Zoom lens and imaging apparatus

Abstract

To provide a zoom lens that is small-sized, has a wide angle of view and a high magnification varying ratio, and can obtain high optical performance.SOLUTION: A zoom lens has a plurality of lens groups comprising a first lens group U1 having a positive refractive power that does not move in zooming, at least two movable lens groups U2-U4 that move in zooming, and a final lens group U5 having a positive refractive power that does not move in zooming. The first lens group includes at least one negative lens and at least one positive lens, and when the Abbe number based on the d-line of a first positive lens Lp1 included in the at least one positive lens is defined as νp1, the condition of 10.0≤νp1≤17.4 is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Zoom lenses are expected to be small, have a wide angle of view, a high zoom ratio, and have high optical performance, as well as to have uniform resolution from the center to the periphery of the imaging angle of view.

[0003] Patent Documents 1 and 2 disclose positive-lead zoom lenses as compact, wide-angle, and high-zoom-ratio zoom lenses, which are arranged in order from the object side to the image side and include a first lens group with positive refractive power that does not move during zooming, at least two movable lens groups that move during zooming, and a final lens group with positive refractive power that does not move during zooming. These zoom lenses employ an inner focus system in which a focus lens group within the first lens group moves during focusing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-120152 [Patent Document 2] International Publication No. WO2017-130478 Summary of the Invention [Problem to be solved by the invention]

[0005] In a positive-lead zoom lens, in order to achieve a small size, a wide angle of view, a high zoom ratio, and high optical performance throughout the entire zoom range, it is necessary to appropriately configure the first lens group. In the zoom lenses disclosed in Patent Documents 1 and 2, strengthening the refractive power of the negative lens closest to the object in the first lens group is effective for further widening the angle of view. However, the dispersion of the positive lens closest to the negative lens closest to the object is insufficient, making it difficult to correct chromatic aberration within the first lens group. As a result, lateral chromatic aberration fluctuates significantly throughout the entire zoom range.

[0006] The present invention provides a zoom lens that is compact, has a wide angle of view, a high zoom ratio, and provides high optical performance over the entire zoom range. [Means for solving the problem]

[0007] A zoom lens according to one aspect of the present invention has a plurality of lens groups arranged in order from the object side to the image side, the plurality of lens groups being composed of a first lens group having positive refractive power that does not move during zooming, at least two movable lens groups that move during zooming, and a final lens group having positive refractive power that does not move during zooming, and the spacing between adjacent lens groups changes during zooming. The first lens group includes at least one negative lens and at least one positive lens, and when the Abbe number of the first positive lens included in the at least one positive lens is taken as νp1, the Abbe number is expressed as νp1. 10.0≦νp1≦17.4 The present invention is characterized in that the following conditions are satisfied: An imaging device including the zoom lens described above also constitutes another aspect of the present invention. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a zoom lens that is compact, has a wide angle of view, a high zoom ratio, and provides high optical performance over the entire zoom range. [Brief explanation of the drawings]

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

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

[0011] 1, 3, 5, 7, 9, and 11 show cross sections of the zoom lenses of Examples 1 to 6 at the wide-angle end in a state where the lenses are focused on an object at infinity (hereinafter referred to as the infinity focused state). In each cross section, the left side is the object side (front side) and the right side is the image side (rear side).

[0012] First, we will explain matters common to all the embodiments before specifically explaining Examples 1 to 6. The zoom lenses of the embodiments are used in various imaging devices such as broadcast cameras, cinema cameras, video cameras, surveillance cameras, digital still cameras, and cameras for silver halide film.

[0013] The zoom lens of each embodiment has, arranged in order from the object side to the image side, a first lens group U1 with positive refractive power that does not move during zooming, at least two movable lens groups Um (m=2 to 5) that move during zooming, and a final lens group Ur (r=5 or 6) with positive refractive power that does not move during zooming.

[0014] In a zoom lens, a lens group is a group of one or more lenses that may or may not move as a unit during zooming (variable magnification) 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 the zoom states with the maximum and minimum angles of view (shortest focal lengths) when the lens group that moves during zooming is located at the ends of its mechanically or controllably movable range on the optical axis.

[0015] SP is the aperture stop. IP is the image plane. The image plane IP is where the imaging surface (light receiving surface) of an imaging element such as a CCD sensor or CMOS sensor or the film surface (photosensitive surface) of a silver halide film is located.

[0016] In the zoom lens of each embodiment, the first lens unit U1, which is the heaviest, remains stationary (fixed) during zooming, thereby suppressing changes in the center of gravity of the zoom lens that occur during zooming. Also, by imparting positive refractive power to the first lens unit U1, the diameter of the light beam entering the second lens unit U2 is suppressed, mainly at the telephoto end. This allows the size of each movable lens unit that moves during zooming to be reduced.

[0017] Furthermore, in the zoom lens of each embodiment, the final lens unit Ur is fixed during zooming, so that a mechanism for adjusting the flange focal length by moving the final lens unit Ur can be installed.

[0018] In the zoom lens of each embodiment, the first lens unit U1 includes at least one negative lens and at least one positive lens. When the Abbe number of the first positive lens Lp1 included in the at least one positive lens is νp1, the Abbe number is expressed as νp1 with respect to the d-line. 10.0≦νp1≦17.4 (1) The following conditions are satisfied.

[0019] The first lens group U1 includes at least one negative lens and at least one positive lens, and the Abbe number νp1 of the material used for the first positive lens Lp1 is set to satisfy the condition of formula (1). This enables favorable correction of zoom fluctuations in lateral chromatic aberration when the refractive power of the negative lens is strengthened to widen the angle of view of the zoom lens. If νp1 exceeds the upper limit of formula (1), the material of the first positive lens Lp1 becomes a low-dispersion material with an Abbe number that is too large, making it difficult for the first positive lens Lp1 to correct (achromatize) the chromatic aberration generated by the negative lens. This results in an inability to suppress lateral chromatic aberration throughout the entire zoom range, which is undesirable. If νp1 falls below the lower limit of formula (1), the Abbe number of the first positive lens Lp1 becomes too small, which weakens the refractive power of the first positive lens Lp1 when correcting the chromatic aberration generated by the negative lens, making it difficult to correct spherical aberration at the telephoto end, which is undesirable.

[0020] It is more preferable to set the numerical range of the formula (1) as follows:

[0021] 12.0≦νp1≦17.2 (1a) Furthermore, it is more preferable to set the numerical range of formula (1) as follows:

[0022] 14.0≦νp1≦17.1 (1b) By satisfying the above configuration and conditions, it is possible to realize a zoom lens that is compact, has a wide angle of view, a high zoom ratio, and provides high optical performance over the entire zoom range.

[0023] It is preferable that the zoom lens of each embodiment satisfies at least one of the conditions and configurations of the following expressions (2) to (12).

[0024] In the zoom lens of each embodiment, when the refractive index at the d-line of the first positive lens Lp1 is Np1, it is preferable that the condition of the following formula (2) be satisfied.

[0025] 1.95≦Np1≦2.35 (2) If Np1 is below the lower limit of formula (2), the refractive index of the first positive lens Lp1 becomes too small, making it difficult to correct image height fluctuations due to lateral chromatic aberration at the wide-angle end, which is undesirable.If Np1 is above the upper limit of formula (2), with existing materials, the partial dispersion ratio of the first positive lens Lp1 at the g-line and F-line becomes too large, making it difficult to correct secondary spectrum of lateral chromatic aberration at the wide-angle end, which is undesirable.

[0026] It is more preferable to set the numerical range of the formula (2) as follows:

[0027] 1.96≦Np1≦2.25 (2a) Furthermore, it is more preferable to set the numerical range of the formula (2) as follows.

[0028] 1.97≦Np1≦2.22 (2b) In the zoom lens of each embodiment, the first lens unit U1 preferably has, arranged in order from the object side to the image side, a first sub-unit U11 with negative refractive power, a second sub-unit U12 with positive refractive power, and a third sub-unit U13 with positive refractive power. During focusing, it is preferable that the first sub-unit U11 does not move, and that at least the second sub-unit U12 of the second and third sub-units U12 and U13 moves. By configuring the first lens unit U1 in this way, the angle of view of the zoom lens can be increased, the amount of movement of the sub-units that move during focusing can be reduced, and changes in the angle of view (breathing) and aberration fluctuations that accompany the movement of the sub-units during focusing can be suppressed.

[0029] In the zoom lens of each embodiment, it is preferable that the first sub-unit U11 having negative refractive power includes at least one negative lens and the first positive lens Lp1. In this case, the average Abbe number of the at least one negative lens with respect to the d-line is set to νn1. ave , the average partial dispersion ratio for the g-line and F-line is θn1 ave When the partial dispersion ratio of the first positive lens Lp1 at the g-line and F-line is θp1, it is preferable that the following expressions (3) and (4) be satisfied.

[0030] 5≦νn1 ave -νp1≦40 (3) -0.0065≦(θn1 ave -θp1) / (νn1 ave -νp1)≦-0.0025 (4) The condition in equation (3) indicates the relationship of the appropriate Abbe number for achromatization in the first subgroup U11. ave If -νp1 exceeds the upper limit of formula (3), the difference in Abbe number between the negative lens and the first positive lens Lp1 in the first sub-unit U11 becomes too large, making it difficult to achieve both achromatism of the first sub-unit U11 and aberration correction at the reference wavelength (d-line). This is particularly undesirable because it becomes difficult to suppress spherical aberration at the telephoto end. aveIf -νp1 falls below the lower limit of equation (3), the difference in Abbe number between the negative lens and the first positive lens Lp1 in the first subunit U11 becomes too small, making it difficult to achromatize the first subunit U11 and making it impossible to suppress chromatic aberration of magnification throughout the entire zoom range, which is undesirable.

[0031] The condition of the formula (4) indicates the relationship of the appropriate partial dispersion ratio for correcting the second-order spectrum of the chromatic aberration of the first subgroup U11. (θn1 ave -θp1) / (νn1 ave If (θn1 -νp1) exceeds the upper limit of equation (4), the difference in partial dispersion ratio between the negative lens and the first positive lens Lp1 in the first subunit U11 becomes too large. As a result, the secondary spectrum of lateral chromatic aberration will be undercorrected, particularly at the wide-angle end, which is undesirable. ave -θp1) / (νn1 ave If −νp1) falls below the lower limit of equation (4), the difference in partial dispersion ratio between the negative lens and the first positive lens Lp1 in the first subunit U11 becomes too small, which is undesirable, especially at the telephoto end, because the secondary spectrum of axial chromatic aberration is overcorrected.

[0032] It is more preferable to set the numerical ranges of the formulas (3) and (4) as follows:

[0033] 8≦νn1 ave -νp1≦37 (3a) -0.0062≦(θn1 ave -θp1) / (νn1 ave -νp1)≦-0.0027 (4a) Furthermore, it is more preferable to set the numerical ranges of the formulas (3) and (4) as follows:

[0034] 9≦νn1 ave -νp1≦35 (3b) -0.0060≦(θn1 ave -θp1) / (νn1 ave -νp1)≦-0.0030 (4b) In the zoom lens of each embodiment, when the focal length of the negative lens Ln1 that is closest to the object among at least one negative lens in the first subgroup U11 is fn1, the focal length of the first positive lens Lp1 is fp1, and the focal length of the first subgroup U11 is f11, it is preferable that at least one of the following expressions (5) and (6) be satisfied.

[0035] 0.4≦fn1 / f11≦2.0 (5) -6.00≦fp1 / f11≦-0.60 (6) The condition of formula (5) indicates an appropriate relationship between the focal length of the negative lens closest to the object in the first sub-group U11 and the focal length of the first sub-group U11. If fn1 / f11 exceeds the upper limit of formula (5), the refractive power of the negative lens closest to the object becomes too weak, making it difficult to achieve a wide angle of view for the zoom lens, which is undesirable. If fn1 / f11 falls below the lower limit of formula (5), the refractive power of the negative lens closest to the object becomes too strong, making it difficult to correct zoom fluctuations in lateral chromatic aberration, which is undesirable.

[0036] The condition of formula (6) indicates an appropriate relationship between the focal length of the first positive lens Lp1 in the first sub-group U11 and the focal length of the first sub-group U11. If fp1 / f11 exceeds the upper limit of formula (6), the refractive power of the first positive lens Lp1 becomes too weak, making it difficult to correct chromatic aberration in the first sub-group U11, which is undesirable. If fp1 / f11 falls below the lower limit of formula (6), the refractive power of the first positive lens Lp1 becomes too strong, making it difficult to correct spherical aberration, particularly at the telephoto end, which is undesirable.

[0037] It is more preferable to set the numerical ranges of the formulas (5) and (6) as follows:

[0038] 0.43≦fn1 / f11≦1.65 (5a) -5.5≦fp1 / f11≦-0.70 (6a) Furthermore, it is more preferable to set the numerical ranges of the formulas (5) and (6) as follows:

[0039] 0.45≦fn1 / f11≦1.40 (5b) -4.9≦fp1 / f11≦-0.85 (6b) It is preferable that the zoom lens of each embodiment satisfies the condition of the following formula (7), where f1 is the focal length of the first lens unit U1 and ft is the focal length of the zoom lens at the telephoto end.

[0040] 2.50≦ft / f1≦5.00 (7) The condition of formula (7) indicates the appropriate relationship between the focal length of the first lens group U1 and the focal length of the zoom lens at the telephoto end. If ft / f1 falls below the lower limit of formula (7), the focal length of the first lens group U1 becomes too long, which increases the overall length of the high-magnification zoom lens and makes compactness difficult, which is undesirable. If ft / f1 exceeds the upper limit of formula (7), the focal length of the first lens group U1 becomes too short, which makes it difficult to correct chromatic aberration of magnification at the telephoto end, which is also undesirable.

[0041] It is more preferable to set the numerical range of the formula (7) as follows:

[0042] 2.55≦ft / f1≦4.50 (7a) Furthermore, it is more preferable to set the numerical range of the formula (7) as follows.

[0043] 2.60≦ft / f1≦4.00 (7b) In the zoom lens of each embodiment, it is preferable that at least one of the at least two movable lens groups that move during zooming has negative refractive power, and when the focal length of the movable lens group with negative refractive power that is closest to the object is denoted by f2, the condition of the following expression (8) is satisfied:

[0044] 1.0≦|f1 / f2|≦6.0 (8) The condition of equation (8) indicates the appropriate relationship between the focal length of the negative movable lens group closest to the object and the focal length of the first lens group U1. If |f1 / f2| falls below the lower limit of equation (8), the refractive power of the negative movable lens group closest to the object becomes too weak relative to the refractive power of the first lens group, resulting in a large amount of movement of the negative movable lens group closest to the object during zooming. This undesirably increases the overall length of the zoom lens, making compactness difficult. If |f1 / f2| exceeds the upper limit of equation (8), the refractive power of the negative movable lens group closest to the object becomes too strong relative to the refractive power of the first lens group, resulting in large fluctuations in aberrations during zooming, undesirably.

[0045] It is more preferable to set the numerical range of the formula (8) as follows:

[0046] 1.2≦|f1 / f2|≦5.8 (8a) Furthermore, it is more preferable to set the numerical range of the formula (8) as follows.

[0047] 1.3≦|f1 / f2|≦5.7 (8b) In the zoom lens of each embodiment, the negative movable lens unit closest to the object side described above has a negative lens Ln2 and a second positive lens Lp2. When the Abbe number of the negative lens Ln2 with respect to the d-line is vn2 and the partial dispersion ratio at the g-line and F-line is θn2, it is preferable that the following expressions (9) and (10) be satisfied.

[0048] 60≦νn2≦105 (9) -0.002≦θn2+0.001×νn2−0.603≦0.050 (10) Furthermore, when the Abbe number of the second positive lens Lp2 with respect to the d-line is νp2 and the partial dispersion ratio at the g-line and F-line is θp2, it is preferable that the following expressions (11) and (12) be satisfied.

[0049] 20≦νp2≦40 (11) 0.648≦θp2+0.00253×νp2≦0.680 (12) The conditions of equations (9) and (10) indicate the appropriate relationship between the Abbe number and partial dispersion ratio of the negative lens Ln2 included in the negative movable lens group closest to the object. If vn2 exceeds the upper limit of equation (9), the refractive index of the negative lens Ln2 will be too small for existing materials, making it difficult to suppress fluctuations in field curvature throughout the entire zoom range, which is undesirable. If vn2 falls below the lower limit of equation (9), the material of the negative lens Ln2 will be a high-dispersion material with an Abbe number that is too small, making it difficult to correct chromatic aberrations in the negative movable lens group closest to the object, and making it difficult to suppress fluctuations in lateral chromatic aberration throughout the entire zoom range, which is also undesirable.

[0050] If θn2+0.001×νn2−0.603 exceeds the upper limit of formula (10), the partial dispersion ratio of the negative lens Ln2 becomes too large, resulting in over-correction of the secondary spectrum of axial chromatic aberration, particularly at the telephoto end, which is undesirable.If θn2+0.001×νn2−0.603 falls below the lower limit of formula (10), the partial dispersion ratio of the negative lens Ln2 becomes too small, resulting in under-correction of the secondary spectrum of lateral chromatic aberration, particularly at the wide-angle end, which is undesirable.

[0051] Furthermore, the conditions of equations (11) and (12) indicate the appropriate relationship between the Abbe number and partial dispersion ratio of the second positive lens Lp2 included in the negative movable lens group closest to the object. If vp2 exceeds the upper limit of equation (11), the material of the second positive lens Lp2 becomes a low-dispersion material with an Abbe number that is too large, making it difficult to correct chromatic aberration in the negative movable lens group closest to the object and suppressing fluctuations in lateral chromatic aberration throughout the zoom range, which is undesirable. If vp2 falls below the lower limit of equation (11), the material of the second positive lens Lp2 becomes a high-dispersion material with an Abbe number that is too small. As a result, it becomes difficult to achieve both achromatism and aberration correction for the reference wavelength (d-line) in the negative movable lens group closest to the object, making it difficult to suppress spherical aberration, particularly at the telephoto end, which is undesirable.

[0052] If θp2+0.00253×νp2 exceeds the upper limit of equation (12), the partial dispersion ratio of the second positive lens Lp2 becomes too large, resulting in under-correction of the secondary spectrum of lateral chromatic aberration, particularly at the wide-angle end, which is undesirable.If θp2+0.00253×νp2 falls below the lower limit of equation (12), the partial dispersion ratio of the second positive lens Lp2 becomes too small, resulting in over-correction of the secondary spectrum of axial chromatic aberration, particularly at the telephoto end, which is undesirable.

[0053] It is more preferable that the numerical ranges of the formulas (9) to (12) are as follows:

[0054] 62≦νn2≦90 (9a) 0.000≦θn2+0.001×νn2-0.603≦0.030 (10a) 20≦νp2≦30 (11a) 0.655≦θp2+0.00253×νp2≦0.678 (12a) Furthermore, it is more preferable to set the numerical ranges of the formulas (9) to (12) as follows:

[0055] 63≦νn2≦80 (9b) 0.002≦θn2+0.001×νn2-0.603≦0.014 (10b) 24≦νp2≦26 (11b) 0.660≦<θp2+0.00253×νp2≦0.677 (12b) The specific configurations of the zoom lenses of Examples 1 to 6 will be described below. [Examples 1 to 3] The zoom lenses of Examples 1 to 3 shown in FIGS. 1, 3, and 5 are configured, arranged in this order from the object side to the image side, with a first lens group U1 having positive refractive power that does not move during zooming, a second lens group U2 having negative refractive power, a third lens group U3 having negative refractive power, and a fourth lens group U4 having positive refractive power that serve as movable lenses that move during zooming, and a fifth (final) lens group U5 having positive refractive power for imaging that does not move during zooming.

[0056] The first lens unit U1 in Examples 1 and 2 is composed of seven lenses, and includes, in order from the object side to the image side, a first sub-unit U11 with negative refractive power, a second sub-unit U12 with positive refractive power, and a third sub-unit U13 with positive refractive power. As indicated by the arrows in the figure, during focusing from infinity to a close distance, the first sub-unit U11 does not move, the second sub-unit U12 moves toward the image side, and the third sub-unit U13 moves toward the object side.

[0057] The first lens group U1 in Example 3 is composed of nine lenses, and includes, in order from the object side to the image side, a first sub-group U11 with negative refractive power, a second sub-group U12 with positive refractive power, and a third sub-group U13 with positive refractive power. During focusing from infinity to a close distance, the first sub-group U11 does not move, the second sub-group U12 moves toward the image side, and the third sub-group U13 does not move.

[0058] In Examples 1 to 3, the second lens unit U2 is a variator that moves toward the image side during zooming from the wide-angle end to the telephoto end, as indicated by the arrow in the figure. The third lens unit U3 moves toward the object side and then moves toward the image side during zooming from the wide-angle end to the telephoto end. The fourth lens unit U4 moves toward the image side and then moves toward the object side during zooming from the wide-angle end to the telephoto end.

[0059] An aperture stop SP is disposed inside the fifth lens unit U5 in Examples 1 and 2. An aperture stop SP is disposed closest to the object side of the fifth lens unit U5 in Example 3. An extender lens for converting focal length or the like may be inserted or removed into the space inside the fifth lens unit U5 in Examples 1 to 3. [Example 4] The zoom lens of Example 4 shown in FIG. 7 is composed of, arranged in order from the object side to the image side, a first lens group U1 with positive refractive power that does not move during zooming, 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 that serve as movable lenses that move during zooming, and a fifth (final) lens group U5 with positive refractive power for imaging that does not move during zooming.

[0060] The first lens group U1 is composed of seven lenses, and from the object side to the image side, it has a first subgroup U11 with negative refractive power, a second subgroup U12 with positive refractive power, and a third subgroup U13 with positive refractive power. During focusing from infinity to a close distance, the first subgroup U11 does not move, the second subgroup U12 moves toward the image side, and the third subgroup U13 moves toward the object side.

[0061] The second lens unit U2 is a variator that moves toward the image side during zooming from the wide-angle end to the telephoto end, as indicated by the arrow in the figure. The third lens unit U3 moves toward the image side during zooming from the wide-angle end to the telephoto end. The fourth lens unit U4 moves toward the image side and then toward the object side during zooming from the wide-angle end to the telephoto end.

[0062] An aperture stop SP is disposed inside the fifth lens unit U5. An extender lens for converting focal length or the like may be inserted or removed into the space inside the fifth lens unit U5. [Example 5] The zoom lens of Example 4 shown in FIG. 9 is composed of, arranged in order from the object side to the image side, a first lens group U1 with positive refractive power that does not move during zooming, a second lens group U2 with negative refractive power and a third lens group U3 with negative refractive power that serve as movable lenses that each move during zooming, and a fourth (final) lens group U4 with positive refractive power for imaging that does not move during zooming.

[0063] The first lens group U1 is composed of 10 lenses, and includes, in order from the object side to the image side, a first subgroup U11 with negative refractive power, a second subgroup U12 with positive refractive power, and a third subgroup U13 with positive refractive power. During focusing from infinity to a close distance, the first subgroup U11 does not move, the second subgroup U12 moves toward the image side, and the third subgroup U13 does not move.

[0064] The second lens unit U2 is a variator that moves toward the image side during zooming from the wide-angle end to the telephoto end, as indicated by the arrow in the figure. The third lens unit U3 moves toward the object side during zooming from the wide-angle end to the telephoto end, and then moves toward the image side.

[0065] An aperture stop SP is disposed closest to the object side of the fourth lens unit U4. An extender lens for converting focal length or the like may be inserted or removed into the space within the fourth lens unit U4. [Example 6] The zoom lens of Example 6 shown in FIG. 11 is composed of, arranged in order from the object side to the image side, a first lens group U1 with positive refractive power that does not move during zooming, a second lens group U2 with negative refractive power, a third lens group U3 with negative refractive power, a fourth lens group U4 with negative refractive power, and a fifth lens group U5 with positive refractive power that serve as movable lenses that move during zooming, and a sixth (final) lens group U6 with positive refractive power for imaging that does not move during zooming.

[0066] The first lens group U1 is composed of seven lenses, and from the object side to the image side, it has a first subgroup U11 with negative refractive power, a second subgroup U12 with positive refractive power, and a third subgroup U13 with positive refractive power. During focusing from infinity to a close distance, the first subgroup U11 does not move, the second subgroup U12 moves toward the image side, and the third subgroup U13 moves toward the object side.

[0067] The second lens unit U2 is a variator that moves toward the image side during zooming from the wide-angle end to the telephoto end, as indicated by the arrow in the figure. The third lens unit U3 moves toward the image side during zooming from the wide-angle end to the telephoto end. The fourth lens unit U4 moves toward the object side and then moves toward the image side during zooming from the wide-angle end to the telephoto end. The fifth lens unit U4 moves toward the image side and then moves toward the object side during zooming from the wide-angle end to the telephoto end.

[0068] An aperture stop SP is arranged closest to the object side of the sixth lens unit U6. An extender lens for converting focal length or the like may be inserted or removed into the space within the sixth lens unit U6.

[0069] Numerical Examples 1 to 6 corresponding to Examples 1 to 6, respectively, are shown below. In each numerical example, i indicates the order of the surface when counted from the object side, r is the radius of curvature of the ith surface, and d is the distance on the optical axis between the ith surface and the (i+1)th surface. nd and vd are the refractive index at the d-line of the optical material between the ith surface and the (i+1)th surface and the Abbe number based on the d-line, respectively. The Abbe number vd based on the d-line is given by, where Nd, NF, and NC are the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer lines, respectively. It is expressed as νd=(Nd-1) / (NF-NC).

[0070] The focal length, F-number, and half angle of view (°) are all values ​​when focused at infinity. BF stands for 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) to the paraxial image plane, expressed as the air-equivalent length. "Total lens length" 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.

[0071] An asterisk (*) next to a surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following equation, where X is the displacement from the vertex of the surface in the optical axis direction, H is the height from the optical axis in a direction perpendicular to the optical axis, the direction of light propagation is positive, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, A10, A12, A14, and A16 are aspherical coefficients.

[0072]

number

[0073] The aspherical coefficient "ex" is x10 -x means.

[0074] The values ​​of the above-mentioned formulas (1) to (12) in Numerical Examples 1 to 6 are summarized in Table 1. The zoom lens of each Numerical Example satisfies all of the conditions of formulas (1) to (12).

[0075] 2, 4, 6, 8, 10, and 12 show longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lenses of Numerical Examples 1 to 6 at infinity focus at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end, respectively.

[0076] In the spherical aberration diagram, Fno indicates the F-number, the solid line indicates the spherical aberration for the d-line (wavelength 587.6 nm), and the dashed line indicates the spherical aberration for the g-line (wavelength 435.8 nm). In the astigmatism diagram, the solid line S indicates the sagittal image plane, and the dashed line M indicates the meridional image plane. Distortion aberration indicates distortion aberration at the d-line. The chromatic aberration diagram indicates chromatic aberration of magnification at the g-line. ω is the half angle of view (°). [Numerical example 1] Unit: mm Surface Data Surface number rd nd νd 1 -262.221 2.80 1.88300 40.8 2 136.383 0.83 3 125.967 5.07 1.98612 16.5 4 186.541 4.40 5 287.598 13.25 1.43875 94.7 6* -131.259 0.20 7 152.530 2.40 1.85478 24.8 8 79.117 0.10 9 79.291 12.66 1.52841 76.5 10 16020.988 12.32 11 120.675 9.25 1.59522 67.7 12 -1242.044 0.99 13 79.870 9.07 1.61800 63.3 14 394.020 (variable) 15* 937.239 1.20 2.00100 29.1 16 23.833 7.39 17 -31.989 0.80 1.52841 76.5 18 33.447 6.30 1.85478 24.8 19 -35.704 1.57 20 -25.250 0.80 1.85150 40.8 21 -98.722 (variable) 22 -52.270 0.90 1.88300 40.8 23 115.728 3.24 1.84666 23.8 24 -131.697 (variable) 25* 75.874 7.07 1.76385 48.5 26 -93.140 0.15 27 93.986 1.20 1.85478 24.8 28 40.250 5.98 1.59522 67.7 29 384.407 (variable) 30 123.330 6.78 1.53775 74.7 31 -75.958 1.00 32 (Aperture) ∞ 3.77 33 -64.702 1.10 1.88300 40.8 34 -621.569 43.69 35 63.004 6.86 1.48749 70.2 36 -58.073 6.50 37 53.379 6.82 1.80810 22.8 38 -41.160 1.00 2.00100 29.1 39 40.107 2.17 40 73.759 8.09 1.48749 70.2 41 -23.016 1.00 1.88300 40.8 42 206.320 0.20 43 30.833 1.10 1.88300 40.8 44 23.095 8.53 1.51633 64.1 45 -112.087 (variable) Image plane ∞ Aspheric data Page 6 K =-7.43182e-01 A 4=-2.89706e-09 A 6=-1.11754e-12 A 8= 4.96240e-16 Page 15 K = 1.90407e+00 A 4= 5.34417e-06 A 6=-3.53145e-09 A 8= 2.39390e-11 A10=-9.28133e-14 A12= 2.17422e-16 Page 25 K = 2.00007e+00 A 4=-2.21894e-06 A 6= 1.31120e-10 A 8=-1.99758e-13 Various data Zoom ratio 11.52 Wide-angle Mid-range Telephoto Focal length 24.94 147.25 287.17 F-number 2.73 2.73 4.10 Half angle of view (°) 30.69 5.74 2.95 Image height 14.80 14.80 14.80 Lens total length 316.78 316.78 316.78 BF 40.00 40.00 40.00 d14 1.13 48.57 55.04 d21 49.56 3.30 2.23 d24 9.44 14.95 1.15 d29 8.10 1.41 9.81 d45 40.00 40.00 40.00 Lens group data Group starting plane focal length 1 1 81.37 2 15 -19.45 3 22 -94.92 4 25 51.96 5 30 121.13 [Numerical example 2] Unit: mm Surface Data Surface number rd nd νd 1 -222.510 2.80 1.83481 42.7 2 135.461 0.86 3 125.774 4.68 2.10420 17.0 4 174.042 4.52 5 266.403 13.84 1.43875 94.7 6* -125.918 0.20 7 154.501 2.40 1.85478 24.8 8 79.852 0.10 9 80.012 12.58 1.52841 76.5 10 5722.539 11.37 11 119.682 9.28 1.59522 67.7 12 -1282.377 0.99 13 79.728 9.04 1.61800 63.3 14 374.302 (variable) 15* 1483.600 1.20 2.00100 29.1 16 24.488 7.54 17 -33.212 0.80 1.52841 76.5 18 34.824 6.35 1.85478 24.8 19 -36.978 1.69 20 -25.739 0.80 1.85150 40.8 21 -88.739 (variable) 22 -50.625 0.90 1.88300 40.8 23 96.830 3.08 1.84666 23.8 24 -138.820 (variable) 25* 67.696 7.08 1.76385 48.5 26 -95.092 0.15 27 105.353 1.20 1.85478 24.8 28 39.840 6.03 1.59522 67.7 29 456.810 (variable) 30 137.653 5.74 1.53775 74.7 31 -121.385 1.00 32 (Aperture) ∞ 2.89 33 -95.228 1.10 1.88300 40.8 34 -443.742 43.67 35 54.129 6.78 1.48749 70.2 36 -55.319 0.20 37 47.350 6.69 1.80810 22.8 38 -47.081 1.00 2.00100 29.1 39 35.342 2.31 40 70.136 7.74 1.48749 70.2 41 -23.162 1.00 1.88300 40.8 42 130.827 0.20 43 31.488 1.10 1.88300 40.8 44 23.902 7.05 1.51633 64.1 45 -174.582 (variable) Image plane ∞ Aspheric data Page 6 K =-6.86455e-01 A 4=-3.29932e-09 A 6=-6.71576e-13 A 8= 5.31527e-16 Page 15 K = 2.00021e+00 A 4= 5.29834e-06 A 6=-3.12907e-09 A 8= 1.80902e-11 A10=-6.59395e-14 A12= 1.53082e-16 Page 25 K = 1.79114e+00 A 4=-2.63811e-06 A 6= 8.58692e-11 A 8=-2.68690e-13 Various data Zoom ratio 11.51 Wide-angle Mid-range Telephoto Focal length 24.94 145.66 287.15 F-number 2.73 2.73 4.03 Half angle of view (°) 30.69 5.80 2.95 Image height 14.80 14.80 14.80 Lens total length 307.08 307.08 307.08 BF 40.00 40.00 40.00 d14 1.20 48.44 54.88 d21 45.98 3.23 2.19 d24 12.81 15.57 1.13 d29 9.10 1.85 10.89 d45 40.00 40.00 40.00 Lens group data Group starting plane focal length 1 1 81.37 2 15 -20.31 3 22 -87.04 4 25 51.36 5 30 128.82 [Numerical example 3] Unit: mm Surface Data Surface number rd nd νd 1* 1074.667 2.80 1.89190 37.1 2 43.685 27.00 3 -75.730 2.20 1.62041 60.3 4 -383.133 0.20 5 159.909 5.50 2.00000 13.8 6 588.066 1.20 7 214.936 12.31 1.59522 67.7 8* -91.857 9.80 9 1347.924 9.09 1.67270 32.1 10 -98.393 2.00 1.80810 22.8 11 -283.387 0.20 12 220.290 2.00 1.80810 22.8 13 56.042 17.27 1.48749 70.2 14 -156.232 0.20 15 106.333 10.64 1.75500 52.3 16 -156.038 (variable) 17* 98.991 1.25 2.00100 29.1 18 22.833 7.34 19 -35.043 0.90 1.52841 76.5 20 34.343 5.08 1.85478 24.8 21 -72.398 3.46 22 -24.031 1.00 1.85150 40.8 23 -33.833 (variable) 24 -34.890 0.80 1.65160 58.5 25 77.193 2.52 1.80810 22.8 26 1302.716 (variable) 27* 69.685 5.67 1.89190 37.1 28 -136.223 (variable) 29 (Aperture) ∞ 1.35 30 44.026 7.79 1.48749 70.2 31 -125.688 0.25 32 2346.338 1.20 2.00100 29.1 33 31.968 5.71 1.51633 64.1 34 -18847.507 1.00 35 -186.120 5.60 1.53172 48.8 36 -32.247 1.10 1.88300 40.8 37 -62.513 41.06 38 86.756 6.86 1.48749 70.2 39 -52.385 2.04 40 42.959 8.71 1.80810 22.8 41 -41.800 0.90 2.00100 29.1 42 30.823 1.30 43 27.833 10.81 1.43875 94.7 44 -33.867 1.00 1.88300 40.8 45 68.068 0.50 46 42.446 6.64 1.48749 70.2 47 -67.429 (variable) Image plane ∞ Aspheric data Front page K = 1.29203e+00 A 4= 5.24187e-07 A 6= 4.61325e-10 A 8=-5.10222e-13 A10= 2.62566e-16 A12=-6.64497e-20 A14= 5.01622e-24 A16= 4.88118e-28 Side 8 K = 2.00160e+00 A 4= 1.02407e-06 A 6= 1.11216e-10 A 8= 2.34881e-15 A10=-2.21128e-17 A12= 8.84415e-21 Page 17 K = 0.00000e+00 A 4= 4.40622e-06 A 6=-3.89061e-09 A 8= 4.26997e-11 A10=-3.46781e-13 A12= 2.00503e-15 A14=-6.39102e-18 A16= 9.26900e-21 Page 27 K = 0.00000e+00 A 4=-2.05020e-06 A 6= 8.77473e-10 A 8=-9.04950e-13 Various data Zoom ratio 7.69 Wide-angle Mid-range Telephoto Focal length 15.09 84.97 116.08 F-number 2.72 2.73 3.65 Half angle of view (°) 44.45 9.88 7.27 Image height 14.80 14.80 14.80 Lens total length 339.07 339.07 339.07 BF 46.16 46.16 46.16 d16 0.99 47.53 51.30 d23 34.51 2.01 4.27 d26 14.21 7.66 1.16 d28 8.97 1.49 1.96 d47 46.16 46.16 46.16 Lens group data Group starting plane focal length 1 1 43.85 2 17 -26.48 3 24 -57.90 4 27 52.37 5 29 89.82 [Numerical example 4] Unit: mm Surface Data Surface number rd nd νd 1 -234.607 2.80 1.80000 29.8 2 123.876 1.48 3 123.657 8.98 1.98612 16.5 4 248.835 8.63 5 3015.789 10.91 1.43875 94.7 6* -198.524 0.20 7 185.639 2.40 1.85478 24.8 8 89.418 0.12 9 89.526 22.57 1.59522 67.7 10 -361.527 17.82 11 126.164 12.44 1.59522 67.7 12 -66204.123 0.99 13 90.527 9.72 1.61800 63.3 14 299.858 (variable) 15* 101.155 1.20 2.00100 29.1 16 19.596 7.05 17 -26.943 0.80 1.53775 74.7 18 29.174 5.79 1.85478 24.8 19 -34.855 1.70 20 -21.077 0.80 1.85150 40.8 21 -95.436 (variable) 22 -101.598 0.90 1.89190 37.1 23 100.000 2.85 1.95375 32.3 24 -100.000 (variable) 25* 139.476 5.44 1.76385 48.5 26 -77.855 0.15 27 110.985 1.20 1.85478 24.8 28 46.272 3.31 1.59522 67.7 29 104.465 (variable) 30 49.701 6.11 1.53775 74.7 31 -1706.072 2.00 32∞2.13 33 -82.892 1.10 1.88300 40.8 34 -173.594 41.31 35 69.389 6.48 1.48749 70.2 36 -76.960 1.62 37 47.766 6.85 1.80810 22.8 38 -77.028 1.00 2.00100 29.1 39 32.182 3.59 40 41.879 10.98 1.48749 70.2 41 -26.286 1.00 1.88300 40.8 42 135.907 1.64 43 34.805 1.10 1.88300 40.8 44 25.461 12.09 1.51633 64.1 45 -57.644 (variable) Image plane ∞ Aspheric data Page 6 K = 1.87422e+00 A 4= 6.06065e-08 A 6=-5.94865e-13 A 8= 2.77145e-16 Page 15 K = 1.93424e+00 A 4= 7.69049e-06 A 6=-5.40926e-09 A 8= 7.81922e-11 A10=-3.67064e-13 A12= 1.38416e-15 Page 25 K =-1.06448e+00 A 4=-6.38038e-07 A 6= 2.88984e-10 A 8=-1.48020e-13 Various data Zoom ratio 9.13 Wide-angle Mid-range Telephoto Focal length 26.51 129.61 242.04 F-number 2.73 2.73 3.54 Half angle of view (°) 29.17 6.51 3.50 Image height 14.80 14.80 14.80 Lens total length 347.11 347.11 347.11 BF 40.36 40.36 40.36 d14 0.98 54.03 61.27 d21 5.93 3.01 1.94 d24 28.20 18.30 2.18 d29 42.39 2.16 12.12 d45 40.36 40.36 40.36 Lens group data Group starting plane focal length 1 1 89.20 2 15 -15.87 3 22 652.19 4 25 83.64 5 30 83.03 [Numerical example 5] Unit: mm Surface Data Surface number rd nd νd 1* 299.063 2.40 1.80100 35.0 2 47.242 29.22 3 -68.809 1.80 1.64000 60.1 4 3277.662 0.18 5 174.767 7.08 1.97000 17.2 6 -1403.793 1.99 7 166.263 13.96 1.59522 67.7 8* -123.567 6.05 9 1467.907 7.95 1.49700 81.5 10 -116.803 1.50 1.85478 24.8 11 -209.556 0.18 12 124.190 1.50 1.84666 23.8 13 56.386 14.54 1.43875 94.9 14 -890.919 0.20 15 151.623 9.63 1.49700 81.5 16 -162.827 0.20 17 76.261 8.36 1.77250 49.6 18 500.978 (variable) 19* 66.238 1.30 1.77250 49.6 20 18.513 8.77 21 -40.984 0.90 1.61800 63.3 22 59.872 0.20 23 40.922 3.90 1.85478 24.8 24 -177.075 3.41 25 -20.480 0.90 1.77250 49.6 26 -30.520 (variable) 27 -31.035 0.90 1.72916 54.7 28 50.102 3.27 1.84666 23.8 29 1167.319 (variable) 30 (Aperture) ∞ 1.29 31 781.806 5.86 1.69680 55.5 32 -39.881 0.20 33 134.518 4.03 1.58913 61.1 34 -122.542 0.20 35 99.184 6.78 1.51633 64.1 36 -42.877 1.20 2.00100 29.1 37 -515.005 0.20 38 24.881 8.90 1.53172 48.8 39 -790.849 1.20 2.00069 25.5 40 56.714 23.87 41 317.045 2.04 1.48749 70.2 42 -138.893 0.69 43 45.897 5.37 1.92286 18.9 44 -26.794 0.80 1.95375 32.3 45 35.069 5.00 46 67.619 6.71 1.48749 70.2 47 -15.476 0.90 2.00069 25.5 48 -181.661 0.20 49 59.528 5.82 1.48749 70.2 50 -30.623 (variable) Image plane ∞ Aspheric data Front page K = 2.08900e+00 A 4= 1.47874e-07 A 6=-2.01389e-10 A 8=-9.65277e-14 A10=-4.80338e-18 A12= 1.26093e-21 A14=-3.90133e-24 A16= 1.61420e-27 A 5= 6.71921e-09 A 7= 2.89590e-12 A 9= 1.02254e-15 A11= 5.02702e-19 A13=9.11228e-23 A15=-1.07211e-25 Side 8 K =-1.64835e-01 A 4= 3.85957e-07 A 6= 1.36318e-10 A 8= 7.63474e-14 A10= 5.50955e-17 A12=-1.14094e-19 A14= 7.22772e-23 A16=-5.03682e-26 A 5=-6.61305e-10 A 7=-8.86213e-12 A 9= 3.44021e-15 A11=-2.02141e-18 A13=-2.61905e-22 A15= 1.81827e-24 Page 19 K = 5.74778e+00 A 4= 4.06473e-06 A 6=-1.48659e-09 A 8= 1.63620e-09 A10= 9.99256e-12 A12= 8.21366e-14 A14= 4.04250e-16 A16= 1.44245e-19 A 5= 1.30693e-07 A 7=-8.16603e-09 A 9=-1.54282e-10 A11=-7.60139e-13 A13=-7.35462e-15 A15=-1.18718e-17 Various data Zoom ratio 7.80 Wide-angle Mid-range Telephoto Focal length 17.53 89.43 136.77 F-number 2.73 2.72 3.60 Half angle of view (°) 40.17 9.40 6.18 Image height 14.80 14.80 14.80 Lens total length 296.68 296.68 296.68 BF 39.78 39.78 39.78 d18 0.62 35.42 39.75 d26 33.49 2.31 4.80 d29 11.25 7.64 0.82 d50 39.78 39.78 39.78 Lens group data Group starting plane focal length 1 1 42.18 February 19 -22.09 3 27 -45.70 4 30 33.54 [Numerical example 6] Unit: mm Surface Data Surface number rd nd νd 1 -246.005 2.80 2.00069 25.5 2 136.245 1.73 3 139.638 10.10 1.98612 16.5 4 995.648 6.87 5 -494.694 9.89 1.49700 81.5 6* -128.329 0.20 7 170.961 2.40 1.85478 24.8 8 75.289 0.00 9 75.289 13.22 1.61800 63.3 10 -5634.563 15.66 11 107.022 8.66 1.61800 63.3 12 -12144.069 1.00 13 83.339 7.10 1.60738 56.8 14 255.900 (variable) 15* 541.383 1.20 2.00100 29.1 16 24.442 7.80 17 -34.564 0.80 1.53775 74.7 18 35.003 6.33 1.85478 24.8 19 -41.232 (variable) 20 -26.291 0.80 1.85150 40.8 21 -64.971 (variable) 22 -48.609 0.90 1.88300 40.8 23 86.503 5.25 1.84666 23.8 24 -132.431 (variable) 25* 77.530 6.64 1.76385 48.5 26 -105.305 0.15 27 423.721 1.20 1.85478 24.8 28 57.657 5.82 1.59522 67.7 29 -207.164 (variable) 30 379.906 4.01 1.53775 74.7 31 -93.283 1.00 32 (Aperture) ∞ 3.64 33 -82.075 1.10 1.88300 40.8 34 -149.835 51.17 35 58.740 6.97 1.48749 70.2 36 -65.662 1.59 37 45.594 7.38 1.80810 22.8 38 -76.825 1.00 2.00100 29.1 39 33.739 2.41 40 49.804 8.98 1.48749 70.2 41 -25.532 1.00 1.88300 40.8 42 66.673 0.20 43 28.565 1.10 1.88300 40.8 44 21.232 8.77 1.51633 64.1 45 -106.834 (variable) Image plane ∞ Aspheric data Page 6 K =-9.97613e-01 A 4=-4.09736e-08 A 6=-4.86324e-12 A 8= 4.88793e-16 Page 15 K =-1.85176e+00 A 4= 4.83789e-06 A 6=-2.17941e-09 A 8= 1.05210e-11 A10=-3.73368e-14 A12= 9.16654e-17 Page 25 K = 2.00003e+00 A 4=-2.23694e-06 A 6= 1.74032e-10 A 8=-1.78911e-13 Various data Zoom ratio 10.03 Wide-angle Mid-range Telephoto Focal length 24.94 141.94 250.08 F-number 2.73 2.73 3.81 Half angle of view (°) 30.69 5.95 3.39 Image height 14.80 14.80 14.80 Lens total length 326.63 326.63 326.63 BF 41.55 41.55 41.55 d14 1.25 48.10 54.49 d19 2.07 2.75 2.99 d21 50.44 2.04 3.17 d24 10.95 14.03 1.48 d29 3.50 1.30 6.08 d45 41.55 41.55 41.55 Lens group data Group starting plane focal length 1 1 82.18 2 15 -61.55 3 20 -52.36 4 22 -84.73 5 25 58.55 6 30 111.88

[0077] [Table 1]

[0078] (imaging device) 13 shows an imaging device (broadcast camera) that uses the zoom lens of Examples 1 to 6 as an imaging optical system. 101 is the zoom lens of any of Examples 1 to 6. 124 is the camera body. The zoom lens 101 is detachable from the camera body 124. 125 is an imaging device configured by attaching the zoom lens 101 to the camera body 124.

[0079] The zoom lens 101 has a first lens group F, a magnification variable section LZ, and an R lens group R for imaging. The first lens group F includes a subgroup that moves during focusing. The magnification variable section LZ includes at least two movable lens groups that move during zooming. SP is an aperture diaphragm. Reference numerals 114 and 115 denote drive mechanisms such as helicoids or cams that drive the first lens group F and the magnification variable section LZ in the optical axis direction, respectively. Reference numerals 116 to 118 denote motors 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, and photosensors that detect the positions of the first lens group F and the magnification variable section LZ on the optical axis and the aperture diameter of the aperture diaphragm SP.

[0080] In the camera body 124, reference numeral 109 denotes a glass block corresponding to an optical filter within the camera 124, and reference numeral 110 denotes an imaging element such as a CCD sensor or a CMOS sensor that photoelectrically converts the subject image formed by the zoom lens 101 (capturing the subject). Reference numerals 111 and 122 denote control units such as a CPU that control various driving operations of the camera body 124 and the zoom lens 101.

[0081] In this way, by using the zoom lens of each embodiment as an imaging optical system, an imaging device with high optical performance can be realized. Note that the imaging device may be a lens-interchangeable camera or a lens-integrated camera, and may be a single-lens reflex camera with a quick-return mirror or a mirrorless camera without a quick-return mirror.

[0082] The above embodiment includes the following configurations.

[0083] (Configuration 1) A zoom lens having a plurality of lens groups arranged in order from the object side to the image side, the plurality of lens groups being composed of a first lens group having positive refractive power that does not move during zooming, at least two movable lens groups that move during zooming, and a final lens group having positive refractive power that does not move during zooming, wherein the spacing between adjacent lens groups changes during zooming, the first lens group includes at least one negative lens and at least one positive lens; When the Abbe number of a first positive lens included in the at least one positive lens is taken as νp1, the Abbe number is taken as νp1. 10.0≦νp1≦17.4 A zoom lens characterized by satisfying the following conditions: (Configuration 2) When the refractive index of the first positive lens at the d-line is Np1, 1.95≦Np1≦2.35 The zoom lens according to configuration 1, characterized in that the following condition is satisfied: (Configuration 3) the first lens group includes, arranged in order from the object side to the image side, a first subgroup having negative refractive power, a second subgroup having positive refractive power, and a third subgroup having positive refractive power; 3. The zoom lens according to configuration 1 or 2, wherein during focusing, the first subgroup does not move, and of the second subgroup and the third subgroup, at least the second subgroup moves. (Configuration 4) The zoom lens according to Configuration 3, wherein the first positive lens is included in the first subgroup. (Configuration 5) the first subgroup includes at least one negative lens; The average value of the Abbe numbers of the negative lenses in the first subgroup with respect to the d-line is νn1 ave , the average partial dispersion ratio for the g-line and F-line is θn1 ave When the partial dispersion ratio of the first positive lens at the g-line and the F-line is θp1, 5≦νn1 ave -νp1≦40 -0.0065≦(θn1ave -θp1) / (νn1 ave -νp1)≦-0.0025 5. The zoom lens according to any one of configurations 1 to 4, wherein the following condition is satisfied: (Configuration 6) the first subgroup includes at least one negative lens; When the focal length of the negative lens closest to the object among the at least one negative lens in the first sub-group is fn1 and the focal length of the first sub-group is f11, 0.4≦fn1 / f11≦2.0 6. The zoom lens according to any one of configurations 1 to 5, wherein the following condition is satisfied: (Configuration 7) When the focal length of the first positive lens is fp1 and the focal length of the first subgroup is f11, -6.00≦fp1 / f11≦-0.60 7. The zoom lens according to any one of configurations 1 to 6, wherein the following condition is satisfied: (Configuration 8) When the focal length of the first lens group is f1 and the focal length of the zoom lens at the telephoto end is ft, 2.50≦ft / f1≦5.00 8. The zoom lens according to any one of configurations 1 to 7, wherein the following condition is satisfied: (Configuration 9) at least one of the at least two movable lens groups has negative refractive power; When the focal length of the movable lens group closest to the object side among the at least one movable lens group having negative refractive power is f2 and the focal length of the first lens group is f1, 1.0≦|f1 / f2|≦6.0 9. The zoom lens according to any one of configurations 1 to 8, wherein the following condition is satisfied: (Configuration 10) at least one of the at least two movable lens groups has negative refractive power; the movable lens group closest to the object side among the at least one movable lens group having negative refractive power includes a negative lens; When the Abbe number of the negative lens in the movable lens unit closest to the object side with respect to the d-line is νn2 and the partial dispersion ratio at the g-line and the F-line is θn2, 60≦νn2≦105 -0.002≦θn2+0.001×νn2-0.603≦0.050 10. The zoom lens according to any one of configurations 1 to 9, wherein the following condition is satisfied: (Configuration 11) at least one of the at least two movable lens groups has negative refractive power; the movable lens group closest to the object side among the at least one movable lens group having negative refractive power includes a second positive lens; When the Abbe number of the second positive lens with respect to the d-line as a reference is νp2 and the dispersion ratio at the g-line and the F-line is θp2, 20≦νp2≦40 0.648≦θp2+0.00253×νp2≦0.680 11. The zoom lens according to any one of configurations 1 to 10, wherein the following condition is satisfied: (Configuration 12) a zoom lens according to any one of configurations 1 to 11; and an image sensor for capturing an image of a subject through the zoom lens.

[0084] The embodiments described above are merely representative examples, and various modifications and alterations are possible to each embodiment when implementing the present invention. [Explanation of symbols]

[0085] U1 First lens group U2 Second lens group U3 Third lens group U4 4th lens group U5 Fifth lens group U6 6th lens group SP aperture stop U11 1st subgroup U12 2nd subgroup U13 3rd subgroup

Claims

1. A zoom lens having a plurality of lens groups arranged in order from the object side to the image side, the plurality of lens groups being composed of a first lens group having positive refractive power that does not move during zooming, at least two movable lens groups that move during zooming, and a final lens group having positive refractive power that does not move during zooming, wherein the spacing between adjacent lens groups changes during zooming, the first lens group includes at least one negative lens and at least one positive lens; When the Abbe number of the first positive lens included in the at least one positive lens is taken as νp1 with respect to the d-line, 10.0≦νp1≦17.4 A zoom lens characterized by satisfying the following conditions:

2. When the refractive index of the first positive lens at the d-line is Np1, 1.95≦Np1≦2.35 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. the first lens group includes, arranged in order from the object side to the image side, a first subgroup having negative refractive power, a second subgroup having positive refractive power, and a third subgroup having positive refractive power; 2. The zoom lens according to claim 1, wherein, during focusing, the first subgroup does not move, and at least the second subgroup of the second and third subgroups moves.

4. 4. The zoom lens according to claim 3, wherein the first positive lens is included in the first subgroup.

5. the first subgroup includes at least one negative lens; The average value of the Abbe numbers of the negative lenses in the first subgroup with respect to the d-line is set to νn1 ａｖｅ , the average partial dispersion ratio for the g-line and F-line is θn1 ａｖｅ When the partial dispersion ratio of the first positive lens at the g-line and the F-line is θp1, 5≦νn1 ａｖｅ -νp1≦40 -0.0065≦(θ.1 ａｖｅ -θp1) / (νn1 ａｖｅ -νK1)≦-0.0025 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. the first subgroup includes at least one negative lens; When the focal length of the negative lens closest to the object among the at least one negative lens in the first sub-group is fn1 and the focal length of the first sub-group is f11, 0.4≦fn1 / f11≦2.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. When the focal length of the first positive lens is fp1 and the focal length of the first subgroup is f11, −6.00≦fp1 / f11≦−0.60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

8. When the focal length of the first lens group is f1 and the focal length of the zoom lens at the telephoto end is ft, 2.50≦ft / f1≦5.00 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

9. at least one of the at least two movable lens groups has negative refractive power; When the focal length of the movable lens group closest to the object side among the at least one movable lens group having negative refractive power is f2 and the focal length of the first lens group is f1, 1.0≦|f1 / f2|≦6.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

10. at least one of the at least two movable lens groups has negative refractive power; the movable lens group closest to the object side among the at least one movable lens group having negative refractive power includes a negative lens; When the Abbe number of the negative lens in the movable lens unit closest to the object side with respect to the d-line is νn2 and the partial dispersion ratio at the g-line and the F-line is θn2, 60≦νn2≦105 −0.002≦θn2+0.001×νn2−0.603≦0.050 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. at least one of the at least two movable lens groups has negative refractive power; the movable lens group closest to the object side among the at least one movable lens group having negative refractive power includes a second positive lens; When the Abbe number of the second positive lens with respect to the d-line is νp2 and the dispersion ratio between the g-line and the F-line is θp2, 20≦νp2≦40 0.648≦θp2+0.00253×νp2≦0.680 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. a zoom lens according to any one of claims 1 to 11; and an image sensor for capturing an image of a subject through the zoom lens.

Images