Zoom lens and imaging apparatus

Abstract

To provide a zoom lens having excellent optical performance over a wide wavelength range with a high zoom ratio.SOLUTION: A zoom lens includes, in order from an object side to an image side, a positive first lens group that does not move for zooming, a zoom lens group that moves during zooming, and a rear lens group that does not move for zooming. Distances between the adjacent lens groups all change for zooming. The rear lens group includes a positive lens and a negative lens including a first negative lens, and further includes a rear sub-lens group having a negative refractive power and composed of two or three lenses adjacent to each other. An Abbe number with reference to a d-line and a partial dispersion ratio from a C-line to a t-line of the first negative lens, an average value of Abbe numbers with reference to the d-line and an average value of partial dispersion ratios from the C-line to the t-line of positive lenses included in the rear sub-lens group, and an average value of Abbe numbers with reference to the d-line and an average value of partial dispersion ratios from the C-line to the t-line of negative lenses included in the rear sub-lens group are appropriately set.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Zoom lenses for surveillance cameras used for long-distance monitoring, etc., require a high zoom ratio and excellent optical performance from the visible light region to the near-infrared region. As such a zoom lens, Patent Documents 1 and 2 disclose a positive-lead type zoom lens having, arranged in order from the object side to the image side, a first lens group with positive refractive power, a zooming group that moves for zooming, and a subsequent relay group.

[0003] The zoom lens of Patent Document 1 achieves a high zoom ratio of up to about 80x by moving the second and third lens groups. The zoom lens of Patent Document 2 achieves a high zoom ratio of up to about 38x by moving the second and third lens groups. The zoom lenses of Patent Documents 1 and 2 use a glass material for the positive lens group in the subsequent relay group that is advantageous for correcting chromatic aberration in the near-infrared wavelength range. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-60971 [Patent Document 2] Japanese Patent Application Publication No. 2023-79735 [Non-patent literature]

[0005] [Non-Patent Document 1] Yoshiya Matsui, 23rd Conference on Applied Physics (1962) Summary of the Invention [Problem to be solved by the invention]

[0006] To effectively correct axial chromatic aberration throughout the entire zoom range from the visible light region to the near-infrared light region, the negative lens group in the subsequent relay group may be configured with a positive lens element made of heavy niobium phosphate glass, which has high dispersion and high anomalous dispersion, adjacent to a negative lens element made of lanthanum glass, which has high dispersion and low anomalous dispersion. However, with this configuration, significant lateral chromatic aberration remains in the near-infrared light region. Furthermore, effectively correcting axial chromatic aberration at the telephoto end can easily result in overcorrection of axial chromatic aberration in the infrared light region at the wide-angle end.

[0007] The zoom lenses disclosed in Patent Documents 1 and 2 are unable to reduce both axial chromatic aberration and lateral chromatic aberration from the visible light region to the near-infrared light region. In particular, to obtain good optical performance in the near-infrared light region around 1000 to 2000 nm (the so-called NIR (Near Infrared Rays) to SWIR (Short Wavelength Infrared) region), it is important to more appropriately set the type of zoom lens and the lens configuration of each lens group. The present invention provides a zoom lens that has a high zoom ratio and good optical performance over a wide wavelength range from the visible light region to the SWIR region. [Means for solving the problem]

[0008] A zoom lens according to one aspect of the present invention comprises, in order from the object side to the image side, a first lens group having positive refractive power that does not move for varying magnification, a variable magnification lens group that moves when varying magnification, and a rear lens group that does not move for varying magnification, the spacing between adjacent lens groups changing for varying magnification, the rear lens group including at least one positive lens and at least one negative lens including a first negative lens, and a rear sub-lens group having negative refractive power that is made up of two or three lenses adjacent to each other, wherein the Abbe number referenced to the d-line and the partial dispersion ratio from the C-line to the t-line of the first negative lens are respectively νdN and θctN, the average values ​​of the Abbe number referenced to the d-line and the partial dispersion ratio from the C-line to the t-line of at least one positive lens included in the rear sub-lens group are respectively νdp and θctp, and the average values ​​of the Abbe number referenced to the d-line and the partial dispersion ratio from the C-line to the t-line of at least one negative lens included in the rear sub-lens group are respectively νdn and θctn, 0.4958≦θct-0.00417×νdN≦0.5635 -4.0×10 -3 ≦(θctn-θctp) / (νdp-νdn)≦4.0×10 -3 -40≦νdp-νdn≦0 The present invention is characterized in that the following conditions are satisfied: [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a zoom lens that has a high zoom ratio and good optical performance over a wide wavelength range from the visible light region to the SWIR region. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of the zoom lens of Example 1 at the wide-angle end (focal length 25 mm) and in a state where the lens is focused at infinity. [Figure 2] 1A to 1C are longitudinal aberration diagrams of the zoom lens of Example 1 at infinity focus at (a) the wide-angle end, (b) a middle zoom position (focal length 175 mm), and (c) the telephoto end (focal length 500 mm). [Figure 3]4A and 4B are lateral aberration diagrams of the zoom lens of Example 1 at the telephoto end and in an infinity-focused state, respectively, before and after image blur correction. [Figure 4] FIG. 10 is a cross-sectional view of the zoom lens of Example 2 at the wide-angle end (focal length 16 mm) and in a state where the lens is focused at infinity. [Figure 5] 10A to 10C are longitudinal aberration diagrams of the zoom lens of Example 2 at infinity focus at (a) the wide-angle end, (b) a middle zoom position (focal length 111.84 mm), and (c) the telephoto end (focal length 768 mm). [Figure 6] 10A and 10B are lateral aberration diagrams of the zoom lens of Example 2 at the telephoto end and in an infinity-focused state, respectively, before and after image blur correction. [Figure 7] FIG. 10 is a cross-sectional view of the zoom lens of Example 3 at the wide-angle end (focal length 14.3 mm) and in a state focused at infinity. [Figure 8] 10A to 10C are longitudinal aberration diagrams of the zoom lens of Example 3 at infinity focus at (a) the wide-angle end, (b) a middle zoom position (focal length 155.9 mm), and (c) the telephoto end (focal length 1287 mm). [Figure 9] 10A and 10B are lateral aberration diagrams of the zoom lens of Example 3 at the telephoto end and in an infinity-focused state, respectively, before and after image blur correction. [Figure 10] FIG. 10 is a cross-sectional view of the zoom lens of Example 4 at the wide-angle end (focal length 45 mm) and in a state focused at infinity. [Figure 11] 10A to 10C are longitudinal aberration diagrams of the zoom lens of Example 4 at infinity focus at (a) the wide-angle end, (b) a middle zoom position (focal length 270 mm), and (c) the telephoto end (focal length 1000 mm). [Figure 12] 10A and 10B are lateral aberration diagrams of the zoom lens of Example 4 at the telephoto end and in an infinity-focused state, respectively, before and after image blur correction. [Figure 13] FIG. 10 is a cross-sectional view of the zoom lens of Example 5 at the wide-angle end (focal length 11.5 mm) and in a state focused at infinity. [Figure 14]10A to 10C are longitudinal aberration diagrams of the zoom lens of Example 5 at infinity focus at (a) the wide-angle end, (b) a middle zoom position (focal length 58.46 mm), and (c) the telephoto end (focal length 300 mm). [Figure 15] 10A and 10B are lateral aberration diagrams of the zoom lens of Example 5 at the telephoto end and in an infinity-focused state, respectively, before and after image blur correction. [Figure 16] FIG. 10 is a cross-sectional view of the zoom lens of Example 6 at the wide-angle end (focal length 8 mm) and in a state focused at infinity. [Figure 17] 10A to 10C are longitudinal aberration diagrams of the zoom lens of Example 6 at infinity focus at (a) the wide-angle end, (b) a middle zoom position (focal length 91 mm), and (c) the telephoto end (focal length 1040 mm). [Figure 18] 13A and 13B are lateral aberration diagrams of the zoom lens of Example 6 at the telephoto end and in an infinity-focused state, respectively, before and after image blur correction. [Figure 19] FIG. 1 is a distribution map of existing optical materials. [Figure 20] FIG. 1 is a diagram illustrating the configuration of an imaging device equipped with a zoom lens according to any one of Examples 1 to 6. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Prior to describing specific Examples 1 to 6, we will explain matters common to the zoom lenses of each Example. In a zoom lens, a lens group is a group of one or more lenses that move together on the optical axis during zooming between the wide-angle end and the telephoto end. That is, the spacing between adjacent lens groups changes during zooming. The lens group may include an aperture stop. The wide-angle end and the telephoto end refer to zoom states with the maximum angle of view (shortest focal length) and the minimum angle of view (maximum focal length), respectively, when the lens group that moves during zooming is located at both ends of the range of movement on the optical axis that is mechanically or controllably possible.

[0012] The zoom lens in each embodiment is a positive-lead type zoom lens in which a first lens group having positive refractive power is positioned closest to the object side, and the zoom lens has, on the image side of the first lens group, two or more variable power lens groups (lens groups that move during magnification variation) including at least one negative lens group, and a rear lens group.

[0013] The zoom lens of each embodiment has features such as the power arrangement within the zoom lens and the properties of the optical materials of the lenses that make up each lens group, in order to achieve a high zoom ratio and high optical performance across the entire zoom range from the visible wavelength range to the near-infrared wavelength range. As a result, a zoom lens is provided that has a zoom ratio of about 20 to 130 times and excellent correction of lateral chromatic aberration from the visible wavelength range to the near-infrared wavelength range.

[0014] In the zoom lens of each embodiment, focus adjustment (focusing) can be performed by moving the entire or part of the first lens group in the optical axis direction.

[0015] Referring to FIG. 1, the zoom lens of each embodiment includes a first lens group U1 with positive refractive power, located closest to the object and not moving for zooming. It also includes a first movable lens group (U2) with negative refractive power, located closer to the image than the first lens group U1 and moving for zooming, and a second movable lens group (U3) located closer to the image than the first movable lens group and moving for zooming. It also includes an aperture stop (SP) and a rear lens group (UR) located closer to the image than the second movable lens group. DG denotes dummy glass, and is typically equivalent to the optical resolution optical system of a three-chip camera. The image plane IP is where the imaging surface (light-receiving surface) of the image sensor and the film surface (photosensitive surface) of the silver halide film are located.

[0016] Furthermore, the rear lens group UR of the zoom lens of each embodiment includes a sub-lens group (rear sub-lens group URs) with negative refractive power composed of two or three lenses adjacent to each other, and the rear sub-lens group URs has at least one positive lens and one negative lens.

[0017] When the Abbe number of a specific negative lens (first negative lens) included in the rear sub-lens group URs with respect to the d-line is νdN, the partial dispersion ratio of the first negative lens from the C-line to the t-line is θctN, the average Abbe number of at least one positive lens included in the rear sub-lens group URs with respect to the d-line is νdp, the average Abbe number of at least one negative lens included in the rear sub-lens group URs with respect to the d-line is νdn, the average partial dispersion ratio of at least one positive lens included in the rear sub-lens group URs from the C-line to the t-line is θctp, and the average partial dispersion ratio of at least one negative lens included in the rear sub-lens group URs from the C-line to the t-line is θctn, 0.4958≦θctN−0.00417×νdN≦0.5635 (1) -4.0×10 -3 ≦(θctn-θctp) / (νdp-νdn)≦4.0×10 -3 ···(2) -40≦νdp-νdn≦0 (3) The following condition is satisfied.

[0018] Conditional expressions (1) to (3) indicate preferable relationships regarding the optical materials constituting the at least one positive lens and the at least one negative lens included in the rear sub-lens group URs.

[0019] Conditional formula (1) indicates an appropriate relationship between the Abbe number and partial dispersion ratio of the first negative lens, which is advantageous for correcting axial chromatic aberration in the near-infrared wavelength region. Conditional formulas (2) and (3) indicate appropriate relationships between the average values ​​of the Abbe number and partial dispersion ratio of at least one positive lens and at least one negative lens (optical material forming the lenses) included in the rear sub-lens group URs.

[0020] The Abbe number and partial dispersion ratio are indices that indicate the magnitude of dispersion and the magnitude of anomalous dispersion of an optical material, respectively. The Abbe number νd based on the d-line of an optical material is given by Nd, NC, and NF, respectively, when the refractive indices of the optical material at the d-line (wavelength 587.6 nm), C-line (wavelength 656.3 nm), and F-line (wavelength 486.1 nm) are: νd=(Nd-1) / (NF-NC) is defined as:

[0021] Furthermore, the partial dispersion ratio θct from the C-line to the t-line of an optical material is expressed as follows, when the refractive index of the optical material at the t-line (1014.0 nm) is Nt: θct=(NC-Nt) / (NF-NC) The values ​​of the Abbe number νd and the partial dispersion ratio θct can be easily found from the catalogs of each glass manufacturer.

[0022] Here, the relationship between the Abbe number vd, partial dispersion ratio θct, and chromatic aberration correction will be explained. As shown in Figure 19, the Abbe number vd of existing optical materials is distributed over a narrow range, and the larger the Abbe number vd, the larger the partial dispersion ratio θct tends to be. The axial chromatic aberration coefficient L and the lateral chromatic aberration coefficient T of a thin, closely-coupled system consisting of two lenses, a lens Gp with a positive refractive power Φp and a lens Gn with a negative refractive power Φn, are expressed by the following equations (A) to (C). L=h×h×(Φp / νdp+Φn / νdn) (A) T=h×H×(Φp / νdp+Φn / νdn) (a) Φ=Φp+Φn (c) Here, νdp is the Abbe number based on the d-line of the lens Gp, νdn is the Abbe number based on the d-line of the lens Gn, h is the incident height of the axial paraxial ray, and H is the incident height of the pupil paraxial ray.

[0023] An axial paraxial ray is defined as a paraxial ray that is incident on the optical system parallel to the optical axis at an incident height of 1, with the focal length at the wide-angle end of the entire optical system normalized to 1. Additionally, a pupil paraxial ray is defined as a paraxial ray that is incident on the image plane at the maximum image height, and that passes through the intersection of the entrance pupil of the optical system and the optical axis, with the focal length at the wide-angle end of the entire optical system normalized to 1.

[0024] The refractive powers Φp and Φn of the lenses Gp and Gn are normalized so that Φ in equation (C) is 1. The same can be said for thin, close-contact systems consisting of three or more lenses. In equations (A) and (B), if L = 0 and T = 0, the imaging positions of the C-line and F-line coincide on the axis and on the image plane. Correcting chromatic aberration for two specific wavelengths in this way is generally called dual-wavelength achromatism (first-order spectral correction or first-order chromatic aberration correction). In particular, in high-magnification zoom lenses, the chromatic aberration of each lens group, i.e., L and T, are corrected to approximately zero in order to suppress fluctuations in chromatic aberration that occur during magnification changes.

[0025] In this case, when the object distance is infinity and a light beam is incident on the zoom lens, the amount of deviation of the axial chromatic aberration of the C-line relative to the t-line and the amount of deviation of the chromatic aberration of magnification are respectively defined as the second-order spectral amount of the axial chromatic aberration Δs and the second-order spectral amount of the chromatic aberration of magnification Δy. These are expressed as follows: Δs=-h×h×(θctp-θctn) / (νdp-νdn)×f (d) Δy=-h×H×(θctp-θctn) / (νdp-νdn)×Y (o) In equations (d) and (e), f is the focal length of the entire zoom lens system, and Y is the image height. θctp and θctn are the partial dispersion ratios from the C-line to the t-line of lenses Gp and Gn, respectively. In this way, correcting chromatic aberration for three specific wavelengths by adding a specific wavelength to the two wavelengths is generally called three-wavelength achromatism (second-order spectrum correction or second-order chromatic aberration correction).

[0026] Zoom lenses used in surveillance cameras and the like are required to have longer focal lengths, and as the focal length f in formula (d) increases, axial chromatic aberration tends to increase. Furthermore, with the use of large-format image sensors compatible with wavelengths from the visible to near-infrared ranges, lateral chromatic aberration tends to increase as the image height Y in formula (e) increases. Therefore, it is important to reduce the values ​​of formulas (d) and (e) by appropriately determining the refractive powers of the positive and negative lens groups that make up the zoom lens and the arrangement of optical materials.

[0027] By satisfying conditional expression (1), it becomes possible to provide a first negative lens element in the rear sub-lens unit URs that uses an optical material with low dispersion and a low partial dispersion ratio, thereby enabling excellent correction of the secondary spectrum of axial chromatic aberration, particularly in the near-infrared light region. Exceeding the upper limit of conditional expression (1) is not preferable because it increases the partial dispersion ratio of the first negative lens element, increasing axial chromatic aberration, particularly in the near-infrared light region at the wide-angle end, and degrading the optical performance of the zoom lens. If the lower limit of conditional expression (1) is not reached, then with currently available optical materials, a low refractive index and high partial dispersion material must be used for the first negative lens, which makes it difficult to achieve chromatic aberration in both the visible light region and the near-infrared light region, which is undesirable.

[0028] It is more preferable to set the numerical range of conditional expression (1) as follows: 0.5260≦θctN-0.00417×νdN≦0.5508 (1a) It is even more preferable to set the numerical range of conditional expression (1a) as follows: 0.5290≦θctN-0.00417×νdN≦0.5490 (1b)

[0029] By satisfying conditional expressions (2) and (3), it is possible to achieve both good first-order and second-order spectral correction of axial chromatic aberration in the near-infrared wavelength range by the positive and negative lenses included in the rear sub-lens group URs. If the upper limit of conditional expression (2) is exceeded, the positive and negative dispersion values ​​become too close, making first-order spectral correction difficult and resulting in insufficient correction of chromatic aberration in the visible wavelength range, which is undesirable. If the lower limit of conditional expression (2) is not reached, then with currently available optical materials, a difference will arise in the partial dispersion ratio between the positive lens element and the negative lens element, particularly in the near-infrared wavelength region, making secondary spectral correction difficult, and it will become difficult to achieve good correction of chromatic aberration in both the visible wavelength region and the near-infrared wavelength region, which is undesirable.

[0030] It is more preferable to set the numerical range of conditional expression (2) as follows: -2.8×10 -3 ≦(θctn-θctp) / (νdp-νdn)≦3.2×10 -3 (2a) It is even more preferable to set the numerical range of conditional expression (2a) as follows: -2.0×10 -3 ≦(θctn-θctp) / (νdp-νdn)≦0.2×10 -3 (2b) Moreover, it is even more preferable to set the numerical range of conditional expression (2b) as follows: -1.5×10 -3 ≦(θctn-θctp) / (νdp-νdn)≦-0.8×10 -3 (2c)

[0031] Furthermore, exceeding the upper limit of conditional formula (3) is undesirable because it becomes difficult to separate the dispersion values ​​of the positive and negative lenses sufficiently with currently available optical materials, resulting in insufficient first-order spectral correction and increased chromatic aberration.On the other hand, falling below the lower limit of conditional formula (3) is undesirable because it becomes difficult to achieve good chromatic aberration correction due to insufficient second-order spectral correction in the visible and near-infrared wavelength regions.

[0032] It is more preferable to set the numerical range of conditional expression (3) as follows: -28≦νdp-νdn≦-5 (3a) It is even more preferable to set the numerical range of conditional expression (3a) as follows: -24≦νdp-νdn≦-12 (3b) Moreover, it is even more preferable to set the numerical range of conditional expression (3b) as follows: -18≦νdp-νdn≦-14 (3c)

[0033] The zoom lens of each embodiment simultaneously satisfies conditional expressions (1) to (3), and therefore, even though it is a high-magnification zoom lens particularly for surveillance applications, it can achieve good first- and second-order spectral correction of axial chromatic aberration throughout the entire zoom range, from the visible wavelength range to the near-infrared wavelength range.

[0034] It is preferable that the zoom lens of each embodiment satisfies at least one of the following conditional expressions (4) to (10) and configurations a to e. The Abbe number νdN of the first negative lens included in the rear sub-lens unit URs with respect to the d-line is 25≦νdN≦61 (4) It is preferable to satisfy the following condition:

[0035] Conditional expression (4) indicates an appropriate range for the Abbe number of the first negative lens. By satisfying conditional expression (4), it is possible to provide dispersion characteristics that are advantageous for first-order spectral correction of axial chromatic aberration, particularly in the visible to near-infrared wavelength range. If the upper limit of conditional expression (4) is exceeded, the refractive index becomes too low for currently available optical materials, making it impossible to provide the first negative lens with appropriate refractive power, resulting in insufficient correction of the Petzval sum, which is undesirable. If the lower limit of conditional expression (4) is not reached, the Abbe numbers of the positive lens and the negative lens cannot be sufficiently separated, which is unfavorable for first-order spectral correction of axial chromatic aberration, and is therefore undesirable.

[0036] It is more preferable to set the numerical range of conditional expression (4) as follows: 33≦νdN≦55 (4a) It is even more preferable to set the numerical range of conditional expression (4a) as follows: 43≦νdN≦52 (4b)

[0037] The refractive index NdN of the first negative lens included in the rear sub-lens group URs based on the d-line is 1.59≦NdN≦2.00 (5) It is preferable to satisfy the following condition:

[0038] Conditional expression (5) defines an appropriate range for the refractive index of the first negative lens. Satisfying conditional expression (5) is particularly effective in correcting curvature of field and astigmatism, and makes it possible to appropriately reduce the Petzval sum, which tends to remain positive throughout the entire zoom lens. Exceeding the upper limit of conditional expression (5) is undesirable because existing optical materials have too high dispersion, which is unfavorable for first-order spectral correction of axial chromatic aberration, whereas falling below the lower limit of conditional expression (5) is undesirable because the Petzval sum cannot be sufficiently reduced by the first negative lens, which is unfavorable for correction of field curvature and astigmatism.

[0039] It is more preferable to set the numerical range of conditional expression (5) as follows: 1.69≦NdN≦1.86 (5a) It is even more preferable to set the numerical range of conditional expression (5a) as follows: 1.70≦NdN≦1.80 (5b)

[0040] When the focal length of the rear sub-lens unit URs is fs and the focal length of the first negative lens is fNL, 0.6≦fNL / fs≦1.3 (6) It is preferable to satisfy the following condition:

[0041] Conditional expression (6) shows an appropriate relationship between the focal length of the first negative lens included in the rear sub-lens unit URs and the focal length of the rear sub-lens unit URs. By satisfying conditional expression (6), it is possible to give the first negative lens, which uses a glass material that is advantageous for correcting chromatic aberration in the near-infrared light region, an appropriate power, thereby making it possible to advantageously correct chromatic aberration in the visible light region to the near-infrared light region. If the upper limit of conditional expression (6) is exceeded, the first negative lens element will not have power, which is unfavorable for correcting the first-order spectrum of axial chromatic aberration, and if the lower limit of conditional expression (6) is exceeded, the radius of curvature of the first negative lens element will become excessively small, which is unfavorable because it will be difficult to suppress the occurrence of high-order aberrations in particular.

[0042] It is more preferable to set the numerical range of conditional expression (6) as follows: 0.62≦fNL / fs≦1.22 (6a) It is even more preferable to set the numerical range of conditional expression (6a) as follows: 0.76≦fNL / fs≦1.15 (6b) Moreover, it is even more preferable to set the numerical range of conditional expression (6b) as follows: 0.78≦fNL / fs≦1.10 (6c)

[0043] The rear sub-lens group URs is an image stabilizing lens group that can correct image blur by moving in a direction having a component perpendicular to the optical axis. When the lateral magnification of the rear sub-lens group URs is βs and the lateral magnification of the lens group disposed closer to the image side than the rear sub-lens group URs is βr, -1.40≦(1-βs)×βr≦-0.60 (7) It is preferable to satisfy the following condition:

[0044] A preferred embodiment in which the rear sub lens unit URs of the present invention is used as an image stabilizing lens unit will be described below. In the zoom lens of the present invention, it is preferable that the vibration reduction lens group is composed of one positive lens and one negative lens, or one positive lens and two negative lenses.

[0045] In order to effectively suppress the occurrence of decentration aberrations due to image stabilization drive as shown in equations (c) to (l) described below, it is preferable that the image stabilization lens group be configured to include a cemented lens formed by cementing a positive lens and a negative lens. This makes it easy to achieve an image stabilization lens group that is small and lightweight overall, while appropriately controlling the sensitivity to decentration aberrations using the cemented lens surface. Note that the image stabilization lens group does not necessarily have to be a cemented lens; a positive lens and a negative lens may each be incorporated into the lens barrel. Using a cemented lens offers advantages such as reduced aberration sensitivity and a simpler mechanism.

[0046] In television cameras, photographic cameras, etc., it becomes easy to insert optical systems such as optical filters and color separation prisms between the lens and the image pickup surface. Also, by providing a partial lens group with positive refractive power on the image side of the vibration-reduction lens group, it becomes easy to appropriately set the sensitivity to axis deviation for vibration reduction.

[0047] Next, the occurrence of decentering aberrations in the zoom lens of the present invention when a partial lens group in the optical system is decentered in a direction perpendicular to the optical axis will be described from the standpoint of aberration theory, based on the method disclosed in Non-Patent Document 1.

[0048] When a lens group (decentred lens group) p in a photographic lens is decentered in parallel by an amount E, the amount of aberration Δ′Y of the entire system is the sum of the amount of aberration ΔY before decentering and the amount of decentering aberration ΔY(E) caused by decentering, as shown in equation (a).

number

[0049] Here, the amount of decentering aberration ΔY(E) is expressed by the first-order decentering coma (IIE), the first-order decentering astigmatism (IIIE), the first-order decentering curvature of field (PE), the first-order decentering distortion (VE1), the first-order decentering additional distortion (VE2), and the first-order origin shift ΔE, as shown in formula (b).

number

[0050] Here, when the focal length of the entire system is normalized to 1, the angles of incidence and emergence of the axial marginal ray of the paraxial ray to the decentered lens group p are respectively α p , α p ', and the incident angle and the exit angle of the chief ray passing through the center of the pupil are respectively

number

number

number

number

number

number

number

[0051] Similarly, the amount of chromatic aberration ΔcYa of the entire system when the decentered lens unit p is decentered by E is the sum of the aberration ΔcY before the decentering and the aberration ΔcY(E) caused by the decentering, as shown in formula (i).

number

[0052] Here, the aberration ΔcY before parallel decentration and the decentration aberration ΔcY(E) can be expressed as formula (j) and formula (k), respectively, using the axial chromatic aberration L, the lateral chromatic aberration T, and the first-order decentration chromatic aberration coefficient TE.

number

number

[0053] As shown in equation (l), the first-order decentering chromatic aberration coefficient (TE) is the axial chromatic aberration coefficient L of the decentering lens unit p. p , lateral chromatic aberration coefficient T pand the axial chromatic aberration coefficient L of the entire lens group q, which is located closer to the image side than the parallel decentered lens group p, q , lateral chromatic aberration coefficient T q It can be expressed using:

number

[0054] Of these, the primary origin shift (ΔE) represents the displacement of the image due to decentering, while (IIE), (IIIE), (PE), and (TE) affect the imaging performance. In order to reduce the occurrence of decentering aberrations, it is first necessary to reduce the amount of decentering E of the decentered lens unit p, as shown in formula (b).

[0055] Secondly, in order to minimize the decentering aberration coefficients of the decentering lens unit p shown in equations (c) to (g), the various aberration coefficients I p , II p , III p , P p , V p It is necessary to set a small value or to set the various aberration coefficients in a balanced manner so that they cancel each other out. In particular, it is necessary to appropriately set the paraxial amounts and aberration coefficients of the decentered lens unit p that is decentered in parallel and the lens unit q that is arranged on the image side thereof so that the decentering aberration coefficients shown in the above equations (c) to (g) become small values.

[0056] That is, in order to suppress deterioration in image quality of the central image caused by vibration reduction (image blur correction), it is necessary to effectively correct primarily the first-order decentering coma aberration shown in formula (c). When the rear sub lens unit URs is defined as the decentering lens unit p and the lens unit located closer to the image side than the rear sub lens unit URs within the rear lens unit UR is defined as the lens unit q, it is preferable that the first-order decentering coma aberration coefficient (IIE) satisfy the following conditional formula (8): -0.080≦(IIE)≦0.080 (8)

[0057] Furthermore, in order to effectively correct degradation in image quality of peripheral images caused by image stabilization, it is necessary to effectively correct primarily the first-order decentering astigmatism shown in formula (d). When the rear sub lens unit URs is defined as a decentering lens unit p, and the lens unit within the rear lens unit UR that is located closer to the image than the rear sub lens unit URs is defined as a lens unit q, it is preferable that the first-order decentering astigmatism coefficient (IIIE) satisfy the following conditional formula (9): -0.060≦(IIIE)≦0.060 (9) Of course, it is also desirable to effectively correct other aberrations as well.

[0058] Third, in order to minimize the first-order decentration chromatic aberration coefficient (TE) shown in formula (l), it is necessary to appropriately set the chromatic aberration coefficient of the decentered lens unit p and the entire lens unit q arranged on the image side thereof. When the rear sub lens unit URs is the decentered lens unit p and the lens unit arranged on the image side of the rear sub lens unit UR within the rear lens unit UR is the lens unit q, it is preferable that the first-order decentration chromatic aberration coefficient (TE) satisfy the following conditional formula (10): -0.020≦(TE)≦0.020 (10) The zoom lens having an image stabilization function (image blur correction function) of the present invention is constructed taking into consideration the above items 1 to 3.

[0059] Next, we will explain the focus change that occurs when a partial system in the optical system is displaced along the optical axis. When a decentered lens unit p in the photographing lens is displaced by a predetermined amount δ along the optical axis, the focus movement amount ΔSK(δ) is calculated by multiplying the lateral magnification of the decentered lens unit p by β p , the lateral magnification of the lens unit q arranged on the image side of the decentered lens unit p is β q When

number

number

[0060] Therefore, in order to appropriately control the amount of movement ΔSK(δ), it is necessary to control the refractive power arrangement of the lens group q on the object side of the decentered lens group p in accordance with the refractive power of the partial lens group for image blur correction (the decentered lens group p). The zoom lens with image stabilization function of the present invention is configured taking the above points into consideration. Here, it can be seen from formula (m) that the lateral magnification of the lens group q arranged on the image side of the decentered lens group p also contributes to ΔSK(δ). The incident converted tilt angle α to the lens group q arranged on the image side of the decentered lens group p q is the output conversion tilt angle α from the decentered lens unit p p In the zoom lens of the present invention, the lens group q is the optical system arranged closest to the image side.

[0061] Therefore, the lateral magnification β p When is determined, the lateral magnification β q is also determined, the incident conversion tilt angle α p Furthermore, the decentering amount Ep of the decentering lens unit p required to obtain a predetermined image blur correction amount ΔY on the image plane is given by the formula (b) when R=0, ω=0, and α k This is expressed by the following equation, assuming ´=1.

number

[0062] Since the primary origin shift (ΔE) is expressed by equation (h), the decentering amount Ep required to obtain the required image blur correction amount ΔY is calculated by multiplying the incident tilt angle α of the axial marginal ray with respect to the decentered lens group p by p and the output conversion angle α´ pThe sensitivity described in this specification refers to Δ(δ) / δ, where the element of interest fluctuates by Δ(δ) when the lens thickness, radius of curvature, amount of lens decentering, etc. fluctuates by a small amount δ.

[0063] The movement sensitivity TS of the decentered lens unit p is expressed as β p , the lateral magnification of the lens unit q arranged closer to the image than the decentered lens unit p is β q Then, it can be expressed as follows:

number

[0064] Based on the relationships expressed by the above-mentioned equations, the decentering amount Ep and movement sensitivity TS of the decentered lens unit p when achieving the image blur correction amount ΔY on the image plane are set under mechanical constraints so as to maintain good optical performance before and after image vibration reduction.

[0065] Conditional expression (7) relates to the movement sensitivity during image stabilization expressed by expression (p). It shows the appropriate relationship between the lateral magnification βs of the rear sub lens group URs and the lateral magnification βr of the lens group q arranged on the image side of the rear sub lens group URs when the rear sub lens group URs is used as a decentered lens group p for image stabilization. By satisfying conditional expression (7), it is possible to achieve a desired amount of image blur correction on the image plane while keeping the amount of decentering of the rear sub lens group URs to a realistic value.

[0066] Exceeding the upper limit of conditional expression (7) is undesirable because the amount of decentering of the rear sub lens unit increases, which is detrimental to making the zoom lens smaller and lighter.Failing below the lower limit of conditional expression (7) is undesirable because the movement sensitivity of the rear sub lens unit URs and its sensitivity to aberrations increase, making it more difficult to correct optical performance in terms of realistic image stabilization drive control accuracy and manufacturing accuracy, which is detrimental to maintaining good optical performance before and after image stabilization.

[0067] It is more preferable to set the numerical range of conditional expression (7) as follows: -1.36≦(1-βs)×βr≦-0.69 (7a) It is even more preferable to set the numerical range of conditional expression (7a) as follows: -1.08≦(1-βs)×βr≦-0.78 (7b)

[0068] It is more preferable to set the numerical range of conditional expression (8) as follows: -0.060≦(IIE)≦0.060 (8a) It is more preferable to set the numerical range of conditional expression (8a) as follows: -0.050≦(IIE)≦0.050 (8b) It is more preferable to set the numerical range of conditional expression (8b) as follows: -0.032≦(IIE)≦0.032 (8c) It is even more preferable to set the numerical range of conditional expression (8c) as follows: -0.015≦(IIE)≦0.015 (8d)

[0069] It is more preferable to set the numerical range of conditional expression (9) as follows: -0.052≦(IIIE)≦0.052 (9a) It is more preferable to set the numerical range of conditional expression (9a) as follows: -0.045≦(IIIE)≦0.045 (9b) It is more preferable to set the numerical range of conditional expression (9b) as follows: -0.032≦(IIIE)≦0.032 (9c) It is more preferable to set the numerical range of conditional expression (9c) as follows: -0.026≦(IIIE)≦0.026 (9d)

[0070] It is more preferable to set the numerical range of conditional expression (10) as follows: -0.017≦(TE)≦0.017 (10a) It is more preferable to set the numerical range of conditional expression (10a) as follows: -0.014≦(TE)≦0.014 (10b) It is even more preferable to set the numerical range of conditional expression (10b) as follows: -0.012≦(TE)≦0.012 (10c) It is even more preferable to set the numerical range of conditional expression (10c) as follows: -0.007≦(TE)≦0.007 (10d) [Example]

[0071] FIG. 1 shows a cross-sectional view of a zoom lens according to Example 1 (Numerical Example 1) at the wide-angle end (focal length 25 mm) and in a state where the lens is focused at infinity. The zoom lens of Example 1 comprises, in order from the object side to the image side, a first lens unit U1 with positive refractive power that does not move for varying magnification, a variable magnification lens unit that moves for varying magnification, and a fourth lens unit U4 as a rear lens unit UR with positive refractive power that does not move for varying magnification and has an image-forming effect. The spacing between adjacent lens units all changes for varying magnification.

[0072] The first lens group U1 includes, in order from the object side to the image side, a first sub-lens group U11 with positive refractive power, a second sub-lens group U12 with positive refractive power, and a third sub-lens group U13 with negative refractive power. The second sub-lens group U12 moves toward the object side for focusing from the infinity side to the close-up side, and the spacing between adjacent sub-lens groups within the first lens group U1 changes during focusing.

[0073] The variable magnification lens group is composed of, from the object side to the image side, a second lens group U2 with negative refractive power and a third lens group U3 with negative refractive power. The second lens group U2 moves toward the image side when changing magnification from the wide-angle end to the telephoto end. The third lens group U3 moves along the optical axis in conjunction with the movement of the second lens group U2 to correct image plane fluctuations that occur when changing magnification.

[0074] The fourth lens group U4, which is the rear lens group UR, includes a rear sub-lens group URs. An aperture stop SP is located on the object side of the fourth lens group U4 (between the third lens group U3 and the fourth lens group U4). DG in FIG. 1 denotes a glass block (dummy glass) such as a prism or optical filter that does not have the refractive power equivalent to a camera optical system.

[0075] In the zoom lens of Example 1, the first lens unit U1 corresponds to surfaces 1 to 15. The second lens unit U2 corresponds to surfaces 16 to 24. The third lens unit U3 corresponds to surfaces 25 to 27. Surface 28 is an aperture stop SP. The fourth lens unit U4 corresponds to surfaces 29 to 54. Surfaces 55 to 57 are dummy glass DG. The first sub-lens group U11 corresponds to the first to ninth surfaces, the second sub-lens group U12 corresponds to the tenth to thirteenth surfaces, and the third sub-lens group U13 corresponds to the fourteenth to fifteenth surfaces.

[0076] In the zoom lens of Example 1, the rear sub-lens unit URs corresponds to surfaces No. 36 to No. 41 and is composed of three lenses, in order from the object side to the image side: a negative lens, a positive lens, and a negative lens. Of these, the negative lens represented by surfaces No. 36 to No. 37, which has a stronger negative refractive power, corresponds to the first negative lens that is advantageous for correcting chromatic aberration in the near-infrared wavelength range. The first negative lens in the zoom lens of the present invention may be a single lens, as in this example, or may be a cemented lens. This also applies to the other examples described below.

[0077] The effective diameters of the three lenses that make up the rear sub-lens group URs are 2.6 mm larger than the effective diameters of the lenses based on the desired F-number and peripheral illumination ratio. This is the amount of expansion in diameter that corresponds to an image stabilization shift of ±1.3 mm, which corresponds to image stabilization compensation of approximately 20% above and below the vertical screen dimension of the image sensor assumed in this embodiment, and appropriately avoids vignetting of light rays during image stabilization.

[0078] In the rear lens unit UR, the lens surfaces corresponding to the lens units in the rear sub-lens unit URs on the object side are surfaces No. 29 to No. 35. In the rear lens unit UR, the lens surfaces corresponding to the lens units arranged on the image side of the rear sub-lens unit URs are surfaces No. 42 to No. 54.

[0079] Table 1 summarizes the numerical values ​​corresponding to conditional expressions (1) to (10) in Numerical Example 1, which corresponds to Example 1. Numerical Example 1 satisfies all of conditional expressions (1) to (10). By optimizing the chromatic aberration correction and power arrangement of the rear sub-lens unit URs, high magnification and high optical performance are achieved, particularly suppression of fluctuations in axial chromatic aberration in the infrared wavelength range and good performance correction before and after image stabilization.

[0080] It is desirable for the zoom lens of the present invention to satisfy all of conditional expressions (1) to (10), but as long as conditional expressions (1) to (3) are satisfied, it is not necessary to satisfy all of conditional expressions (4) to (10). If at least one of conditional expressions (4) to (10) is satisfied in addition to satisfying conditional expressions (1) to (3), higher optical performance can be obtained.

[0081] Fig. 2(a) shows the longitudinal aberration (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end in Numerical Example 1, Fig. 2(b) shows the longitudinal aberration at the intermediate zoom position (focal length 175 mm), and Fig. 2(c) shows the longitudinal aberration at the telephoto end (focal length 500 mm). All of these figures show the longitudinal aberration when the lens is focused at infinity.

[0082] 3(a) shows the lateral aberration before image blur correction at the telephoto end in Numerical Example 1, and FIG. 3(b) shows the lateral aberration after image blur correction. The lateral aberration diagram after image blur correction shows the aberration in a corrected state after the rear sub lens unit URs is driven 1.3 mm in a direction perpendicular to the optical axis. Both diagrams show the lateral aberration in a state where the lens is focused at infinity.

[0083] In the spherical aberration diagram, Fno indicates the F-number, the solid line indicates spherical aberration for the d-line, and the two-dot chain line indicates spherical aberration for the g-line (wavelength 435.8 nm). The dot-dash line indicates spherical aberration for the C-line, the long dashed line indicates spherical aberration for the F-line, the short dashed line indicates spherical aberration for the t-line, and the thick solid line indicates spherical aberration for a wavelength of 1700 nm. In the astigmatism diagram, the solid line indicates astigmatism at the sagittal image plane, and the dashed line indicates astigmatism at the meridional image plane. The distortion diagram shows distortion for the d-line.

[0084] The chromatic aberration diagram shows lateral chromatic aberration at the d-line, g-line, C-line, F-line, and t-line, as well as at 1700 nm. ω is the half angle of view (°). The diagram also shows spherical aberration on a scale of 0.4 mm, astigmatism on a scale of 0.4 mm, distortion on a scale of 5%, and lateral chromatic aberration on a scale of 0.1 mm. As shown in Figures 2 and 3, all aberrations are well corrected. [Example]

[0085] FIG. 4 shows a cross-sectional view of the zoom lens of Example 2 (Numerical Example 2) at the wide-angle end (focal length 16 mm) and in a state where the lens is focused at infinity. The zoom lens of Example 2 comprises, in order from the object side to the image side, a first lens unit U1 with positive refractive power that does not move for varying magnification, a variable magnification lens unit that moves for varying magnification, and a fifth lens unit U5 as a rear lens unit UR with positive refractive power that does not move for varying magnification and has an imaging function. The spacing between adjacent lens units all changes for varying magnification.

[0086] The first lens group includes, from the object side to the image side, a first sub-lens group U11 with positive refractive power that does not move for focusing, and a second sub-lens group U12 with positive refractive power that moves toward the object side for focusing from the infinity side to the close-up side. Within the first lens group U1, the spacing between adjacent sub-lens groups changes for focusing.

[0087] The variable magnification lens group is composed of, from the object side to the image side, a second lens group U2 with negative refractive power, a third lens group U3 with negative refractive power, and a fourth lens group U4 with positive refractive power. The second lens group U2 moves toward the image side when changing magnification from the wide-angle end to the telephoto end. The third lens group U3 moves toward the image side when changing magnification from the wide-angle end to the telephoto end. The fourth lens group U4 moves along the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3 to correct image plane fluctuations that occur when changing magnification.

[0088] The fifth lens unit U5, which is the rear lens unit UR, includes a rear sub-lens unit URs. An aperture stop SP is disposed in the fifth lens unit U5.

[0089] In Example 2, the first lens group U1 corresponds to surfaces 1 to 14. The second lens group U2 corresponds to surfaces 15 to 24. The third lens group U3 corresponds to surfaces 25 to 29. The fourth lens group U4 corresponds to surfaces 30 to 31. The fifth lens group U5 corresponds to surfaces 32 to 52. Of these, surface 35 is an aperture stop SP. Surfaces 53 to 55 are dummy glass DG. The first sub-lens group U11 corresponds to the first to eighth surfaces, and the second sub-lens group U12 corresponds to the ninth to fourteenth surfaces, respectively.

[0090] In this embodiment, the rear sub-lens unit URs corresponds to surfaces No. 36 to No. 40, and is composed of, in order from the object side to the image side, three lenses: a cemented lens consisting of a negative lens and a positive lens, and a negative lens. Of these, the negative lens represented by surfaces Nos. 36 to 37, which has a stronger negative refractive power, corresponds to the first negative lens that is advantageous for correcting chromatic aberration in the near-infrared wavelength range.

[0091] The effective diameters of the three lenses that make up the rear sub-lens group URs are 2.74 mm larger than the effective diameters of the lenses based on the desired F-number and peripheral illumination ratio. This is the amount of expansion in diameter that corresponds to an image stabilization shift of ±1.37 mm, which corresponds to image stabilization compensation of approximately 20% above and below the vertical screen dimension of the image sensor assumed in this embodiment, and appropriately avoids vignetting of light rays during image stabilization.

[0092] In the rear lens unit UR, the lens surfaces corresponding to the lens units arranged on the object side of the rear sub-lens unit URs are surfaces No. 32 to No. 34. In the rear lens unit UR, the lens surfaces corresponding to the lens units arranged on the image side of the rear sub-lens unit URs are surfaces No. 41 to No. 52.

[0093] Table 1 summarizes the numerical values ​​corresponding to conditional expressions (1) to (10) in Numerical Example 2, which corresponds to Example 2. Numerical Example 2 satisfies all of conditional expressions (1) to (10). By optimizing the chromatic aberration correction and power arrangement of the rear sub-lens unit URs, it is possible to achieve high magnification and high optical performance, particularly suppression of fluctuations in axial chromatic aberration in the infrared wavelength range, and good performance correction before and after image stabilization.

[0094] Fig. 5(a) shows the longitudinal aberration (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end in Numerical Example 2, Fig. 5(b) shows the longitudinal aberration at the intermediate zoom position (focal length 111.84 mm), and Fig. 5(c) shows the longitudinal aberration at the telephoto end (focal length 768 mm). All of these figures show the longitudinal aberration when the lens is focused at infinity.

[0095] Fig. 6(a) shows the lateral aberration before image blur correction at the telephoto end in Numerical Example 2, and Fig. 6(b) shows the lateral aberration after image blur correction. The lateral aberration diagram after image blur correction shows the aberration in a corrected state after the rear sub-lens unit URs is driven 1.37 mm in a direction perpendicular to the optical axis. Both diagrams show the lateral aberration in a state where the lens is focused at infinity.

[0096] In the aberration diagrams in Figures 5 and 6, spherical aberration is plotted on a scale of 0.4 mm, astigmatism on a scale of 0.4 mm, distortion on a scale of 5%, and lateral chromatic aberration on a scale of 0.1 mm. As shown in Figures 5 and 6, all aberrations are well corrected. [Example]

[0097] FIG. 7 shows a cross-sectional view of the zoom lens of Example 3 (Numerical Example 3) at the wide-angle end (focal length 14.3 mm) and in a state where the lens is focused at infinity. The zoom lens of Example 3 comprises, in order from the object side to the image side, a first lens unit U1 with positive refractive power that does not move for varying magnification, a variable magnification lens unit that moves for varying magnification, and a fifth lens unit U5 with positive refractive power that does not move for varying magnification but has an imaging function. The spacing between adjacent lens units all changes for varying magnification.

[0098] The first lens group U1 includes, in order from the object side to the image side, a first sub-lens group U11 with positive refractive power that does not move for focusing, and a second sub-lens group U12 with positive refractive power that moves toward the object side for focusing from the infinity side to the close-up side. Within the first lens group U1, the spacing between adjacent sub-lens groups changes for focusing.

[0099] The variable magnification lens group is composed of, from the object side to the image side, a second lens group U2 with negative refractive power, a third lens group U3 with positive refractive power, and a fourth lens group U4 with positive refractive power. The second lens group U2 moves toward the image side when changing magnification from the wide-angle end to the telephoto end. The third lens group U3 moves toward the object side when changing magnification from the wide-angle end to the telephoto end. The fourth lens group U4 moves along the optical axis in conjunction with the movement of the second lens group U2 and the third lens group U3 to correct image plane fluctuations that occur when changing magnification.

[0100] The fifth lens unit U5 as the rear lens unit UR includes a rear sub-lens unit URs. An aperture stop SP is disposed between the fourth lens unit U4 and the fifth lens unit U5.

[0101] In Example 3, the first lens unit U1 corresponds to surfaces 1 to 14. The second lens unit U2 corresponds to surfaces 15 to 24. The third lens unit U3 corresponds to surfaces 25 to 30. The fourth lens unit U4 corresponds to surfaces 31 to 35. Surface 36 is an aperture stop SP. The fifth lens unit U5 corresponds to surfaces 37 to 58. Surfaces 59 to 61 are dummy glass DG. The first sub-lens group U11 corresponds to the first to eighth surfaces, and the second sub-lens group U12 corresponds to the ninth to fourteenth surfaces, respectively.

[0102] In this embodiment, the rear sub-lens unit URs corresponds to surfaces No. 37 to No. 42, and is composed of, in order from the object side to the image side, three lenses: a negative lens, a positive lens, and a negative lens. Of these, the negative lens represented by surfaces No. 41 to No. 42, which has a stronger negative refractive power, corresponds to the first negative lens that is advantageous for correcting chromatic aberration in the near-infrared wavelength range.

[0103] The effective diameters of the three lenses that make up the rear sub-lens group URs are 3.10 mm larger than the effective diameters of the lenses based on the desired F-number and peripheral illumination ratio. This is the amount of expansion in diameter that corresponds to an image stabilization shift of ±1.55 mm, which corresponds to image stabilization compensation of approximately 20% above and below the vertical screen dimension of the image sensor assumed in this embodiment, and appropriately avoids vignetting of light rays during image stabilization. The lens surfaces corresponding to the lens units in the rear lens unit UR that are arranged closer to the image side than the rear sub-lens unit URs are surfaces Nos. 43 to 58.

[0104] Table 1 summarizes the numerical values ​​corresponding to conditional expressions (1) to (10) in Numerical Example 3, which corresponds to Example 3. Numerical Example 3 satisfies all of conditional expressions (1) to (10). By optimizing the chromatic aberration correction and power arrangement of the rear sub-lens unit URs, it is possible to achieve high magnification and high optical performance, particularly suppression of fluctuations in axial chromatic aberration in the infrared wavelength range, and good performance correction before and after image stabilization.

[0105] Fig. 8(a) shows the longitudinal aberration (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end in Numerical Example 3, Fig. 8(b) shows the longitudinal aberration at the intermediate zoom position (focal length 155.9 mm), and Fig. 8(c) shows the longitudinal aberration at the telephoto end (focal length 1287 mm). All of these figures show the longitudinal aberration when the lens is focused at infinity.

[0106] 9(a) shows the lateral aberration before image blur correction at the telephoto end in Numerical Example 3, and FIG. 9(b) shows the lateral aberration after image blur correction. The lateral aberration diagram after image blur correction shows the aberration in a corrected state after the rear sub lens unit URs is driven 1.55 mm in a direction perpendicular to the optical axis. Both diagrams show the lateral aberration in a state where the lens is focused at infinity.

[0107] In the aberration diagrams in Figures 8 and 9, spherical aberration is plotted on a scale of 0.4 mm, astigmatism on a scale of 0.4 mm, distortion on a scale of 5%, and lateral chromatic aberration on a scale of 0.1 mm. As shown in Figures 8 and 9, all aberrations are well corrected. [Example]

[0108] FIG. 10 shows a cross-sectional view of the zoom lens of Example 4 (Numerical Example 4) at the wide-angle end (focal length 45 mm) and in a state where the lens is focused at infinity. The zoom lens of Example 4 comprises, in order from the object side to the image side, a first lens unit U1 with positive refractive power that does not move for varying magnification, a variable magnification lens unit that moves for varying magnification, and a fourth lens unit U4 as a rear lens unit UR with positive refractive power that does not move for varying magnification and has an imaging function. The spacing between adjacent lens units all changes for varying magnification.

[0109] The first lens group U1 includes, in order from the object side to the image side, a first sub-lens group U11 with positive refractive power that does not move for focusing, and a second sub-lens group U12 with positive refractive power that moves toward the object side for focusing from the infinity side to the close-up side. Within the first lens group U1, the spacing between adjacent sub-lens groups changes for focusing.

[0110] The variable magnification lens group is composed of, from the object side to the image side, a second lens group U2 with negative refractive power and a third lens group U3 with negative refractive power. The second lens group U2 moves toward the image side when changing magnification from the wide-angle end to the telephoto end. The third lens group U3 moves along the optical axis in conjunction with the movement of the second lens group U2 to correct image plane fluctuations that occur during magnification.

[0111] The fourth lens unit U4, which is the rear lens unit UR, includes a rear sub-lens unit URs. An aperture stop SP is also disposed in the fourth lens unit U4.

[0112] In Example 4, the first lens unit U1 corresponds to surfaces 1 to 12. The second lens unit U2 corresponds to surfaces 13 to 20. The third lens unit U3 corresponds to surfaces 21 to 23. The fourth lens unit U4 corresponds to surfaces 24 to 48. Of these, surface 34 is an aperture stop SP. The first sub-lens group U11 corresponds to the first to eighth surfaces, and the second sub-lens group U12 corresponds to the ninth to twelfth surfaces, respectively.

[0113] In this embodiment, the rear sub-lens unit URs corresponds to surfaces No. 35 to No. 37, and is composed of, in order from the object side to the image side, two lenses: a positive lens and a negative lens. The first negative lens, which is advantageous for correcting chromatic aberration in the near-infrared wavelength range, corresponds to the negative lens indicated by surfaces No. 36 to No. 37.

[0114] The effective diameters of the two lenses that make up the rear sub-lens group URs are 6.92 mm larger than the effective diameters of the lenses based on the desired F-number and peripheral illumination ratio. This is the amount of expansion in diameter that corresponds to an image stabilization shift of ±3.46 mm, which corresponds to image stabilization compensation of approximately 20% above and below the vertical screen dimension of the image sensor assumed in this embodiment, and appropriately avoids vignetting of light rays during image stabilization. In the rear lens unit UR, the lens surfaces corresponding to the lens units arranged closer to the object side than the rear sub-lens unit URs are surfaces No. 24 to No. 33. In the rear lens unit UR, the lens surfaces corresponding to the lens units arranged closer to the image side than the rear sub-lens unit URs are surfaces No. 38 to No. 48.

[0115] Numerical values ​​corresponding to conditional expressions (1) to (10) in Numerical Example 4 corresponding to Example 4 are summarized in Table 1. Numerical Example 4 satisfies all of conditional expressions (1) to (10). By optimizing the chromatic aberration correction and power arrangement of the rear sub-lens unit URs, it is possible to achieve high magnification and high optical performance, particularly suppression of fluctuations in axial chromatic aberration in the infrared wavelength range, and good performance correction before and after image stabilization.

[0116] Fig. 11(a) shows the longitudinal aberration (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end in Numerical Example 4, Fig. 11(b) shows the longitudinal aberration at the intermediate zoom position (focal length 270 mm), and Fig. 11(c) shows the longitudinal aberration at the telephoto end (focal length 1000 mm). All of these figures show the longitudinal aberration when the lens is focused at infinity.

[0117] Fig. 12(a) shows the lateral aberration before image blur correction at the telephoto end in Numerical Example 4, and Fig. 12(b) shows the lateral aberration after image blur correction. The lateral aberration diagram after image blur correction shows the aberration in a corrected state after the rear sub lens unit URs is driven 3.46 mm in a direction perpendicular to the optical axis. Both diagrams show the lateral aberration in a state where the lens is focused at infinity.

[0118] In the aberration diagrams in Figures 11 and 12, spherical aberration is plotted on a scale of 1.0 mm, astigmatism on a scale of 1.0 mm, distortion on a scale of 5%, and lateral chromatic aberration on a scale of 0.25 mm. As shown in Figures 11 and 12, all of the aberrations are well corrected. [Example]

[0119] FIG. 13 shows a cross-sectional view of the zoom lens of Example 5 (Numerical Example 5) at the wide-angle end (focal length 11.5 mm) and in a state where the lens is focused at infinity. The zoom lens of Example 5 comprises, in order from the object side to the image side, a first lens unit U1 with positive refractive power that does not move for varying magnification, a variable magnification lens unit that moves for varying magnification, and a fifth lens unit U5 as a rear lens unit UR with positive refractive power that does not move for varying magnification and has an imaging function. The spacing between adjacent lens units all changes for varying magnification.

[0120] The first lens group U1 includes, in order from the object side to the image side, a first sub-lens group U11 with positive refractive power that does not move for focusing, and a second sub-lens group U12 with positive refractive power that moves toward the object side for focusing from the infinity side to the close-up side. Within the first lens group U1, the spacing between adjacent sub-lens groups changes for focusing.

[0121] The variable magnification lens group is composed of, from the object side to the image side, a second lens group U2 with negative refractive power, a third lens group U3 with negative refractive power, and a fourth lens group U4 with positive refractive power. The second lens group U2 moves toward the image side when changing magnification from the wide-angle end to the telephoto end. The third lens group U3 moves when changing magnification from the wide-angle end to the telephoto end. The fourth lens group U4 moves in the optical axis direction in conjunction with the movement of the second lens group U2 and the third lens group U3 to correct image plane fluctuations that occur when changing magnification.

[0122] The fifth lens unit U5, which is the rear lens unit UR, includes a rear sub-lens unit URs. An aperture stop SP is disposed on the object side of the fourth lens unit U4, and moves together with the fourth lens unit U4 in the optical axis direction along the same locus.

[0123] In Example 5, the first lens unit U1 corresponds to surfaces 1 to 12. The second lens unit U2 corresponds to surfaces 13 to 20. The third lens unit U3 corresponds to surfaces 21 to 25. The aperture stop corresponds to surface 26. The fourth lens unit U4 corresponds to surfaces 27 to 28. The fifth lens unit U5 corresponds to surfaces 29 to 47. The first sub-lens group U11 corresponds to the first to sixth surfaces, and the second sub-lens group U12 corresponds to the seventh to twelfth surfaces, respectively.

[0124] In this embodiment, the rear sub-lens unit URs corresponds to surfaces No. 34 to No. 39, and is composed of, in order from the object side to the image side, three lenses: a negative lens, a positive lens, and a negative lens. Of these, the negative lenses represented by surfaces No. 38 to No. 39, which have stronger negative refractive power, correspond to the first negative lens that is advantageous for correcting chromatic aberration in the near-infrared wavelength range.

[0125] The effective diameters of the three lenses that make up the rear sub-lens group HRs are 2.2 mm larger than the effective diameters of the lenses based on the desired F-number and peripheral illumination ratio. This is the amount of expansion in diameter that corresponds to an image stabilization shift of ±1.1 mm, which corresponds to image stabilization compensation of approximately 20% above and below the vertical screen dimension of the image sensor assumed in this embodiment, and appropriately avoids vignetting of light rays during image stabilization. The lens surfaces corresponding to the lens groups in the rear lens unit UR that are located closer to the object side than the rear sub lens unit URs are surfaces No. 29 to No. 33. The lens surfaces corresponding to the lens groups in the rear lens unit UR that are located closer to the image side than the rear sub lens unit URs are surfaces No. 40 to No. 47.

[0126] Numerical values ​​corresponding to conditional expressions (1) to (10) in Numerical Example 5 corresponding to Example 5 are summarized in Table 1. Numerical Example 5 satisfies all of conditional expressions (1) to (10). By optimizing the chromatic aberration correction and power arrangement of the rear sub-lens unit URs, it is possible to achieve high magnification and high optical performance, particularly suppression of fluctuations in axial chromatic aberration in the infrared wavelength range, and good performance correction before and after image stabilization.

[0127] Fig. 14(a) shows the longitudinal aberration (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end in Numerical Example 5, Fig. 14(b) shows the longitudinal aberration at the intermediate zoom position (focal length 58.46 mm), and Fig. 14(c) shows the longitudinal aberration at the telephoto end (focal length 300 mm). All of these figures show the longitudinal aberration when the lens is focused at infinity.

[0128] Figure 15(a) shows the lateral aberration before image blur correction at the telephoto end in Numerical Example 5, and Figure 15(b) shows the lateral aberration after image blur correction. The lateral aberration diagram after image blur correction shows the aberration in a corrected state after the rear sub lens unit URs is driven 1.1 mm in a direction perpendicular to the optical axis. Both diagrams show the lateral aberration in a state where the lens is focused at infinity.

[0129] In the aberration diagrams of Figures 14 and 15, spherical aberration is plotted on a scale of 0.4 mm, astigmatism on a scale of 0.4 mm, distortion on a scale of 5%, and lateral chromatic aberration on a scale of 0.1 mm. As shown in Figures 14 and 15, all aberrations are well corrected. [Example]

[0130] FIG. 16 shows a cross-sectional view of the zoom lens of Example 6 (Numerical Example 6) at the wide-angle end (focal length 8 mm) and in a state where the lens is focused at infinity. The zoom lens of Example 6 comprises, in order from the object side to the image side, a first lens unit U1 with positive refractive power that does not move for varying magnification, a variable magnification lens unit that moves for varying magnification, and a fifth lens unit U5 as a rear lens unit UR with positive refractive power that does not move for varying magnification and has an imaging function. The distances between adjacent lens units all change for varying magnification.

[0131] The first lens group includes, from the object side to the image side, a first sub-lens group U11 with positive refractive power, a second sub-lens group U12 with positive refractive power, and a third sub-lens group U13 with positive refractive power. During focusing from the infinity side to the close-up side, the second sub-lens group U12 and the third sub-lens group U13 move toward the object side along different trajectories. Within the first lens group U1, the spacing between adjacent sub-lens groups all changes during focusing.

[0132] The variable magnification lens unit U1 is composed of, from the object side to the image side, a second lens unit U2 with negative refractive power, a third lens unit U3 with positive refractive power, and a fourth lens unit U4 with positive refractive power. The second lens unit U2 moves toward the image side when changing magnification from the wide-angle end to the telephoto end. The third lens unit U3 moves toward the image side when changing magnification from the wide-angle end to the telephoto end. The fourth lens unit U4 moves along the optical axis in conjunction with the movement of the second lens unit U2 and the third lens unit U3 to correct image plane fluctuations that occur when changing magnification.

[0133] The fifth lens unit U5, which is the rear lens unit UR, includes a rear sub-lens unit URs. An aperture stop SP is disposed between the fourth lens unit U4 and the fifth lens unit U5.

[0134] In Example 6, the first lens unit U1 corresponds to surfaces 1 to 14. The second lens unit U2 corresponds to surfaces 15 to 24. The third lens unit U3 corresponds to surfaces 25 to 30. The fourth lens unit U4 corresponds to surfaces 31 to 35. The aperture stop is surface 36. The fifth lens unit U5 corresponds to surfaces 37 to 58. The first sub-lens group U11 corresponds to the first to eighth surfaces, the second sub-lens group U12 corresponds to the ninth to twelfth surfaces, and the third sub-lens group U13 corresponds to the thirteenth and fourteenth surfaces.

[0135] In this embodiment, the rear sub-lens unit URs corresponds to surfaces No. 37 to No. 42, and is composed of, in order from the object side to the image side, three lenses: a negative lens, a positive lens, and a negative lens. Of these, the negative lens corresponding to surfaces No. 37 to No. 38, which has a stronger negative refractive power, corresponds to the first negative lens, which is advantageous for correcting chromatic aberration in the near-infrared wavelength region.

[0136] The effective diameters of the three lenses that correspond to the rear sub-lens group URs are 1.6 mm larger than the effective diameters of the lenses based on the desired F-number and peripheral illumination ratio. This is the amount of expansion in diameter that corresponds to an image stabilization shift of ±0.8 mm, which corresponds to image stabilization compensation of approximately 20% above and below the vertical screen dimension of the image sensor assumed in this embodiment, and appropriately avoids vignetting of light rays during image stabilization. The lens surfaces corresponding to the lens groups in the rear lens group UR that are located closer to the image side than the rear sub-lens group URs are surfaces No. 43 to No. 58.

[0137] Numerical values ​​corresponding to conditional expressions (1) to (10) in Numerical Example 6 corresponding to Example 6 are summarized in Table 1. Numerical Example 6 satisfies all of conditional expressions (1) to (10). By optimizing the chromatic aberration correction and power arrangement of the rear sub-lens unit URs, it is possible to achieve high magnification and high optical performance, particularly suppression of fluctuations in axial chromatic aberration in the infrared wavelength range, and good performance correction before and after image stabilization.

[0138] 17(a) shows the longitudinal aberration (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end in Numerical Example 6, FIG. 17(b) shows the longitudinal aberration at the intermediate zoom position (focal length 91 mm), and FIG. 17(c) shows the longitudinal aberration at the telephoto end (focal length 1040 mm). All of these figures show the longitudinal aberration when the lens is focused at infinity.

[0139] 18(a) shows the lateral aberration before image blur correction at the telephoto end in Numerical Example 6, and FIG. 18(b) shows the lateral aberration after image blur correction. The lateral aberration diagram after image blur correction shows the aberration in a corrected state in which the rear sub lens unit URs is driven 0.8 mm in a direction perpendicular to the optical axis. Both diagrams show the lateral aberration in a state where the lens is focused at infinity.

[0140] In the aberration diagrams of Figures 17 and 18, spherical aberration is plotted on a scale of 0.4 mm, astigmatism on a scale of 0.4 mm, distortion on a scale of 5%, and lateral chromatic aberration on a scale of 0.1 mm. As shown in Figures 17 and 18, all aberrations are well corrected.

[0141] (Numerical example) Numerical Examples 1 to 6 corresponding to Examples 1 to 6 are shown below. In each numerical example, for surface number i from the object side, the paraxial radius of curvature r (mm) of each surface, the distance d (mm) on the optical axis between each surface and the next surface, the refractive index nd of the optical material between each surface and the next surface for the d-line, the Abbe number vd, and the partial dispersion ratio θct from the C-line to the t-line are listed.

[0142] BF represents back focus (mm). Back focus is the distance on the optical axis from the final surface of the zoom lens (the lens surface closest to the image, including the dummy glass) to the paraxial image plane. The total lens length (mm) is the distance on the optical axis from the frontmost surface of the zoom lens (the lens surface closest to the object) to the final surface plus the back focus. An "*" next to a surface number means that the surface has an aspherical shape.

[0143] The aspherical shape is expressed by the following formula, where X is the displacement from the vertex of the surface in the optical axis direction, H is the height from the optical axis in a direction perpendicular to the optical axis, the direction of light travel is positive, R is the paraxial radius of curvature, k is the conic constant, and A4, A6, A8, A10, and A12 are aspherical coefficients. Also, "eZ" is "×10 -Z " means.

number

[0144] [Numerical Example 1] Unit: mm Surface Data Surface number rd nd vd θct Effective diameter 1 158.463 9.48 1.48749 70.2 0.8924 100.85 2 662.376 0.20 99.30 3 86.146 16.00 1.43387 95.1 0.8091 96.09 4 986.180 5.11 94.70 5 95.481 2.80 1.65160 58.5 0.8525 84.04 6 55.983 15.38 1.43875 94.9 0.8373 76.89 7 259.572 4.85 74.85 8 -3409.091 2.40 1.75500 52.3 0.8092 73.01 9 70.182 14.29 67.49 10 89.436 8.00 1.43387 95.1 0.8091 66.71 11 10221.472 0.20 66.25 12 75.597 7.25 1.43387 95.1 0.8091 63.36 13 289.201 1.48 62.26 14 125.140 2.50 1.65100 56.2 0.8345 59.80 15 104.794 (variable) 57.95 16 110.275 0.90 1.75106 43.1 0.7097 25.12 17 18.874 4.17 22.34 18 118.472 5.50 1.73800 32.3 0.7154 22.10 19 -19.429 0.80 1.69930 51.1 0.7593 21.75 20 34.764 0.30 20.33 21 20.494 3.28 1.67300 38.3 0.7481 20.32 22 95.304 1.80 19.83 23 -45.147 0.80 1.59522 67.7 0.7953 19.71 24 55.269 (variable) 19.19 25 -44.219 0.80 1.69930 51.1 0.7593 17.93 26 42.014 2.29 1.85478 24.8 0.6739 18.62 27 185.687 (variable) 18.90 28 (Aperture) ∞ 0.50 26.23 29 62.014 6.05 1.59522 67.7 0.7953 27.13 30* -36.953 0.15 27.33 31 857.496 3.02 1.43875 94.7 0.8410 26.49 32 -60.960 0.20 26.16 33 78.864 5.84 1.43875 94.7 0.8410 24.78 34 -24.927 0.90 1.80610 40.9 0.7483 23.94 35 634.807 3.00 23.46 36 -149.287 0.90 1.69930 51.1 0.7593 25.61 37 117.071 0.15 25.53 38 45.968 2.06 1.73800 32.3 0.7154 25.60 39 81.435 2.46 25.34 40 -84.763 0.90 1.76385 48.5 0.7686 25.30 41 2888.447 2.01 25.39 42 -169.745 2.32 1.58913 61.1 0.8366 23.00 43 -56.093 30.00 23.17 44 60.694 0.80 1.65160 58.5 0.8525 21.14 45 25.072 5.59 1.43875 94.9 0.8373 20.84 46 -30.873 1.00 20.91 47 -136.619 0.80 1.64000 60.1 0.8645 20.28 48 17.804 3.51 1.65412 39.7 0.7554 19.88 49 59.120 1.00 19.74 50 56.904 2.62 1.56732 42.8 0.7589 19.78 51 -270.638 6.71 19.62 52 427.028 3.50 1.54072 47.2 0.7766 18.24 53 -22.285 0.80 1.85920 33.0 0.6855 18.02 54 -68.140 5.00 18.09 55 ∞ 33.00 1.60859 46.4 0.7534 40.00 56 ∞ 13.20 1.51680 64.2 0.8698 40.00 57 ∞ 7.40 40.00 Image plane ∞ Aspheric data Page 30 K = 0.00000e+00 A 4= 1.90640e-06 A 6= 2.06266e-09 A 8=-1.44180e-11 A10= 2.82641e-14 Various data Zoom ratio 20.00 Focal length 25.00 175.00 500.00 F-number 2.90 2.90 5.00 Angle of view 12.41 1.80 0.63 Lens total length 340.07 340.07 340.07 BF 7.40 7.40 7.40 d15 1.55 55.60 66.03 d24 61.73 3.55 16.13 d27 20.82 24.94 1.94 Entrance pupil position 212.55 1091.87 2309.04 Exit pupil position -261.91 -261.91 -261.91 Front principal point position 235.22 1153.16 1880.74 Back principal point position -17.60 -167.60 -492.60 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 157.47 89.94 12.16 -64.86 2 16 -21.24 17.55 4.79 -6.38 3 25 -59.55 3.09 0.36 -1.33 4 28 55.47 137.98 39.97 -118.79 Single lens data Lens starting surface focal length 1 1 424.66 2 3 216.39 3 5 -213.67 4 6 159.02 5 8 -91.05 6 10 207.90 7 12 233.50 8 14 -1040.54 9 16 -30.45 10 18 23.01 11 19 -17.71 12 21 38.12 13 23 -41.62 14 25 -30.69 15 26 63.06 16 29 39.81 17 31 129.85 18 33 43.92 19 34 -29.74 20 36 -93.70 21 38 139.57 22 40 -107.79 23 42 141.14 24 44 -66.15 25 45 32.53 26 47 -24.56 27 48 37.68 28 50 83.12 29 52 39.28 30 53 -38.86 31 55 0.00 32 56 0.00

[0145] [Numerical Example 2] Unit: mm Surface Data Surface number rd nd vd θct Effective diameter 1 272.713 3.00 1.75500 52.3 0.8092 120.00 2 161.299 0.44 118.53 3 150.757 18.60 1.43387 95.1 0.8091 118.89 4 -345.041 -0.27 118.79 5 611.798 3.00 1.75500 52.3 0.8092 116.68 6 118.493 1.70 113.18 7 120.623 13.03 1.43387 95.1 0.8091 113.86 8 559.208 8.49 113.77 9 150.630 10.08 1.43387 95.1 0.8091 114.03 10 728.392 0.20 113.77 11 134.764 10.56 1.43387 95.1 0.8091 111.12 12 595.465 0.22 110.60 13 101.333 9.84 1.43387 95.1 0.8091 103.76 14 211.175 (variable) 102.37 15 -526.857 1.40 1.69930 51.1 0.7593 44.16 16 63.092 3.61 40.74 17 119.587 7.17 1.61310 44.4 0.8010 39.55 18 -53.697 1.30 1.49700 81.5 0.8258 38.54 19 -162.530 0.54 36.07 20 -437.470 1.30 1.63858 55.2 0.7865 34.61 21 40.713 5.55 1.67300 38.3 0.7481 31.57 22 -231.840 1.91 30.39 23 -68.575 1.20 1.59522 67.7 0.7953 29.29 24* 29.050 (variable) 26.35 25 -1139.718 1.00 1.69930 51.1 0.7593 16.54 26 13.145 3.38 1.74951 35.3 0.7308 16.22 27 60.553 1.82 16.07 28 -30.530 1.00 1.59522 67.7 0.7953 16.07 29 65.113 (variable) 16.56 30* 62.370 3.88 1.59522 67.7 0.7953 25.39 31 -72.073 (variable) 25.60 32 65.712 1.00 1.63775 42.4 0.7883 25.65 33 24.041 6.40 1.43875 94.9 0.8373 25.17 34 -76.039 1.50 25.17 35 (Aperture) ∞ 3.00 24.79 36 -338.255 1.00 1.75106 43.1 0.7097 27.12 37 44.783 3.00 1.78880 28.4 0.6943 26.97 38 181.906 1.20 26.86 39 -206.469 1.00 1.75106 43.1 0.7097 26.85 40 311.718 4.00 26.92 41 -446.161 3.50 1.43875 94.9 0.8373 24.68 42 -68.763 33.28 24.96 43 30.758 5.90 1.49700 81.5 0.8258 24.96 44 -65.291 0.20 24.35 45 22.185 6.14 1.43875 94.9 0.8373 21.59 46 -44.557 1.00 1.65160 58.5 0.8525 19.83 47 16.589 8.76 17.36 48 -49.700 2.21 1.48749 70.2 0.8924 17.31 49 -24.940 1.00 2.00100 29.1 0.6838 17.46 50 -91.483 0.83 18.04 51 233.428 3.90 1.78880 28.4 0.6943 18.54 52 -34.286 4.87 18.90 53 ∞ 33.00 1.60859 46.4 0.7534 30.00 54 ∞ 13.20 1.51680 64.2 0.8698 30.00 55 ∞ 9.00 30.00 Image plane ∞ Aspheric data Page 24 K = 0.00000e+00 A 4=-6.67496e-06 A 6=-1.05486e-08 A 8=-2.85611e-11 A10=3.94702e-13 A12=-1.07416e-15 Page 30 K =-5.07198e+00 A 4=-2.42936e-07 A 6=-8.32235e-09 A 8= 1.57061e-10 A10=-1.02253e-12 A12= 2.29504e-15 Various data Zoom ratio 48.00 Focal length 16.00 111.84 768.00 F-number 2.79 2.79 6.40 Angle of view 18.97 2.82 0.41 Lens total length 400.00 400.00 400.00 BF 9.00 9.00 9.00 d14 4.01 76.54 89.34 d24 45.49 5.71 43.27 d29 31.98 29.00 1.32 d31 55.70 25.93 3.24 Entrance pupil position 140.03 931.91 6012.33 Exit pupil position -251.82 -251.82 -251.82 Front principal point position 155.05 995.79 4518.93 Back principal point position -7.00 -102.83 -758.99 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 147.31 78.88 37.74 -20.94 2 15 -32.44 23.98 12.30 -3.11 3 25 -26.17 7.20 4.21 -0.75 4 30 56.78 3.88 1.14 -1.32 5 32 69.88 139.87 57.61 -64.28 Single lens data Lens starting surface focal length 1 1 -529.07 2 3 244.59 3 5 -195.15 4 7 351.32 5 9 435.39 6 11 398.70 7 13 437.17 8 15 -80.49 9 17 61.41 10 18 -161.99 11 20 -58.27 12 21 51.88 13 23 -34.13 14 25 -18.58 15 26 21.74 16 28 -34.78 17 30 56.78 18 32 -60.00 19 33 42.46 20 36 -52.60 21 37 74.60 22 39 -165.23 23 41 184.76 24 43 42.94 25 45 34.73 26 46 -18.43 27 48 99.77 28 49 -34.51 29 51 38.14 30 53 0.00 31 54 0.00

[0146] [Numerical Example 3] Unit: mm Surface Data Surface number rd nd vd θct Effective diameter 1 460.758 6.00 1.75500 52.3 0.8092 190.68 2 227.153 2.23 187.65 3 227.208 35.78 1.43875 94.9 0.8373 188.56 4 -392.317 0.80 188.44 5 -438.907 6.00 1.69680 55.5 0.8330 187.87 6 532.162 1.00 188.46 7 414.431 19.92 1.43387 95.1 0.8091 189.53 8 -789.381 27.30 189.73 9 356.634 19.70 1.43387 95.1 0.8091 188.91 10 -1289.000 0.25 188.31 11 296.913 13.81 1.43387 95.1 0.8091 183.20 12 1058.300 1.52 181.99 13 194.264 13.65 1.43875 94.7 0.8410 173.54 14 377.710 (variable) 171.63 15 -586.221 1.40 1.69930 51.1 0.7593 45.28 16 34.713 5.77 40.34 17 92.067 13.13 1.61310 44.4 0.8010 40.23 18 -28.278 1.30 1.59522 67.7 0.7953 39.64 19 203.083 4.35 37.17 20 -134.194 1.30 1.63858 55.2 0.7865 36.56 21 63.020 7.63 1.67300 38.3 0.7481 36.26 22 -69.143 1.83 36.42 23 -63.166 1.20 1.59522 67.7 0.7953 36.06 24* 111.986 (variable) 36.49 25 134.588 5.00 1.59522 67.7 0.7953 59.50 26* 442.688 0.50 59.47 27 80.090 11.02 1.43875 94.9 0.8373 60.05 28 -169.812 0.35 59.63 29 958.073 2.60 1.61310 44.4 0.8010 58.24 30 117.378 (variable) 56.71 31 4306.259 6.31 1.43875 94.9 0.8373 55.98 32 -110.510 0.50 55.75 33 -434.969 2.50 1.61310 44.4 0.8010 54.55 34 128.064 5.88 1.59522 67.7 0.7953 53.45 35* -1908.884 (variable) 52.93 36 (Aperture) ∞ 3.14 31.68 37 53.719 1.20 1.75106 43.1 0.7097 33.32 38 30.751 2.37 32.23 39 29.858 4.45 1.73800 32.3 0.7154 32.41 40 57.785 4.06 31.40 41 498.772 1.20 1.85920 33.0 0.6855 30.50 42 63.834 12.15 29.97 43 -88.470 1.00 1.75500 52.3 0.8092 26.48 44 150.000 4.25 1.43875 94.9 0.8373 26.76 45 -81.943 0.29 27.19 46 1527.739 1.60 2.00100 29.1 0.6838 27.34 47 31.133 10.71 1.85478 24.8 0.6739 27.54 48 -119.386 23.87 28.36 49 -193.045 6.80 1.43875 94.9 0.8373 28.97 50 -79.814 2.00 29.35 51 69.774 1.80 1.64000 60.1 0.8645 28.99 52 26.465 10.66 1.59522 67.7 0.7953 28.09 53 -61.505 0.60 27.17 54 207.853 5.99 1.59551 39.2 0.7402 25.72 55 -52.126 1.80 1.95375 32.3 0.6988 24.40 56 129.782 1.00 23.76 57 101.348 5.25 1.43875 94.9 0.8373 23.59 58 157.387 19.65 22.72 59 ∞ 33.00 1.60859 46.4 0.7534 60.00 60 ∞ 13.20 1.51633 64.2 0.8676 60.00 61 ∞ 13.40 60.00 Image plane ∞ Aspheric data Page 24 K =-3.79813e+01 A 4= 9.41596e-07 A 6=-5.38380e-09 A 8= 7.42674e-12 A10=-9.02145e-15 A12= 5.43576e-18 Page 26 K = 0.00000e+00 A 4= 3.97598e-07 A 6=-4.62748e-12 A 8= 5.82597e-14 A10=-2.37917e-17 A12=-7.42504e-22 Page 35 K = 0.00000e+00 A 4= 2.00714e-07 A 6= 1.45041e-10 A 8=-2.89471e-13 A10=2.88143e-16 A12=-9.54591e-20 Various data Zoom ratio 90.00 Focal length 14.30 155.90 1287.00 F-number 2.95 2.95 6.77 Angle of view 21.04 2.02 0.24 Lens total length 785.45 785.45 785.45 BF 13.40 13.40 13.40 d14 3.68 152.55 191.31 d24 346.10 143.24 2.00 d30 26.75 6.70 176.07 d35 2.93 76.99 10.08 Entrance pupil position 180.29 1373.10 19947.89 Exit pupil position -336.49 -336.49 -336.49 Front principal point position 194.00 1459.53 16501.03 Back principal point position -0.90 -142.49 -1273.59 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 265.94 147.97 85.48 -26.76 2 15 -33.53 37.91 8.25 -15.84 3 25 147.81 19.46 -2.39 -15.18 4 31 353.05 15.20 4.51 -5.62 5 36 117.63 172.04 86.54 -9.04 Single lens data Lens starting surface focal length 1 1 -600.05 2 3 333.81 3 5 -344.32 4 7 629.51 5 9 646.19 6 11 946.01 7 13 891.41 8 15 -46.82 9 17 36.81 10 18 -41.61 11 20 -66.98 12 21 50.15 13 23 -67.68 14 25 322.93 15 27 125.73 16 29 -218.44 17 31 245.68 18 33 -161.10 19 34 201.85 20 37 -97.95 21 39 78.41 22 41 -85.31 23 43 -73.57 24 44 121.46 25 46 -31.77 26 47 29.87 27 49 304.56 28 51 -67.72 29 52 32.56 30 54 70.59 31 55 -38.81 32 57 630.74 33 59 0.00 34 60 0.00

[0147] [Numerical Example 4] Unit: mm Surface Data Surface number rd nd vd θct Effective diameter 1 347.292 12.73 1.48749 70.2 0.8924 125.01 2 -439.368 0.50 124.17 3 172.902 3.70 1.65160 58.5 0.8525 116.81 4 100.217 2.00 111.46 5 95.181 25.21 1.43875 94.9 0.8373 111.41 6 -345.551 1.63 110.21 7 -275.277 3.20 1.65100 56.2 0.8345 109.78 8 172.843 18.08 104.96 9 160.562 13.98 1.43875 94.9 0.8373 105.04 10 -452.770 0.15 104.60 11 111.956 7.00 1.43875 94.9 0.8373 98.64 12 186.418 (variable) 97.47 13 75.662 1.20 1.59522 67.7 0.7953 40.01 14 30.332 11.78 35.84 15 -33.846 1.00 1.75106 43.1 0.7097 35.14 16 110.569 6.74 1.78880 28.4 0.6943 36.49 17 -51.337 0.20 36.80 18 -352.797 5.00 1.75500 52.3 0.8092 35.82 19 -52.329 1.00 1.61800 63.3 0.8089 35.51 20* 93.567 (variable) 34.38 21 -57.770 1.15 1.69930 51.1 0.7593 27.09 22 32.942 4.71 1.73800 32.3 0.7154 28.73 23 222.529 (variable) 29.19 24* 63.832 8.39 1.49700 81.5 0.8258 42.77 25 -83.727 0.20 42.99 26 314.153 3.66 1.43875 94.9 0.8373 42.61 27 -170.449 0.50 42.44 28 72.391 8.29 1.43875 94.9 0.8373 41.11 29 -58.812 1.00 1.64000 60.1 0.8645 40.48 30 85.581 0.75 38.94 31 64.893 10.64 1.43875 94.9 0.8373 38.84 32 -39.078 1.20 1.69930 51.1 0.7593 38.20 33 -90.485 8.00 38.11 34 (Aperture) ∞ 38.16 34.59 35 152.941 1.72 1.67300 38.3 0.7481 30.13 36 313.807 1.20 1.69930 51.1 0.7593 29.97 37 53.098 20.00 29.71 38 34.886 3.57 1.49700 81.5 0.8258 25.30 39 102.308 3.18 24.95 40 -73.232 1.00 1.69930 51.1 0.7593 24.75 41 108.279 6.12 1.59522 67.7 0.7953 24.91 42 -34.290 1.50 25.14 43 -28.177 6.17 1.85478 24.8 0.6739 24.76 44 -26.324 1.20 1.85920 33.0 0.6855 26.20 45 -171.858 1.00 27.28 46 289.444 6.26 1.73800 32.3 0.7154 27.94 47 -26.259 1.20 1.69930 51.1 0.7593 28.23 48 -97.006 60.58 28.79 Image plane ∞ Aspheric data Page 20 K = 0.00000e+00 A 4=-1.86484e-06 A 6=-3.90155e-09 A 8= 3.35098e-11 A10=-1.18225e-13 A12= 1.40261e-16 Page 24 K = 0.00000e+00 A 4=-7.88004e-07 A 6= 2.37425e-11 A 8= 1.94688e-12 A10=-3.84138e-15 A12= 2.86644e-18 Various data Zoom ratio 22.22 Focal length 45.00 270.00 1000.00 F-number 4.65 4.65 8.32 Angle of view 18.21 3.14 0.85 Lens total length 459.19 459.19 459.19 BF 60.58 60.58 60.58 d12 1.67 100.30 128.47 d20 116.91 12.94 13.80 d23 24.15 29.50 0.47 Entrance pupil position 158.95 891.12 2949.83 Exit pupil position -97.42 -97.42 -97.42 Front principal point position 191.13 699.73 -2379.65 Back principal point position 15.58 -209.42 -939.46 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 210.78 88.19 35.90 -37.62 2 13 -40.41 26.92 5.67 -14.44 3 21 -69.63 5.86 0.73 -2.63 4 24 54.97 134.91 0.20 -127.84 Single lens data Lens starting surface focal length 1 1 400.02 2 3 -373.36 3 5 173.11 4 7 -162.64 5 9 272.04 6 11 621.02 7 13 -85.91 8 15 -34.40 9 16 45.28 10 18 80.80 11 19 -54.16 12 21 -29.84 13 22 51.85 14 24 74.28 15 26 252.43 16 28 75.41 17 29 -54.32 18 31 57.38 19 32 -99.31 20 35 441.41 21 36 -91.57 22 38 104.67 23 40 -62.33 24 41 44.47 25 43 184.75 26 44 -36.32 27 46 32.90 28 47 -51.85

[0148] [Numerical Example 5] Unit: mm Surface Data Surface number rd nd vd θct Effective diameter 1 -207.919 1.50 1.74100 52.6 0.8155 72.49 2 89.996 0.70 71.39 3 90.474 12.02 1.43387 95.1 0.8091 71.78 4 -210.275 0.20 71.89 5 204.195 5.78 1.43387 95.1 0.8091 71.61 6 -438.286 12.21 71.45 7 128.481 7.89 1.43387 95.1 0.8091 69.63 8 -313.204 0.23 69.21 9 93.534 7.25 1.43387 95.1 0.8091 66.54 10 13791.068 1.48 66.09 11 86.760 3.93 1.43875 94.9 0.8373 62.07 12 144.866 (variable) 61.17 13* 179.865 0.60 1.78000 40.0 0.6950 27.25 14 15.475 9.54 22.84 15 -26.336 4.40 1.73800 32.3 0.7154 22.48 16 -14.769 0.80 1.75106 43.1 0.7097 22.91 17 -61.812 0.18 24.45 18 64.931 4.34 1.73800 32.3 0.7154 25.06 19 -48.318 0.60 1.75106 43.1 0.7097 25.01 20 -105.206 (variable) 24.96 21 54.270 0.50 1.59410 60.5 0.7800 16.95 22 12.764 3.19 1.74951 35.3 0.7308 16.53 23 32.355 3.90 16.20 24 -20.076 0.50 1.59522 67.7 0.7953 16.08 25 105.119 (variable) 16.74 26 (Aperture) ∞ 0.50 23.59 27* 33.431 6.24 1.43875 94.7 0.8410 24.97 28 -38.691 (variable) 25.41 29 104.734 4.24 1.43875 94.9 0.8373 25.37 30 -38.459 0.20 25.27 31 94.850 5.30 1.59522 67.7 0.7953 23.90 32 -22.882 1.00 1.64000 60.1 0.8645 23.41 33 146.947 2.04 21.92 34 -436.540 1.00 1.59410 60.5 0.7800 24.00 35 114.074 2.40 23.50 36 -77.754 2.00 1.61340 44.3 0.7825 23.30 37 -46.274 0.30 23.10 38 -116.457 1.00 1.59410 60.5 0.7800 22.80 39 42.296 34.00 22.30 40 26.786 5.03 1.43875 94.9 0.8373 18.67 41 -23.777 1.82 18.53 42 -31.267 3.10 1.59522 67.7 0.7953 17.16 43 -14.228 1.00 1.91650 31.6 0.7059 17.00 44 257.802 4.22 17.62 45 53.925 3.82 1.75520 27.5 0.6797 19.46 46 -33.773 1.00 1.78000 40.0 0.6950 19.53 47 -52.414 4.80 19.61 48 ∞ 33.00 1.60859 46.4 0.7534 40.00 49 ∞ 13.20 1.51633 64.1 0.8687 40.00 50 ∞ 7.28 40.00 Image plane ∞ Aspheric data Page 13 K =-1.91806e+00 A 4= 1.55051e-05 A 6= 2.58312e-09 A 8=-2.98420e-10 A10= 1.76312e-12 A12=-3.51543e-15 Page 27 K =-2.01917e+00 A 4=-1.35536e-05 A 6= 2.27122e-08 A 8=-1.65376e-10 A10=8.77892e-13 A12=-1.90769e-15 Various data Zoom ratio 26.09 Focal length 11.50 58.46 300.00 F-number 2.68 2.68 4.89 Angle of view 25.56 5.37 1.05 Lens total length 300.32 300.32 300.32 BF 7.28 7.28 7.28 d12 1.91 52.48 69.79 d20 55.25 1.00 4.37 d25 18.95 19.07 2.29 d28 3.97 7.53 3.63 Entrance pupil position 63.20 289.68 999.33 Exit pupil position 329.26 262.65 337.37 Front principal point position 75.11 361.52 1571.98 Back principal point position -4.22 -51.18 -292.72 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 91.01 53.19 35.59 -1.02 2 13 -28.53 20.46 -3.88 -24.07 3 21 -30.63 8.09 8.18 1.25 4 26 41.99 6.74 2.57 -2.39 5 29 64.73 124.47 68.93 -50.62 Single lens data Lens starting surface focal length 1 1 -84.58 2 3 147.58 3 5 321.93 4 7 211.13 5 9 217.02 6 11 483.04 7 13 -21.74 8 15 39.23 9 16 -26.03 10 18 38.16 11 19 -119.51 12 21 -28.22 13 22 26.29 14 24 -28.28 15 27 41.99 16 29 64.70 17 31 31.50 18 32 -30.86 19 34 -152.13 20 36 181.93 21 38 -52.10 22 40 29.61 23 42 41.08 24 43 -14.69 25 45 28.02 26 46 -124.67 27 48 0.00 28 49 0.00

[0149] [Numerical Example 6] Unit: mm Surface Data Surface number rd nd vd θgf Effective diameter 1 -2112.116 5.00 1.73400 51.5 0.8067 210.02 2 262.469 2.23 195.51 3 258.284 31.27 1.43387 95.1 0.8091 194.63 4 -564.624 0.78 192.66 5 -901.580 5.00 1.65160 58.5 0.8525 188.72 6 930.273 0.97 182.33 7 531.883 20.77 1.43387 95.1 0.8091 181.85 8 -432.999 23.64 182.37 9 402.439 16.59 1.43387 95.1 0.8091 184.40 10 -1735.382 0.25 184.03 11 241.460 17.77 1.43387 95.1 0.8091 179.92 12 1456.245 1.37 178.72 13 179.703 13.93 1.43875 94.9 0.8373 168.93 14 351.843 (variable) 167.01 15 -6005.276 1.40 1.75106 43.1 0.7097 46.94 16 25.626 8.99 37.77 17 218.561 11.63 1.61310 44.4 0.8010 37.47 18 -25.162 1.30 1.69930 51.1 0.7593 36.94 19 50.815 6.06 36.13 20 -385.010 1.30 1.59522 67.7 0.7953 37.16 21 76.760 11.97 1.67300 38.3 0.7481 38.49 22 -31.149 0.13 39.20 23 -38.595 1.20 1.61800 63.3 0.8089 37.52 24* ∞ (variable) 37.68 25 98.168 5.00 1.59522 67.7 0.7953 59.24 26* 297.861 0.50 59.16 27 89.667 7.87 1.61800 63.3 0.8089 59.47 28 -1450.928 0.20 58.92 29 204.230 2.60 1.61310 44.4 0.8010 57.94 30 56.359 (variable) 55.24 31 52.781 15.39 1.43875 94.9 0.8373 55.49 32 -77.148 0.50 54.77 33 -104.347 2.50 1.61310 44.4 0.8010 52.93 34 118.393 5.78 1.59522 67.7 0.7953 50.55 35* -579.904 (variable) 49.74 36 (Aperture) ∞ 3.94 30.87 37 -260.817 1.20 1.59410 60.5 0.7800 30.93 38 28.551 0.19 29.87 39 25.954 4.98 1.78880 28.4 0.6943 30.15 40 72.832 4.73 29.55 41 -63.945 1.20 1.69930 51.1 0.7593 29.02 42 90.031 6.15 28.97 43 -126.297 1.00 1.75500 52.3 0.8092 27.81 44 150.000 10.34 1.43875 94.9 0.8373 28.27 45 -63.088 0.20 30.44 46 123.501 1.60 2.00100 29.1 0.6838 31.00 47 30.053 10.71 1.85478 24.8 0.6739 30.83 48 6775.780 2.99 31.19 49 153.958 5.29 1.43875 94.9 0.8373 31.60 50 -56.169 1.40 31.62 51 109.306 1.80 1.69930 51.1 0.7593 30.45 52 30.713 6.59 1.59522 67.7 0.7953 29.29 53 -283.222 0.60 28.76 54 278.414 6.24 1.59551 39.2 0.7402 28.23 55 -31.106 1.80 1.95375 32.3 0.6988 27.46 56 122.696 1.00 27.20 57 60.041 7.28 1.43875 94.9 0.8373 27.43 58 -39.671 19.65 27.25 59 ∞ 33.00 1.60859 46.4 0.7534 60.00 60 ∞ 13.20 1.51633 64.2 0.8676 60.00 61 ∞ 12.73 60.00 Image plane ∞ Aspheric data Page 24 K =-1.90112e+13 A 4=-2.11772e-06 A 6=-1.26820e-09 A 8=-3.59273e-12 A10= 1.28928e-14 A12=-2.03701e-17 Page 26 K = 0.00000e+00 A 4= 1.51186e-07 A 6=-3.49177e-10 A 8= 8.43268e-13 A10=-8.43439e-16 A12= 3.34414e-19 Page 35 K = 0.00000e+00 A 4= 8.88237e-07 A 6= 1.54056e-09 A 8=-4.51352e-12 A10=6.73149e-15 A12=-3.58815e-18 Various data Zoom ratio 130.00 Focal length 8.00 91.00 1040.00 F-number 2.40 2.40 6.00 Angle of view 34.51 3.46 0.30 Lens total length 700.09 700.09 700.09 BF 12.73 12.73 12.73 d14 3.15 157.50 199.78 d24 308.80 111.70 1.98 d30 1.49 1.49 2.48 d35 2.98 45.73 112.17 Entrance pupil position 133.34 993.87 12953.59 Exit pupil position -283.51 -283.51 -283.51 Front principal point position 141.13 1056.91 10342.70 Back principal point position 4.73 -78.27 -1027.23 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 245.14 139.58 88.39 -8.42 2 15 -25.15 43.97 2.82 -30.97 3 25 237.37 16.16 -14.73 -23.41 4 31 111.97 24.17 1.13 -15.39 5 36 96.00 147.06 72.16 7.13 Single lens data Lens starting surface focal length 1 1 -317.78 2 3 413.21 3 5 -701.90 4 7 553.74 5 9 754.72 6 11 664.20 7 13 816.99 8 15 -33.97 9 17 37.48 10 18 -23.90 11 20 -107.41 12 21 34.46 13 23 -62.45 14 25 243.73 15 27 136.92 16 29 -127.82 17 31 74.11 18 33 -90.08 19 34 165.69 20 37 -43.25 21 39 48.83 22 41 -53.30 23 43 -90.67 24 44 102.74 25 46 -40.02 26 47 35.29 27 49 94.52 28 51 -61.66 29 52 46.92 30 54 47.34 31 55 -25.87 32 57 55.68 33 59 0.00 34 60 0.00

[0150] [Table 1]

[0151] FIG. 20 shows the configuration of an imaging device (television camera system) using the zoom lens of each of the above-described embodiments as a photographing optical system. In FIG. 20, 101 denotes the zoom lens of any of the first to sixth embodiments. 124 denotes a camera. The zoom lens 101 is detachable from the camera 124. 125 denotes an imaging device configured by attaching the zoom lens 101 to the camera 124. The zoom lens 101 includes a first lens group F, a zoom section LZ, a rear lens group R, and the like. The first lens group F includes the first lens group U1 used for focusing in each embodiment. The zoom section LZ includes a variable magnification lens group (such as U2) that moves during magnification variation, and an aperture diaphragm SP. 114 and 115 denote driving mechanisms such as helicoids and cams that drive the first lens group F and the zoom section LZ in the optical axis direction, respectively. While the zoom lens of the imaging device shown in FIG. 20 is illustrated as including the aperture diaphragm SP in the zoom section LZ, the present invention is not limited to this configuration. As described in the first to sixth embodiments, the aperture stop SP may be disposed in the variable magnification lens group or in the rear lens group R.

[0152] Reference numerals 116 to 118 denote actuators that electrically drive the drive mechanisms 114 and 115 and the aperture diaphragm SP. Reference numerals 119 to 121 denote detectors such as encoders, potentiometers, or photosensors for detecting the positions of the first lens group F, the zoom section LZ, and the aperture diaphragm SP on the optical axis and the aperture diameter of the aperture diaphragm SP. In the camera 124, reference numeral 109 denotes a glass block corresponding to an optical filter or color separation optical system within the camera 124, and reference numeral 110 denotes a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor that receives the subject image formed by the zoom lens 101. Reference numerals 111 and 122 denote CPUs that control various driving operations of the camera 124 and the zoom lens 101. In this way, by using the zoom lens of each embodiment in an imaging device, it is possible to realize an imaging device that has a high zoom ratio and good optical performance over a wide wavelength range from the visible light region to the SWIR region.

[0153] Although the preferred embodiments 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 thereof.

[0154] The disclosure of this embodiment includes the following configuration. (Configuration 1) The optical system has, in order from the object side to the image side, a first lens group with positive refractive power that does not move for varying magnification, a magnification-varying lens group that moves when varying magnification, and a rear lens group that does not move for varying magnification, The spacing between adjacent lens groups changes due to magnification, the rear lens group includes at least one positive lens and at least one negative lens including a first negative lens, and includes a rear sub-lens group having negative refractive power and composed of two or three lenses adjacent to each other; When the Abbe number of the first negative lens referenced to the d-line and the partial dispersion ratio from the C-line to the t-line are respectively νdN and θctN, the average value of the Abbe number of at least one positive lens referenced to the d-line and the average value of the partial dispersion ratio from the C-line to the t-line of the rear sub-lens group are respectively νdp and θctp, and the average value of the Abbe number of at least one negative lens referenced to the d-line and the average value of the partial dispersion ratio from the C-line to the t-line of the rear sub-lens group are respectively νdn and θctn, 0.4958≦θctN-0.00417×νdN≦0.5635 -4.0×10 -3 ≦(θctn-θctp) / (νdp-νdn)≦4.0×10 -3 -40≦νdp-νdn≦0 A zoom lens characterized by satisfying the following conditions: (Configuration 2) 25≦νdN≦61 The zoom lens according to configuration 1, characterized in that the following condition is satisfied: (Configuration 3) When the refractive index of the first negative lens with respect to the d-line is NdN, 1.59≦NdN≦2.00 3. The zoom lens according to configuration 1 or 2, characterized in that the following condition is satisfied: (Configuration 4) When the focal length of the rear sub-lens group is fs and the focal length of the first negative lens is fNL, 0.6≦fNL / fs≦1.3 4. The zoom lens according to any one of configurations 1 to 3, characterized in that the following conditions are satisfied: (Configuration 5) the rear sub-lens group has a function of correcting image blur by moving in a direction including a component perpendicular to the optical axis, When the lateral magnification of the rear sub lens group is βs and the lateral magnification of the lens group arranged closer to the image than the rear sub lens group is βr, -1.40≦(1-βs)×βr≦-0.60 5. A zoom lens according to any one of configurations 1 to 4, characterized in that the following conditions are satisfied: (Configuration 6) 6. The zoom lens according to any one of configurations 1 to 5, wherein the variable magnification lens group is made up of two or three lens groups. (Configuration 7) The zoom lens according to any one of configurations 1 to 6, wherein the rear sub-lens group is composed of, in order from the object side to the image side, a lens with negative refractive power, a lens with positive refractive power, and a lens with negative refractive power. (Configuration 8) 8. A zoom lens according to any one of configurations 1 to 7, wherein the rear sub-lens group is composed of, in order from the object side to the image side, a lens having a positive refractive power and a lens having a negative refractive power. (Configuration 9) 9. A zoom lens according to any one of configurations 1 to 8, wherein the first lens group includes a sub-lens group that moves toward the object side for focusing from the infinity side to the close-up side. (Configuration 10) 9. A zoom lens according to any one of configurations 1 to 8, wherein the first lens group comprises, in order from the object side to the image side, a first sub-lens group with positive refractive power, and a second sub-lens group with positive refractive power that moves toward the object side for focusing from the infinity side to the close-up side. (Configuration 11) In the decentration aberration caused by the movement of the rear sub lens unit in a direction perpendicular to the optical axis, the first-order decentration coma aberration coefficient is expressed as (IIE), -0.080≦(IIE)≦0.080 11. The zoom lens according to any one of configurations 1 to 10, characterized in that the following conditions are satisfied: (Configuration 12) In the decentering aberration caused by the movement of the rear sub-lens unit in a direction perpendicular to the optical axis, when the first-order decentering astigmatism coefficient is (IIIE), -0.060≦(IIIE)≦0.060 12. A zoom lens according to any one of configurations 1 to 11, characterized in that the following conditions are satisfied: (Configuration 13) In the decentration aberration caused by the movement of the rear sub-lens unit in a direction perpendicular to the optical axis, the first-order decentration chromatic aberration coefficient is (TE), -0.020≦(TE)≦0.020 13. A zoom lens according to any one of configurations 1 to 12, characterized in that the following condition is satisfied: (Configuration 14) a zoom lens according to any one of configurations 1 to 13; an image sensor that receives a subject image formed by the zoom lens. [Explanation of symbols]

[0155] U1 First lens group U2 Second lens group U3 Third lens group U4 4th lens group U5 Fifth lens group UR rear lens group URs posterior sub-lens group

Claims

1. The optical system has, in order from the object side to the image side, a first lens group with positive refractive power that does not move for varying magnification, a magnification-varying lens group that moves when varying magnification, and a rear lens group that does not move for varying magnification, The spacing between adjacent lens groups changes due to magnification, the rear lens group includes at least one positive lens and at least one negative lens including a first negative lens, and includes a rear sub-lens group having negative refractive power and consisting of two or three lenses adjacent to each other; When the Abbe number of the first negative lens based on the d-line and the partial dispersion ratio from the C-line to the t-line are respectively νdN and θctN, the average value of the Abbe number of at least one positive lens included in the rear sub-lens group based on the d-line and the average value of the partial dispersion ratio from the C-line to the t-line are respectively νdp and θctp, and the average value of the Abbe number of at least one negative lens included in the rear sub-lens group based on the d-line and the average value of the partial dispersion ratio from the C-line to the t-line are respectively νdn and θctn, 0.4958≦θctN−0.00417×νdN≦0.5635 -4.0×10 －３ ≦(θctn-θctp) / (νdp-νdn)≦4.0×10 －３ −40≦νdp−νdn≦0 A zoom lens characterized by satisfying the following conditions:

2. 25≦νdN≦61 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. When the refractive index of the first negative lens with respect to the d-line is NdN, 1.59≦NdN≦2.00 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. When the focal length of the rear sub-lens group is fs and the focal length of the first negative lens is fNL, 0.6≦fNL / fs≦1.3 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. the rear sub-lens group has a function of correcting image blur by moving in a direction including a component perpendicular to the optical axis, When the lateral magnification of the rear sub lens group is βs and the lateral magnification of the lens group disposed closer to the image side than the rear sub lens group is βr, -1.40≦(1-βs)×βr≦-0.60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. 2. The zoom lens according to claim 1, wherein the variable magnification lens group is composed of two or three lens groups.

7. 2. The zoom lens according to claim 1, wherein the rear sub-lens group is composed of, in order from the object side to the image side, a lens having a negative refractive power, a lens having a positive refractive power, and a lens having a negative refractive power.

8. 2. The zoom lens according to claim 1, wherein the rear sub-lens group is composed of, in order from the object side to the image side, a lens having a positive refractive power and a lens having a negative refractive power.

9. 2. The zoom lens according to claim 1, wherein the first lens group includes a sub-lens group that moves toward the object side for focusing from the infinity side to the close-up side.

10. 2. The zoom lens according to claim 1, wherein the first lens group comprises, in order from the object side to the image side, a first sub-lens group with positive refractive power and a second sub-lens group with positive refractive power that moves toward the object side for focusing from the infinity side to the close-up side.

11. In the decentration aberration caused by the movement of the rear sub lens unit in a direction perpendicular to the optical axis, when the first-order decentration coma aberration coefficient is (IIE), -0.080≦(IIE)≦0.080 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. In the decentering aberration caused by the movement of the rear sub-lens unit in a direction perpendicular to the optical axis, when the first-order decentering astigmatism coefficient is (IIIE), -0.060≦(IIIE)≦0.060 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

13. When the first-order decentering chromatic aberration coefficient in decentering aberrations caused by movement of the rear sub-lens group in a direction perpendicular to the optical axis is (TE), -0.020≦(TE)≦0.020 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

14. A zoom lens according to any one of claims 1 to 13; an image sensor that receives a subject image formed by the zoom lens.

Images