Converter lens, lens device, and imaging device

Abstract

This invention provides a converter lens that achieves excellent axial chromatic aberration correction in the visible light wavelength range to the SWIR wavelength range. [Solution] A converter lens that can be inserted into or removed from the optical path of a master lens, or can replace some of the lens groups of the master lens, and which makes the focal length of the entire system longer than the focal length of the master lens alone, wherein the converter lens is composed of a front lens group with positive refractive power and a rear lens group with negative refractive power, in order from the object side to the image side, with the maximum air gap on the optical axis between the lenses included in the converter lens as the boundary, the front lens group has a front negative lens with negative refractive power, and the partial dispersion ratio of the front negative lens with respect to the C line and t line, and the Abbe number with respect to the d line are appropriately set.

Description

[Technical Field]

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

[0002] Lenses for surveillance cameras used for long-distance monitoring require a wide focal length range to accommodate wide-area shooting and high-magnification shooting of distant subjects, as well as high optical performance to capture subjects sharply. When it is desired to further increase the shooting magnification beyond that of the master lens, a converter lens is used, which is inserted into or removed from the master lens to make the focal length of the entire system longer than that of the master lens alone. Patent documents 1 and 2 disclose such converter lenses, which are either positioned on the image side of the master lens or inserted between lens groups, and which make the focal length of the entire system longer than that of the master lens alone. Patent documents 1 and 2 disclose converter lenses that extend the focal length by about 1.4 to 2.5 times. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-60093 [Patent Document 2] Japanese Patent Publication No. 2020-12910 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In the converter lenses described above, the longitudinal aberration remaining in the master lens is magnified by the square of the converter lens's magnification. As the focal length of the lens increases further and the pixel count of the image sensor increases, color fringing due to axial chromatic aberration can become more pronounced. Therefore, it is important to reduce axial chromatic aberration over a wide wavelength range by correcting it with a second-order spectral correction in addition to the first-order spectral correction.

[0005] Furthermore, in the market for surveillance camera lenses, there is a demand for lenses that can accurately capture wavelengths from near-infrared (NIR) to short-wavelength infrared (SWIR) in addition to the visible light wavelength range, thereby improving shooting sensitivity and eliminating haze. The zoom lenses and converter lenses disclosed in Patent Documents 1 and 2 are designed to correct axial chromatic aberration in the visible light wavelength range, but there is no description of suppressing axial chromatic aberration up to the near-infrared region. As a result, significant chromatic aberration remains in the near-infrared to short-wavelength infrared wavelength range, making it difficult to obtain good images. In order to obtain good images in the visible light wavelength range to short-wavelength infrared wavelength range, it is necessary to adopt a lens configuration and glass materials suitable for appropriate chromatic aberration correction.

[0006] The present invention aims to provide a converter lens that achieves good axial chromatic aberration correction over a wide wavelength range from the visible light wavelength range to the short-wave infrared wavelength range. [Means for solving the problem]

[0007] A converter lens as one aspect of the present invention is a converter lens that is inserted into or removed from the optical path of a master lens, or replaced with a part of the lens group of the master lens, to make the focal length of the entire system longer than the focal length of the master lens alone, wherein the converter lens is composed of a front lens group with positive refractive power and a rear lens group with negative refractive power, in order from the object side to the image side, with the maximum air gap on the optical axis between the lenses included in the converter lens as the boundary, the front lens group has a front negative lens with negative refractive power, and when the partial dispersion ratio of the front negative lens with respect to the C line and t line is θctf, and the Abbe number with respect to the d line of the front negative lens is νdnf, 0.55 < θctf - 0.0049 × νdnf < 0.60 20<νdnf<52 It is characterized by satisfying the following conditions. Another aspect of the present invention is a converter lens that is placed in the optical path of a master lens, or replaces some of the lens groups of the master lens, to make the focal length of the entire system longer than the focal length of the master lens alone, wherein the distance between the lenses included in the converter lens is divided into a front lens group with positive refractive power and a rear lens group with negative refractive power, in order from the object side to the image side, with the maximum air distance as the boundary. The front lens group has a front negative lens, and when the partial dispersion ratio of the front negative lens with respect to the C line and t line is θctf, and the Abbe number of the front negative lens with respect to the d line is νdnf, 0.55 < θctf - 0.0049 × νdnf < 0.60 It is characterized by satisfying the following conditions. [Effects of the Invention]

[0008] According to the present invention, a converter lens can be provided that achieves good axial chromatic aberration correction over a wide wavelength range from the visible light wavelength range to the short-wave infrared wavelength range. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of the Master Lens M1 at its wide-angle end (focal length 28mm) and when focused at infinity. [Figure 2] These are longitudinal aberration diagrams of the Master Lens M1 at infinity focus at (a) wide-angle end, (b) intermediate zoom position (focal length 196mm), and (c) telephoto end (focal length 504mm). [Figure 3] This is a cross-sectional view of the zoom lens at its wide-angle end (focal length 56mm) and focused at infinity, with the converter lens of Example 1 inserted into the master lens M1. [Figure 4] These are longitudinal aberration diagrams at (a) wide-angle end, (b) intermediate zoom position (focal length 392mm), and (c) telephoto end (focal length 1008mm) when the zoom lens is focused at infinity, with the converter lens of Example 1 inserted into the master lens M1. [Figure 5]Cross-sectional view of the zoom lens at the wide-angle end (focal length: 70 mm) and at infinity focus with the converter lens of Example 2 inserted into the master lens M1. [Figure 6] Longitudinal aberration diagrams at infinity focus of the zoom lens at (a) the wide-angle end, (b) the intermediate zoom position (focal length: 490 mm), and (c) the telephoto end (focal length: 1260 mm) with the converter lens of Example 2 inserted into the master lens M1. [Figure 7] Cross-sectional view of the zoom lens at the wide-angle end (focal length: 80 mm) and at infinity focus with the converter lens of Example 3 inserted into the master lens M1. [Figure 8] Longitudinal aberration diagrams at infinity focus of the zoom lens at (a) the wide-angle end, (b) the intermediate zoom position (focal length: 560 mm), and (c) the telephoto end (focal length: 1440 mm) with the converter lens of Example 3 inserted into the master lens M1. [Figure 9] Cross-sectional view of the master lens M2 at the wide-angle end (focal length: 14.3 mm) and at infinity focus. [Figure 10] Longitudinal aberration diagrams at infinity focus of the master lens M2 at (a) the wide-angle end, (b) the intermediate zoom position (focal length: 156 mm), and (c) the telephoto end (focal length: 1287 mm). [Figure 11] Cross-sectional view of the zoom lens at the wide-angle end (focal length: 28.6 mm) and at infinity focus with the converter lens of Example 4 inserted into the master lens M2. [Figure 12] Longitudinal aberration diagrams at infinity focus of the zoom lens at (a) the wide-angle end (focal length: 28.6 mm), (b) the intermediate zoom position (focal length: 312 mm), and (c) the telephoto end (focal length: 2574 mm) with the converter lens of Example 4 inserted into the master lens M2. [Figure 13] Cross-sectional view of the zoom lens at the wide-angle end (focal length: 20 mm) and at infinity focus with the converter lens of Example 5 inserted into the master lens M2. [Figure 14]The longitudinal aberration diagrams at infinity focus of the zoom lens in the state where the converter lens of Example 5 is inserted into the master lens M2, at (a) the wide-angle end (focal length: 20 mm), (b) the intermediate zoom position (focal length: 218 mm), and (c) the telephoto end (focal length: 1800 mm). [Figure 15] The distribution diagram of the partial dispersion ratio with respect to the Abbe number of existing optical materials. [Figure 16] The diagram showing an imaging apparatus provided with the zoom lens according to any one of Examples 1 to 5.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings. Numerical examples corresponding to Examples 1 to 5 will be described according to the features of the lens configurations of Examples 1 to 5. The master lenses M1 and M2 will be described respectively in association with Numerical Examples 1 and 4. In each lens cross-sectional view, the left side is the subject (object) side (front), and the right side is the image side (rear).

[0011] First, the master lens M1 into which the converter lens IE of each of Numerical Examples 1 to 3 is inserted into the optical path and the master lens M2 into which the converter lens IE of Numerical Examples 4 to 5 is inserted into the optical path by being interchanged with a part of the lens group IE0 will be described.

[0012] FIG. 1 is a cross-sectional view of the master lens M1 at the wide-angle end and at infinity focus. The wide-angle end and the telephoto end of each of the master lenses M1 and M2 indicate the zoom positions when the second lens group U2 is located at both ends of the range where it can move mechanically or under control.<S

[0013] U1 is the first lens group with positive refractive power that does not move for zooming. A portion of the first lens group U1 is movable along the optical axis as a focusing lens group for focusing from infinity to close. U2 is the second lens group with negative refractive power for magnification, which moves toward the image side when zooming from the wide-angle end (short focal length end) to the telephoto end (long focal length end). U3 is the third lens group with negative refractive power that corrects image plane fluctuations associated with magnification. U4 is a relay lens group that includes the aperture diaphragm SP, which is fixed during zooming, and has an imaging function. DG is a dummy optical element equivalent to a prism or filter. IP is the image plane, which corresponds to the imaging plane of a solid-state image sensor (photoelectric conversion element).

[0014] Figure 2 shows the longitudinal aberration diagrams of the master lens M1 at (a) the wide-angle end, (b) the middle zoom range, and (c) the telephoto end. In the spherical aberration diagram, Fno indicates the F number, the solid line is the e line (wavelength 546.07 nm), the dashed line is the F line (486.13 nm), the dashed line is the C line (656.27 nm), the long dashed line is the t line (1013.98 nm), and the short dashed line shows the spherical aberration for 1700 nm.

[0015] In the astigmatism diagram, the solid line S represents astigmatism on the sagittal image plane, and the dashed line M represents astigmatism on the meridional image plane. The distortion diagram shows distortion relative to the e-line. The chromatic aberration diagram shows lateral chromatic aberration on the e-line, F-line, C-line, t-line, and at a wavelength of 1700 nm. ω is the half-angle of view (°). Furthermore, for the master lens M1, spherical aberration is depicted on a scale of 0.5 mm, astigmatism on 0.5 mm, distortion on 5%, and lateral chromatic aberration on 0.05 mm.

[0016] Figure 9 is a cross-sectional view of the master lens M2 at its wide-angle end when focused at infinity. U1 is the first lens group with positive refractive power that does not move for zooming. A portion of the lens group U1 is made movable along the optical axis as a focusing lens group for focusing from infinity to close. The master lens M2 employs a floating focus system in which multiple lens groups move simultaneously along different trajectories during focusing.

[0017] U2 is a second lens group with negative refractive power that moves toward the image side for magnification when zooming from the wide-angle end (short focal length end) to the telephoto end (long focal length end). U3 is a third lens group with positive refractive index that moves toward the object side for magnification when zooming. U4 is a fourth lens group with positive refractive power that corrects image plane fluctuations associated with magnification. U5 is a relay lens group that includes a fixed aperture diaphragm SP and has an imaging function when zooming. DG is a dummy optical element equivalent to a prism or filter. IP is the image plane, which corresponds to the imaging plane of a solid-state image sensor (photoelectric conversion element).

[0018] Figure 10 shows the longitudinal aberration diagrams of the master lens M2 at (a) the wide-angle end, (b) the intermediate zoom range, and (c) the telephoto end. For the master lens M2, spherical aberration is depicted on a scale of 0.5 mm, astigmatism on 0.5 mm, distortion on 5%, and chromatic aberration on 0.05 mm.

[0019] Each master lens, M1 and M2, features a high magnification ratio and high optical performance across the entire zoom range from the visible light wavelength range to the SWIR wavelength range, thanks to its power distribution within the zoom lens (lens assembly) and the characteristics of the optical materials of the lenses constituting each lens group. This provides zoom lenses with magnification ratios of 18x and 90x, with well-corrected chromatic aberration from the visible light wavelength range to the SWIR wavelength range.

[0020] The master lenses M1 and M2, into which the converter lens IE described in this invention can be inserted and removed, are merely examples of zoom lenses in which the converter lens IE is inserted into and removed from the optical path. The present invention does not limit the scope of application of the chromatic aberration correction technology in the visible light wavelength range to the SWIR wavelength range in the converter lens IE. The present invention can be applied to various converter lens IEs having similar technology within the range of each conditional expression.

[0021] Next, the converter lens IE of the present invention will be described using Example 1 as an example. Example 1 corresponds to Numerical Example 1 and will be described as a configuration in which the converter lens IE is inserted into the master lens M1. The converter lens IE of Example 1 is a converter (extender) lens IE that doubles the focal length of the entire lens system by being inserted into the air gap in the relay lens group U4 of the master lens M1.

[0022] Figure 3 is a cross-sectional view of the converter lens IE of Embodiment 1 (Numerical Embodiment 1) of the present invention when inserted into the master lens M1, at the wide-angle end and infinity focus. The converter lens IE of Embodiment 1 corresponds to the 34th to 44th surfaces of Numerical Embodiment 1. The converter lens IE is composed of, in order from the object side to the image side, a cemented lens of a positive lens and a negative lens, a positive lens, a cemented lens of a negative lens and a positive lens, and a cemented lens of a positive lens and a negative lens separated by the largest air gap on the optical axis within the converter lens IE.

[0023] The converter lens IE in each embodiment is removable from the optical path within the master lens M1, or replaces a portion of the lens group IE0 in the master lens M2, thereby making the focal length of the entire system longer than the focal lengths of the master lenses M1 and M2 alone. In each embodiment, the converter lens IE is composed of a front lens group Cf with positive refractive power on the object side and a rear lens group Cr with negative refractive power on the image side, separated by the largest air gap among the distances between the lenses included in the converter lens IE.

[0024] The front lens group Cf has at least one negative front lens Lnf with negative refractive power, and when the partial dispersion ratio of the optical material of the negative front lens Lnf with respect to the C line and t line is θctf, and the Abbe number with respect to the d line is νdnf, 0.55<θctf-0.0049×νdnf<0.60 (1) 20 < νdnf < 52 ···(2) It is characterized by satisfying the following conditions.

[0025] Here, the Abbe number and partial dispersion ratio are indicators of the magnitude of dispersion and anomalous dispersion of an optical material, respectively. The Abbe number νd, relative to the d-line of the optical material, and the partial dispersion ratio θct for the C-line and t-line are given by Nd, NC, NF, and Nt, respectively, when the refractive indices of the optical material at the d-line (wavelength 587.56 nm), C-line (wavelength 656.27 nm), F-line (wavelength 486.13 nm), and t-line (wavelength 1013.98 nm) are Nd, NC, NF, and Nt, respectively. νd = (Nd-1) / (NF-NC) θct = (NC - Nt) / (NF - NC) It is defined as follows.

[0026] These Abbe number νd and partial dispersion ratio θct values ​​can be easily confirmed from the catalogs of various glass manufacturers. Conditional equations (1) and (2) show combinations of Abbe number and partial dispersion ratio that are advantageous for correcting axial chromatic aberration in the near-infrared wavelength range, for the material of at least one specific negative lens (front negative lens Lnf) included in the front lens group Cf.

[0027] Here, we will explain the relationship between the Abbe number, partial dispersion ratio, and chromatic aberration correction. As shown in Figure 15, existing optical materials have a narrow distribution of partial dispersion ratios relative to the Abbe number, and there is a tendency for the partial dispersion ratio to be larger as the Abbe number increases. Let Φ be the predetermined refractive power, Φp be the positive refractive power, Φn be the negative refractive power, νp and νn be the Abbe numbers, h be the incident height of the paraxial ray on the axial side, and H be the incident height of the paraxial ray in the pupil. In this case, the axial chromatic aberration coefficient L and the lateral chromatic aberration coefficient T of a thin-walled, tightly fitting system composed of two lenses, Gp with a positive refractive power Φp and Gn with a negative refractive power Φn, are expressed by the following equations (a) and (b). L=h×h×(Φp / νp+Φn / νn) ···(A) T=h×H×(Φp / νp+Φn / νn) ···(A) Here, the refractive force Φ is, Φ = Φp + Φn ···(U) It is represented as follows.

[0028] On-axial paraxial rays and pupillary paraxial rays are defined as follows: On-axial paraxial rays are paraxial rays incident on the optical system at an incident height of 1, parallel to the optical axis, with the focal length at the wide-angle end of the entire optical system normalized to 1. Pupillary paraxial rays are paraxial rays that pass through the intersection of the entrance pupil of the optical system and the optical axis, among the rays incident on the image plane at the maximum image height, with the focal length at the wide-angle end of the entire optical system normalized to 1.

[0029] The refractive powers of lenses Gp and Gn are normalized so that the refractive power Φ shown in equation (c) is 1. The same consideration can be applied to thin-walled, tightly fitting lens systems with three or more lens components. In equations (a) and (b), if L=0 and T=0, the image formation positions on the axis and on the image plane of the C and F lines coincide. Correcting chromatic aberration for two specific wavelengths in this way is generally called two-wavelength aberration correction (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, is corrected to be approximately near zero in order to suppress fluctuations in chromatic aberration associated with zooming.

[0030] In this case, assuming the object distance is infinity and the light beam is incident on the zoom lens, if we denote the amount of axial chromatic aberration shift of the C line relative to the t line and the amount of lateral chromatic aberration shift as the second-order spectral amount of axial chromatic aberration Δs and the second-order spectral amount of lateral chromatic aberration Δy, respectively, then these are: Δs=-h×h×(θp-θn) / (νp-νn)×f (d) Δy=-h×H×(θp-θn) / (νp-νn)×Y (o) It is expressed as follows. In equations (E) and (O), f is the focal length of the entire zoom lens system, and Y is the image height. Correcting chromatic aberration for a specific set of three wavelengths by adding a specific wavelength to two wavelengths in this way is generally called three-wavelength aberration correction (second-order spectral correction or second-order chromatic aberration correction).

[0031] Zoom lenses used in surveillance cameras and other applications require longer focal lengths, and as the focal length f in equation (E) increases, axial chromatic aberration tends to increase. Furthermore, with the use of large-format image sensors that cover the range from visible light wavelengths to SWIR wavelengths, as the image height Y in equation (O) increases, lateral chromatic aberration tends to increase. Therefore, it is important to appropriately determine the refractive power and optical material arrangement of the positive and negative lens groups that constitute the zoom lens to suppress the values ​​in equations (E) and (O).

[0032] By satisfying conditions (1) and (2), it is possible to employ optical materials with high dispersion and a high partial dispersion ratio in the negative front lens Lnf, which in particular makes it possible to effectively correct the second-order spectrum of axial chromatic aberration in the SWIR wavelength range.

[0033] If θctf-0.0049×νdnf exceeds the upper limit of condition (1), the partial dispersion ratio of the negative front lens Lnf becomes excessively high, resulting in excessive axial chromatic aberration correction, especially in the SWIR wavelength range at the wide-angle end, which degrades the optical performance of the zoom lens and is therefore undesirable. If θctf-0.0049×νdnf falls below the lower limit of condition (1), axial chromatic aberration correction in the SWIR wavelength range becomes insufficient, making it difficult to achieve a balance between chromatic aberration in the visible light wavelength range and the SWIR wavelength range, which is also undesirable.

[0034] Furthermore, it is preferable to set the numerical range of condition (1) as follows. 0.554<θctf-0.0049×νdnf<0.586 (1a) Furthermore, it is even preferable to set the numerical range of conditional expression (1) as follows. 0.556<θctf-0.0049×νdnf<0.557 (1aa)

[0035] Furthermore, if νdnf exceeds the upper limit of condition (2), a low-dispersion material will be selected, making it impossible to adequately achieve the Abbe number difference with the opposing positive lens, thus reducing the primary spectral correction power, which is undesirable. If νdnf falls below the lower limit of condition (2), existing glass materials cannot maintain a high partial dispersion ratio, making secondary spectral correction difficult, which is also undesirable.

[0036] Furthermore, it is preferable to set the numerical range of condition (2) as follows. 24<νdnf<48 ···(2a) Furthermore, it is even preferable to set the numerical range of conditional expression (2) as follows. 27<νdnf<45 ···(2aa)

[0037] The converter lens IE in each embodiment satisfies the conditions of condition (1) and condition (2) simultaneously, thereby realizing a converter lens IE that achieves both good first-order and second-order spectral correction of axial chromatic aberration from the visible light wavelength range to the SWIR wavelength range.

[0038] Furthermore, it is preferable that the converter lens IE of each embodiment satisfies at least one of the following conditions (3) to (8). The rear lens group Cr includes at least one negative rear negative lens Lnr, and when the partial dispersion ratio of the optical material of the rear negative lens Lnr with respect to the C line and t line is θctr, and the Abbe number with respect to the d line is νdnr, 0.48<θctr-0.0041×νdnr<0.55 (3) 25 < νdnr < 61 (4) It is preferable to satisfy the following conditions.

[0039] Conditional equations (3) and (4) show combinations of Abbe number and partial dispersion ratio that are advantageous for correcting axial chromatic aberration in the SWIR wavelength range as a material for the rear negative lens Lnr. By satisfying conditions (3) and (4), it is possible to achieve good correction of the primary and secondary spectra of axial chromatic aberration in the SWIR wavelength range by the rear negative lens Lnr.

[0040] Conditional equations (3) and (4) show the appropriate relationship between the Abbe number νdnr and the partial dispersion ratio θctr of the rear negative lens Lnr. When θctr - 0.0041 × νdnr satisfies conditional equation (3), a glass material with a low partial dispersion ratio can be selected for the rear negative lens Lnr, which is particularly effective in suppressing the increase in axial chromatic aberration in the SWIR wavelength range.

[0041] If θctr -0.0041 × νdnr exceeds the upper limit of condition equation (3), it results in the selection of a glass material with a high partial dispersion ratio relative to the Abbe number, which is undesirable because it does not sufficiently suppress the increase in axial chromatic aberration. If θctr -0.0041 × νdnr falls below the lower limit of condition equation (3), it becomes necessary to select a high-dispersion material from the available glass materials, which makes it difficult to ensure a difference in dispersion values ​​between the rear negative lens Lnr and the adjacent positive lens, resulting in insufficient first-order spectral correction, which is also undesirable.

[0042] Furthermore, it is preferable to set the numerical range of conditional expression (3) as follows. 0.49<θctr-0.0041×νdnr<0.53 (3a) Furthermore, it is even preferable to set the numerical range of conditional expression (3) as follows. 0.495<θctr-0.0041×νdnr<0.525 (3aa) Furthermore, it is even more preferable to set the numerical range of condition (3) as follows. 0.50<θctr-0.0041×νdnr<0.52 (3aaa)

[0043] Furthermore, if νdnr exceeds the upper limit of condition (4), it becomes necessary to use a material with high partial dispersion and low refractive index from existing glass materials, which is undesirable because it results in insufficient correction of axial chromatic aberration and Petzval sum. If νdnr falls below the lower limit of condition (4), the dispersion becomes too high, making it impossible to secure a sufficient Abbe number difference between the rear negative lens Lnr and the adjacent positive lens, which is undesirable because it results in unfavorable primary spectral correction.

[0044] Furthermore, it is preferable to set the numerical range of conditional expression (4) as follows. 30 < νdnr < 55 ···(4a) Furthermore, it is even preferable to set the numerical range of conditional expression (4) as follows. 32<νdnr<52 ···(4aa)

[0045] Furthermore, the front lens group Cf includes a positive lens and a negative lens arranged adjacent to each other, and when the partial dispersion ratios of the optical materials of the positive lens and the negative lens with respect to the C line and t line are θpf and θnf, respectively, and the Abbe numbers with respect to the d line are νpf and νnf, respectively, 0<(θpf-θnf) / (νpf-νnf)<2.5×10 -3 ...(5) It is preferable to satisfy the following conditions.

[0046] Conditional equation (5) shows the appropriate relationship between the Abbe number and partial dispersion ratio of a specific negative lens placed in the front lens group Cf and a positive lens placed adjacent to it that provides chromatic aberration correction. In the front lens group Cf, it is possible to suppress the occurrence of chromatic aberration within the front lens group Cf by placing a glass material with a low partial dispersion ratio for the positive lens and a glass material with a high partial dispersion ratio for the negative lens. Conditional equation (5) defines the range of slope of the line connecting the glass materials of the positive and negative lenses in the θct-νd glass map shown in Figure 15. By making the slope of this line gentler, good second-order spectral correction of chromatic aberration in the SWIR wavelength range of the converter lens IE can be achieved.

[0047] If (θpf-θnf) / (νpf-νnf) exceeds the upper limit of condition (5), the second-order spectral correction for chromatic aberration in the SWIR wavelength range becomes excessive, which is undesirable as it causes an increase in chromatic aberration. Also, with existing glass materials, the difference in Abbe numbers between the negative and positive lenses cannot be sufficiently secured, resulting in insufficient first-order spectral correction, which is undesirable. If (θpf-θnf) / (νpf-νnf) falls below the lower limit of condition (5), the correction power for chromatic aberration, especially in the SWIR wavelength range, is insufficient, which is undesirable.

[0048] Furthermore, it is preferable to set the numerical range of conditional expression (5) as follows. 5.0×10 -4 <(θpf-θnf) / (νpf-νnf)<2.3×10 -3 ...(5a) Furthermore, it is even preferable to set the numerical range of conditional expression (5) as follows. 7.0×10 -4 <(θpf-θnf) / (νpf-νnf)<1.9×10 -3 ...(5aa)

[0049] Furthermore, the rear lens group Cr has a positive lens and a negative lens arranged adjacent to each other, and when the partial dispersion ratios of the optical materials of the positive lens and the negative lens with respect to the C line and the t line are θpr and θnr, respectively, and the Abbe numbers with respect to the d line are νpr and νnr, respectively, 0<(θpr-θnr) / (νpr-νnr)<4.0×10 -3 ...(6) It is preferable to satisfy the following conditions.

[0050] Conditional equation (6) shows the appropriate relationship between the Abbe number and partial dispersion ratio of a specific negative lens located in the rear lens group Cr and a positive lens located adjacent to it that provides chromatic aberration correction. By placing a glass material with a low partial dispersion ratio for the negative lens in the rear lens group Cr and a glass material with a high partial dispersion ratio for the adjacent positive lens, it is possible to suppress the occurrence of chromatic aberration within the rear lens group Cr. Conditional equation (6) defines the range of slope of the line connecting the glass materials of the positive and negative lenses in the θct-νd glass map shown in Figure 15. By making the slope of this line gentler, good second-order spectral correction of chromatic aberration in the SWIR wavelength range within the converter lens IE can be achieved.

[0051] If (θpr - θnr) / (νpr - νnr) exceeds the upper limit of conditional expression (6), the secondary spectrum correction for chromatic aberration in the SWIR wavelength range is insufficient, which causes residual chromatic aberration and is not preferable. If (θpr - θnr) / (νpr - νnr) is below the lower limit of conditional expression (6), the secondary spectrum correction for chromatic aberration in the SWIR wavelength range becomes excessive, which causes an increase in chromatic aberration and is not preferable. Also, in existing optical materials, the Abbe number difference between the negative lens and the positive lens cannot be sufficiently ensured, resulting in insufficient primary spectrum correction and is not preferable.

[0052] Note that it is more preferable if the numerical range of conditional expression (6) is as follows. 5.0×10 -4 <(θpr - θnr) / (νpr - νnr)<3.3×10 -3 ···(6a) Also, it is even more preferable if the numerical range of conditional expression (6) is as follows. 1.0×10 -3 <(θpr - θnr) / (νpr - νnr)<2.9×10 -3 ···(6aa)

[0053] Furthermore, in the zoom lens where the converter lens IE of the present invention is inserted into the optical path within the master lenses M1 and M2, when the focal length at the wide-angle end when the master lenses M1 and M2 are focused at infinity is fwm and the focal length at the wide-angle end when the zoom lens is focused at infinity is fwc, 1.3 < fwc / fwm < 3.0 ···(7) It is preferable to satisfy the condition.

[0054] Conditional equation (7) defines the ratio of focal lengths at the wide-angle end of the entire lens system before and after insertion of the converter lens IE into the master lenses M1 and M2, and defines the converter magnification. If fwc / fwm exceeds the upper limit of conditional equation (7), the refractive power of each lens constituting the converter lens IE becomes stronger, worsening spherical aberration and field curvature when the converter lens IE is inserted, which is undesirable. If fwc / fwm falls below the lower limit of conditional equation (7), the converter magnification is low, and the function as an extender is insufficient, which is also undesirable.

[0055] Furthermore, it is preferable to set the numerical range of conditional expression (7) as follows. 1.35 <fwc / fwm<2.9 ···(7a) Furthermore, it is preferable to set the numerical range of conditional expression (7) as follows. 1.39 <fwc / fwm<2.87 ···(7aa) Furthermore, it is preferable to set the numerical range of conditional expression (7) as follows. 1.98 <fwc / fwm<2.6 ···(7aaa)

[0056] Furthermore, in the converter lens IE of the present invention, when Lc is the distance along the optical axis from the object-side surface to the image-side surface of the converter lens IE, and Dc is the effective diameter of the object-side surface, 0.8 <Lc / Dc<1.8 ···(8) It is preferable to satisfy the following conditions.

[0057] Conditional equation (8) specifies the ratio of the optical axis length to the effective diameter of the converter lens IE. If Lc / Dc exceeds the upper limit of conditional equation (8), the converter lens IE becomes relatively larger, leading to an increase in the overall size of the lens system, which is undesirable. If Lc / Dc falls below the lower limit of conditional equation (8), the power of each lens in the converter lens IE becomes large, making it difficult to adequately correct performance such as spherical aberration, which is also undesirable.

[0058] Furthermore, it is preferable to set the numerical range of conditional expression (8) as follows. 1.0 <Lc / Dc<1.7 ···(8a) Furthermore, it is preferable to set the numerical range of conditional expression (8) as follows. 1.3 <Lc / Dc<1.6 ···(8aa)

[0059] The converter lenses IE of Examples 1 to 5 will be described in detail below. After Example 5, the numerical values ​​corresponding to Examples 1 to 5 will be shown. [Examples]

[0060] Figure 3 shows a cross-sectional view of the zoom lens at its wide-angle end (focal length 56mm) and infinity focus, with the converter lens IE of Example 1 (Numerical Example 1) inserted into the master lens M1. The converter magnification (extender magnification) of Example 1 is 2x.

[0061] Numerical values ​​corresponding to Example 1 In Example 1, i indicates the order of the surfaces (optical surfaces such as lens surfaces and aperture surfaces) when counted from the object side, ri indicates the radius of curvature of the i-th surface (mm), and di indicates the distance on the optical axis between the i-th and (i+1)-th surfaces (mm). Also, ndi, νdi, and θcti indicate the refractive index of the medium (optical material) between the i-th and (i+1)-th surfaces at the d-line, the Abbe number with respect to the d-line, and the partial dispersion ratio with respect to the C-line and t-line, respectively.

[0062] BF stands for back focus (mm). Back focus BF is the distance along the optical axis from the final surface of the zoom lens (the optical surface closest to the image, including the dummy glass) to the paraxial image plane. The total length of the lens (mm) is the distance along the optical axis from the frontmost lens surface (the lens surface closest to the object) to the final surface of the zoom lens plus the back focus BF.

[0063] The asterisk (*) next to the surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following equation, where X is the displacement from the surface vertex in the direction of the optical axis, H is the height from the optical axis in the direction perpendicular to the optical axis, the direction of light propagation is positive, R is the radius of paraxial curvature, k is the cone constant, and A4, A6, A8, A10, A12, and A14 are aspherical coefficients. Also, "eZ" is "×10 -Z It means "...".

number

[0064] In Numerical Example 1, the converter lens IE corresponds to the 34th to 44th surfaces. It consists of 4 groups and 7 elements, arranged from the object side toward the image side: a cemented lens of a positive and a negative lens, a positive lens, a cemented lens of a negative and a positive lens, and a cemented lens of a positive and a negative lens separated by the maximum air gap on the optical axis within the converter lens IE. Here, in the description of the example, "group" as used within the converter lens IE refers to a unit separated by an air gap, and "element" refers to the number of individual lenses.

[0065] The front lens group Cf corresponds to surfaces 34 to 41. The rear lens group Cr corresponds to surfaces 42 to 44. Within the front lens group Cf, the characteristic negative lens (front negative lens Lnf) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 35 to 36. Similarly, within the rear lens group Cr, the characteristic negative lens (rear negative lens Lnr) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 43 to 44. In this invention, these characteristic negative lenses may be cemented lenses, as in this embodiment, or single lenses. This is also true in other embodiments described later.

[0066] Figure 4(a) shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of Numerical Example 1 at the wide-angle end (focal length 56 mm). Figure 4(b) shows the longitudinal aberrations of Numerical Example 1 at the intermediate zoom position (focal length 392 mm). Figure 4(c) shows the longitudinal aberrations of Numerical Example 1 at the telephoto end (focal length 1008 mm). All figures show the longitudinal aberrations when focused at infinity. In Numerical Example 1, 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 0.1 mm.

[0067] Table 1 summarizes the numerical values ​​corresponding to conditional equations (1) to (8) in Numerical Example 1. Numerical Example 1 satisfies all conditional equations (1) to (8), and in particular, it effectively corrects axial chromatic aberration in the SWIR wavelength range. Ideally, all conditions (1) to (8) should be satisfied, but if conditions (1) to (2) are satisfied, it is not necessary to satisfy all of conditions (3) to (8). Higher optical performance can be obtained if conditions (1) to (2) are satisfied and at least one of conditions (3) to (8) is also satisfied. [Examples]

[0068] Figure 5 shows a cross-sectional view of the zoom lens at its wide-angle end (focal length 70mm) and at infinity focus with the converter lens IE of Example 2 (Numerical Example 2) inserted into the master lens M1. The converter magnification (extender magnification) of Example 2 is 2.5x.

[0069] In numerical example 2, the converter lens IE corresponds to the 34th to 44th surfaces. It consists of 7 elements in 4 groups, arranged from the object side towards the image side: a cemented lens of a positive and a negative lens, a positive lens, a cemented lens of a negative and a positive lens, and a cemented lens of a positive and a negative lens separated by the maximum air gap on the optical axis within the converter lens IE.

[0070] The front lens group Cf corresponds to surfaces 34 to 41. The rear lens group Cr corresponds to surfaces 42 to 44. Within the front lens group Cf, the characteristic negative lens (front negative lens Lnf) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 35 to 36. Similarly, within the rear lens group Cr, the characteristic negative lens (rear negative lens Lnr) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 43 to 44.

[0071] Figure 6(a) shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of Numerical Example 2 at the wide-angle end (focal length 70 mm). Figure 6(b) shows the longitudinal aberrations of Numerical Example 2 at the intermediate zoom position (focal length 490 mm). Figure 6(c) shows the longitudinal aberrations of Numerical Example 2 at the telephoto end (focal length 1260 mm). All figures show the longitudinal aberrations when the lens is focused at infinity. In Numerical Example 2, spherical aberration is depicted on a scale of 1.25 mm, astigmatism on 1.25 mm, distortion on 5%, and chromatic aberration on 0.125 mm.

[0072] As shown in Table 1, Numerical Example 2 satisfies all of the conditions (1) to (8), and in particular, it effectively corrects axial chromatic aberration in the SWIR wavelength range. [Examples]

[0073] Figure 7 shows a cross-sectional view of the zoom lens at its wide-angle end (focal length 80mm) and infinity focus, with the converter lens IE of Example 3 (Numerical Example 3) inserted into the master lens M1. The converter magnification (extender magnification) of Example 3 is 2.86x.

[0074] In numerical example 3, the converter lens IE corresponds to surfaces 34 to 44. It consists of 7 elements in 4 groups, arranged from the object side towards the image side: a positive lens, a cemented lens of a negative lens and a positive lens, a cemented lens of a negative lens and a positive lens, and a cemented lens of a positive lens and a negative lens separated by the maximum air gap on the optical axis within the converter lens IE. The front lens group Cf corresponds to surfaces 34 to 41. The rear lens group Cr corresponds to surfaces 42 to 44. Within the front lens group Cf, the characteristic negative lens (front negative lens Lnf) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 36 to 37. Also, within the rear lens group Cr, the characteristic negative lens (rear negative lens Lnr) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 43 to 44.

[0075] Figure 8(a) shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of Numerical Example 3 at the wide-angle end (focal length 80 mm). Figure 8(b) shows the longitudinal aberrations of Numerical Example 3 at the intermediate zoom position (focal length 560 mm). Figure 8(c) shows the longitudinal aberrations of Numerical Example 3 at the telephoto end (focal length 1800 mm). All figures show the longitudinal aberrations when the lens is focused at infinity. In Numerical Example 3, spherical aberration is depicted on a scale of 1.5 mm, astigmatism on 1.5 mm, distortion on 5%, and chromatic aberration on 0.15 mm.

[0076] As shown in Table 1, Numerical Example 3 satisfies all of the conditions (1) to (8), and in particular, it effectively corrects axial chromatic aberration in the SWIR wavelength range. [Examples]

[0077] Figure 11 shows a cross-sectional view of the zoom lens at its wide-angle end (focal length 28.6 mm) and at infinity focus, with the converter lens IE of Example 4 (Numerical Example 4) inserted into the master lens M2. The converter magnification (extender magnification) of Example 4 is 2x.

[0078] In numerical example 4, the converter lens IE corresponds to surfaces 43 to 53. It consists of 4 groups of 7 elements, arranged from the object side toward the image side: a cemented lens of a negative lens and a positive lens, a cemented lens of a positive lens and a negative lens, a cemented lens of a negative lens and a positive lens separated by the maximum air gap on the optical axis within the converter lens, and a negative lens.

[0079] The front lens group Cf corresponds to surfaces 43 to 48. The rear lens group Cr corresponds to surfaces 49 to 53. Within the front lens group Cf, the characteristic negative lens (front negative lens Lnf) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 43 to 44. Similarly, within the rear lens group Cr, the characteristic negative lens (rear negative lens Lnr) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 52 to 53.

[0080] Figure 12(a) shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of numerical example 4 at the wide-angle end (focal length 28.6 mm). Figure 12(b) shows the longitudinal aberrations of numerical example 4 at the intermediate zoom position (focal length 312 mm). Figure 12(c) shows the longitudinal aberrations of numerical example 4 at the telephoto end (focal length 2574 mm). All figures show the longitudinal aberrations when the image is focused at infinity. In numerical example 4, spherical aberration is depicted on a scale of 1.0 mm, astigmatism on 1.0 mm, distortion on 5%, and chromatic aberration on 0.1 mm.

[0081] As shown in Table 1, Numerical Example 4 satisfies all of the conditions (1) to (8), and in particular, it effectively corrects axial chromatic aberration in the SWIR wavelength range. [Examples]

[0082] Figure 13 shows a cross-sectional view of the zoom lens at its wide-angle end (focal length 20.0 mm) and at infinity focus, with the converter lens IE of Example 5 (Numerical Example 5) inserted into the master lens M2. The converter magnification (extender magnification) of Example 5 is 1.4x.

[0083] In numerical example 5, the converter lens IE corresponds to surfaces 43 to 50. It consists of four elements in four groups: a positive lens, a negative lens, and two more positive and negative lenses separated by the maximum air gap on the optical axis within the converter lens, moving from the object side towards the image side.

[0084] The front lens group Cf corresponds to surfaces 43 to 46. The rear lens group Cr corresponds to surfaces 47 to 50. Within the front lens group Cf, the characteristic negative lens (front negative lens Lnf) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 45 to 46. Similarly, within the rear lens group Cr, the characteristic negative lens (rear negative lens Lnr) that is advantageous for correcting chromatic aberration in the SWIR wavelength range corresponds to surfaces 49 to 50.

[0085] Figure 14(a) shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of numerical example 5 at the wide-angle end (focal length 20.0 mm). Figure 14(b) shows the longitudinal aberrations of numerical example 5 at the intermediate zoom position (focal length 218 mm). Figure 14(c) shows the longitudinal aberrations of numerical example 4 at the telephoto end (focal length 1800 mm). All figures show the longitudinal aberrations when the lens is focused at infinity. In numerical example 5, spherical aberration is depicted on a scale of 0.7 mm, astigmatism on 0.7 mm, distortion on 5%, and chromatic aberration on 0.07 mm.

[0086] As shown in Table 1, Numerical Example 5 satisfies all of the conditions (1) to (8), and in particular, it effectively corrects axial chromatic aberration in the SWIR wavelength range.

[0087] <Numerical Data> [Master Lens M1] Unit: mm Surface data Face number rd nd vd θct Effective diameter 1 115.332 10.18 1.58913 61.15 0.8543 104.14 2 302.999 0.80 103.34 3 75.153 18.02 1.43387 95.10 0.8092 97.88 4 317.078 1.12 95.29 5 101.505 3.30 1.72916 54.68 0.8244 88.09 6 50.993 19.99 1.43875 94.66 0.8410 77.48 7 2058.240 2.46 75.64 8 -878.835 3.00 1.72916 54.68 0.8244 74.14 9 61.193 20.26 66.67 10 97.412 7.06 1.43387 95.10 0.8092 66.00 11 2777.966 0.20 65.63 12 69.087 6.04 1.49700 81.54 0.8258 63.03 13 159.129 (variable) 62.19 14 127.960 1.00 1.69930 51.11 0.7593 24.32 15 19.611 4.31 21.89 16 2221.996 5.80 1.65412 39.68 0.7554 21.68 17 -17.043 0.90 1.59522 67.74 0.7953 21.43 18 36.034 0.48 20.19 19 24.335 3.11 1.61340 44.27 0.7825 20.22 20 105.537 2.03 19.78 21 -35.686 0.90 1.59522 67.74 0.7953 19.70 22 -304.103 (variable) 19.64 23 -42.344 0.90 1.69930 51.11 0.7593 19.36 24 37.850 2.48 1.85478 24.80 0.6739 20.27 25 151.127 (variable) 20.55 26 ∞ 0.63 27.88 27 76.675 5.18 1.59522 67.74 0.7953 28.86 28 -46.891 0.50 29.09 29 70.327 3.02 1.43875 94.93 0.8373 28.45 30 -1394.511 2.95 28.11 31 45.962 6.13 1.43875 94.66 0.8410 26.41 32 -35.548 1.00 1.80610 40.92 0.7483 25.66 33 90.932 40.00 24.99 34 74.212 4.20 1.43875 94.93 0.8373 22.56 35 -35.057 5.66 22.39 36 -35.043 0.80 1.65160 58.54 0.8525 20.33 37 15.870 5.58 1.69349 50.81 0.7740 20.57 38 -175.848 10.00 20.56 39 94.319 4.73 1.51633 64.14 0.8687 19.60 40 -18.653 1.00 1.69930 51.11 0.7593 19.41 41 -60.269 5.00 19.46 42 ∞ 33.00 1.60859 46.44 0.7534 40.00 43 ∞ 13.20 1.51680 64.17 0.8698 40.00 44 ∞ 7.39 40.00 Image plane ∞ Various data Zoom ratio 18.00 Focal length 28.00 196.00 504.00 F-number 2.85 2.85 4.84 Half-angle 11.11 1.61 0.63 Image height 5.50 5.50 5.50 Lens length 350.01 350.01 350.01 BF 7.39 7.39 7.39 d13 3.67 61.84 72.45 d22 62.25 2.16 11.26 d25 19.77 21.69 1.98 Entrance pupil position 231.44 1128.51 2118.83 Exit pupil position -407.61 -407.61 -407.61 Front principal point position 257.55 1231.94 2010.75 Back principal point position -20.61 -188.61 -496.61 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 168.25 92.43 18.71 -67.54 2 14 -24.21 18.53 3.81 -8.80 3 23 -55.03 3.38 0.46 -1.39 4 26 62.32 142.60 50.53 -140.50 Single lens data Lens starting plane, focal length 1 1 308.62 2 3 221.45 3 5 -143.90 4 6 118.52 5 8 -78.01 6 10 231.91 7 12 239.60 8 14 -33.09 9 16 25.73 10 17 -19.25 11 19 50.55 12 21 -67.77 13 23 -28.32 14 24 57.93 15 27 49.49 16 29 152.31 17 31 46.64 18 32 -31.41 19 34 54.77 20 36 -16.59 21 37 21.14 22 39 30.49 23 40 -38.84

[0088] [Numerical Example 1] Unit: mm Surface data Face number rd nd vd θct Effective diameter 1 115.332 10.18 1.58913 61.15 0.8543 104.14 2 302.999 0.80 103.34 3 75.153 18.02 1.43387 95.10 0.8092 97.88 4 317.078 1.12 95.29 5 101.505 3.30 1.72916 54.68 0.8244 88.09 6 50.993 19.99 1.43875 94.66 0.8410 77.48 7 2058.240 2.46 75.64 8 -878.835 3.00 1.72916 54.68 0.8244 74.14 9 61.193 20.26 66.67 10 97.412 7.06 1.43387 95.10 0.8092 66.00 11 2777.966 0.20 65.63 12 69.087 6.04 1.49700 81.54 0.8258 63.03 13 159.129 (variable) 62.19 14 127.960 1.00 1.69930 51.11 0.7593 24.32 15 19.611 4.31 21.89 16 2221.996 5.80 1.65412 39.68 0.7554 21.68 17 -17.043 0.90 1.59522 67.74 0.7953 21.43 18 36.034 0.48 20.19 19 24.335 3.11 1.61340 44.27 0.7825 20.22 20 105.537 2.03 19.78 21 -35.686 0.90 1.59522 67.74 0.7953 19.70 22 -304.103 (variable) 19.64 23 -42.344 0.90 1.69930 51.11 0.7593 19.36 24 37.850 2.48 1.85478 24.80 0.6739 20.27 25 151.127 (variable) 20.55 26 ∞ 0.63 27.88 27 76.675 5.18 1.59522 67.74 0.7953 28.86 28 -46.891 0.50 29.09 29 70.327 3.02 1.43875 94.93 0.8373 28.45 30 -1394.511 2.95 28.11 31 45.962 6.13 1.43875 94.66 0.8410 26.41 32 -35.548 1.00 1.80610 40.92 0.7483 25.66 33 90.932 2.48 24.99 34 33.969 6.31 1.59522 67.74 0.7953 24.75 35 -34.721 1.00 1.73800 32.33 0.7154 24.16 36 -357.754 2.74 23.48 37 1034.755 3.29 1.49700 81.54 0.8258 22.11 38 -41.996 3.01 21.55 39 -39.448 1.00 1.64000 60.08 0.8645 18.90 40 24.205 3.52 1.65412 39.68 0.7554 17.94 41 -73.716 8.20 17.62 42 -51.393 3.67 1.72047 34.71 0.7267 12.54 43 -10.046 0.80 1.69930 51.11 0.7593 12.07 44 20.048 3.98 11.14 45 74.212 4.20 1.43875 94.93 0.8373 22.56 46 -35.057 5.66 22.39 47 -35.043 0.80 1.65160 58.54 0.8525 20.33 48 15.870 5.58 1.69349 50.81 0.7740 20.57 49 -175.848 10.00 20.56 50 94.319 4.73 1.51633 64.14 0.8687 19.60 51 -18.653 1.00 1.69930 51.11 0.7593 19.41 52 -60.269 5.00 19.46 53 ∞ 33.00 1.60859 46.44 0.7534 40.00 54 ∞ 13.20 1.51680 64.17 0.8698 40.00 55 ∞ 7.39 40.00 Image plane ∞ Various data Zoom ratio 18.00 Focal length 56.00 392.00 1008.00 F-number 5.70 5.70 9.68 Half-angle 5.61 0.80 0.31 Lens length: 350.02 350.02 350.02 BF 7.39 7.39 7.39 d13 3.67 61.84 72.45 d22 62.25 2.16 11.26 d25 19.77 21.69 1.98 Entrance pupil position 231.44 1128.51 2118.83 Exit pupil position -101.60 -101.60 -101.60 Front principal point position 258.66 110.68 -6195.28 Back principal point position -48.61 -384.60 -1000.60 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 168.25 92.43 18.71 -67.54 2 14 -24.21 18.53 3.81 -8.80 3 23 -55.03 3.38 0.46 -1.39 4 26 31.68 142.60 -13.95 -111.29 Single lens data Lens starting plane, focal length 1 1 308.62 2 3 221.45 3 5 -143.90 4 6 118.52 5 8 -78.01 6 10 231.91 7 12 239.60 8 14 -33.09 9 16 25.73 10 17 -19.25 11 19 50.55 12 21 -67.77 13 23 -28.32 14 24 57.93 15 27 49.49 16 29 152.31 17 31 46.64 18 32 -31.41 19 34 29.77 20 35 -51.79 21 37 81.05 22 39 -23.20 23 40 28.09 24 42 16.60 25 43 -9.42 26 45 54.77 27 47 -16.59 28 48 21.14 29 50 30.49 30 51 -38.84

[0089] [Numerical Example 2] Unit: mm Surface data Face number rd nd vd θct Effective diameter 1 115.332 10.18 1.58913 61.15 0.8543 104.14 2 302.999 0.80 103.34 3 75.153 18.02 1.43387 95.10 0.8092 97.88 4 317.078 1.12 95.29 5 101.505 3.30 1.72916 54.68 0.8244 88.09 6 50.993 19.99 1.43875 94.66 0.8410 77.48 7 2058.240 2.46 75.64 8 -878.835 3.00 1.72916 54.68 0.8244 74.14 9 61.193 20.26 66.67 10 97.412 7.06 1.43387 95.10 0.8092 66.00 11 2777.966 0.20 65.63 12 69.087 6.04 1.49700 81.54 0.8258 63.03 13 159.129 (variable) 62.19 14 127.960 1.00 1.69930 51.11 0.7593 24.32 15 19.611 4.31 21.89 16 2221.996 5.80 1.65412 39.68 0.7554 21.68 17 -17.043 0.90 1.59522 67.74 0.7953 21.43 18 36.034 0.48 20.19 19 24.335 3.11 1.61340 44.27 0.7825 20.22 20 105.537 2.03 19.78 21 -35.686 0.90 1.59522 67.74 0.7953 19.70 22 -304.103 (variable) 19.64 23 -42.344 0.90 1.69930 51.11 0.7593 19.36 24 37.850 2.48 1.85478 24.80 0.6739 20.27 25 151.127 (variable) 20.55 26 ∞ 0.63 27.88 27 76.675 5.18 1.59522 67.74 0.7953 28.86 28 -46.891 0.50 29.09 29 70.327 3.02 1.43875 94.93 0.8373 28.45 30 -1394.511 2.95 28.11 31 45.962 6.13 1.43875 94.66 0.8410 26.41 32 -35.548 1.00 1.80610 40.92 0.7483 25.66 33 90.932 2.72 24.99 34 23.011 7.47 1.53775 74.70 0.8203 24.66 35 -36.244 1.00 1.74951 35.33 0.7308 23.78 36 37.552 1.26 22.34 37 33.614 4.90 1.50127 56.50 0.8095 22.23 38 -48.855 0.65 21.73 39 -124.296 1.00 1.64000 60.08 0.8645 20.71 40 21.452 4.19 1.88300 40.76 0.7397 19.42 41 -377.353 10.46 18.68 42 -15.649 1.69 1.85478 24.80 0.6739 9.72 43 -8.953 0.70 1.69930 51.11 0.7593 9.60 44 15.999 3.96 8.91 45 74.212 4.20 1.43875 94.93 0.8373 22.56 46 -35.057 5.66 22.39 47 -35.043 0.80 1.65160 58.54 0.8525 20.33 48 15.870 5.58 1.69349 50.81 0.7740 20.57 49 -175.848 10.00 20.56 50 94.319 4.73 1.51633 64.14 0.8687 19.60 51 -18.653 1.00 1.69930 51.11 0.7593 19.41 52 -60.269 5.00 19.46 53 ∞ 33.00 1.60859 46.44 0.7534 40.00 54 ∞ 13.20 1.51680 64.17 0.8698 40.00 55 ∞ 7.39 40.00 56 Image plane Various data Zoom ratio 18.00 Focal length 70.00 490.00 1260.00 F-number 7.12 7.12 12.10 Half-angle 4.50 0.64 0.25 Lens length: 350.02 350.02 350.02 BF 7.39 7.39 7.39 d13 3.67 61.84 72.45 d22 62.25 2.16 11.26 d25 19.77 21.69 1.98 d55 7.39 7.39 7.39 Entrance pupil position 231.44 1128.51 2118.83 Exit pupil position -90.92 -90.92 -90.92 Front principal point position 251.61 -820.98 -12750.48 Back principal point position -62.56 -482.31 -1251.84 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 168.25 92.43 18.71 -67.54 2 14 -24.21 18.53 3.81 -8.80 3 23 -55.03 3.38 0.46 -1.39 4 26 25.00 142.60 -24.88 -103.39 Single lens data Lens starting plane, focal length 1 1 308.62 2 3 221.45 3 5 -143.90 4 6 118.52 5 8 -78.01 6 10 231.91 7 12 239.60 8 14 -33.09 9 16 25.73 10 17 -19.25 11 19 50.55 12 21 -67.77 13 23 -28.32 14 24 57.93 15 27 49.49 16 29 152.31 17 31 46.64 18 32 -31.41 19 34 27 30 20 35 -24.30 21 37 40.36 22 39 -28.40 23 40 22.97 24 42 21.70 25 43 -8.08 26 45 54.77 27 47 -16.59 28 48 21.14 29 50 30.49 30 51 -38.84

[0090] [Numerical Example 3] Unit: mm Surface data Face number rd nd vd θct Effective diameter 1 115.332 10.18 1.58913 61.15 0.8543 104.14 2 302.999 0.80 103.34 3 75.153 18.02 1.43387 95.10 0.8092 97.88 4 317.078 1.12 95.29 5 101.505 3.30 1.72916 54.68 0.8244 88.09 6 50.993 19.99 1.43875 94.66 0.8410 77.48 7 2058.240 2.46 75.64 8 -878.835 3.00 1.72916 54.68 0.8244 74.14 9 61.193 20.26 66.67 10 97.412 7.06 1.43387 95.10 0.8092 66.00 11 2777.966 0.20 65.63 12 69.087 6.04 1.49700 81.54 0.8258 63.03 13 159.129 (variable) 62.19 14 127.960 1.00 1.69930 51.11 0.7593 24.32 15 19.611 4.31 21.89 16 2221.996 5.80 1.65412 39.68 0.7554 21.68 17 -17.043 0.90 1.59522 67.74 0.7953 21.43 18 36.034 0.48 20.19 19 24.335 3.11 1.61340 44.27 0.7825 20.22 20 105.537 2.03 19.78 21 -35.686 0.90 1.59522 67.74 0.7953 19.70 22 -304.103 (variable) 19.64 23 -42.344 0.90 1.69930 51.11 0.7593 19.36 24 37.850 2.48 1.85478 24.80 0.6739 20.27 25 151.127 (variable) 20.55 26 ∞ 0.63 27.88 27 76.675 5.18 1.59522 67.74 0.7953 28.86 28 -46.891 0.50 29.09 29 70.327 3.02 1.43875 94.93 0.8373 28.45 30 -1394.511 2.95 28.11 31 45.962 6.13 1.43875 94.66 0.8410 26.41 32 -35.548 1.00 1.80610 40.92 0.7483 25.66 33 90.932 2.22 24.99 34* 25.843 4.85 1.59522 67.74 0.7953 24.70 35 62.934 0.49 23.48 36 20.816 1.00 1.67300 38.26 0.7481 22.26 37 11.880 9.24 1.49700 81.54 0.8258 19.86 38 271.557 2.44 17.56 39 30.500 1.00 1.64000 60.08 0.8645 14.80 40 6.852 3.30 1.65412 39.68 0.7554 12.13 41 10.594 9.38 11.22 42 -26.353 2.30 1.84666 23.78 0.6614 8.04 43 -7.608 0.80 1.85920 33.00 0.6855 7.92 44 60.904 2.99 7.77 45 74.212 4.20 1.43875 94.93 0.8373 22.56 46 -35.057 5.66 22.39 47 -35.043 0.80 1.65160 58.54 0.8525 20.33 48 15.870 5.58 1.69349 50.81 0.7740 20.57 49 -175.848 10.00 20.56 50 94.319 4.73 1.51633 64.14 0.8687 19.60 51 -18.653 1.00 1.69930 51.11 0.7593 19.41 52 -60.269 5.00 19.46 53 ∞ 33.00 1.60859 46.44 0.7534 40.00 54 ∞ 13.20 1.51680 64.17 0.8698 40.00 55 ∞ 7.40 40.00 Image plane ∞ Aspherical data Page 34 K = 0.00000e+00 A 4=-5.72540e-07 A 6= 1.65501e-09 A 8= 3.24738e-11 A10=-1.95868e-13 A12= 6.28377e-16 Various data Zoom ratio 18.00 Focal length 80.00 560.00 1440.00 F-number 8.15 8.15 13.83 Half-angle 3.93 0.56 0.22 Lens length: 350.02 350.02 350.02 BF 7.40 7.40 7.40 d13 3.67 61.84 72.45 d22 62.25 2.16 11.26 d25 19.77 21.69 1.98 Entrance pupil position 231.44 1128.51 2118.83 Exit pupil position -91.71 -91.71 -91.71 Front principal point position 246.86 -1476.00 -17365.77 Back principal point position -72.61 -552.62 -1432.65 Zoom lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 168.25 92.43 18.71 -67.54 2 14 -24.21 18.53 3.81 -8.80 3 23 -55.03 3.38 0.46 -1.39 4 26 22.70 142.60 -28.68 -104.38 Single lens data Lens starting plane, focal length 1 1 308.62 2 3 221.45 3 5 -143.90 4 6 118.52 5 8 -78.01 6 10 231.91 7 12 239.60 8 14 -33.09 9 16 25.73 10 17 -19.25 11 19 50.55 12 21 -67.77 13 23 -28.32 14 24 57.93 15 27 49.49 16 29 152.31 17 31 46.64 18 32 -31.41 19 34 69.99 20 36 -42.80 21 37 24.63 22 39 -13.98 23 40 21.84 24 42 11.84 25 43 -7.77 26 45 54.77 27 47 -16.59 28 48 21.14 29 50 30.49 30 51 -38.84

[0091] [Master Lens M2] Unit: mm Surface data Surface No. r d nd vd θct Effective diameter 1 460.758 6.00 1.75500 52.32 0.8092 197.47 2 227.153 2.23 194.17 3 227.208 35.78 1.43875 94.93 0.8373 195.15 4 -392.317 0.80 195.10 5 -438.907 6.00 1.69680 55.53 0.8330 194.48 6 532.162 1.00 195.18 7 414.431 19.92 1.43387 95.10 0.8092 196.36 8 -789.381 27.30 196.49 9 356.634 19.70 1.43387 95.10 0.8092 195.75 10 -1289.000 0.25 195.33 11 296.913 13.8" 1.43387 95.10 0.8092 189.90 12 1058.300 1.52 18"8.95 13 194.264 13.65 1.43875 94.66 0.8410 179.56 14 377.710 (Variable) 178.08 15 -586.221 1.40 1.69930 51.11 0.7593 45.23 16 34.713 5.77 40.31 17 92.067 13.13 1.61310 44.36 0.8010 40.21 18 -28.278 1.30 1.59522 67.74 0.7953 39.62 19 203.083 4.35 37.16 20 -134.194 1.30 1.63858 55.18 0.7865 36.55 [[ID=?]]21 63.020 7.63 1.67300 38.26 0.7481 36.28 22 -69.143 1.83 36.50 23 -63.166 1.20 1.59522 67.74 0.7953 36.13 24* 111.986 (variable) 36.55 25 134.588 5.00 1.59522 67.74 0.7953 59.35 26* 442.688 0.50! 59.31 27 80.090 11.02 1.43875 94.93 0.8373 59.88 28 -169.812 0.35 59.46 29 958.073 2.60 1.61310 44.36 0.8010 58.06 30 117.378 (variable) 56.53 31 4306.259 6.31 1.43875 94. ? 0.8373 55.93 32 -110.510 0.50 55.69 33 -434.969 2.50 1.61310 44.36 0.8010 54.50 34 128.064 5.88 1.59522 67.74 0.7953 53.40 35* -1908.884 (variable) 52.87 36 ∞ 3.14 31.69 It seems there are some unclear or potentially incorrect notations in the original text (like "! 59.31" and "94. ?" which are not standard notations). The translation is done as accurately as possible based on the available clear parts.37 53.719 1.20 1.75106 43.10 0.7097 33.32 38 30.751 2.37 32.22 39 29.858 4.45 1.73800 32.33 0.7154 32.41 40 57.785 4.06 31.40 41 498.772 1.20 1.85920 33.00 0.6855 30.50 42 63.834 12.15 29.97 43 -88.470 1.00 1.75500 52.32 0.8092 26.49 44 150.000 4.25 1.43875 94.93 0.8373 26.77 45 -81.943 0.29 27.21 46 1527.739 1.60 2.00100 29.14 0.6838 27.36 47 31.133 10.71 1.85478 24.80 0.6739 27.55 48 -119.386 23.87 28.38 49 -193.045 6.80 1.43875 94.93 0.8373 28.99 50 -79.814 2.00 29.37 51 69.774 1.80 1.64000 60.08 0.8645 29.01 52 26.465 10.66 1.59522 67.74 0.7953 28.10 53 -61.505 0.60 27.18 54 207.853 5.99 1.59551 39.24 0.7402 25.67 55 -52.126 1.80 1.95375 32.32 0.6988 24.34 56 129.782 1.00 23.71 57 101.348 5.25 1.43875 94.93 0.8373 23.54 58 158.030 19.65 22.67 59 ∞ 33.00 1.60859 46.44 0.7534 60.00 60 ∞ 13.20 1.51633 64.15 0.8676 60.00 61 ∞ 13.40 60.00 Image plane ∞ Aspherical data The 24th surface K = -3.79813e+01 A4 = 9.41596e-07 A6 = -5.38380e-09 A8 = 7.42674e-12 A10 = -9.02145e-15 A12 = 5.43576e-18 [[ID=...]] The 26th surface K = 0.00000e+00 A4 = 3.97598e-07 A6 = -4.62748e-12 A8 = 5.82597e-14 A10 = -...2.37917e-17 A12 = -7.42504e-22 The 35th surface K = 0.00000e+00 A4 = 2.00714e-07 A6 = 1.45041e-10 A8 = -2.89471e-13 A10 = 2.88143e-16 A12 = -9.54591e-20 Various data Zoom ratio 90.00 <... Focal length 14.30 156.00 1287.00 F-number 2.94 2.95 6.77 Half angle of view 21.04 2.02 0.24 Overall length of lens 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 Note: There seems to be an ellipsis in the translation of line as the original text has some unclear characters in "A10 = -...2.37917e-17 A12 = -7.42504e-22". You may need to check and correct it according to the accurate original content.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 plane, 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

[0092] [Numerical Example 4] Unit: mm Surface data Face number rd nd vd θct Effective diameter 1 460.758 6.00 1.75500 52.32 0.8092 190.68 2 227.153 2.23 187.65 3 227.208 35.78 1.43875 94.93 0.8373 188.56 4 -392.317 (variable) 188.44 5 -438.907 6.00 1.69680 55.53 0.8330 187.87 6 532.162 1.00 188.46 7 414.431 19.92 1.43387 95.10 0.8092 189.53 8 -789.381 27.30 189.73 9 356.634 19.70 1.43387 95.10 0.8092 188.91 10 -1289.000 0.25 188.31 11 296.913 13.81 1.43387 95.10 0.8092 183.20 12 1058.300 1.52 181.99 13 194.264 13.65 1.43875 94.66 0.8410 173.54 14 377.710 (Variable) 171.63 15 -586.221 1.40 1.69930 51.11 0.7593 45.28 16 34.713 5.77 40.34 17 92.067 13.13 1.61310 44.36 0.8010 40.23 18 -28.278 1.30 1.59522 67.74 0.7953 39.64 19 203.083 4.35 37.17 20 -134.194 1.30 1.63858 55.18 0.7865 36.56 21 63.020 7.63 1.67300 38.26 0.7481 36.26 22 -69.143 1.83 36.42 23 -63.166 1.20 1.59522 67.74 0.7953 36.06 24* 111.986 (variable) 36.49 25 134.588 5.00 1.59522 67.74 0.7953 59.50 26* 442.688 0.50 59.47 27 80.090 11.02 1.43875 94.93 0.8373 60.05 28 -169.812 0.35 59.63 29 958.073 2.60 1.61310 44.36 0.8010 58.24 30 117.378 (variable) 56.71 31 4306.259 6.31 1.43875 94.93 0.8373 55.98 32 -110.510 0.50 55.75 33 -434.969 2.50 1.61310 44.36 0.8010 54.55 34 128.064 5.88 1.59522 67.74 0.7953 53.45 35* -1908.884 (variable) 52.93 36 ∞ 3.14 31.68 37 53.719 1.20 1.75106 43.10 0.7097 33.32 38 30.751 2.37 32.22 39 29.858 4.45 1.73800 32.33 0.7154 32.41 40 57.785 4.06 31.40 41 498.772 1.20 1.85920 33.00 0.6855 30.50 42 63.834 6.00 29.97 43 -261.078 1.00 1.61340 44.27 0.7825 26.73 44 57.260 4.08 1.59522 67.74 0.7953 26.78 45 -90.532 1.45 26.81 46 26.809 4.09 1.60738 56.81 0.7982 25.96 47 112.709 1.00 1.67300 38.26 0.7481 25.25 48 37.125 19.82 24.14 49 -1555.568 1.00 1.83481 42.74 0.7533 17.95 50 23.200 4.07 1.75520 27.51 0.6797 17.45 51 -52.118 4.36 17.19 52 -27.370 1.00 1.75106 43.10 0.7097 14.94 53 175.099 6.00 14.83 54 -193.045 6.80 1.43875 94.93 0.8373 28.97 55 -79.814 2.00 29.35 56 69.774 1.80 1.64000 60.08 0.8645 28.99 57 26.465 10.66 1.59522 67.74 0.7953 28.09 58 -80.000 0.60 27.17 59 207.853 5.99 1.59551 39.24 0.7402 25.72 60 -52.126 1.80 1.95375 32.32 0.6988 24.40 61 129.782 1.00 23.76 62 101.348 5.25 1.43875 94.93 0.8373 23.59 63 157.387 19.65 22.72 64 ∞ 33.00 1.60859 46.44 0.7534 60.00 65 ∞ 13.20 1.51633 64.15 0.8676 60.00 66 ∞ 13.40 60.00 Image plane ∞ Aspherical 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 28.60 311.78 2574.00 F-number 5.88 5.90 13.55 Half-angle 10.89 1.01 0.12 Lens 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 -115.31 -115.31 -115.31 Front principal point position 202.53 929.65 -28952.90 Back principal point position -15.20 -298.38 -2560.58 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 -139.54 172.04 60.97 -72.88 Single lens data Lens starting plane, 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 -76.47 24 44 59.54 25 46 56.89 26 47 -82.70 27 49 -27.37 28 50 21.76 29 52 -31.45 30 54 304.56 31 56 -67.72 32 57 34.71 33 59 70.59 34 60 -38.81 35 62 630.74

[0093] [Numerical Example 5] Unit: mm Surface data Face number rd nd vd θct Effective diameter 1 460.758 6.00 1.75500 52.32 0.8092 190.68 2 227.153 2.23 187.65 3 227.208 35.78 1.43875 94.93 0.8373 188.56 4 -392.317 0.80 188.44 5 -438.907 6.00 1.69680 55.53 0.8330 187.87 6 532.162 1.00 188.46 7 414.431 19.92 1.43387 95.10 0.8092 189.53 8 -789.381 27.30 189.73 9 356.634 19.70 1.43387 95.10 0.8092 188.91 10 -1289.000 0.25 188.31 11 296.913 13.81 1.43387 95.10 0.8092 183.20 12 1058.300 1.52 181.99 13 194.264 13.65 1.43875 94.66 0.8410 173.54 14 377.710 (Variable) 171.63 15 -586.221 1.40 1.69930 51.11 0.7593 45.28 16 34.713 5.77 40.34 17 92.067 13.13 1.61310 44.36 0.8010 40.23 18 -28.278 1.30 1.59522 67.74 0.7953 39.64 19 203.083 4.35 37.17 20 -134.194 1.30 1.63858 55.18 0.7865 36.56 21 63.020 7.63 1.67300 38.26 0.7481 36.26 22 -69.143 1.83 36.42 23 -63.166 1.20 1.59522 67.74 0.7953 36.06 24* 111.986 (variable) 36.49 25 134.588 5.00 1.59522 67.74 0.7953 59.50 26* 442.688 0.50 59.47 27 80.090 11.02 1.43875 94.93 0.8373 60.05 28 -169.812 0.35 59.63 29 958.073 2.60 1.61310 44.36 0.8010 58.24 30 117.378 (variable) 56.71 31 4306.259 6.31 1.43875 94.93 0.8373 55.98 32 -110.510 0.50 55.75 33 -434.969 2.50 1.61310 44.36 0.8010 54.55 34 128.064 5.88 1.59522 67.74 0.7953 53.45 35* -1908.884 (variable) 52.93 36 ∞ 3.14 31.68 37 53.719 1.20 1.75106 43.10 0.7097 33.32 38 30.751 2.37 32.22 39 29.858 4.45 1.73800 32.33 0.7154 32.41 40 57.785 4.06 31.40 41 498.772 1.20 1.85920 33.00 0.6855 30.50 42 63.834 20.00 29.97 43 30.840 4.00 1.43875 94.93 0.8373 26.03 44 88.929 1.00 25.41 45 88.853 1.00 1.61310 44.36 0.8010 25.11 46 40.214 11.95 24.50 47 446.894 4.16 1.78880 28.43 0.6943 23.51 48 -46.601 3.36 23.31 49 -33.857 1.00 1.69930 51.11 0.7593 21.47 50 370.779 7.40 21.34 51 -193.045 6.80 1.43875 94.93 0.8373 28.97 52 -79.814 2.00 29.35 53 69.774 1.80 1.64000 60.08 0.8645 28.99 54 26.465 10.66 1.59522 67.74 0.7953 28.09 55 -80.000 0.60 27.17 56 207.853 5.99 1.59551 39.24 0.7402 25.72 57 -52.126 1.80 1.95375 32.32 0.6988 24.40 58 129.782 1.00 23.76 59 101.348 5.25 1.43875 94.93 0.8373 23.59 60 157.387 19.65 22.72 61 ∞ 33.00 1.60859 46.44 0.7534 60.00 62 ∞ 13.20 1.51633 64.15 0.8676 60.00 63 ∞ 13.40 60.00 Image plane ∞ Aspherical 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 20.00 218.00 1800.00 F-number 4.12 4.13 9.48 Half-angle 15.38 1.45 0.18 Lens 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 -160.30 -160.30 -160.30 Front principal point position 197.98 1317.46 3095.51 Back principal point position -6.60 -204.62 -1786.58 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 36 821.96 172.04 209.95 121.67 Single lens data Lens starting plane, 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 43 105.40 24 45 -120.77 25 47 53.70 26 49 -44.32 27 51 304.56 28 53 -67.72 29 54 34.71 30 56 70.59 31 57 -38.81 32 59 630.74

[0094] Table 1: Numerical values ​​corresponding to conditional expressions (1) to (8) in numerical examples 1 to 5 [Table 1]

[0095] Figure 16 shows the configuration of an imaging device (television camera system) that uses a zoom lens consisting of a master lens equipped with a converter lens IE of each of the above embodiments as the imaging optical system. In Figure 16, 101 is a zoom lens consisting of a master lens M1 or M2 and a converter lens IE of any of embodiments 1 to 5. 124 is a camera. The zoom lens 101 is detachable from the camera 124. 125 is an imaging device configured by attaching the zoom lens 101 to the camera 124.

[0096] The zoom lens 101 includes a first lens group F, a zoom section LZ, and a relay lens group R, etc. The first lens group F includes a first lens group U1 for focusing in each embodiment. The zoom section LZ includes a lens group that moves during zooming (such as a second lens group U2) and an aperture diaphragm SP. 114 and 115 are drive mechanisms such as helicoids and cams that drive the first lens group F and the zoom section LZ in the optical axis direction, respectively. 116 to 118 are actuators that electrically drive the drive mechanisms 114 and 115 and the aperture diaphragm SP. 119 to 121 are detectors such as encoders, potentiometers, or photosensors for detecting the optical axis position of the first lens group F, the zoom section LZ, and the aperture diaphragm SP, and the aperture diameter of the aperture diaphragm SP.

[0097] 123 is a lens group including the relay lens group R and converter lens IE after the aperture diaphragm SP. The converter lens IE of the present invention is included here, and the focal length is changed by inserting and removing it into the optical path by replacing the air gap or some lens group provided in the relay lens group R of the master lens. The insertion and removal can be driven electrically or manually. In the camera 124, 109 is a glass block corresponding to the optical filter and color separation optical system inside the camera 124, and 110 is 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. Also, 111 and 122 are CPUs that control various drives of the camera 124 and the zoom lens 101. In this way, by using the converter lens IE of each embodiment in the imaging device, an imaging device with high optical performance can be realized.

[0098] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist.

[0099] This embodiment includes the following configuration. (Composition 1) A converter lens that can be inserted into or removed from the optical path of a master lens, or can replace some of the lens groups of the master lens, and which makes the focal length of the entire system longer than the focal length of the master lens alone, The converter lens is composed of a front lens group with positive refractive power and a rear lens group with negative refractive power, arranged in order from the object side to the image side, with the maximum air gap on the optical axis between the lenses included in the converter lens as the boundary. The front lens group has a negative front lens with negative refractive power, and when the partial dispersion ratio of the negative front lens with respect to the C line and t line is θctf, and the Abbe number with respect to the d line is νdnf, 0.55 < θctf - 0.0049 × νdnf < 0.60 20<νdnf<52 A converter lens characterized by satisfying the following conditions. (Configuration 2) The aforementioned rear lens group has a negative rear lens with negative refractive power, and when the partial dispersion ratio of the rear lens with respect to the C line and t line is θctr and the Abbe number with respect to the d line is νdnr, 0.48 < θctr - 0.0041 × νdnr < 0.55 25<νdnr<61 A converter lens according to configuration 1, characterized in that it satisfies the following conditions. (Composition 3) The aforementioned front lens group includes a positive lens and a negative lens that are arranged adjacent to each other. When the partial dispersion ratios of the positive lens and the negative lens with respect to the C line and the t line are θpf and θnf, respectively, and the Abbe numbers with respect to the d line are νpf and νnf, respectively, 0<(θpf-θnf) / (νpf-νnf)<2.5×10 -3 A converter lens according to configuration 1 or 2, characterized in that it satisfies the following conditions. (Composition 4) The aforementioned rear lens group includes positive and negative lenses that are arranged adjacent to each other. When the partial dispersion ratios of the positive lens and the negative lens with respect to the C line and the t line are θpr and θnr, respectively, and the Abbe numbers with respect to the d line are νpr and νnr, respectively, 0<(θpr-θnr) / (νpr-νnr)<4.0×10 -3 A converter lens described in any of configurations 1 to 3, characterized by satisfying the following conditions. (Composition 5) When Lc is the distance along the optical axis from the surface closest to the object to the surface closest to the image, and Dc is the effective diameter of the surface closest to the object, 0.8 <Lc / Dc<1.8 A converter lens described in any of configurations 1 to 4, characterized by satisfying the following conditions. (Composition 6) A converter lens that can be inserted into or removed from the optical path within a master lens, or can replace some of the lens groups of the master lens, and which makes the focal length of the entire system longer than the focal length of the master lens alone, The converter lens is composed of a front lens group with positive refractive power and a rear lens group with negative refractive power, arranged in order from the object side to the image side, with the maximum air gap on the optical axis between the lenses included in the converter lens as the boundary. The aforementioned rear lens group has a negative rear lens with negative refractive power, and when the partial dispersion ratio of the rear lens with respect to the C line and t line is θctr and the Abbe number with respect to the d line is νdnr, 0.48 < θctr - 0.0041 × νdnr < 0.55 25<νdnr<61 A converter lens characterized by satisfying the following conditions. (Composition 7) The aforementioned front lens group includes a positive lens and a negative lens that are arranged adjacent to each other. When the partial dispersion ratios of the positive lens and the negative lens with respect to the C line and the t line are θpf and θnf, respectively, and the Abbe numbers with respect to the d line are νpf and νnf, respectively, 0<(θpf-θnf) / (νpf-νnf)<2.5×10 -3 The converter lens according to configuration 6, characterized in that it satisfies the following conditions. (Composition 8) A converter lens that can be inserted into or removed from the optical path within a master lens, or can replace some of the lens groups of the master lens, and which makes the focal length of the entire system longer than the focal length of the master lens alone, The converter lens is composed of a front lens group with positive refractive power and a rear lens group with negative refractive power, arranged in order from the object side to the image side, with the maximum air gap on the optical axis between the lenses included in the converter lens as the boundary. The front lens group has a negative front lens with negative refractive power, and when the partial dispersion ratio of the front lens with respect to the C line and t line is θctf, and the Abbe number of the front lens with respect to the d line is νdnf, 0.55 < θctf - 0.0049 × νdnf < 0.60 A converter lens characterized by satisfying the following conditions. (Composition 9) Master lens and, A lens device having a converter lens according to any one of configurations 1 to 8, which is insertable into or removable from the optical path within the master lens, or replaceable with a part of the lens group of the master lens, When the converter lens is inserted into the optical path, the focal length of the lens device is longer than the focal length of the master lens alone. When the focal length at the wide-angle end when the master lens is focused at infinity is fwm, and the focal length at the wide-angle end when the converter lens is inserted into the master lens is fwc, 1.3 <fwc / fwm<3.0 A lens device characterized by satisfying the following conditions. (Composition 10) A lens device having a master lens and a converter lens according to any one of configurations 1 to 8, which can be inserted into or removed from the optical path within the master lens, or which can be replaced with a part of the lens group of the master lens. An imaging device characterized by having an image sensor that captures an image of a subject through the aforementioned lens device. [Explanation of Symbols]

[0100] Cf front lens group Cr rear lens group IE Converter Lens Lnf negative lens LNR rear negative lens

Claims

1. A converter lens that can be inserted into or removed from the optical path within a master lens, or can replace some of the lens groups of the master lens, and which makes the focal length of the entire system longer than the focal length of the master lens alone, The converter lens is composed of a front lens group with positive refractive power and a rear lens group with negative refractive power, arranged in order from the object side to the image side, with the maximum air gap on the optical axis between the lenses included in the converter lens as the boundary. The front lens group has a negative front lens with negative refractive power, and when the partial dispersion ratio of the negative front lens with respect to the C line and the t line is θctf, and the Abbe number with respect to the d line is νdnf, 0.55<θctf-0.0049×νdnf<0.60 20 < νdnf < 52 A converter lens characterized by satisfying the following conditions.

2. The aforementioned rear lens group includes a rear negative lens with negative refractive power, and when the partial dispersion ratio of the rear negative lens with respect to the C line and the t line is θctr, and the Abbe number with respect to the d line is νdnr, 0.48<θctr-0.0041×νdnr<0.55 25 < νdnr < 61 The converter lens according to claim 1, characterized in that it satisfies the following conditions.

3. The aforementioned front lens group includes a positive lens and a negative lens that are arranged adjacent to each other. When the partial dispersion ratios of the positive lens and the negative lens with respect to the C line and t line are θpf and θnf, respectively, and the Abbe numbers with respect to the d line are νpf and νnf, respectively, 0<(θπ-θνφ) / (νπ-ννφ)<2.5×10 －３ The converter lens according to claim 1, characterized in that it satisfies the following conditions.

4. The aforementioned rear lens group includes positive and negative lenses that are arranged adjacent to each other. When the partial dispersion ratios of the positive lens and the negative lens with respect to the C line and the t line are θpr and θrn, respectively, and the Abbe numbers with respect to the d line are νpr and νrn, respectively, 0<(θpr-θnr) / (νpr-νnr)<4.0×10 －３ The converter lens according to claim 1, characterized in that it satisfies the following conditions.

5. When Lc is the distance along the optical axis from the surface closest to the object to the surface closest to the image, and Dc is the effective diameter of the surface closest to the object, 0.8<Lc / Dc<1.8 The converter lens according to claim 1, characterized in that it satisfies the following conditions.

6. A converter lens that can be inserted into or removed from the optical path within a master lens, or can replace some of the lens groups of the master lens, and which makes the focal length of the entire system longer than the focal length of the master lens alone, The converter lens is composed of a front lens group with positive refractive power and a rear lens group with negative refractive power, arranged in order from the object side to the image side, with the maximum air gap on the optical axis between the lenses included in the converter lens as the boundary. The aforementioned rear lens group includes a rear negative lens with negative refractive power, and when the partial dispersion ratio of the rear negative lens with respect to the C line and the t line is θctr, and the Abbe number with respect to the d line is νdnr, 0.48<θctr-0.0041×νdnr<0.55 25 < νdnr < 61 A converter lens characterized by satisfying the following conditions.

7. The aforementioned front lens group includes a positive lens and a negative lens that are arranged adjacent to each other. When the partial dispersion ratios of the positive lens and the negative lens with respect to the C line and t line are θpf and θnf, respectively, and the Abbe numbers with respect to the d line are νpf and νnf, respectively, 0<(θπ-θνφ) / (νπ-ννφ)<2.5×10 －３ The converter lens according to claim 6, characterized in that it satisfies the following conditions.

8. A converter lens that can be inserted into or removed from the optical path within a master lens, or can replace some of the lens groups of the master lens, and which makes the focal length of the entire system longer than the focal length of the master lens alone, The converter lens is composed of a front lens group with positive refractive power and a rear lens group with negative refractive power, arranged in order from the object side to the image side, with the maximum air gap on the optical axis between the lenses included in the converter lens as the boundary. The front lens group has a negative front lens with negative refractive power, and when the partial dispersion ratio of the front lens with respect to the C line and t line is θctf, and the Abbe number of the front lens with respect to the d line is νdnf, 0.55<θctf-0.0049×νdnf<0.60 A converter lens characterized by satisfying the following conditions.

9. Master lens and, A lens device having a converter lens according to any one of claims 1 to 8, which is insertable into or removable from the optical path within the master lens, or replaceable with a part of the lens group of the master lens, When the converter lens is inserted into the optical path, the focal length of the lens device is longer than the focal length of the master lens alone. When the focal length at the wide-angle end when the master lens is focused at infinity is fwm, and the focal length at the wide-angle end when the converter lens is inserted into the master lens is fwc, 1.3<fwc / fwm<3.0 A lens device characterized by satisfying the following conditions.

10. A lens device having a master lens and a converter lens according to any one of claims 1 to 8, which is insertable into or removable from the optical path within the master lens, or interchangeable with a portion of the lens group of the master lens, An imaging device characterized by having an image sensor that captures an image of a subject through the aforementioned lens device.

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