Zoom lens and image capturing device

Abstract

To provide a zoom lens which is advantageous in terms of high optical performance over a wavelength range of visible light to SWIR light and compactness, for example.SOLUTION: A zoom lens disclosed herein comprises a first lens group with positive refractive power configured to be stationary for zooming, an intermediate group comprising multiple lens groups configured to move for zooming, and a rear lens group, arranged in order from the object side to the image side, and is configured such that a distance between each pair of adjacent lens groups changes while zooming. The intermediate group includes a lens group with negative refractive power having a negative lens LN that satisfies the following conditions: 1.60<ndLN<2.00, 25.0<νdLN<60.0, 0.490<θCtLN-0.00417×νdLN<0.550, where ndLN, νdLN, and θCtLN respectively represent a refractive index of a material for the d-ray, an Abbe number of the material for the d-ray, and a partial dispersion ratio of the material for the C-ray and t-ray.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, zoom lenses used in imaging devices are desired to have a high zoom ratio and a small size. Furthermore, zoom lenses for surveillance cameras are desired to be able to capture images with high optical performance both day and night. Surveillance cameras may use visible light for daytime imaging and near-infrared light for nighttime imaging. Imaging with near-infrared light is less affected by scattering in dense fog than imaging with visible light. Therefore, it is preferable that zoom lenses for surveillance cameras have aberration correction in a wide wavelength range from the visible range to the near-infrared range. In addition, a high zoom ratio and brightness are required for both wide-area and long-distance surveillance applications.

[0003] Patent Document 1 discloses a zoom lens with a high zoom ratio, which is composed of first to fourth lens groups having positive, negative, negative, and positive refractive powers, respectively, from the object side to the image side, and in which the spacing between adjacent lens groups changes during zooming. Patent Document 2 discloses a zoom lens with a high zoom ratio, which is composed of first to fourth lens groups having positive, negative, positive, and positive refractive powers, respectively, from the object side to the image side, and in which the spacing between adjacent lens groups changes during zooming. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-95448 A [Patent Document 2] Patent Publication No. 2021-76781 Summary of the Invention [Problem to be solved by the invention]

[0005] Among near-infrared light, SWIR (Short Wavelength Infrared) light having a wavelength of 1000 nm to 2500 nm is highly useful for surveillance cameras. Therefore, there is an increasing demand for a zoom lens in which chromatic aberration is corrected across a wavelength range from the visible range to the SWIR range. In order to correct chromatic aberration across such a wide band, the zoom lens tends to become large, which may make it difficult to meet the demand for a compact surveillance camera. The present invention aims to provide a zoom lens that is advantageous in terms of high optical performance and small size in the wavelength range from visible light to SWIR light, for example. [Means for solving the problem]

[0006] One aspect of the present invention is a zoom lens having, in order from the object side to the image side, a first lens group having positive refractive power that does not move for zooming, an intermediate group including a plurality of lens groups that move for zooming, and a rear lens group, The spacing between adjacent lens groups changes during zooming. In the intermediate group, the refractive index for the d-line, the Abbe number for the d-line, the partial dispersion ratios for the C-line and the t-line of the material are respectively defined as ndLN, νdLN, and θCtLN. 1.60 <ndLN<2.00 25.0<νdLN<60.0 0.490<θCtLN―0.00417×νdLN<0.550 The zoom lens is characterized by including a lens group having negative refractive power, which includes a negative lens LN that satisfies the following condition: Effect of the Invention

[0007] According to the present invention, for example, it is possible to provide a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a zoom lens at the wide-angle end and focused at infinity according to a first embodiment; [Diagram 2] Diagram showing aberrations when focused at infinity and at (a) the wide-angle end, (b) the mid-range, or (c) the telephoto end. [Diagram 3] 1 is a cross-sectional view of a zoom lens at the wide-angle end and focused at infinity according to a second embodiment; [Figure 4] Diagram showing aberrations when focused at infinity and at (a) the wide-angle end, (b) the mid-range, or (c) the telephoto end. [Diagram 5] 1 is a cross-sectional view of a zoom lens at the wide-angle end and focused at infinity according to a third embodiment; [Figure 6] Diagram showing aberrations when focused at infinity and at (a) the wide-angle end, (b) the mid-range, or (c) the telephoto end. [Figure 7] 1 is a cross-sectional view of a zoom lens at the wide-angle end and focused at infinity according to a fourth embodiment; [Figure 8] Diagram showing aberrations when focused at infinity and at (a) the wide-angle end, (b) the mid-range, or (c) the telephoto end. [Figure 9] 13 is a cross-sectional view of a zoom lens at the wide-angle end and focused at infinity according to the fifth embodiment; [Figure 10] Diagram showing aberrations when focused at infinity and at (a) the wide-angle end, (b) the mid-range, or (c) the telephoto end. [Figure 11] 13 is a cross-sectional view of a zoom lens at the wide-angle end and focused at infinity according to Example 6. [Figure 12] Diagram showing aberrations when focused at infinity and at (a) the wide-angle end, (b) the mid-range, or (c) the telephoto end. [Figure 13] 13 is a cross-sectional view of a zoom lens at the wide-angle end and focused at infinity according to Example 7. [Figure 14] Diagram showing aberrations when focused at infinity and at (a) the wide-angle end, (b) the mid-range, or (c) the telephoto end. [Figure 15] FIG. 1 is a diagram showing an example of the configuration of an imaging device; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in principle (unless otherwise specified) throughout all the drawings for explaining the embodiment, the same members are given the same reference numerals and the repeated description thereof will be omitted.

[0010] [Embodiment] FIG. 1 is a cross-sectional view of a zoom lens at the wide-angle end and at infinity focusing according to Example 1 described later. Example 1 corresponds to Numerical Example 1 described later. FIG. 2 is a diagram showing aberrations at infinity focusing and (a) at the wide-angle end, (b) at the intermediate end, or (c) at the telephoto end in Numerical Example 1 (refer to Numerical Example 1 for the respective focal lengths). In the diagrams showing the aberrations, the straight line, the two-dot chain line, the one-dot chain line, the long dashed line, the short wavy line, and the two-dot chain line in the spherical aberration correspond to the d-line, the g-line, the C-line, the F-line, the t-line, and the wavelength of 1970 nm, respectively. Note that the wavelength of the d-line is 587.6 nm, the wavelength of the g-line is 435.8 nm, the wavelength of the C-line is 656.3 nm, the wavelength of the F-line is 486.1 nm, and the wavelength of the t-line is 1014.0 nm. The dashed line and the solid line in the astigmatism correspond to the meridional image plane and the sagittal image plane, respectively. Distortion corresponds to the d-line. The solid line, two-dot chain line, one-dot chain line, and dashed line for lateral chromatic aberration correspond to the d-line, g-line, C-line, and F-line, respectively. Fno represents the F-number, and ω represents the half angle of view. Spherical aberration is plotted with a full scale of ±0.400 mm on the horizontal axis. Astigmatism is plotted with a full scale of ±0.400 mm on the horizontal axis. Distortion is plotted with a full scale of ±5.000% on the horizontal axis. Magnification chromatic aberration is plotted with a full scale of ±0.100 mm on the horizontal axis.

[0011] The components of the zoom lens will be described in order from the object side to the image side with reference to FIG. 1. L1 is a first lens group with positive refractive power that does not move for variable magnification (zooming). A first sub-lens group L1a in the first lens group L1 does not move for focusing. A second sub-lens group L1b in the first lens group L1 moves toward the object side for focusing from an object at infinity to a close object.

[0012] LM is an intermediate group having a plurality of lens groups that move during magnification change. L2 in the intermediate group is a second lens group with negative refractive power that moves during magnification change, and L3 is a third lens group with negative refractive power that moves during magnification change.

[0013] L2 moves monotonically on the optical axis toward the image side for changing the magnification from the wide-angle end to the telephoto end. L3 moves non-monotonically on the optical axis as illustrated for changing the magnification from the wide-angle end to the telephoto end. SP is an aperture stop that does not move during the magnification change. LR is a rear lens group (relay lens group) with positive refractive power that does not move during the magnification change. I is the image plane (plane on which an image is formed) of the zoom lens, and the image sensor captures the image (takes an image). In the zoom lens, the interval between adjacent lens groups changes during the magnification change. The aperture stop can be disposed between the middle group and the rear lens group, or between the last lens group and the penultimate lens group in the middle group. The aperture stop can also be disposed in the rear lens group, or in the last lens group in the middle group. In FIG. 1, the arrow in the intermediate group LM indicates the movement trajectory of the lens group when zooming from the wide-angle end to the telephoto end, and the hook-shaped arrow indicates the movement direction of the sub-lens group for focusing from the infinity end to the close-up end (the same is true for cross-sectional views of other zoom lenses).

[0014] The zoom lens according to this embodiment is composed of, in order from the object side to the image side, a first lens group with positive refractive power that does not move for zooming, an intermediate group including a plurality of lens groups that move for zooming, and a rear lens group. In this zoom lens, the intervals between adjacent lens groups all change for zooming. The refractive index of the negative lens (lens having negative refractive power) LN for the d-line is ndLN, the Abbe number of the negative lens LN for the d-line is νdLN, and the partial dispersion ratio of the negative lens LN for the C-line and the t-line is θCtLN, and the intermediate group is 1.60 <ndLN<2.00···(1) 25.0<νdLN<60.0 (2) 0.490<θCtLN−0.00417×νdLN<0.550 (3) The first embodiment includes a negative lens group (lens group having negative refractive power) including a negative lens LN that satisfies the following conditions: According to the present embodiment, it is possible to provide a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. In the first embodiment, the second lens group L2 having negative refractive power has a negative lens LN that satisfies the following conditions (1) to (3).

[0015] Here, the Abbe number νd and the partial dispersion ratio θCt are expressed by the following formulas, where nF, nC, nd, and nt are the refractive indices of the material for the F line (486.1 nm), C line (656.3 nm), d line (wavelength 587.6 nm), and t line (1014.0 nm), respectively. νd=(nd-1) / (nF-nC), and θCt=(nC-nt) / (nF-nC) The refractive index nd for the d-line, the Abbe number vd for the d-line, and the partial dispersion ratio θCt for the C-line and t-line are also simply referred to as the refractive index nd, the Abbe number vd, and the partial dispersion ratio θCt.

[0016] Here, the technical significance of formulas (1) to (3) will be explained. Note that "formula" is also called "inequality", "conditional formula", or "condition". Formulas (1) to (3) indicate the conditions for obtaining a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. If the condition of formula (1) is not satisfied with respect to the upper limit value, a material with excessively high dispersion will be selected for the material of the negative lens LN, and the variation of chromatic aberration during zooming will be excessively large. If the condition of formula (1) is not satisfied with respect to the lower limit value, the radius of curvature of the negative lens LN will be excessively small, and the lens will be excessively large. As a result, the zoom lens will be excessively large. Or, it will be difficult to obtain a zoom lens with a high zoom ratio. If the condition of formula (2) is not satisfied with respect to the upper limit value, a material with an excessively low refractive index will be selected, and the zoom lens will be excessively large. Or, it will be difficult to obtain a zoom lens with a high zoom ratio. If the condition in formula (2) is not met for the lower limit, then an excessively high dispersion material will be selected, resulting in excessively large chromatic aberration variations during zooming. If the condition in formula (3) is not met, then excessively large chromatic aberration variations during zooming will occur.

[0017] Examples of glass materials that satisfy the formulas (1) to (3) include S-LAL20 manufactured by Ohara Corporation, and K-GIR79 and K-GIR140 manufactured by Sumita Corporation.

[0018] The focal length of the lens group N1 having the strongest negative refractive power (negative refractive power with the largest absolute value; the same applies below) in the intermediate group is fN1. The lens group having the focal length fN1 includes a negative lens LN. The focal length of the negative lens LN1 having the strongest negative refractive power among the negative lenses LN in the lens group N1 is fLN1. The zoom lens according to this embodiment has 0.3 <fLN1 / fN1<5.0···(4) It is preferable to satisfy the following condition. Equation (4) shows the condition for obtaining a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. If the condition of equation (4) is not satisfied for the upper limit value, the refractive power of the negative lens LN becomes too weak, resulting in excessively large fluctuations in chromatic aberration during zooming. If the condition of equation (4) is not satisfied for the lower limit value, the refractive power of the negative lens LN becomes too strong, resulting in excessively large fluctuations in various aberrations (including chromatic aberration) during zooming.

[0019] In the zoom lens according to this embodiment, the focal length of the first lens group is f1, and -12.0 <f1 / fN1<-2.0···(5) It is preferable to satisfy the following condition. Expression (5) shows the condition for obtaining a zoom lens advantageous in terms of a high zoom ratio, small size, and high optical performance. If the condition of expression (5) is not satisfied for the upper limit value, the refractive power of the lens group N1 having the strongest negative refractive power in the intermediate group becomes excessively strong, and the fluctuation of aberration during magnification becomes excessively large. If the condition of expression (5) is not satisfied for the lower limit value, the refractive power of the lens group N1 having the strongest negative refractive power in the intermediate group becomes excessively weak. As a result, the amount of movement of the lens group N1 having the strongest negative refractive power in the intermediate group becomes excessively large, and the zoom lens becomes excessively large. Or, it becomes difficult to obtain a zoom lens with a high zoom ratio.

[0020] In the zoom lens according to this embodiment, the average value of the refractive index for the d-line of all the lenses included in the lens group N1 having the strongest negative refractive power in the intermediate group is defined as ndN1a, 1.55 <ndN1a<1.90···(6) It is preferable to satisfy the following condition. Equation (6) shows the condition for obtaining a zoom lens that is advantageous in terms of a high zoom ratio, small size, and high optical performance. If the condition of equation (6) is not satisfied for the upper limit, a high dispersion material will be selected for the lenses included in lens group N1, and the variation in chromatic aberration during zooming will be excessively large. If the condition of equation (6) is not satisfied for the lower limit, the radius of curvature of the lenses included in lens group N1 will be excessively small, and the lenses will be excessively large. This will result in an excessively large zoom lens. Alternatively, it will be difficult to obtain a zoom lens with a high zoom ratio.

[0021] The average value of the Abbe numbers of all lenses having positive refractive power included in the lens group N1, which has the strongest negative refractive power in the intermediate group, is vdN1p, and the average value of the Abbe numbers of all lenses having negative refractive power included in the lens group N1 is vdN1n. -40.0<νdN1p-νdN1n<-5.0...(7) It is preferable to satisfy the following condition. Equation (7) shows the condition for obtaining a zoom lens that is advantageous in terms of a high zoom ratio, small size, and high optical performance. If the condition of equation (7) is not satisfied for the upper limit, the variation of chromatic aberration during zooming becomes excessively large. Alternatively, the refractive power of the lenses included in lens group N1 becomes excessively strong, and the variation of various aberrations (including chromatic aberration) during zooming becomes excessively large. If the condition of equation (7) is not satisfied for the lower limit, materials with excessively different partial dispersion ratios θCt are selected for the positive lens and the negative lens included in lens group N1, and the variation of second-order chromatic aberration during zooming becomes excessively large.

[0022] The average value of the partial dispersion ratios θCt of all the lenses having positive refractive power included in the lens group N1, which has the strongest negative refractive power in the intermediate group, is set to θCtN1p, and the average value of the partial dispersion ratios θCt of all the lenses having negative refractive power included in the lens group N1 is set to θctN1n. -0.050<θCtN1p-θCtN1n<0.050...(8) It is preferable to satisfy the following condition. Equation (8) shows the condition for obtaining a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light. If the condition of equation (8) is not satisfied, the fluctuation of second-order chromatic aberration during zooming becomes excessively large.

[0023] In the zoom lens according to this embodiment, the focal length of the lens group Nm including the negative lens LNm having the strongest negative refractive power among the negative lenses LN is fNm, and the focal length of the negative lens LNm is fLNm. 0.3 <fLNm / fNm<4.0···(9) It is preferable to satisfy the following condition. Equation (9) shows the condition for obtaining a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. If the condition of equation (9) is not satisfied for the upper limit value, the refractive power of the negative lens LN becomes too weak, resulting in excessively large fluctuations in chromatic aberration during zooming. If the condition of equation (9) is not satisfied for the lower limit value, the refractive power of the negative lens LN becomes too strong, resulting in excessively large fluctuations in various aberrations (including chromatic aberration) during zooming.

[0024] In the zoom lens according to this embodiment, the average value of the refractive index for the d-line of all lenses included in the lens group Nm including the negative lens LNm having the strongest negative refractive power among the negative lenses LN is defined as ndNma, 1.55 <ndNma<1.90···(10) It is preferable to satisfy the following condition. Equation (10) shows the condition for obtaining a zoom lens that is advantageous in terms of a high zoom ratio, small size, and high optical performance. If the condition of equation (10) is not satisfied for the upper limit, a high dispersion material will be selected for the lens material included in the lens group Nm, and chromatic aberration during zooming will be excessively large. If the condition of equation (10) is not satisfied for the lower limit, the radius of curvature of the lens included in the lens group Nm will be excessively small, and the zoom lens will be excessively large. Alternatively, it will be difficult to obtain a zoom lens with a high zoom ratio.

[0025] The average value of the Abbe numbers of all lenses with positive refractive power included in the lens group Nm, which includes the negative lens LNm having the strongest negative refractive power among the negative lenses LN, is set to νdNmp, and the average value of the Abbe numbers of all lenses with negative refractive power included in the lens group Nm is set to νdNmn. -40.0<νdNmp-νdNmn<-5.0...(11) It is preferable to satisfy the following condition. Equation (11) shows the condition for obtaining a zoom lens that is advantageous in terms of a high zoom ratio, small size, and high optical performance. If the condition of equation (11) is not satisfied for the upper limit, the variation of chromatic aberration during zooming becomes excessively large. Alternatively, the refractive power of the lenses included in the lens group Nm becomes excessively strong, and the variation of various aberrations during zooming becomes excessively large. If the condition of equation (11) is not satisfied for the lower limit, materials with excessively different partial dispersion ratios θCt are selected for the positive and negative lenses included in the lens group Nm, and the variation of second-order chromatic aberration during zooming becomes excessively large.

[0026] The average value of the partial dispersion ratios θCt of all the lenses having positive refractive power included in the lens group Nm, which includes the negative lens LNm having the strongest negative refractive power among the negative lenses LN, is set to θCtNmp. Also, the average value of the partial dispersion ratios θCt of all the lenses having negative refractive power included in the lens group Nm is set to θCtNmn. The zoom lens according to this embodiment has -0.050<θCtNmp-θCtNmn<0.050...(12) It is preferable to satisfy the following condition. Equation (12) shows the condition for obtaining a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light. If the condition of equation (12) is not satisfied, the fluctuation of second-order chromatic aberration during zooming becomes excessively large.

[0027] The intermediate group, in order from the object side to the image side, is composed of a sub-intermediate group V having a negative refractive power and a focal length at the wide-angle end, which is composed of at least one lens group that moves monotonically toward the image side for zooming, and at least one lens group. The sub-intermediate group V includes a negative lens LN, and the focal length (composite focal length) of the sub-intermediate group V at the wide-angle end is fV, and the focal length of the negative lens LNVm that has the strongest negative refractive power in the sub-intermediate group V among the negative lenses LN is fLNVm. The zoom lens according to this embodiment has the following features: 0.3 <fLNVm / fV<4.0···(13) It is preferable to satisfy the following condition. Equation (13) shows the condition for obtaining a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. If the condition of equation (13) is not satisfied for the upper limit value, the refractive power of the negative lens LNVm becomes too weak, and the fluctuation of chromatic aberration during zooming becomes too large. If the condition of equation (13) is not satisfied for the lower limit value, the refractive power of the negative lens LNVm becomes too strong, and the fluctuation of various aberrations (including chromatic aberration) during zooming becomes too large.

[0028] The intermediate group, in order from the object side to the image side, is composed of at least one lens group that moves monotonically toward the image side for zooming, a sub-intermediate group V having a negative focal length at the wide-angle end and at least one lens group. The focal length of the first lens group is f1, and the focal length (composite focal length) of the sub-intermediate group V at the wide-angle end is fV. The zoom lens according to this embodiment has the following: -12.0 <f1 / fv<-2.0···(14) It is preferable to satisfy the following condition. Expression (14) indicates a condition for obtaining a zoom lens that is advantageous in terms of a high zoom ratio, small size, and high optical performance. If the upper limit of expression (14) is not satisfied, the refractive power of the sub-intermediate group V will be excessively weak, the amount of movement of the sub-intermediate group V will be excessively large, and the zoom lens will be excessively large. Alternatively, it will be difficult to obtain a zoom lens with a high zoom ratio. If the lower limit of expression (14) is not satisfied, the refractive power of the sub-intermediate group V will be excessively strong, and fluctuations in aberrations during magnification will be excessively large.

[0029] The intermediate group, in order from the object side to the image side, is composed of a sub-intermediate group V having a negative refractive power and a focal length at the wide-angle end, the sub-intermediate group V being composed of at least one lens group that moves monotonically toward the image side for zooming, and at least one lens group. The average value of the refractive indexes for the d-line of all the lenses included in the sub-intermediate group V is set to ndVa. The zoom lens according to this embodiment has the following: 1.55 <ndVa<1.9···(15) It is preferable to satisfy the following condition. Equation (15) indicates the condition for obtaining a zoom lens that is advantageous in terms of a high zoom ratio, small size, and high optical performance. If the condition of equation (15) is not satisfied for the upper limit, a high-dispersion material will be selected for the lens included in the sub-intermediate group V, and the variation in chromatic aberration during zooming will be excessively large. If the condition of equation (15) is not satisfied for the lower limit, the radius of curvature of the lens included in the sub-intermediate group V will be excessively small, and the zoom lens will be excessively large. Alternatively, it will be difficult to obtain a zoom lens with a high zoom ratio.

[0030] The intermediate group, in order from the object side to the image side, is composed of a sub-intermediate group V having a negative refractive power and a focal length at the wide-angle end, which is composed of at least one lens group that moves monotonically toward the image side for zooming, and at least one lens group. The average value of the Abbe numbers of all the lenses having positive refractive power included in the sub-intermediate group V is vdVp, and the average value of the Abbe numbers of all the lenses having negative refractive power included in the sub-intermediate group V is vdVn. The zoom lens according to this embodiment has -40.0<νdVp-νdVn<-5.0...(16) It is preferable to satisfy the following condition. Equation (16) indicates the condition for obtaining a zoom lens that is advantageous in terms of a high zoom ratio, small size, and high optical performance. If the condition of equation (16) is not satisfied for the upper limit, the fluctuation of chromatic aberration during zooming becomes excessively large. Alternatively, the refractive power of the lenses included in the sub-intermediate group V becomes excessively strong, and the fluctuation of various aberrations (including chromatic aberration) during zooming becomes excessively large. If the condition of equation (16) is not satisfied for the lower limit, materials with excessively different partial dispersion ratios are selected for the positive lens and the negative lens included in the sub-intermediate group V, and the fluctuation of second-order chromatic aberration during zooming becomes excessively large.

[0031] The intermediate group, in order from the object side to the image side, is composed of a sub-intermediate group V having a negative refractive power and a focal length at the wide-angle end consisting of at least one lens group that moves monotonically toward the image side for zooming, and at least one lens group. The average value of the partial dispersion ratios θCt of all the lenses having positive refractive power included in the sub-intermediate group V is θCtVp, and the average value of the partial dispersion ratios θCt of all the lenses having negative refractive power included in the sub-intermediate group V is θCtVn. The zoom lens according to this embodiment has -0.050<θCtVp-θCtVn<0.050...(17) It is preferable to satisfy the following condition. Equation (17) shows the condition for obtaining a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light. If the condition of equation (17) is not satisfied, the fluctuation of second-order chromatic aberration during zooming becomes excessively large.

[0032] In the zoom lens according to this embodiment, the average value of the partial dispersion ratios θCt of all the lenses having positive refractive power included in the first lens group is θCt1p, and the average value of the partial dispersion ratios θCt of all the lenses having negative refractive power included in the first lens group is θCt1n, -0.030<θCt1p-θCt1n<0.030...(18) It is preferable to satisfy the following condition. Equation (18) shows the condition for obtaining a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light. If the condition of equation (18) is not satisfied, the second-order axial chromatic aberration at the telephoto end and the fluctuation of the second-order chromatic aberration during zooming will be excessively large.

[0033] It is more preferable that the zoom lens according to this embodiment satisfies the following conditions (1a) to (18a). 1.65 <ndLN<1.90···(1a) 30.0<νdLN<55.0 (2a) 0.500<θCtLN−0.00417×νdLN<0.549 (3a) 0.5 <fLN1 / fN1<3.0···(4a) -10.0 <f1 / fN1<-2.5···(5a) 1.60 <ndN1a<1.88···(6a) -35.0<νdN1p-νdN1n<-8.0...(7a) -0.045<θCtN1p-θCtN1n<0.045...(8a) 0.5 <fLNm / fNm<3.0···(9a) 1.60 <ndNma<1.88···(10a) -35.0<νdNmp-νdNmn<-8.0 (11a) -0.045<θCtNmp-θCtNmn<0.045 (12a) 0.5 <fLNVm / fV<3.0···(13a) -10.0 <f1 / fv<-2.5···(14a) 1.60 <ndVa<1.88···(15a) -35.0<νdVp-νdVn<-8.0 (16a) -0.045<θCtVp-θCtVn<0.045 (17a) -0.015<θCt1p-θCt1n<0.015 (18a)

[0034] [Embodiment Related to Imaging Apparatus] Here, FIG. 15 is a diagram showing a configuration example of an imaging device. In FIG. 15, 101 is a zoom lens according to any one of the first to seventh embodiments. 124 is a camera (imaging unit; imaging device body). The zoom lens 101 is detachable from the camera 124. 125 is an imaging device configured by mounting the zoom lens 101 to the camera 124. The zoom lens 101 has a first lens group, an intermediate group including a plurality of lens groups that move for zooming, and a rear lens group that does not move for variable magnification. In FIG. 15, the first lens group is described as F, the intermediate group as LZ, and the rear lens group as R. As described above, the first lens group may include a sub lens group that moves for focusing. In addition, in the same figure, SP is an aperture stop, and 114 and 115 are driving mechanisms including, for example, a helicoid or a cam for driving the sub lens group for focusing and the lens group for zooming, respectively. Also, 116 to 118 are motors (actuators) that drive the driving mechanisms 114 and 115 and the aperture stop SP, respectively. 119 to 121 are detection units including, for example, an encoder, a potentiometer, a photosensor, etc., for detecting the positions of the sub-lens group for focusing and the lens group for zooming, and the aperture diameter of the aperture stop SP. In the camera 124, 109 is a glass block including, for example, an optical filter, etc., and 110 is an imaging element (photoelectric conversion element) including, for example, a CCD or CMOS device, etc., that takes (images) the subject image formed by the zoom lens 101. Also, 111 and 122 are processing units including, for example, a processor such as a CPU, that perform various processes and controls in the camera 124 and the zoom lens 101, respectively. According to the imaging device according to this embodiment, it is possible to provide a useful imaging device that enjoys the advantageous effects of the zoom lens according to the above-mentioned embodiment.

[0035] Examples 1 to 7 of the zoom lens according to the above-mentioned embodiment and Numerical Examples 1 to 7 corresponding to Examples 1 to 7, respectively, will be described below.

[0036] Example 1 In FIG. 1, the configuration of the lens group and the sub-lens group according to the first embodiment is as described above. In the figure, the first lens group L1 has the first to fifteenth surfaces. The first sub-lens group L1a has the first to seventh surfaces, and is composed of one negative lens and three positive lenses. The second sub-lens group L1b has the eighth to fifteenth surfaces, and is composed of two negative lenses and three positive lenses. The intermediate group LM is composed of the second lens group L2 and the third lens group L3. The second lens group L2 has 16 to 24 surfaces, and is composed of three negative lenses and two positive lenses. The third lens group L3 has 25 to 27 surfaces, and is composed of one negative lens and one positive lens. The aperture stop SP has the 28th surface. The rear lens group LR has the 29th to 47th surfaces, and is composed of one positive lens whose image-side surface is aspherical, three negative lenses, and seven positive lenses. FIG. 2 is a diagram showing the aberration in Numerical Example 1 as described above.

[0037] In this embodiment, the negative lens LN is a lens having surfaces 16 and 17 in the second lens group, and a lens having surfaces 19 and 20 in the second lens group. In this embodiment, the lens group having the strongest negative refractive power in the intermediate group is the second group. In this embodiment, the negative lens LNm having the strongest negative refractive power among the negative lenses LN is a lens having surfaces 19 and 20 in the second lens group. In this embodiment, the sub-intermediate group V is made of the second lens group.

[0038] The values ​​of the formulas (1) to (18) in this embodiment are shown in Table 1. The values ​​of the variables included in the formulas (1) to (18) are shown in Table 2. This embodiment satisfies all the formulas (1) to (18), and thus can provide a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. Here, the zoom lens is obtained by satisfying the formulas (1) to (3), and does not necessarily have to satisfy the formulas (4) to (18). When at least one of the formulas (4) to (18) is satisfied in addition to the formulas (1) to (3), a more remarkable effect or a different effect can be obtained compared to the case where the formulas are not satisfied. The effect when each formula is satisfied is as described above.

[0039] Example 2 FIG. 3 is a cross-sectional view of a zoom lens at the wide-angle end and infinity focusing according to the second embodiment. Referring to the figure, the components of the zoom lens will be described in order from the object side to the image side. L1 is a first lens group with positive refractive power that does not move for zooming. The first sub-lens group L1a in the first lens group L1 does not move for focusing. The second sub-lens group L1b in the first lens group L1 moves toward the object side for focusing from an infinite object to a close object. The third sub-lens group L1c in the first lens group L1 moves toward the object side on a different trajectory from the second sub-lens group for focusing from an infinite object to a close object. LM is an intermediate group having a plurality of lens groups that move during zooming. L2 in the intermediate group is a second lens group with negative refractive power that moves during zooming, L3 in the intermediate group is a third lens group with negative refractive power that moves during zooming, and L4 in the intermediate group is a fourth lens group with positive refractive power that moves during zooming. The second lens group L2 moves monotonically toward the image side during magnification change from the wide-angle end to the telephoto end. The third lens group L3 moves first toward the object side and then toward the image side during the magnification change. The fourth lens group L4 moves (for example, non-monotonically as shown in the figure) during the magnification change. SP is an aperture stop and does not move for magnification change. LR is a rear lens group with positive refractive power that does not move for magnification change.

[0040] The first lens group L1 has surfaces 1 to 14. The first sub-lens group 1a has surfaces 1 to 8 and is composed of two negative lenses and two positive lenses. The second sub-lens group 1b has surfaces 9 to 12 and is composed of two positive lenses. The third sub-lens group 1c has surfaces 13 to 14 and is composed of one positive lens. The second lens group L2 has surfaces 15 to 24 and is composed of one negative lens whose image-side surface is aspheric, two positive lenses, and two negative lenses. The third lens group L3 has surfaces 25 to 29 and is composed of one positive lens and two negative lenses. The fourth lens group L4 has surfaces 30 to 31 and is composed of one positive lens whose object-side surface is aspheric. The aperture stop SP has surface 32. The rear lens group LR has surfaces 33 to 50 and is composed of five negative lenses and six positive lenses. 4 is a diagram showing aberrations at infinity focus and at (a) the wide-angle end, (b) the intermediate end, or (c) the telephoto end (for the respective focal lengths, see Numerical Example 2). The legend is the same as that described with reference to FIG. 2.

[0041] In this embodiment, the LN lens is a lens having surfaces 15 to 16 in the second lens group, and a lens having surfaces 25 to 26 in the third lens group. In this embodiment, the lens group having the strongest negative refractive power in the intermediate group is the second lens group. In this embodiment, the negative lens LNm having the strongest negative refractive power among the negative lenses LN is a lens having surfaces 25 to 26 in the third lens group. In this embodiment, the sub-intermediate group V is made of the second lens group.

[0042] The values ​​of the formulas (1) to (18) in this embodiment are shown in Table 1. The values ​​of the variables included in the formulas (1) to (18) are shown in Table 2. This embodiment satisfies all the formulas (1) to (18), and thus can provide a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. Here, the zoom lens is obtained by satisfying the formulas (1) to (3), and does not necessarily have to satisfy the formulas (4) to (18). When at least one of the formulas (4) to (18) is satisfied in addition to the formulas (1) to (3), a more remarkable effect or a different effect can be obtained compared to the case where the formulas are not satisfied. The effect when each formula is satisfied is as described above.

[0043] Example 3 FIG. 5 is a cross-sectional view of a zoom lens at the wide-angle end and infinity focusing according to the third embodiment. Referring to the figure, the components of the zoom lens will be described in order from the object side to the image side. L1 is a first lens group with positive refractive power that does not move for zooming. LM is an intermediate group having a plurality of lens groups that move for zooming. L2 in the intermediate group is a second lens group with negative refractive power that moves for zooming, and L3 in the intermediate group is a third lens group with positive refractive power that moves for zooming. The second lens group L2 moves monotonically toward the image side during zooming from the wide-angle end to the telephoto end. The third lens group L3 moves monotonically toward the object side during zooming from the wide-angle end to the telephoto end. SP is an aperture stop that does not move for zooming. LR is a rear lens group with positive refractive power that does not move for zooming. The first sub-lens group LRa in the rear lens group LR does not move for focusing. The second sub-lens group LRb in the rear lens group LR moves toward the image side for focusing from an object at infinity to a close object, and the third sub-lens group LRc in the rear lens group LR does not move for focusing.

[0044] The first lens group L1 has surfaces 1 to 10 and is composed of three positive lenses and two negative lenses. The second lens group L2 has surfaces 11 to 22 and is composed of two positive lenses and five negative lenses. The third lens group L3 has surfaces 23 to 32 and is composed of three positive lenses and three negative lenses. The aperture stop SP has a surface 33. The rear lens group LR has surfaces 34 to 48. The first sub-lens group LRa has surfaces 34 to 41 and is composed of three positive lenses and one negative lens. The second sub-lens group LRb has surfaces 42 to 46 and is composed of one positive lens and two negative lenses. The third sub-lens group LRc has surfaces 47 to 48 and is composed of one positive lens. 6 is a diagram showing aberrations at infinity focus and at (a) the wide-angle end, (b) the intermediate end, or (c) the telephoto end (for the respective focal lengths, see Numerical Example 3). The legend is the same as that described with reference to FIG. 2.

[0045] In this embodiment, the negative lens LN is a lens having surfaces 13 to 14 in the second lens group, a lens having surfaces 16 to 17 in the second lens group, and a lens having surfaces 21 to 22 in the second lens group. In this embodiment, the lens group having the strongest negative refractive power in the intermediate group is the second lens group. In this embodiment, the negative lens LNm having the strongest negative refractive power among the negative lenses LN is a lens having surfaces 16 to 17 in the second lens group. In this embodiment, the sub-intermediate group V is made of the second lens group.

[0046] The values ​​of the formulas (1) to (18) in this embodiment are shown in Table 1. The values ​​of the variables included in the formulas (1) to (18) are shown in Table 2. This embodiment satisfies all the formulas (1) to (18), and thus can provide a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. Here, the zoom lens is obtained by satisfying the formulas (1) to (3), and does not necessarily have to satisfy the formulas (4) to (18). When at least one of the formulas (4) to (18) is satisfied in addition to the formulas (1) to (3), a more remarkable effect or a different effect can be obtained compared to the case where the formulas are not satisfied. The effect when each formula is satisfied is as described above.

[0047] Example 4 FIG. 7 is a cross-sectional view of a zoom lens at the wide-angle end and infinity focusing according to the fourth embodiment. Referring to the figure, the components of the zoom lens will be described in order from the object side to the image side. L1 is a first lens group with positive refractive power that does not move for zooming. The first sub-lens group L1a in the first lens group L1 does not move for focusing. The second sub-lens group L1b in the first lens group L1 moves toward the object side for focusing from an infinite object to a close object. The third sub-lens group L1c in the first lens group L1 moves toward the object side on a different trajectory from the second sub-lens group for focusing from an infinite object to a close object. LM is an intermediate group having a plurality of lens groups that move during zooming. L2 in the intermediate group is a second lens group with negative refractive power that moves during zooming, L3 in the intermediate group is a third lens group with positive refractive power that moves during zooming, and L4 in the intermediate group is a fourth lens group with positive refractive power that moves during zooming. The second lens group L2 moves monotonically toward the image side during magnification change from the wide-angle end to the telephoto end. The third lens group L3 moves (for example, non-monotonically as shown in the figure) during the magnification change. The fourth lens group L4 moves monotonically toward the object side during the magnification change. SP is an aperture stop and does not move for magnification change. LR is a rear lens group with positive refractive power that does not move for magnification change. The first sub-lens group LRa in the rear lens group LR moves for image stabilization with a movement amount having a component in a direction perpendicular to the optical axis. The second sub-lens group LRb in the rear lens group LR does not move for image stabilization.

[0048] The first lens group L1 has surfaces 1 to 14. The first sub-lens group L1a has surfaces 1 to 8 and is composed of two negative lenses and two positive lenses. The second sub-lens group 1b has surfaces 9 to 12 and is composed of two positive lenses. The third sub-lens group 1c has surfaces 13 to 14 and is composed of one positive lens. The second lens group L2 has surfaces 15 to 24 and is composed of one negative lens whose image-side surface is aspheric, two positive lenses, and two negative lenses. The third lens group L3 has surfaces 25 to 30 and is composed of one positive lens whose image-side surface is aspheric, one positive lens, and one negative lens. The fourth lens group L4 has surfaces 31 to 35 and is composed of one positive lens whose image-side surface is aspheric, one positive lens, and one negative lens. The aperture stop SP has a 36th surface. The rear lens group LR has a 37th surface to a 57th surface. The first sub-lens group LRa has a 37th surface to a 42nd surface, and is composed of one positive lens and two negative lenses. The second sub-lens group LRb has a 43rd surface to a 57th surface, and is composed of six positive lenses and three negative lenses. FIG. 8 is a diagram showing aberrations at infinity focusing and at (a) the wide-angle end, (b) the intermediate end, or (c) the telephoto end (refer to Numerical Example 4 for each focal length). The legend is the same as that described with reference to FIG. 2.

[0049] In this embodiment, the negative lens LN is a lens having the 15th to 16th surfaces in the second lens group. In this embodiment, the lens group having the strongest negative refractive power in the intermediate group is the second lens group. In this embodiment, the negative lens LNm having the strongest negative refractive power among the negative lenses LN is a lens having the 15th to 16th surfaces in the second lens group. In this embodiment, the sub-intermediate group V is made up of the second lens group.

[0050] The values ​​of the formulas (1) to (18) in this embodiment are shown in Table 1. The values ​​of the variables included in the formulas (1) to (18) are shown in Table 2. This embodiment satisfies all the formulas (1) to (18), and thus can provide a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. Here, the zoom lens is obtained by satisfying the formulas (1) to (3), and does not necessarily have to satisfy the formulas (4) to (18). When at least one of the formulas (4) to (18) is satisfied in addition to the formulas (1) to (3), a more remarkable effect or a different effect can be obtained compared to the case where the formulas are not satisfied. The effect when each formula is satisfied is as described above.

[0051] Example 5 FIG. 9 is a cross-sectional view of a zoom lens according to Example 5 at the wide-angle end and infinity focusing. Referring to the figure, the components of the zoom lens will be described in order from the object side to the image side. L1 is a first lens group with positive refractive power that does not move for zooming. The first sub-lens group L1a in the first lens group L1 does not move for focusing. The second sub-lens group L1b in the first lens group L1 moves toward the object side for focusing from an infinite object to a close object. The third sub-lens group L1c in the first lens group L1 moves toward the object side on a different trajectory from the second sub-lens group for focusing from an infinite object to a close object. LM is an intermediate group having a plurality of lens groups that move during zooming. The intermediate group is composed of L2 to L5. L2 is a second lens group with negative refractive power that moves during magnification, L3 is a third lens group with negative refractive power that moves during magnification, L4 is a fourth lens group with negative refractive power that moves during magnification, and L5 is a fifth lens group with positive refractive power that moves during magnification. The second lens group L2 moves monotonically toward the image side during magnification from the wide-angle end to the telephoto end. The third lens group L3 moves monotonically toward the image side with a movement locus different from that of the second lens group during the magnification. The fourth lens group L4 moves first toward the object side and then toward the image side during the magnification. The fifth lens group L5 moves (for example, non-monotonically as shown in the figure) during the magnification. SP is an aperture stop and does not move for magnification. LR is a rear lens group with positive refractive power that does not move for magnification.

[0052] The first lens group L1 has surfaces 1 to 12. The first sub-lens group 1a has surfaces 1 to 6 and is composed of one negative lens and two positive lenses. The second sub-lens group 1b has surfaces 7 to 10 and is composed of two positive lenses. The third sub-lens group 1c has surfaces 11 to 12 and is composed of one positive lens. The second lens group L2 has surfaces 13 to 14 and is composed of one negative lens whose object-side surface is aspheric. The third lens group L3 has surfaces 15 to 20 and is composed of two positive lenses and two negative lenses. The fourth lens group L4 has surfaces 21 to 25 and is composed of one positive lens and two negative lenses. The fifth lens group L5 has surfaces 26 to 27 and is composed of one positive lens whose object-side surface is aspheric. The aperture stop SP has a surface 28. The rear lens group LR has surfaces No. 29 to No. 46, and is composed of five negative lenses and six positive lenses. Fig. 10 is a diagram showing aberrations at infinity focus and at (a) the wide-angle end, (b) the intermediate end, or (c) the telephoto end (for the respective focal lengths, see Numerical Example 5). The legend is the same as that described with reference to Fig. 2.

[0053] In this embodiment, the negative lens LN is a lens having the 13th to 14th surfaces in the second lens group. In this embodiment, the lens group having the strongest negative refractive power in the intermediate group is the second group. In this embodiment, the negative lens LNm having the strongest negative refractive power among the negative lenses LN is a lens having the 13th to 14th surfaces in the third lens group. In this embodiment, the sub-intermediate group V is composed of the second lens group and the third lens group.

[0054] The values ​​related to formulas (1) to (18) in this embodiment are shown in Table 1. The values ​​of the variables included in formulas (1) to (18) are shown in Table 2. Here, "-" in Tables 1 and 2 indicates that there is no corresponding numerical value. This embodiment satisfies formulas (1) to (6), (9), (10), and (13) to (18), and thus provides a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. Here, the zoom lens is obtained by satisfying formulas (1) to (3), and does not necessarily have to satisfy formulas (4) to (6), (9), (10), and (13) to (18). In addition to formulas (1) to (3), when at least one of formulas (4) to (6), formula (9), formula (10), and formulas (13) to (18) is satisfied, a more significant effect or a different effect can be obtained compared to the case where the formulas are not satisfied. The effect when each formula is satisfied is as described above.

[0055] Example 6 FIG. 11 is a cross-sectional view of a zoom lens at the wide-angle end and infinity focusing according to the sixth embodiment. Referring to the figure, the components of the zoom lens will be described in order from the object side to the image side. L1 is a first lens group with positive refractive power that does not move for zooming. The first sub-lens group L1a in the first lens group L1 does not move for focusing. The second sub-lens group L1b in the first lens group L1 moves toward the object side for focusing from an infinite object to a close object. LM is an intermediate group having a plurality of lens groups that move during zooming. L2 in the intermediate group is a second lens group with negative refractive power that moves during zooming, and L3 in the intermediate group is a third lens group with negative refractive power that moves during zooming. The second lens group L2 moves monotonically toward the image side during zooming from the wide-angle end to the telephoto end. The third lens group L3 moves first toward the object side and then toward the image side during zooming. SP is an aperture stop that does not move for zooming. LR is a rear lens group having a positive refractive power that does not move for varying magnification.

[0056] The first lens group L1 has surfaces 1 to 15. The first sub-lens group 1a has surfaces 1 to 7 and is composed of one negative lens and three positive lenses. The second sub-lens group 1b has surfaces 8 to 15 and is composed of two negative lenses and three positive lenses. The intermediate group LM is composed of the second lens group and the third lens group. The second lens group L2 has surfaces 16 to 24 and is composed of three negative lenses and two positive lenses. The third lens group L3 has surfaces 25 to 27 and is composed of one negative lens and one positive lens. The aperture stop SP has a surface 28. The rear lens group LR has surfaces 29 to 45 and is composed of one positive lens whose image-side surface is aspherical, three negative lenses, and six positive lenses. 12 is a diagram showing aberrations at infinity focus and at (a) the wide-angle end, (b) the intermediate end, or (c) the telephoto end (for the respective focal lengths, see Numerical Example 6). The legend is the same as that described with reference to FIG. 2.

[0057] In this embodiment, the negative lens LN is a lens having surfaces 16 to 17 in the second lens group, a lens having surfaces 19 to 20 in the second lens group, and a lens having surfaces 23 to 24 in the second lens group. In this embodiment, the lens group having the strongest negative refractive power in the intermediate group is the second lens group. In this embodiment, the lens LNm having the strongest negative refractive power among the negative lenses LN is a lens having surfaces 19 to 20 in the second lens group. In this embodiment, the sub-intermediate group V is made of the second lens group.

[0058] The values ​​of the formulas (1) to (18) in this embodiment are shown in Table 1. The values ​​of the variables included in the formulas (1) to (18) are shown in Table 2. This embodiment satisfies all the formulas (1) to (18), and thus can provide a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. Here, the zoom lens is obtained by satisfying the formulas (1) to (3), and does not necessarily have to satisfy the formulas (4) to (18). When at least one of the formulas (4) to (18) is satisfied in addition to the formulas (1) to (3), a more remarkable effect or a different effect can be obtained compared to the case where the formulas are not satisfied. The effect when each formula is satisfied is as described above.

[0059] Example 7 FIG. 13 is a cross-sectional view of a zoom lens at the wide-angle end and infinity focusing according to the seventh embodiment. Referring to the figure, the components of the zoom lens will be described in order from the object side to the image side. L1 is a first lens group with positive refractive power that does not move for zooming. The first sub-lens group L1a in the first lens group L1 does not move for focusing. The second sub-lens group L1b in the first lens group L1 moves toward the object side for focusing from an infinite object to a close object. The third sub-lens group L1c in the first lens group L1 moves toward the object side on a trajectory different from that of the second sub-lens group for focusing from an infinite object to a close object. LM is an intermediate group having a plurality of lens groups that move during zooming. In the intermediate group, L2 is a second lens group with negative refractive power that moves during zooming, L3 is a third lens group with negative refractive power that moves during zooming, and L4 is a fourth lens group with positive refractive power that moves during zooming. The second lens group L2 moves monotonically toward the image side during magnification change from the wide-angle end to the telephoto end. The third lens group L3 moves first toward the object side and then toward the image side during the magnification change. The fourth lens group L4 moves (for example, non-monotonically as shown in the figure) during the magnification change. SP is an aperture stop, which moves together with the fourth lens group L4 during the magnification change. LR is a rear lens group with positive refractive power that does not move for the magnification change.

[0060] The first lens group L1 has surfaces 1 to 12. The first sub-lens group 1a has surfaces 1 to 6 and is composed of one negative lens and two positive lenses. The second sub-lens group 1b has surfaces 7 to 10 and is composed of two positive lenses. The third sub-lens group 1c has surfaces 11 to 12 and is composed of one positive lens. The second lens group L2 has surfaces 13 to 20 and is composed of one negative lens whose object-side surface is aspheric, two positive lenses, and two negative lenses. The third lens group L3 has surfaces 21 to 25 and is composed of one positive lens and two negative lenses. The aperture stop SP has a surface 26. The fourth lens group L4 has surfaces 27 to 28 and is composed of one positive lens whose object-side surface is aspheric. The rear lens group LR has surfaces No. 29 to No. 45, and is composed of five negative lenses and five positive lenses. Fig. 14 is a diagram showing aberrations at infinity focus and at (a) the wide-angle end, (b) the intermediate position, or (c) the telephoto end (for the respective focal lengths, see Numerical Example 7). The legend is the same as that described with reference to Fig. 2.

[0061] In this embodiment, the negative lens LN is a lens having surfaces 13 to 14 in the second lens group, a lens having surfaces 16 to 17 in the second lens group, and a lens having surfaces 19 to 20 in the second lens group. In this embodiment, the lens group having the strongest negative refractive power in the intermediate group is the second group. In this embodiment, the lens LNm having the strongest negative refractive power among the negative lenses LN is a lens having surfaces 13 to 14 in the second lens group. In this embodiment, the sub-intermediate group V is made of the second lens group.

[0062] The values ​​of the formulas (1) to (18) in this embodiment are shown in Table 1. The values ​​of the variables included in the formulas (1) to (18) are shown in Table 2. This embodiment satisfies all the formulas (1) to (18), and thus can provide a zoom lens that is advantageous in terms of high optical performance in the wavelength range from visible light to SWIR light and small size. Here, the zoom lens is obtained by satisfying the formulas (1) to (3), and does not necessarily have to satisfy the formulas (4) to (18). When at least one of the formulas (4) to (18) is satisfied in addition to the formulas (1) to (3), a more remarkable effect or a different effect can be obtained compared to the case where the formulas are not satisfied. The effect when each formula is satisfied is as described above.

[0063] In the first to seventh embodiments, the rear lens group or a part thereof (sub lens group) is not moved except for focusing (changing the object distance), but it may be moved for other purposes. Even if it is done in this way, the above-described effects can be obtained, and such a change is easy for a person skilled in the art. For example, in the first embodiment, a part having the 36th to 47th surfaces in the rear lens group LR may be moved. Since a substantially afocal light beam is incident on the 36th surface from the object side, even if the part moves, the optical characteristics other than the back focus are substantially unchanged. Therefore, the movement can correct the focus change accompanying the state change of the zoom lens related to, for example, zoom, focus, aperture stop, temperature, air pressure, attitude, insertion and removal of the variable magnification optical system, etc.

[0064] Numerical examples are shown below. Numerical details for each numerical example are as follows. In each numerical example, r is the radius of curvature of each surface, d is the surface spacing, nd is the absolute refractive index at 1 atmospheric pressure for the d line of the Fraunhofer line, and νd is the Abbe number for the d line (based on the d line). The "half angle of view" ω is expressed by the formula ω=arctan(Y / fw), where 2Y is the diagonal image size of a camera in which the zoom lens is used, and fw is the focal length of the zoom lens at the wide-angle end. The "maximum image height" corresponds to half Y (e.g., 5.50 mm) of the diagonal image size 2Y (e.g., 11.00 mm). BF is the back focus (air-equivalent length). The last three surfaces are surfaces of a glass block such as a filter belonging to the camera. With the refractive indices for the F, d, C and t lines of the Fraunhofer lines being nF, nd, nC and nt respectively, the Abbe number for the d line νd and the partial dispersion ratio for the C and t lines θCt are expressed as follows. These definitions are the same as those commonly used. νd=(nd-1) / (nF-nC) θCt=(nC-nt) / (nF-nC)

[0065] The shape of an aspheric surface is expressed by taking the X-axis in the direction of the optical axis, the H-axis in a direction perpendicular to the direction of the optical axis, and assuming that the direction of light travel is positive. R is the paraxial radius of curvature, k is the conic constant, and A3 to A16 are aspheric coefficients. The shape of an aspheric surface (deviation from a reference spherical surface) is expressed by the following formula. Note that "eZ" is expressed as "×10 -Z ". Also, an "*" to the right of a surface number indicates that the surface is aspheric.

[0066]

number

[0067] [Numerical Example 1] Unit: mm Surface Data Surface number rd nd vd θct 1 149.055 10.71 1.48749 70.2 0.8924 2 -16894.196 0.19 3 282.981 4.00 1.69680 55.5 0.8330 4 92.069 12.11 1.43875 94.9 0.8373 5 407.576 0.14 6 183.529 4.70 1.43387 95.1 0.8092 7 329.164 17.08 8 178.056 10.07 1.43875 94.9 0.8373 9 -327.739 1.40 1.75500 52.3 0.8092 10 328.276 0.15 11 155.233 8.36 1.43875 94.9 0.8373 12 -837.452 1.40 1.64000 60.1 0.8645 13 318.431 2.19 14 149.307 9.34 1.59522 67.7 0.7953 15 14023.753 (variable) 16 102.708 0.90 1.75106 43.1 0.7097 17 22.063 4.08 18 -892.708 5.35 1.73800 32.3 0.7154 19 -19.085 0.80 1.69930 51.1 0.7593 20 44.172 0.50 21 29.227 3.07 1.67300 38.3 0.7481 22 185.970 1.96 23 -37.284 0.80 1.59522 67.7 0.7953 24 -140.963 (variable) 25 -43.847 0.80 1.71700 47.9 0.7629 26 39.590 2.52 1.84666 23.8 0.6614 27 200.341 (variable) 28(Aperture) ∞ 0.50 29 57.569 7.40 1.59522 67.7 0.7953 30* -47.593 0.09 31 55.727 3.73 1.43875 94.7 0.8410 32 -5550.259 0.11 33 105.240 6.21 1.43875 94.7 0.8410 34 -30.625 0.90 1.80610 40.9 0.7483 35 119.218 34.39 36 62.288 2.84 1.43875 94.7 0.8410 37 -329.012 0.18 38 107.801 3.58 1.43875 94.7 0.8410 39 -50.112 6.62 40 -234.311 0.80 1.65160 58.5 0.8525 41 12.128 3.87 1.60342 38.0 0.7353 42 18.638 0.84 43 17.657 4.06 1.56732 42.8 0.7589 44 -368.192 1.57 45 44.805 3.60 1.54072 47.2 0.7766 46 -24.930 0.80 1.85026 32.3 0.6942 47 77.632 5.00 48 ∞ 33.00 1.60859 46.4 0.7534 49 ∞ 13.20 1.51680 64.2 0.8698 50∞7.40 Image plane ∞ Aspheric Data Page 30 K = 0.00000e+00 A 4= 7.16035e-07 A 6=-3.49782e-10 A 8=-1.85840e-12 A10 = 1.52258e-15 Various data Zoom ratio 20.00 Wide Angle Mid-Telephoto Focal length 25.00 111.80 500.00 F-number 2.90 2.90 5.00 Half angle of view 12.41 2.82 0.63 Image height 5.50 5.50 5.50 Lens total length 350.00 350.00 350.00 BF 7.40 7.40 7.40 d15 8.95 68.36 93.17 d24 76.04 11.02 11.57 d27 21.70 27.31 1.95 d50 7.40 7.40 7.40 Zoom lens group data Group starting plane focal length 1 1 163.84 2 16 -28.11 3 25 -57.52 4 29 40.69

[0068] [Numerical Example 2] Unit: mm Surface Data Surface number rd nd vd θct 1 205.860 3.00 1.75500 52.3 0.8092 2 141.110 3.38 3 162.200 13.67 1.43387 95.1 0.8092 4 -696.139 0.47 5 -8368.031 3.00 1.75500 52.3 0.8092 6 149.934 1.25 7 143.299 12.75 1.43387 95.1 0.8092 8 -24298.691 13.35 9 179.863 8.89 1.43387 95.1 0.8092 10 1161.166 0.20 11 164.642 11.77 1.43387 95.1 0.8092 12 -1365.806 0.48 13 114.265 6.27 1.43387 95.1 0.8092 14 181.786 (variable) 15 176.724 1.40 1.69930 51.1 0.7593 16 35.603 1.89 17 44.882 12.04 1.61310 44.4 0.8010 18 -38.744 1.30 1.59522 67.7 0.7953 19 23.172 5.01 20 53.667 1.30 1.63858 55.2 0.7865 21 30.893 6.45 1.67300 38.3 0.7481 22 -112.312 2.91 23 -33.250 1.20 1.59522 67.7 0.7953 24* 89.826 (variable) 25 -244.613 1.00 1.69930 51.1 0.7593 26 26.463 3.02 1.74951 35.3 0.7308 27 148.787 2.45 28 -41.792 1.00 1.59522 67.7 0.7953 29 442.162 (variable) 30* 52.312 6.45 1.59522 67.7 0.7953 31 -83.486 (variable) 32 (Aperture) ∞ 0.30 33 65.297 3.55 1.43875 94.9 0.8373 34 -248.716 0.20 35 176.843 5.81 1.43875 94.9 0.8373 36 -43.462 1.30 1.64000 60.1 0.8645 37 -134.169 0.20 38 72.500 1.30 1.64000 60.1 0.8645 39 29.388 33.97 40 21.422 7.08 1.43875 94.9 0.8373 41 -52.222 0.20 42 45.862 6.15 1.43875 94.9 0.8373 43 -22.593 1.20 1.65160 58.5 0.8270 44 15.929 2.15 45 22.421 4.13 1.51633 64.1 0.8687 46 -34.989 1.20 2.00100 29.1 0.6838 47 42.073 7.53 48 47.198 4.70 1.78472 25.7 0.6702 49 -74.967 1.20 1.85920 33.0 0.6855 50 -60.279 4.87 51 ∞ 33.00 1.60859 46.4 0.7534 52 ∞ 13.20 1.51680 64.2 0.8698 53∞7.40 Image plane ∞ Aspheric Data Page 24 K = 0.00000e+00 A 4=-1.39031e-05 A 6= 1.23886e-09 A 8= 9.99239e-11 A10=-2.79043e-13 A12= 5.26650e-16 A 3= 2.82395e-06 A 5=-7.46597e-09 A 7=-9.43023e-10 Page 30 K =-5.07198e+00 A 4= 9.50981e-07 A 6=-1.46718e-09 A 8= 4.78513e-13 A10=3.76242e-15 A12=-6.56234e-18 Various data Zoom ratio 40.00 Wide Angle Mid-Telephoto Focal length 14.00 88.54 560.00 F-number 2.80 2.80 5.10 Half angle of view 21.45 3.55 0.56 Image height 5.50 5.50 5.50 Lens total length 400.00 400.00 400.00 BF 7.40 7.40 7.40 d14 1.68 87.59 114.17 d24 90.41 11.68 8.79 d29 26.15 31.09 1.94 d31 15.22 3.10 8.55 d53 7.40 7.40 7.40 Zoom lens group data Group starting plane focal length 1 1 167.49 2 15 -27.85 3 25 -45.66 4 30 55.01 5 33 83.75

[0069] [Numerical Example 3] Unit: mm Surface Data Surface number rd nd vd θct 1 200.145 19.16 1.43387 95.1 0.8092 2 -363.568 7.89 3 -448.706 3.00 1.75500 52.3 0.8092 4 5218.354 0.40 5 197.361 3.00 1.69680 55.5 0.8330 6 113.608 5.84 7 116.289 17.57 1.43875 94.9 0.8373 8 1290.516 0.40 9 249.182 7.29 1.43387 95.1 0.8092 10 753.244 (variable) 11 -625.144 1.50 1.59522 67.7 0.7953 12 99.991 1.33 13 165.266 1.50 1.69930 51.1 0.7593 14 57.402 3.87 15 661.966 11.10 1.74951 35.3 0.7308 16 -28.033 1.50 1.75106 43.1 0.7097 17 -724.442 1.81 18 -104.405 1.50 1.49700 81.5 0.8258 19 38.825 6.12 1.61340 44.3 0.7825 20 287.393 2.12 21 -129.866 1.50 1.69930 51.1 0.7593 22 524.710 (variable) 23 87.668 5.61 1.43875 94.9 0.8373 24 -106.108 0.15 25 47.669 1.00 1.75500 52.3 0.8092 26 39.815 5.65 1.43875 94.9 0.8373 27 227.324 3.24 28 71.788 1.00 1.75500 52.3 0.8092 29 41.978 1.82 30 68.929 6.56 1.59522 67.7 0.7953 31 -55.032 1.00 1.75500 52.3 0.8092 32 596.629 (variable) 33(Aperture) ∞ 2.69 34 -58.820 0.80 1.69930 51.1 0.7593 35 -103.684 0.67 36 67.895 2.53 1.85478 24.8 0.6739 37 204.847 0.15 38 98.539 2.00 1.43875 94.9 0.8373 39 181.733 0.15 40 30.221 3.31 1.43875 94.9 0.8373 41 148.416 2.19 42 721.103 1.93 1.83481 42.7 0.7533 43 -65.197 0.75 1.73400 51.5 0.8067 44 29.158 7.59 45 99.096 0.70 2.05090 26.9 0.6726 46 32.244 11.55 47 972.991 2.66 1.72916 54.7 0.8244 48 -32.990 10.00 49 ∞ 33.00 1.60859 46.4 0.7534 50 ∞ 13.20 1.51633 64.2 0.8676 51∞7.40 Image plane ∞ Various data Zoom ratio 57.00 Wide Angle Mid-Telephoto Focal length 15.00 142.30 855.00 F-number 3.00 3.43 6.60 Half angle of view 20.14 2.21 0.37 Image height 5.50 5.50 5.50 Lens total length 517.40 517.40 517.40 BF 7.40 7.40 7.40 d10 1.75 148.55 185.06 d22 285.74 102.70 1.48 d32 2.22 38.46 103.17 d51 7.40 7.40 7.40 Zoom lens group data Group starting plane focal length 1 1 286.02 2 11 -38.26 3 23 76.84 4 34 209.16

[0070] [Numerical Example 4] Unit: mm Surface Data Surface number rd nd vd θct 1 726.264 6.00 1.75500 52.3 0.8092 2 278.729 2.23 3 277.824 28.23 1.43387 95.1 0.8092 4 -573.275 3.81 5 -798.431 6.00 1.72916 54.7 0.8244 6 468.971 1.00 7 419.612 21.72 1.43387 95.1 0.8092 8 -598.982 30.81 9 312.689 22.46 1.43387 95.1 0.8092 10 -1808.073 0.25 11 308.097 13.75 1.43387 95.1 0.8092 12 1020.309 4.52 13 179.222 12.24 1.43875 94.7 0.8410 14 286.822 (variable) 15 -651.200 1.40 1.69930 51.1 0.7593 16 35.918 4.27 17 55.389 14.46 1.61310 44.4 0.8010 18 -32.695 1.30 1.59522 67.7 0.7953 19 40.943 4.57 20 71.959 1.30 1.63858 55.2 0.7865 21 46.624 6.82 1.67300 38.3 0.7481 22 -1545.600 2.59 23 -87.208 1.20 1.59522 67.7 0.7953 24* 111.316 (variable) 25 86.468 9.40 1.59522 67.7 0.7953 26* -1557.577 5.64 27 110.201 10.86 1.43875 94.9 0.8373 28 -167.754 0.47 29 -537.418 2.60 1.61310 44.4 0.8010 30 69.114 (variable) 31 84.887 11.56 1.43875 94.9 0.8373 32 -142.382 0.50 33 -544.391 2.50 1.61310 44.4 0.8010 34 244.251 4.47 1.59522 67.7 0.7953 35* ∞ (variable) 36(Aperture) ∞ 3.16 37 338.696 1.40 1.43875 94.9 0.8373 38 32.281 0.50 39 24.995 4.24 1.61340 44.3 0.7825 40 53.451 4.69 41 -92.687 1.40 1.43875 94.9 0.8373 42 31.092 8.62 43 36.989 6.98 1.43875 94.9 0.8373 44 -42.288 3.44 45 -47.389 1.60 2.00100 29.1 0.6838 46 20.935 6.98 1.85478 24.8 0.6739 47 -101.285 27.92 48 -4463.147 8.84 1.43875 94.9 0.8373 49 -28.182 1.47 50 -29.887 1.80 1.64000 60.1 0.8645 51 125.196 5.88 1.59522 67.7 0.7953 52 -49.014 0.60 53 141.937 4.44 1.59551 39.2 0.7402 54 -61.689 1.80 1.95375 32.3 0.6988 55 -302.355 1.00 56 207.498 6.17 1.43875 94.9 0.8373 57 -103.658 19.65 58 ∞ 33.00 1.60859 46.4 0.7534 59 ∞ 13.20 1.51633 64.2 0.8676 60∞13.29 Image plane ∞ Aspheric Data Page 24 K = 1.47809e+01 A 4=-4.82145e-06 A 6=-1.63377e-09 A 8=-7.31291e-13 A10=-1.04250e-15 A12=-2.55286e-18 Page 26 K = 2.16390e+02 A 4= 3.40866e-07 A 6=-7.19151e-12 A 8= 1.66846e-14 A10=-7.74881e-18 A12= 2.37323e-21 Page 35 K =-9.69844e+12 A 4= 2.83089e-07 A 6= 1.13389e-10 A 8=-1.14330e-13 A10= 1.18936e-16 A12=-5.02120e-20 Various data Zoom ratio 90.00 Wide Angle Mid-Telephoto Focal length 14.30 135.66 1286.99 F-number 2.95 2.95 6.77 Half angle of view 21.04 2.32 0.24 Image height 5.50 5.50 5.50 Lens total length 778.27 778.27 778.27 BF 13.29 13.29 13.29 d14 3.81 159.26 199.11 d24 345.01 145.23 2.00 d30 5.50 7.31 9.23 d35 2.96 45.47 146.93 d60 13.29 13.29 13.29 Zoom lens group data Group starting plane focal length 1 1 282.68 2 15 -34.71 3 25 201.69 4 31 143.30 5 37 84.86

[0071] [Numerical Example 5] Unit: mm Surface Data Surface number rd nd vd θct 1 -252.130 1.50 1.75500 52.3 0.8092 2 109.669 0.76 3 109.726 9.74 1.43387 95.1 0.8092 4 -243.203 0.20 5 262.783 4.73 1.43387 95.1 0.8092 6 -473.152 17.92 7 153.255 6.31 1.43387 95.1 0.8092 8 -434.667 0.23 9 124.421 6.72 1.43387 95.1 0.8092 10 -530.710 0.29 11 79.139 4.33 1.43387 95.1 0.8092 12 135.544 (variable) 13* -353.175 0.60 1.85920 33.0 0.6855 14 24.649 (variable) 15 -43.151 4.04 1.85478 24.8 0.6739 16 -18.453 0.60 1.59522 67.7 0.7953 17 215.047 0.18 18 52.294 5.02 1.61340 44.3 0.7825 19 -27.308 0.60 1.81600 46.6 0.7690 20 179.155 (variable) 21 -331.471 0.50 1.59410 60.5 0.7800 22 29.451 2.17 1.74951 35.3 0.7308 23 151.446 2.32 24 -40.085 0.50 1.59522 67.7 0.7953 25 139.466 (variable) 26* 57.222 4.02 1.72916 54.7 0.8244 27 -127.689 (variable) 28(Aperture) ∞ 0.29 29 63.811 4.14 1.43875 94.9 0.8373 30 -49.740 0.20 31 60.087 4.86 1.43875 94.9 0.8373 32 -29.821 1.30 1.64000 60.1 0.8645 33 423.022 0.20 34 41.370 1.30 1.64000 60.1 0.8645 35 20.883 33.97 36 72.044 4.70 1.43875 94.9 0.8373 37 -28.530 0.20 38 48.419 4.86 1.43875 94.9 0.8373 39 -26.006 1.20 1.65160 58.5 0.8525 40 -118.676 1.04 41 2087.084 2.74 1.67300 38.3 0.7481 42 -38.379 1.20 2.00100 29.1 0.6838 43 61.949 2.58 44 -124.665 2.97 1.85478 24.8 0.6739 45 -25.665 1.20 1.85920 33.0 0.6855 46 -45.233 4.87 47 ∞ 33.00 1.60859 46.4 0.7534 48 ∞ 13.20 1.51633 64.1 0.8687 49∞7.38 Image plane ∞ Aspheric Data Page 13 K = 8.16505e-01 A 4= 1.77105e-06 A 6= 1.42691e-08 A 8=-6.46440e-10 A10= 1.02519e-11 A12=-8.25095e-14 A14= 3.30010e-16 A16=-5.22438e-19 Page 26 K =-1.84774e+00 A 4=-2.09515e-06 A 6= 1.81035e-09 A 8= 4.21519e-12 A10=-5.59792e-14 A12= 1.80787e-16 Various data Zoom ratio 26.09 Wide Angle Mid-Telephoto Focal length 11.50 58.64 300.00 F-number 2.70 2.70 4.89 Half angle of view 25.56 5.36 1.05 Image height 5.50 5.50 5.50 Lens total length 300.04 300.04 300.04 BF 7.38 7.38 7.38 d12 1.49 57.43 78.08 d14 6.51 5.41 11.42 d20 56.31 2.43 7.22 d25 15.71 21.73 1.02 d27 19.34 12.36 1.62 d49 7.38 7.38 7.38 Zoom lens group data Group starting plane focal length 1 1 100.87 2 13 -26.80 3 15 -122.98 4 21 -48.61 5 26 54.69 6 29 62.51

[0072] [Numerical Example 6] Unit: mm Surface Data Surface number rd nd vd θct 1 180.696 7.69 1.48749 70.2 0.8924 2 910.177 0.19 3 223.463 4.00 1.69680 55.5 0.8330 4 104.591 11.07 1.43875 94.9 0.8373 5 461.529 0.14 6 157.978 4.80 1.43387 95.1 0.8092 7 251.779 18.37 8 125.213 6.57 1.43875 94.9 0.8373 9 288.377 1.40 1.75500 52.3 0.8092 10 86.841 0.99 11 85.047 12.25 1.43875 94.9 0.8373 12 4208.067 1.40 1.64000 60.1 0.8645 13 381.214 0.20 14 121.979 9.62 1.59522 67.7 0.7953 15 658.818 (variable) 16 488.670 0.90 1.75106 43.1 0.7097 17 20.091 4.22 18 -52.580 4.45 1.73800 32.3 0.7154 19 -15.126 0.80 1.69930 51.1 0.7593 20 60.325 0.50 21 36.226 2.69 1.73800 32.3 0.7154 22 3647.881 2.11 23 -25.891 0.80 1.72000 48.0 0.7100 24 -29.968 (variable) 25 -47.579 0.80 1.71700 47.9 0.7629 26 47.847 2.59 1.84666 23.8 0.6614 27 302.539 (variable) 28(Aperture) ∞ 0.50 29 69.533 6.94 1.59522 67.7 0.7953 30* -44.153 0.09 31 111.080 6.91 1.43875 94.7 0.8410 32 -28.162 0.90 1.80610 40.9 0.7483 33 -189.544 32.94 34 45.993 6.71 1.43875 94.7 0.8410 35 -130.394 14.52 36 9967.779 3.58 1.43875 94.7 0.8410 37 -33.126 2.01 38 -28.148 8.56 1.65160 58.5 0.8525 39 18.306 2.57 1.60342 38.0 0.7353 40 28.812 0.74 41 26.113 4.64 1.56732 42.8 0.7589 42 -33.479 1.57 43 44.750 3.60 1.54072 47.2 0.7766 44 -24.930 0.80 1.85026 32.3 0.6942 45 77.632 5.00 46 ∞ 33.00 1.60859 46.4 0.7534 47 ∞ 13.20 1.51680 64.2 0.8698 48∞7.41 Image plane ∞ Aspheric Data Page 30 K = 0.00000e+00 A 4=-1.06062e-07 A 6=-1.17310e-09 A 8=-5.39937e-13 A10=-1.94022e-15 Various data Zoom ratio 20.00 Wide Angle Mid-Telephoto Focal length 25.00 111.80 500.00 F-number 2.90 2.90 5.00 Half angle of view 12.41 2.82 0.63 Image height 5.50 5.50 5.50 Lens total length 370.61 370.61 370.61 BF 7.41 7.41 7.41 d15 22.91 80.68 104.43 d24 77.84 11.50 9.51 d27 15.09 23.66 1.91 d48 7.41 7.41 7.41 Zoom lens group data Group starting plane focal length 1 1 169.38 2 16 -24.07 3 25 -65.76 4 29 46.05

[0073] [Numerical Example 7] Unit: mm Surface Data Surface number rd nd vd θct 1 -199.291 1.50 1.74100 52.6 0.8155 2 92.793 0.75 3 93.134 11.35 1.43387 95.1 0.8092 4 -232.794 0.20 5 175.628 6.59 1.43387 95.1 0.8092 6 -352.777 17.06 7 157.316 6.90 1.43387 95.1 0.8092 8 -320.965 0.23 9 118.129 6.64 1.43387 95.1 0.8092 10 -936.511 0.30 11 85.254 4.81 1.43387 95.1 0.8092 12 177.732 (variable) 13* -300.301 0.60 1.78000 40.0 0.6950 14 17.248 7.34 15 -35.541 4.17 1.73800 32.3 0.7154 16 -17.070 0.80 1.75106 43.1 0.7097 17 -211.013 0.18 18 57.943 4.98 1.73800 32.3 0.7154 19 -39.226 0.60 1.75106 43.1 0.7097 20 -72.989 (variable) 21 -353.750 0.50 1.59410 60.5 0.7800 22 17.521 3.03 1.74951 35.3 0.7308 23 81.160 2.70 24 -35.674 0.50 1.59522 67.7 0.7953 25 68.500 (variable) 26(Aperture) ∞ 0.50 27* 36.914 4.67 1.59522 67.7 0.7953 28 -266.118 (variable) 29 93.731 3.66 1.43875 94.9 0.8373 30 -61.404 0.20 31 84.302 3.81 1.43875 94.9 0.8373 32 -51.430 1.30 1.64000 60.1 0.8645 33 496.250 0.20 34 48.219 1.30 1.64000 60.1 0.8645 35 24.530 33.97 36 30.272 5.01 1.43875 94.9 0.8373 37 -46.240 0.20 38 40.551 5.13 1.43875 94.9 0.8373 39 -21.793 1.00 1.65160 58.5 0.8525 40 -33.506 1.05 41 -40.693 0.60 1.95375 32.3 0.6988 42 37.319 3.29 43 45.065 2.91 1.76182 26.5 0.6757 44 -59.647 1.00 1.88300 40.8 0.7397 45 -672.675 4.87 46 ∞ 33.00 1.60859 46.4 0.7534 47 ∞ 13.20 1.51633 64.1 0.8687 48∞7.39 Image plane ∞ Aspheric Data Page 13 K =-1.83093e+00 A 4= 9.28166e-06 A 6= 4.57095e-08 A 8=-1.46641e-09 A10= 1.79202e-11 A12=-1.15334e-13 A14= 3.82298e-16 A16=-5.14147e-19 Page 27 K =-1.60060e+00 A 4=-2.41963e-06 A 6= 1.17337e-09 A 8=-6.94747e-12 A10= 1.70256e-14 A12=-1.33847e-17 Various data Zoom ratio 26.09 Wide Angle Mid-Telephoto Focal length 11.50 58.64 300.00 F-number 2.70 2.70 4.89 Half angle of view 25.56 5.36 1.05 Image height 5.50 5.50 5.50 Lens total length 300.03 300.03 300.03 BF 7.39 7.39 7.39 d12 1.79 55.13 72.25 d20 54.14 2.02 11.37 d25 25.58 25.44 2.56 d28 8.53 7.45 3.87 d48 7.39 7.39 7.39 Zoom lens group data Group starting plane focal length 1 1 92.49 2 13 -29.44 3 21 -36.79 4 27 54.78 5 29 66.74

[0074] [Table 1]

[0075] [Table 2]

[0076] The disclosure of this embodiment includes the following configuration.

[0077] (Configuration 1) A zoom lens having, in order from an object side to an image side, a first lens group having positive refractive power that does not move for zooming, an intermediate group including a plurality of lens groups that move for zooming, and a rear lens group, The spacing between adjacent lens groups changes during zooming. In the intermediate group, the refractive index for the d-line, the Abbe number for the d-line, the partial dispersion ratios for the C-line and the t-line of the material are respectively defined as ndLN, νdLN, and θCtLN. 1.60 <ndLN<2.00 25.0<νdLN<60.0 0.490<θCtLN―0.00417×νdLN<0.550 A zoom lens comprising a lens group having negative refractive power including a negative lens LN that satisfies the following condition:

[0078] (Configuration 2) The negative lens LN is included in a lens group N1 having the strongest negative refractive power in the intermediate group, the focal length of the lens group N1 is fN1, and the focal length of the negative lens LN1 having the strongest negative refractive power among the negative lenses LN included in the lens group N1 is fLN1, 0.3 <fLN1 / fN1<5.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

[0079] (Configuration 3) The focal length of the first lens group is f1, and the focal length of the lens group N1 having the strongest negative refractive power in the intermediate group is fN1, -12.0 <f1 / fN1<-2.0 3. The zoom lens according to configuration 1 or 2, which satisfies the following conditions:

[0080] (Configuration 4) The average value of the refractive index for the d-line of all the lenses included in the lens group N1 having the strongest negative refractive power in the intermediate group is defined as ndN1a, 1.55 <ndN1a<1.90 4. The zoom lens according to any one of configurations 1 to 3, which satisfies the following conditions:

[0081] (Configuration 5) The average Abbe number for the d-line of all lenses having positive refractive power included in the lens group N1 having the strongest negative refractive power in the intermediate group is νdN1p, The average Abbe number for the d-line of all the lenses having negative refractive power included in the lens group N1 is defined as νdN1n, -40.0<νdN1p-νdN1n<-5.0 5. The zoom lens according to any one of configurations 1 to 4, which satisfies the following conditions:

[0082] (Configuration 6) The average value of the partial dispersion ratios for the C-line and the t-line of all the lenses having positive refractive power included in the lens group N1 having the strongest negative refractive power in the intermediate group is defined as θCtN1p, The average value of the partial dispersion ratios for the C-line and the t-line of all the lenses having negative refractive power included in the lens group N1 is defined as θCtN1n, -0.050<θCtN1p-θCtN1n<0.050 6. The zoom lens according to any one of configurations 1 to 5, which satisfies the following conditions:

[0083] (Configuration 7) The focal length of a lens group Nm including a negative lens LNm having the strongest negative refractive power among the negative lenses LN is fNm, and the focal length of the negative lens LNm is fLNm, 0.3 <fLNm / fNm<4.0 7. The zoom lens according to any one of configurations 1 to 6, characterized in that the following conditions are satisfied:

[0084] (Configuration 8) The average value of the refractive index with respect to the d-line of all lenses included in the lens group Nm including the negative lens LNm having the strongest negative refractive power among the negative lenses LN is defined as ndNma, 1.55 <ndNma<1.90 8. The zoom lens according to any one of configurations 1 to 7, characterized in that the following conditions are satisfied:

[0085] (Configuration 9) The average Abbe number for the d-line of all lenses having positive refractive power included in the lens group Nm including the negative lens LNm having the strongest negative refractive power among the negative lenses LN is νdNmp, The average Abbe number for the d-line of all the lenses having negative refractive power included in the lens group Nm is defined as νdNmn, -40.0<νdNmp-νdNmn<-5.0 9. The zoom lens according to any one of configurations 1 to 8, which satisfies the following conditions:

[0086] (Configuration 10) The average value of the partial dispersion ratio for the C-line and the t-line of all lenses having positive refractive power included in the lens group Nm including the negative lens LNm having the strongest negative refractive power among the negative lenses LN is defined as θCtNmp, The average value of the partial dispersion ratios for the C-line and the t-line of all the lenses having negative refractive power included in the lens group Nm is defined as θCtNmn, -0.050<θCtNmp-θCtNmn<0.050 10. The zoom lens according to any one of configurations 1 to 9, which satisfies the following conditions:

[0087] (Configuration 11) the intermediate group includes, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power and a focal length at a wide-angle end consisting of all lens groups that move monotonically toward the image side for zooming, and at least one lens group, the sub-intermediate group V including the negative lens LN, The focal length of the sub-intermediate lens group V at the wide-angle end is fV, and the focal length of the negative lens LNVm having the strongest negative refractive power in the sub-intermediate lens group V among the negative lenses LN is fLNVm, 0.3 <fLNVm / fV<4.0 11. The zoom lens according to any one of configurations 1 to 10, characterized in that the following conditions are satisfied:

[0088] (Configuration 12) the intermediate group includes, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power and a focal length at a wide-angle end that is made up of all lens groups that move monotonically toward the image side for zooming, and at least one lens group; The focal length of the first lens group is f1, and the focal length of the sub-intermediate lens group V at the wide-angle end is fV, -12.0 <f1 / fv<-2.0 12. The zoom lens according to any one of configurations 1 to 11, characterized in that the following condition is satisfied:

[0089] (Configuration 13) the intermediate group includes, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power and a focal length at a wide-angle end that is made up of all lens groups that move monotonically toward the image side for zooming, and at least one lens group; The average value of the refractive index for the d line of all the lenses included in the sub-intermediate group V is defined as ndVa, 1.55 <ndVa<1.9 13. The zoom lens according to any one of configurations 1 to 12, characterized in that the following condition is satisfied:

[0090] (Configuration 14) the intermediate group includes, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power and a focal length at a wide-angle end that is made up of all lens groups that move monotonically toward the image side for zooming, and at least one lens group; The average value of the Abbe numbers of all the lenses having positive refractive power included in the sub-intermediate group V with respect to the d line is denoted as νdVp, and the average value of the Abbe numbers of all the lenses having negative refractive power included in the sub-intermediate group V with respect to the d line is denoted as νdVn, -40.0<νdVp-νdVn<-5.0 14. The zoom lens according to any one of configurations 1 to 13, characterized in that the following condition is satisfied:

[0091] (Configuration 15) the intermediate group includes, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power and a focal length at a wide-angle end that is made up of all lens groups that move monotonically toward the image side for zooming, and at least one lens group; The average value of the partial dispersion ratios for the C line and the t line of all the lenses having positive refractive power included in the sub-intermediate group V is θCtVp, and the average value of the partial dispersion ratios for the C line and the t line of all the lenses having negative refractive power included in the sub-intermediate group V is θCtVn, -0.050<θCtVp-θCtVn<0.050 15. A zoom lens according to any one of configurations 1 to 14, characterized in that the following conditions are satisfied:

[0092] (Configuration 16) The average value of the partial dispersion ratios for the C-line and the t-line of all the lenses having positive refractive power included in the first lens group is defined as θCt1p, and the average value of the partial dispersion ratios for the C-line and the t-line of all the lenses having negative refractive power included in the first lens group is defined as θCt1n, -0.030<θCt1p-θCt1n<0.030 16. A zoom lens according to any one of configurations 1 to 15, characterized in that the following conditions are satisfied:

[0093] (Configuration 17) A zoom lens according to any one of configurations 1 to 16, further comprising an aperture stop disposed between the intermediate lens group and the rear lens group, or between the last lens group and the penultimate lens group in the intermediate lens group.

[0094] (Configuration 18) 18. The zoom lens of embodiment 17, wherein the aperture stop moves for zooming.

[0095] (Configuration 19) 19. A zoom lens according to any one of configurations 1 to 18, wherein the rear lens group does not move for zooming.

[0096] (Configuration 20) A zoom lens according to any one of configurations 1 to 19, and an image sensor for capturing an image formed by the zoom lens.

[0097] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0098] L1 First lens group LM intermediate group LN Negative Lens LN LR rear lens group

Claims

1. A zoom lens having, in order from the object side to the image side, a first lens group having a positive refractive power that does not move for zooming, an intermediate group including a plurality of lens groups that move for zooming, and a rear lens group, wherein the intervals between adjacent lens groups all change for zooming, the intermediate group includes a lens group having a negative refractive power including a negative lens LN that satisfies the conditions that the refractive index with respect to the d-line of the lens material, the Abbe number with respect to the d-line, and the partial dispersion ratio with respect to the C-line and t-line are ndLN, νdLN, and θCtLN, respectively, 1.60 < ndLN < 2.00 25.0 < νdLN < 60.0 0.490 < θCtLN - 0.00417 × νdLN < 0.550 and includes a lens group having a negative refractive power including a negative lens LN, wherein, for the lens group Nm including the negative lens LNm having the strongest negative refractive power among the negative lenses LN, the average value of the partial dispersion ratios with respect to the C-line and t-line of all the lenses having a positive refractive power included in the lens group Nm is θCtNmp, and the average value of the partial dispersion ratios with respect to the C-line and t-line of all the lenses having a negative refractive power included in the lens group Nm is θCtNmn, -0.050 < θCtNmp - θCtNmn < 0.050 A zoom lens characterized by satisfying the above conditions.

2. The negative lens LN is included in the lens group N1 having the strongest negative refractive power in the intermediate group. Let the focal length of the lens group N1 be fN1 and the focal length of the negative lens LN1 having the strongest negative refractive power among the negative lenses LN included in the lens group N1 be fLN1, 0.3 < fLN1 / fN1 < 5.0 The zoom lens according to claim 1, characterized by satisfying the above conditions.

3. Let the focal length of the first lens group be f1 and the focal length of the lens group N1 having the strongest negative refractive power in the intermediate group be fN1, -12.0 < f1 / fN1 < -2.0 The zoom lens according to claim 1, characterized by satisfying the above conditions.

4. Let the average value of the refractive indices with respect to the d-line of all the lenses included in the lens group N1 having the strongest negative refractive power in the intermediate group be ndN1a, The zoom lens according to claim 1, characterized by satisfying the condition 1.55 < ndN1a < 1.

90.

5. Regarding the average value of the Abbe number for the d-line of all the lenses with positive refractive power included in the lens group N1 having the strongest negative refractive power in the intermediate group as νdN1p, and the average value of the Abbe number for the d-line of all the lenses with negative refractive power included in the lens group N1 as νdN1n, -40.0 < νdN1p - νdN1n < -5.0 The zoom lens according to claim 1, characterized by satisfying the condition.

6. Regarding the average value of the partial dispersion ratio for the C-line and t-line of all the lenses with positive refractive power included in the lens group N1 having the strongest negative refractive power in the intermediate group as θCtN1p, and the average value of the partial dispersion ratio for the C-line and t-line of all the lenses with negative refractive power included in the lens group N1 as θCtN1n, -0.050 < θCtN1p - θCtN1n < 0.050 The zoom lens according to claim 1, characterized by satisfying the condition.

7. Regarding the focal length of the lens group Nm as fNm, and the focal length of the negative lens LNm as fLNm, 0.3 < fLNm / fNm < 4.0 The zoom lens according to claim 1, characterized by satisfying the condition.

8. Regarding the average value of the refractive index for the d-line of all the lenses included in the lens group Nm as ndNma, 1.55 < ndNma < 1.90 The zoom lens according to claim 1, characterized by satisfying the condition.

9. Regarding the average value of the Abbe number for the d-line of all the lenses with positive refractive power included in the lens group Nm as νdNmp, and the average value of the Abbe number for the d-line of all the lenses with negative refractive power included in the lens group Nm as νdNmn, -40.0 < νdNmp - νdNmn < -5.0 The zoom lens according to claim 1, characterized by satisfying the condition.

10. The intermediate group consists of, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power at the wide-angle end consisting of all the lens groups that move monotonically toward the image side for zooming, and at least one lens group. The sub-intermediate group V includes the negative lens LN. Regarding the focal length at the wide-angle end of the sub-intermediate group V as fV, and the focal length of the negative lens LNVm having the strongest negative refractive power in the sub-intermediate group V among the negative lenses LN as fLNVm, 0.3 < fLNVm / fV < 4.0 The zoom lens according to claim 1, characterized by satisfying the condition.

11. The intermediate group consists of, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power with a focal length at the wide-angle end composed of all lens groups that monotonically move toward the image side for zooming, and at least one lens group. Let the focal length of the first lens group be f1 and the focal length at the wide-angle end of the sub-intermediate group V be fV. -12.0 < f1 / fv < -2.0 The zoom lens according to claim 1, characterized by satisfying the condition.

12. The intermediate group consists of, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power with a focal length at the wide-angle end composed of all lens groups that monotonically move toward the image side for zooming, and at least one lens group. Let the average value of the refractive indices of the d lines of all the lenses included in the sub-intermediate group V be ndVa. 1.55 < ndVa < 1.9 The zoom lens according to claim 1, characterized by satisfying the condition.

13. The intermediate group consists of, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power with a focal length at the wide-angle end composed of all lens groups that monotonically move toward the image side for zooming, and at least one lens group. Let the average value of the Abbe numbers of the d lines of all the lenses having positive refractive power included in the sub-intermediate group V be νdVp, and the average value of the Abbe numbers of the d lines of all the lenses having negative refractive power included in the sub-intermediate group V be νdVn. -40.0 < νdVp - νdVn < -5.0 The zoom lens according to claim 1, characterized by satisfying the condition.

14. The intermediate group consists of, in order from the object side to the image side, a sub-intermediate group V having a negative refractive power with a focal length at the wide-angle end composed of all lens groups that monotonically move toward the image side for zooming, and at least one lens group. Let the average value of the partial dispersion ratios of the C lines and t lines of all the lenses having positive refractive power included in the sub-intermediate group V be θCtVp, and the average value of the partial dispersion ratios of the C lines and t lines of all the lenses having negative refractive power included in the sub-intermediate group V be θCtVn. -0.050 < θCtVp - θCtVn < 0.050 The zoom lens according to claim 1, characterized by satisfying the condition.

15. Let the average value of the partial dispersion ratio with respect to the C-line and t-line of the lenses having all positive refractive powers included in the first lens group be θCt1p, and the average value of the partial dispersion ratio with respect to the C-line and t-line of the lenses having all negative refractive powers included in the first lens group be θCt1n. -0.030 < θCt1p - θCt1n < 0.030 The zoom lens according to claim 1, characterized in that the condition is satisfied.

16. The zoom lens according to claim 1, further comprising a diaphragm disposed between the intermediate group and the rear lens group, or between the last lens group and the second last lens group in the intermediate group.

17. The zoom lens according to claim 16, characterized in that the diaphragm moves for zooming.

18. The zoom lens according to claim 1, characterized in that the rear lens group does not move for zooming.

19. A zoom lens according to any one of claims 1 to 18, An imaging device, comprising an imaging element that captures an image formed by the zoom lens.

Images