens at the telephoto end. If the refractive power of the first lens group L1 becomes weak enough to exceed the upper limit of conditional expression (12), the zoom lens will become large, which is undesirable. If the refractive power of the first lens group L1 becomes strong enough to fall below the lower limit of conditional expression (12), it will become difficult to correct aberrations, which is undesirable.

[0045] Conditional expression (13) defines the ratio between the lateral magnification β2t of the second lens group L2 at the telephoto end when focusing on an object at infinity and the lateral magnification β2w of the second lens group L2 at the wide-angle end when focusing on an object at infinity. If the numerical value falls outside the range of conditional expression (13), it becomes difficult to correct aberrations over the entire zoom range, which is not preferable.

[0046] Conditional expression (14) defines the ratio between the lateral magnification β3t of the third lens group L3 at the telephoto end when focusing on an object at infinity and the lateral magnification β3w of the third lens group L3 at the wide-angle end when focusing on an object at infinity. If the numerical value falls outside the range of conditional expression (14), it becomes difficult to correct aberrations over the entire zoom range, which is not preferable.

[0047] Conditional formula (15) defines the ratio between the focal length fn1 of the first negative lens, which is one of the lenses constituting the first lens group L1, and the focal length f1 of the first lens group L1. If the value falls outside the range of the conditional formula (15), it becomes difficult to correct aberrations over the entire zoom range, which is not preferable.

[0048] Conditional expression (16) defines the ratio between the focal length fn2 of the second negative lens, which is one of the lenses constituting the first lens group L1, and the focal length f1 of the first lens group L1. If the numerical value of conditional expression (16) falls outside the range, it becomes difficult to correct aberrations over the entire zoom range, which is not preferable.

[0049] Conditional formula (17) defines the ratio between the focal length fp1 of the first positive lens, which is one of the lenses constituting the first lens group L1, and the focal length f1 of the first lens group L1. If the numerical value of conditional formula (17) falls outside the range, it becomes difficult to correct aberrations over the entire zoom range, which is not preferable.

[0050] Furthermore, it is preferable that the numerical ranges of the conditional expressions (4) to (17) be within the ranges of the following conditional expressions (4a) to (17a).

[0051] 0.33 <BFw / (-f1)<1.11 ···(4a) 0.10 <BFw / TTL<0.27 ···(5a) 2.3 <TTL / (-f1)<5.3 ···(6a) 3.6 <TTL / fw<7.1 ···(7a) 0.17 <f2 / (-f3)<1.12 ···(8a) 0.09 <f2 / f4<0.62 ···(9a) 0.15<(-f3) / f4<1.68 (10a) 0.89<(-f1) / fw<2.11 (11a) 0.39<(-f1) / ft<1.13 (12a) 1.0<β2t / β2w<2.45 (13a) 0.8<β3t / β3w<1.63 (14a) 0.60 <fn1 / f1<1.82 ···(15a) 0.76 <fn2 / f1<8.22 ···(16a) 0.72 <fp1 / (-f1)<4.16 ···(17a) It is even more preferable that the numerical ranges of the conditions (4) to (17) be within the range of (4b) to (17b).

[0052] 0.37 <BFw / (-f1)<0.75 ···(4b) 0.12 <BFw / TTL<0.24 ···(5b) 2.7 <TTL / (-f1)<4.7 ···(6b) 4.3 <TTL / fw<6.8 ···(7b) 0.23 <f2 / (-f3)<0.76 ···(8b) 0.11 <f2 / f4<0.45 ···(9b) 0.17<(-f3) / f4<1.37 (10b) 1.2<(-f1) / fw<1.9 (11b) 0.58<(-f1) / ft<0.90 (12b) 1.5<β2t / β2w<2.0 (13b) 1.09<β3t / β3w<1.26 (14b) 0.68 <fn1 / f1<1.65 ···(15b) 1.0 <fn2 / f1<6.5 ···(16b) 0.9 <fp1 / (-f1)<3.4 ···(17b) Next, the zoom lens of each embodiment will be described in detail.

[0053] The zoom lens of the first embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the first lens group L1 in a direction including a component perpendicular to the optical axis.

[0054] The zoom lens of the second embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the second lens group L2 in a direction including a component perpendicular to the optical axis.

[0055] The zoom lens of the third embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the second lens group L2 in a direction including a component perpendicular to the optical axis.

[0056] The zoom lens of the fourth embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the first lens group L1 in a direction including a component perpendicular to the optical axis.

[0057] The zoom lens of the fifth embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the second lens group L2 in a direction including a component perpendicular to the optical axis.

[0058] The zoom lens of the sixth embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the fourth lens group L4 in a direction including a component perpendicular to the optical axis.

[0059] The zoom lens of the seventh embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the second lens group L2 in a direction including a component perpendicular to the optical axis.

[0060] The zoom lens of the eighth embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. During variable zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. During focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the second lens group L2 in a direction including a component perpendicular to the optical axis.

[0061] The zoom lens of the ninth embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the first lens group L1 in a direction including a component perpendicular to the optical axis.

[0062] The zoom lens of the tenth embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the second lens group L2 in a direction including a component perpendicular to the optical axis.

[0063] The zoom lens of the eleventh embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the first lens group L1 in a direction including a component perpendicular to the optical axis.

[0064] The zoom lens of the twelfth embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the first lens group L1 in a direction including a component perpendicular to the optical axis.

[0065] The zoom lens of the thirteenth embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, and a fourth lens group L4 with positive refractive power, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes, and the first lens group L1 and the fourth lens group L4 are fixed with respect to the image plane IP. When focusing, the third lens group L3 moves. Image blur correction may be performed by moving a part of the first lens group L1 in a direction including a component perpendicular to the optical axis.

[0066] Numerical Examples 1 to 13 corresponding to Examples 1 to 13, respectively, are shown below.

[0067] In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the axial distance (distance on the optical axis) between the mth surface and the (m+1)th surface. Here, m is the surface number counted from the light incident side. In addition, nd represents the refractive index of each optical member with respect to the d-line, and νd represents the Abbe number based on the d-line of the optical member. The Abbe number νd based on the d-line of a certain material 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).

[0068] In each numerical example, d, focal length (mm), F-number, and half angle of view (°) are all values ​​when the zoom lens of each example is focused on an object at infinity. The back focus BF is the distance on the optical axis from the final lens surface (the surface closest to the image) of the zoom lens to the paraxial image surface, expressed as an air-equivalent length. The total lens length of a zoom lens is the distance on the optical axis from the first lens surface (the lens surface closest to the object) to the final lens surface plus the back focus. The lens group is not limited to being composed of multiple lenses, and may be composed of a single lens.

[0069] If the optical surface is aspheric, a * symbol is added to the right of the surface number. The aspheric shape is expressed as follows, where X is the displacement from the apex of the surface in the optical axis direction, h is the height from the optical axis in a direction perpendicular to the optical axis, R is the paraxial radius of curvature, k is the conic constant, and A4, A6, A8, A10, and A12 are the aspheric coefficients of each order: x=(h 2 / R) / [1+{1-(1+k)(h / R) 2} 1 / 2 ]+A4×h 4 +A6×h 6 +A8×h 8 +A10×h 10 +A12×h 12 In addition, "e±XX" in each aspheric coefficient is "×10± XX " It means.

[0070] (Numerical Example 1) Unit: mm Surface Data Surface number rd nd νd 1 31.510 1.00 1.80400 46.5 2 13.253 5.81 3 384.169 1.00 1.59282 68.6 4 16.237 2.57 5 20.027 2.35 1.85478 24.8 6 43.038 2.86 7 -122.389 1.00 1.49700 81.5 8 153.848 (variable) 9 -132.462 2.51 1.48749 70.2 10 -22.094 2.50 11 (Aperture) ∞ 0.50 12 16.955 4.23 1.83481 42.7 13 -15.911 1.90 1.90366 31.3 14 46.587 4.62 15 20.752 0.90 1.80400 46.5 16 8.522 3.98 1.49700 81.5 17 -23.714 (variable) 18 -19.766 0.80 1.56732 42.8 19 209.263 2.07 20* -13.721 2.00 1.53110 55.9 21* -19.057 (variable) 22 -129.610 4.47 1.85150 40.8 23 -26.924 12.29 Image plane ∞ Aspheric Data Page 20 K = 0.00000e+00 A 4= 3.64281e-04 A 6= 2.03779e-06 A 8=-1.61378e-08 Page 21 K = 0.00000e+00 A 4= 3.50063e-04 A 6= 1.61923e-06 A 8=-1.64849e-08 Various data Zoom ratio 2.34 Wide Angle Mid-Telephoto Focal length 12.42 18.65 29.07 F-number 4.10 5.13 6.40 Half angle of view (°) 47.72 36.22 25.17 Image height 11.37 12.86 13.66 Lens length 82.97 82.97 82.97 BF 12.29 12.29 12.29 d 8 18.70 10.05 1.39 d17 1.69 2.74 6.86 d21 3.20 10.80 15.34 Zoom lens group data Group starting plane focal length 1 1 -17.76 2 9 17.38 3 18 -24.70 4 22 39.13 (Numerical Example 2) Unit: mm Surface Data Surface number rd nd νd 1 34.396 1.00 1.77250 49.6 2 13.292 5.69 3 -323.606 1.00 1.59282 68.6 4 16.748 2.92 5 20.652 2.29 1.84666 23.8 6 36.566 (variable) 7 -301.068 3.73 1.48749 70.2 8 -30.039 4.78 9(Aperture) ∞ 0.50 10 19.485 3.34 1.83481 42.7 11 -14.251 1.90 1.90366 31.3 12∞4.14 13 25.728 1.00 1.83481 42.7 14 9.171 3.79 1.49700 81.5 15 -26.368 (variable) 16 -23.072 0.80 1.51742 52.4 17 82.694 2.02 18* -15.829 2.00 1.53110 55.9 19* -21.570 (variable) 20 -120.000 4.42 1.77250 49.6 21 -27.671 12.13 Image plane ∞ Aspheric Data Page 18 K = 0.00000e+00 A 4= 3.32711e-04 A 6= 1.73403e-06 A 8=-1.45204e-08 Page 19 K = 0.00000e+00 A 4= 3.39522e-04 A 6= 1.63472e-06 A 8=-1.61755e-08 Various data Zoom ratio 2.35 Wide Angle Mid-Telephoto Focal length 12.40 18.66 29.10 F-number 4.10 5.10 6.40 Half angle of view (°) 47.76 36.21 25.15 Image height 11.37 12.86 13.66 Lens length 83.44 83.44 83.44 BF 12.13 12.13 12.13 d 6 19.82 10.85 1.88 d15 1.77 2.36 6.01 d19 4.41 12.78 18.10 d21 12.13 12.13 12.13 Zoom lens group data Group starting plane focal length 1 1 -18.26 2 7 17.57 3 16 -27.60 4 20 45.60 (Numerical Example 3) Unit: mm Surface Data Surface number rd nd νd 1 35.706 1.00 1.77250 49.6 2 14.414 5.20 3 -441.444 1.00 1.59282 68.6 4 16.131 3.30 5 21.292 3.27 1.84666 23.8 6 38.733 (variable) 7 -260.840 2.46 1.48749 70.2 8 -33.213 2.00 9(Aperture) ∞ 2.00 10 20.926 4.64 1.85150 40.8 11 -18.671 0.22 12 -17.428 0.80 1.85478 24.8 13 218.347 4.07 14 28.492 1.00 1.72916 54.7 15 9.356 5.18 1.49700 81.5 16 -24.952 (variable) 17 -22.720 0.80 1.57099 50.8 18 148.402 1.72 19* -23.196 2.00 1.53110 55.9 20* -30.564 (variable) 21 -120.000 4.34 1.77250 49.6 22 -27.692 (variable) Image plane ∞ Aspheric Data Page 19 K = 0.00000e+00 A 4= 2.94393e-04 A 6= 7.13003e-07 A 8=-1.72892e-08 Page 20 K = 0.00000e+00 A 4= 3.24911e-04 A 6= 1.01599e-06 A 8=-1.72183e-08 Various data Zoom ratio 2.35 Wide Angle Mid-Telephoto Focal length 12.40 18.69 29.10 F-number 4.10 4.10 4.10 Half angle of view (°) 47.76 36.16 25.15 Image height 11.37 12.86 13.66 Lens total length 82.02 82.02 82.02 BF 12.79 12.79 12.79 d 6 19.99 10.92 1.84 d16 1.66 2.03 5.63 d20 2.58 11.29 16.76 d22 12.79 12.79 12.79 Zoom lens group data Group starting plane focal length 1 1 -19.53 2 7 17.94 3 17 -29.69 4 21 45.67 (Numerical Example 4) Unit: mm Surface Data Surface number rd nd νd 1 114.124 1.00 1.77250 49.6 2 12.042 4.29 3* 43.105 2.50 1.53110 55.9 4* 20.966 1.99 5 35.204 2.90 1.77047 29.7 6 -114.527 1.97 7 -32.492 1.00 1.49700 81.5 8 -70.456 (variable) 9 18.171 1.94 1.77250 49.6 10 -529.066 2.48 11 (Aperture) ∞ 1.38 12 12.421 1.79 1.59282 68.6 13 44.069 0.36 14 -46.037 1.00 1.68893 31.1 15 10.684 0.48 16 25.111 3.36 1.59282 68.6 17 -21.982 (variable) 18* -18.435 2.00 1.53110 55.9 19* -32.813 (variable) 20 -120.000 4.59 1.63854 55.4 21 -29.908 11.78 Image plane ∞ Aspheric Data 3rd page K = 0.00000e+00 A 4=-8.94309e-05 A 6= 7.11824e-07 A 8=-3.52027e-09 Side 4 K = 0.00000e+00 A 4=-1.48535e-04 A 6= 6.59805e-07 A 8=-5.15433e-09 Page 18 K = 0.00000e+00 A 4= 2.68346e-04 A 6= 2.81044e-06 A 8=-9.40023e-08 Page 19 K = 0.00000e+00 A 4= 2.67097e-04 A 6= 1.59679e-06 A 8=-5.11740e-08 Various data Zoom ratio 2.02 Wide Angle Mid-Telephoto Focal length 14.40 20.07 29.10 F-number 4.10 5.02 6.29 Half angle of view (°) 43.40 34.24 25.14 Image height 11.46 12.40 13.17 Lens total length 75.06 75.06 75.06 BF 11.78 11.78 11.78 d 8 16.11 8.43 0.74 d17 1.84 1.00 6.15 d19 10.29 18.81 21.35 d21 11.78 11.78 11.78 Zoom lens group data Group starting plane focal length 1 1 -21.90 2 9 19.73 3 18 -83.23 4 20 61.17 (Numerical Example 5) Unit: mm Surface Data Surface number rd nd νd 1 235.833 1.00 1.77250 49.6 2 10.085 4.16 3* -895.559 2.50 1.53110 55.9 4* 44.647 1.74 5 64.099 1.78 2.05090 26.9 6 -162.178 (variable) 7 -459.615 2.29 1.48749 70.2 8 -33.943 4.00 9 18.560 3.57 1.69680 55.5 10 -16.150 1.00 1.90043 37.4 11 -62.644 1.84 12 (Aperture) ∞ 4.68 13 25.922 1.00 1.83481 42.7 14 8.456 4.21 1.49700 81.5 15 -26.343 (variable) 16 -34.878 0.80 1.61772 49.8 17 139.823 4.14 18* -9.417 2.00 1.53110 55.9 19* -12.991 (variable) 20 -120.000 4.63 1.63854 55.4 21 -24.348 11.50 Image plane ∞ Aspheric Data 3rd page K = 0.00000e+00 A 4=-8.12193e-05 A 6= 8.99724e-07 A 8=-1.19209e-08 Side 4 K = 0.00000e+00 A 4=-1.28410e-04 A 6= 3.69150e-07 A 8=-1.09948e-08 Page 18 K = 0.00000e+00 A 4= 2.77887e-04 A 6= 6.15575e-06 A 8=-2.56537e-08 Page 19 K = 0.00000e+00 A 4= 2.14784e-04 A 6= 3.85389e-06 A 8=-2.47687e-08 Various data Zoom ratio 2.02 Wide Angle Mid-Telephoto Focal length 14.40 20.23 29.10 F-number 4.10 5.04 6.40 Half angle of view (°) 43.30 34.02 25.14 Image height 11.42 12.56 13.22 Lens length 78.52 78.52 78.52 BF 11.50 11.50 11.50 d 6 16.23 8.82 1.41 d15 1.45 2.48 6.02 d19 3.98 10.37 14.24 d21 11.50 11.50 11.50 Zoom lens group data Group starting plane focal length 1 1 -18.40 2 7 18.55 3 16 -28.78 4 20 46.95 (Numerical Example 6) Unit: mm Surface Data Surface number rd nd νd 1 93.086 1.00 1.77250 49.6 2 11.534 5.04 3* 35.096 2.50 1.53110 55.9 4* 18.745 1.76 5 34.034 2.40 1.84666 23.8 6 247.520 (variable) 7 21.135 3.07 1.77250 49.6 8 -83.384 2.42 9(Aperture) ∞ 1.42 10 11.906 1.79 1.60311 60.6 11 24.109 0.36 12 -32.365 1.05 1.72151 29.2 13 11.247 0.46 14 18.005 2.74 1.60311 60.6 15 -16.851 (variable) 16* -20.785 2.00 1.53110 55.9 17* -46.785 (variable) 18 227.811 1.00 1.65844 50.9 19 39.504 5.98 20 41.856 6.15 1.72916 54.7 21 -63.192 13.08 Image plane ∞ Aspheric Data 3rd page K = 0.00000e+00 A 4=-1.05255e-04 A 6= 6.96967e-07 A 8=-3.20460e-09 Side 4 K = 0.00000e+00 A 4=-1.71621e-04 A 6= 6.71606e-07 A 8=-5.21171e-09 Page 16 K = 0.00000e+00 A 4= 2.57526e-04 A 6= 2.11426e-06 A 8=-6.79744e-08 Page 17 K = 0.00000e+00 A 4= 2.59203e-04 A 6= 1.45831e-06 A 8=-4.89468e-08 Various data Zoom ratio 1.97 Wide Angle Mid-Telephoto Focal length 14.47 19.96 28.47 F-number 4.10 5.01 6.22 Half angle of view (°) 43.35 34.39 25.63 Image height 11.42 12.56 13.22 Lens length 72.82 72.82 72.82 BF 13.08 13.08 13.08 d 6 15.12 7.96 0.79 d15 1.64 0.67 4.33 d17 1.83 9.96 13.47 d21 13.08 13.08 13.08 Zoom lens group data Group starting plane focal length 1 1 -22.02 2 7 18.72 3 16 -72.35 4 18 57.69 (Numerical Example 7) Unit: mm Surface Data Surface number rd nd νd 1∞1.50 2 49.839 1.40 1.77250 49.6 3 17.865 9.70 4 -74.024 1.10 1.59282 68.6 5 26.453 2.18 6 28.144 5.42 1.80610 33.3 7 155.531 (variable) 8 24.363 3.01 1.72916 54.7 9 133.320 2.61 10(Aperture) ∞ 2.00 11 42.759 1.00 1.76634 35.8 12 11.137 5.77 1.72916 54.7 13 -107.618 2.85 14 -20.935 1.00 1.53172 48.8 15 38.508 0.15 16* 29.415 7.00 1.49700 81.5 17* -16.643 (variable) 18 26.091 0.80 1.60342 38.0 19 16.431 9.30 20* -50.394 2.40 1.53110 55.9 21* -1001.831 (variable) 22 -200.000 3.26 1.90065 31.6 23 -61.168 12.68 Image plane ∞ Aspheric Data Page 16 K = 0.00000e+00 A 4=-5.16959e-05 A 6=-1.53463e-07 A 8=-3.31876e-09 Page 17 K = 0.00000e+00 A 4= 3.33206e-05 A 6=-2.05294e-07 A 8=-1.88875e-09 Page 20 K = 0.00000e+00 A 4=-3.57991e-05 A 6=-1.41049e-07 A 8=-1.54522e-09 Page 21 K = 0.00000e+00 A 4=-4.36025e-05 A 6=-1.02183e-07 A 8=-4.60803e-10 Various data Zoom ratio 1.89 Wide Angle Mid-Telephoto Focal length 20.60 28.40 39.00 F-number 4.10 4.10 4.10 Half angle of view (°) 46.40 37.29 29.01 Image height 17.94 19.62 20.74 Lens total length 97.01 97.01 97.01 BF 12.68 12.68 12.68 d 7 18.11 9.58 1.05 d17 1.79 1.00 2.86 d21 2.00 11.32 18.00 d23 12.68 12.68 12.68 Zoom lens group data Group starting plane focal length 1 1 -30.37 2 8 24.27 3 18 -41.20 4 22 96.76 (Numerical Example 8) Unit: mm Surface Data Surface number rd nd νd 1 42.299 1.50 1.75500 52.3 2 18.914 8.16 3 -142.144 1.20 1.59282 68.6 4 30.217 5.54 5 33.034 2.03 1.96300 24.1 6 50.217 (variable) 7 3588.151 3.04 1.53775 74.7 8 -40.853 1.62 9 23.007 4.07 1.79952 42.2 10 -26.519 1.01 1.95375 32.3 11 79.436 3.46 12(Aperture) ∞ 5.69 13 28.102 1.00 1.85150 40.8 14 11.348 4.25 1.59522 67.7 15 -45.381 (variable) 16 41.052 0.80 1.51742 52.4 17 15.294 6.27 18* -51.838 2.10 1.53110 55.9 19* -1006.304 (variable) 20 -200.000 5.59 1.77250 49.6 21 -45.565 (variable) Image plane ∞ Aspheric Data Side 18 K = 0.00000e+00 A 4=-2.18376e-04 A 6= 8.06571e-07 A 8=-7.88304e-09 Page 19 K = 0.00000e+00 A 4=-1.88281e-04 A 6= 7.88400e-07 A 8=-4.74781e-09 Various data Zoom ratio 2.35 Wide Angle Mid-Telephoto Focal length 20.60 31.11 48.50 F-number 4.10 5.20 5.88 Half angle of view (°) 46.40 34.81 24.04 Image height 18.22 20.32 21.64 Lens total length 106.52 106.52 106.52 BF 19.41 19.41 19.41 d 6 26.05 13.88 1.70 d15 1.00 2.05 6.67 d19 2.72 13.84 21.40 d21 19.41 19.41 19.41 Zoom lens group data Group starting plane focal length 1 1 -28.51 2 7 23.49 3 16 -31.34 4 20 75.20 (Numerical Example 9) Unit: mm Surface Data Surface number rd nd νd 1 60.703 1.30 1.95375 32.3 2 10.568 5.26 3* -158.794 2.00 1.53110 55.9 4* 35.904 0.68 5 69.552 2.59 1.85478 24.8 6 -37.356 0.90 7 -41.573 1.00 1.43875 94.7 8 -114.793 (variable) 9 19.470 2.27 1.65160 58.5 10 -126.753 6.20 11(Aperture) ∞ 0.80 12 13.509 2.32 1.49700 81.5 13 -29.196 0.23 14 -18.502 2.50 1.59551 39.2 15 10.390 1.45 16 16.003 2.95 1.43875 94.7 17 -17.071 (variable) 18* -18.646 1.50 1.53110 55.9 19* -46.212 (variable) 20 -40.654 3.48 1.43875 94.7 21 -20.238 13.34 Image plane ∞ Aspheric Data 3rd page K = 0.00000e+00 A 4=-1.84708e-04 A 6= 1.47430e-06 A 8=-1.09499e-08 Side 4 K = 0.00000e+00 A 4=-2.31582e-04 A 6= 1.38450e-06 A 8=-1.10945e-08 Side 18 K = 0.00000e+00 A 4= 4.14762e-04 A 6=-1.81540e-06 A 8=-1.40506e-09 Page 19 K = 0.00000e+00 A 4= 4.21395e-04 A 6=-2.16529e-06 A 8= 8.23735e-09 Various data Zoom ratio 2.01 Wide Angle Mid-Telephoto Focal length 14.45 20.17 29.09 F-number 4.10 5.05 6.40 Half angle of view (°) 43.39 34.10 25.15 Image height 11.46 12.41 13.18 Lens length 77.99 77.99 77.99 BF 13.34 13.34 13.34 d 8 16.17 8.48 0.80 d17 0.80 1.51 7.58 d19 10.26 17.23 18.84 d21 13.34 13.34 13.34 Zoom lens group data Group starting plane focal length 1 1 -18.40 2 9 20.41 3 18 -59.99 4 20 87.31 (Numerical Example 10) Unit: mm Surface Data Surface number rd nd νd 1 42.644 1.30 1.72916 54.7 2 17.764 8.77 3 -70.406 1.20 1.53775 74.7 4 25.301 2.36 5 25.884 4.26 1.62588 35.7 6 209.726 (variable) 7 25.792 2.12 1.59522 67.7 8 539.599 5.57 9(Aperture) ∞ 0.88 10 59.108 1.00 1.69895 30.1 11 19.640 2.76 1.72916 54.7 12 -88.410 2.69 13 -18.122 1.01 1.54072 47.2 14 71.719 2.69 15* 23.626 4.90 1.43875 94.7 16* -14.207 (variable) 17 24.461 1.00 1.51633 64.1 18 15.091 9.99 19* -51.360 2.00 1.53110 55.9 20* 199.736 (variable) 21 -991.849 2.03 2.05090 26.9 22 -167.475 12.67 Image plane ∞ Aspheric Data Page 15 K = 0.00000e+00 A 4=-2.76672e-05 A 6=-3.81028e-08 A 8= 1.77147e-09 Page 16 K = 0.00000e+00 A 4= 8.66431e-05 A 6=-1.50654e-07 A 8= 3.16848e-09 Page 19 K = 0.00000e+00 A 4=-2.50400e-05 A 6=-1.73349e-07 A 8=-1.30647e-09 Page 20 K = 0.00000e+00 A 4=-4.36025e-05 A 6=-1.02183e-07 A 8=-4.60803e-10 Various data Zoom ratio 1.88 Wide Angle Mid-Telephoto Focal length 20.92 28.94 39.31 F-number 4.10 4.10 4.10 Half angle of view (°) 45.96 36.78 28.82 Image height 18.00 19.62 20.76 Lens total length 91.22 91.22 91.22 BF 12.67 12.67 12.67 d 6 17.87 9.33 0.80 d16 2.47 0.80 1.28 d20 1.69 11.90 19.95 d22 12.67 12.67 12.67 Zoom lens group data Group starting plane focal length 1 1 -33.47 2 7 23.91 3 17 -36.80 4 21 191.50 (Numerical Example 11) Unit: mm Surface Data Surface number rd nd νd 1 620.156 1.00 1.80610 40.9 2 13.951 3.20 3* 31.386 1.77 1.53110 55.9 4* 16.340 2.55 5 -2188.375 1.00 1.43875 94.7 6 22.775 3.74 1.90043 37.4 7 -107.410 1.34 8 -53.431 1.00 1.43875 94.7 9 -351.116 (variable) 10 18.205 2.17 1.69680 55.5 11 -182.560 2.82 12 (Aperture) ∞ 0.80 13 11.712 2.38 1.43875 94.7 14 -80.486 0.31 15 -25.729 2.00 1.60342 38.0 16 10.136 1.04 17 20.451 2.17 1.43875 94.7 18 -17.817 (variable) 19* -40.343 1.50 1.53110 55.9 20* 106.642 (variable) 21 -547.596 5.61 1.49700 81.5 22 -21.883 (variable) Image plane ∞ Aspheric Data 3rd page K = 0.00000e+00 A 4=-1.92346e-04 A 6= 1.46585e-06 A 8=-5.19278e-09 Side 4 K = 0.00000e+00 A 4=-2.49552e-04 A 6= 1.56459e-06 A 8=-7.02285e-09 Page 19 K = 0.00000e+00 A 4= 2.25885e-04 A 6=-7.11818e-07 A 8=-1.70513e-08 Page 20 K = 0.00000e+00 A 4= 2.83610e-04 A 6=-1.54983e-06 A 8=-2.79368e-09 Various data Zoom ratio 2.01 Wide Angle Mid-Telephoto Focal length 14.44 20.17 29.09 F-number 4.10 5.07 6.40 Half angle of view (°) 43.41 34.11 25.15 Image height 11.46 12.41 13.18 Lens length 74.83 74.83 74.83 BF 13.10 13.10 13.10 d 9 16.17 8.48 0.80 d18 2.41 3.08 8.46 d20 6.75 13.76 16.06 d22 13.10 13.10 13.10 Zoom lens group data Group starting plane focal length 1 1 -22.35 2 10 20.11 3 19 -54.92 4 21 45.70 (Numerical Example 12) Unit: mm Surface Data Surface number rd nd νd 1 333.322 1.00 1.59145 68.4 2 14.457 2.17 3* 16.664 1.75 1.53110 55.9 4* 13.429 3.12 5 72.731 0.99 1.43830 95.0 6 15.506 1.36 7 18.208 3.08 1.80652 46.7 8 82.353 2.05 9 -59.712 1.00 1.43846 94.8 10 1265.032 (variable) 11 16.222 1.79 1.69462 57.7 12 -120.338 0.80 13(Aperture) ∞ 0.80 14 8.920 1.59 1.51616 79.3 15 24.467 0.35 16 -291.423 1.00 1.60753 37.9 17 7.730 2.37 18 15.894 1.71 1.43787 95.3 19 -25.062 (variable) 20* -20.249 1.28 1.53110 55.9 21* -67.405 (variable) 22 1468.914 4.86 1.49667 81.9 23 -26.178 13.10 Image plane ∞ Aspheric Data 3rd page K = 0.00000e+00 A 4=-1.53281e-04 A 6= 1.08426e-06 A 8=-4.18904e-09 Side 4 K = 0.00000e+00 A 4=-2.14777e-04 A 6= 1.34839e-06 A 8=-7.81236e-09 Page 20 K = 0.00000e+00 A 4= 6.82662e-04 A 6=-2.35509e-06 A 8=-8.17593e-08 Page 21 K = 0.00000e+00 A 4= 7.14470e-04 A 6=-3.68516e-06 A 8=-2.76365e-08 Various data Zoom ratio 2.02 Wide Angle Mid-Telephoto Focal length 14.43 20.17 29.10 F-number 4.10 5.00 6.16 Half angle of view (°) 43.42 34.11 25.14 Image height 11.46 12.41 13.18 Lens length 70.63 70.63 70.63 BF 13.10 13.10 13.10 d10 16.17 8.49 0.80 d19 1.57 0.80 3.54 d21 6.72 15.18 20.12 d23 13.10 13.10 13.10 Zoom lens group data Group starting plane focal length 1 1 -24.90 2 11 18.46 3 20 -55.02 4 22 51.84 (Numerical Example 13) Unit: mm Surface Data Surface number rd nd νd 1 206.545 1.30 1.72916 54.7 2 11.330 4.19 3* 62.888 1.81 1.53110 55.9 4* 20.219 0.80 5 24.916 2.72 1.90043 37.4 6 -390.408 2.23 7 -25.898 1.02 1.43875 94.7 8 -47.695 (variable) 9 18.212 1.40 1.69680 55.5 10 63.288 2.25 11(Aperture) ∞ 0.80 12 11.731 2.68 1.53775 74.7 13 -13.536 0.17 14 -12.668 1.50 1.57099 50.8 15 6.966 0.63 16 8.050 3.16 1.43875 94.7 17 -26.152 (variable) 18* -12.552 1.50 1.53110 55.9 19* -21.575 (variable) 20 -28.270 2.55 1.49700 81.5 21 -19.416 16.10 Image plane ∞ Aspheric Data 3rd page K = 0.00000e+00 A 4=-1.14002e-04 A 6= 1.79201e-06 A 8=-9.57523e-09 Side 4 K = 0.00000e+00 A 4=-1.76654e-04 A 6= 1.89620e-06 A 8=-1.42839e-08 Side 18 K = 0.00000e+00 A 4= 9.49757e-04 A 6= 5.59399e-06 A 8=-2.76077e-07 Page 19 K = 0.00000e+00 A 4= 8.99649e-04 A 6= 3.06165e-06 A 8=-1.04329e-07 Various data Zoom ratio 2.02 Wide Angle Mid-Telephoto Focal length 14.42 20.24 29.10 F-number 4.10 5.06 6.28 Half angle of view (°) 43.44 34.01 25.15 Image height 11.46 12.41 13.18 Lens length 69.58 69.58 69.58 BF 16.10 16.10 16.10 d 8 16.17 8.48 0.80 d17 2.79 0.79 2.42 d19 3.84 13.52 19.58 d21 16.10 16.10 16.10 Zoom lens group data Group starting plane focal length 1 1 -23.46 2 9 18.06 3 18 -59.97 4 20 113.86 Various values ​​in each numerical example are summarized in Tables 1 and 2 below.

[0071] [Table 1]

[0072] [Table 2]

[0073] [Imaging device] Next, an embodiment of a digital still camera (imaging device) using the zoom lens of each embodiment as an imaging optical system will be described with reference to FIG. 27. FIG. 27 is a diagram showing the configuration of an imaging device 10. The imaging device 10 includes a camera body 13, a lens device 11 including a zoom lens of any one of the above-mentioned embodiments 1 to 13, and an imaging element (light receiving element) 12 that photoelectrically converts an image formed by the zoom lens. An imaging element such as a CCD sensor or a CMOS sensor can be used as the imaging element 12. The lens device 11 and the camera body 13 may be integrally configured, or may be detachably configured. The camera body 13 may be a so-called single-lens reflex camera having a quick-turn mirror, or may be a so-called mirrorless camera not having a quick-turn mirror. The imaging device 10 of this embodiment is small and lightweight, and can obtain high optical performance.

[0074] The imaging device 10 of this embodiment is not limited to the digital still camera shown in FIG. 27, but can be applied to various imaging devices such as broadcast cameras, cameras for silver halide film, and surveillance cameras.

[0075] [Imaging system] An imaging system (surveillance camera system) may be configured including the zoom lens of each embodiment and a control unit that controls the zoom lens. In this case, the control unit can control the zoom lens so that each lens group moves as described above during zooming, focusing, and image blur correction. In this case, the control unit does not need to be configured integrally with the zoom lens, and the control unit may be configured separately from the zoom lens. For example, a configuration may be adopted in which a control unit (control device) disposed far away from a drive unit that drives each lens of the zoom lens includes a transmission unit that sends a control signal (command) for controlling the zoom lens. With such a control unit, the zoom lens can be remotely operated.

[0076] Also, the control unit may be provided with an operation unit such as a controller or buttons for remotely controlling the zoom lens, so that the zoom lens is controlled in response to a user's input to the operation unit. For example, a zoom-in button and a zoom-out button may be provided as the operation unit. Then, the control unit may be configured to send a signal to a drive unit of the zoom lens L0 so that the magnification of the zoom lens increases when the user presses the zoom-in button, and decreases when the user presses the zoom-out button.

[0077] The imaging system may also have a display unit such as a liquid crystal panel that displays information (movement state) related to the zoom of the zoom lens. The information related to the zoom of the zoom lens is, for example, the zoom magnification (zoom state) and the movement amount (movement state) of each lens group. In this case, the user can remotely operate the zoom lens via the operation unit while viewing the information related to the zoom of the zoom lens displayed on the display unit. In this case, the display unit and the operation unit may be integrated by adopting, for example, a touch panel.

[0078] The disclosure of each of the above embodiments includes the following configurations.

[0079] (Configuration 1) A zoom lens comprising, arranged in order from an object side to an image side, a first lens group L1 having negative refractive power, a second lens group L2 having positive refractive power, a third lens group L3 having negative refractive power, and a fourth lens group L4 having positive refractive power, wherein the distance between adjacent lens groups changes during zooming from a wide-angle end to a telephoto end, the first lens group is composed of three or more lenses, During zooming from the wide-angle end to the telephoto end, the first lens group is fixed with respect to an image plane, Let f1 be the focal length of the first lens group, f2 be the focal length of the second lens group, f4 be the focal length of the fourth lens group, LD1 be the distance on the optical axis from the object side lens surface of the lens located closest to the object in the first lens group to the image side lens surface of the lens located closest to the image in the first lens group, and TTL be the air-equivalent length of the distance on the optical axis from the object side lens surface of the lens located closest to the object in the zoom lens at the wide-angle end to the image plane. 0.85<(-f1) / f2<2.00 0.00<(-f1) / f4<0.55 0.00 <LD1 / TTL<0.27 A zoom lens characterized by satisfying the following conditional expressions: (Configuration 2) When the air equivalent of the distance on the optical axis from the image-side lens surface of the lens arranged closest to the image side in the zoom lens at the wide-angle end to the image plane is BFw, 0.30 <BFw / (-f1)<1.50 2. The zoom lens according to claim 1, wherein the following condition is satisfied: (Configuration 3) When the air equivalent of the distance on the optical axis from the image-side lens surface of the lens arranged closest to the image side in the zoom lens at the wide-angle end to the image plane is BFw, 0.07 <BFw / TTL<0.30 3. The zoom lens according to configuration 1 or 2, wherein the following condition is satisfied: (Configuration 4) 2.0 <TTL / (-f1)<6.0 4. The zoom lens according to any one of configurations 1 to 3, wherein the following condition is satisfied: (Configuration 5) When the focal length of the zoom lens at the wide-angle end is fw, 3.0 <TTL / fw<7.5 5. The zoom lens according to any one of configurations 1 to 4, wherein the following condition is satisfied: (Configuration 6) When the focal length of the third lens group is f3, 0.1 <f2 / (-f3)<1.5 6. The zoom lens according to any one of configurations 1 to 5, wherein the following condition is satisfied: (Configuration 7) 0.05 <f2 / f4<0.80 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 third lens group is f3, 0.1<(-f3) / f4<2.0 8. The zoom lens according to any one of configurations 1 to 7, wherein the following condition is satisfied: (Configuration 9) When the focal length of the zoom lens at the wide-angle end is fw, 0.5<(-f1) / fw<2.5 9. The zoom lens according to any one of configurations 1 to 8, wherein the following condition is satisfied: (Configuration 10) When the focal length of the zoom lens at the telephoto end is ft, 0.2<(-f1) / ft<1.4 10. The zoom lens according to any one of configurations 1 to 9, wherein the following condition is satisfied: (Configuration 11) When the lateral magnification of the second lens group at the telephoto end is β2t and the lateral magnification of the second lens group at the wide-angle end is β2w, 0.5<β2t / β2w<3.0 11. The zoom lens according to any one of configurations 1 to 10, wherein the following condition is satisfied: (Configuration 12) When the lateral magnification of the third lens group at the telephoto end is β3t and the lateral magnification of the third lens group at the wide-angle end is β3w, 0.5<β3t / β3w<2.0 12. The zoom lens according to any one of configurations 1 to 11, wherein the following condition is satisfied: (Configuration 13) the first lens group includes a first negative lens, When the focal length of the first negative lens is fn1, 0.5 <fn1 / f1<2.0 13. The zoom lens according to any one of configurations 1 to 12, wherein the following condition is satisfied: (Configuration 14) the first lens group includes a second negative lens, When the focal length of the second negative lens is fn2, 0.5 <fn2 / f1<10.0 14. The zoom lens according to any one of configurations 1 to 13, wherein the following condition is satisfied: (Configuration 15) the first lens group includes a first positive lens, When the focal length of the first positive lens is fp1, 0.5 <fp1 / (-f1)<5.0 15. The zoom lens according to any one of configurations 1 to 14, wherein the following condition is satisfied: (Configuration 16) 16. The zoom lens according to any one of configurations 1 to 15, wherein the first lens group L1 is composed only of lenses having refractive power. (Configuration 17) 17. The zoom lens according to any one of configurations 1 to 16, wherein during zooming from the wide-angle end to the telephoto end, the fourth lens group is fixed with respect to the image plane. (Configuration 18) 18. A zoom lens according to any one of configurations 1 to 17, wherein the second lens group includes an aperture stop. (Configuration 19) 19. The zoom lens according to any one of configurations 1 to 18, wherein the fourth lens group is composed of one positive single lens. (Configuration 20) 20. The zoom lens according to any one of configurations 1 to 19, wherein the first lens group is composed of a negative lens, a negative lens, and a positive lens arranged in this order from the object side to the image side. (Configuration 21) 20. The zoom lens according to any one of configurations 1 to 19, wherein the first lens group is composed of, in order from the object side to the image side, a negative lens, a negative lens, a positive lens, and a negative lens. (Configuration 22) 20. The zoom lens according to any one of configurations 1 to 19, wherein the first lens group is composed of, in order from the object side to the image side, a negative lens, a negative lens, a negative lens, a positive lens, and a negative lens. (Configuration 23) 23. The zoom lens according to any one of configurations 1 to 22, wherein the third lens group is a focus lens group that moves during focusing. (Configuration 24) 24. The zoom lens according to configuration 23, wherein the third lens group is composed of one negative single lens. (Configuration 25) 24. The zoom lens according to configuration 23, wherein the third lens group is composed of two negative single lenses. (Configuration 26) 26. An imaging device comprising: the zoom lens according to any one of configurations 1 to 25; and an imaging element that receives an image formed by the zoom lens. (Configuration 27) 26. An imaging system comprising: the zoom lens according to any one of configurations 1 to 25; and a control unit that controls the zoom lens during zooming. (Configuration 28) 28. The imaging system according to configuration 27, wherein the control unit is configured separately from the zoom lens and has a transmission unit that transmits a control signal for controlling the zoom lens. (Configuration 29) 29. The imaging system according to configuration 27 or 28, wherein the control unit is configured as a separate entity from the zoom lens and has an operation unit for operating the zoom lens. (Configuration 30) 30. The imaging system according to any one of configurations 27 to 29, further comprising a display unit that displays information related to the zoom of the zoom lens.

[0080] Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0081] L1 First lens group L2 Second lens group L3: Third lens group L4 4th lens group

Claims

1. A zoom lens comprising, arranged in order from the object side to the image side, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power, wherein the spacing between adjacent lens groups changes during zooming from the wide-angle end to the telephoto end, the first lens group is composed of three or more lenses, the first lens group includes a first negative lens and a second negative lens disposed on the image side of the first negative lens, During zooming from the wide-angle end to the telephoto end, the first lens group is fixed with respect to the image plane, the third lens group is composed of one negative single lens or two negative single lenses, the third lens group is a focus lens group that moves during focusing, Let f1 be the focal length of the first lens group, f2 be the focal length of the second lens group, f4 be the focal length of the fourth lens group, LD1 be the distance on the optical axis from the object-side lens surface of the lens located closest to the object in the first lens group to the image-side lens surface of the lens located closest to the image in the first lens group, TTL be the air-equivalent length of the distance on the optical axis from the object-side lens surface of the lens located closest to the object in the zoom lens at the wide-angle end to the image plane, BFw be the air-equivalent amount of the distance on the optical axis from the image-side lens surface of the lens located closest to the image in the zoom lens at the wide-angle end to the image plane, and fn2 be the focal length of the second negative lens. 0.85<(-f1) / f2<2.00 0.00<(-f1) / f4<0.55 0.00<LD1 / TTL<0.27 0.37<BFw / (-f1)<1.50 1.34≦fn2 / f1<10.0 A zoom lens characterized by satisfying the following conditional expressions:

2. When the air equivalent of the distance on the optical axis from the image-side lens surface of the lens arranged closest to the image side in the zoom lens at the wide-angle end to the image plane is BFw, 0.07<BFw / TTL<0.30 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. 2.0<TTL / (-f1)<6.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. When the focal length of the zoom lens at the wide-angle end is fw, 3.0<TTL / fw<7.5 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the focal length of the third lens group is f3, 0.1<f2 / (-f3)<1.5 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. 0.05<f2 / f4<0.80 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. When the focal length of the third lens group is f3, 0.1<(-f3) / f4<2.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

8. When the focal length of the zoom lens at the wide-angle end is fw, 0.5<(-f1) / fw<2.5 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

9. When the focal length of the zoom lens at the telephoto end is ft, 0.2<(-f1) / ft<1.4 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

10. When the lateral magnification of the second lens group at the telephoto end is β2t and the lateral magnification of the second lens group at the wide-angle end is β2w, 0.5<β2t / β2w<3.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. When the lateral magnification of the third lens group at the telephoto end is β3t and the lateral magnification of the third lens group at the wide-angle end is β3w, 0.5<β3t / β3w<2.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. the first lens group includes a first negative lens, When the focal length of the first negative lens is fn1, 0.5<fn1 / f1<2.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

13. the first lens group includes a first positive lens, When the focal length of the first positive lens is fp1, 0.5<fp1 / (-f1)<5.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

14. 2. The zoom lens according to claim 1, wherein the first lens group is composed solely of lenses having refractive power.

15. 2. The zoom lens according to claim 1, wherein the fourth lens group is fixed relative to an image plane during zooming from the wide-angle end to the telephoto end.

16. 2. The zoom lens according to claim 1, wherein the second lens group includes an aperture stop.

17. 2. The zoom lens according to claim 1, wherein the fourth lens group is composed of one positive single lens element.

18. 2. The zoom lens according to claim 1, wherein the first lens group is composed of a negative lens, a negative lens, and a positive lens arranged in this order from the object side to the image side.

19. 2. The zoom lens according to claim 1, wherein the first lens group is composed of, in order from the object side to the image side, a negative lens, a negative lens, a positive lens, and a negative lens.

20. 2. The zoom lens according to claim 1, wherein the first lens group is composed of, in order from the object side to the image side, a negative lens, a negative lens, a negative lens, a positive lens, and a negative lens.

21. 21. An imaging device comprising: the zoom lens according to claim 1; and an imaging element that receives an image formed by the zoom lens.

22. 21. An imaging system comprising: the zoom lens according to claim 1; and a control unit that controls the zoom lens during zooming.

23. 23. The imaging system according to claim 22, wherein the control unit is configured as a separate unit from the zoom lens and includes a transmission unit that transmits a control signal for controlling the zoom lens.

24. 23. The imaging system according to claim 22, wherein the control unit is configured as a separate unit from the zoom lens and has an operation unit for operating the zoom lens.

25. 23. The imaging system according to claim 22, further comprising a display unit that displays information related to the zoom of the zoom lens.

Images