Zoom lens and image capturing device

Abstract

To provide a zoom lens which is compact, has a high zoom ratio, and offers high optical performance.SOLUTION: A zoom lens disclosed herein consists of, in order from the object side to the image side, a positive first lens group L1 configured to be stationary for zooming, multiple intermediate lens groups L2-L4 configured to move for zooming, and a final lens group L5 configured to be stationary for zooming. The intermediate lens groups include lens groups having negative refractive power and lens groups having positive refractive power. All positive lens groups of the intermediate lens groups move toward the object side while zooming from the wide-angle end to the telephoto end. An N-th lens group having the most negative refractive power among the intermediate lens groups includes two negative lenses and one positive lens. The zoom lens satisfies conditions expressed as: -3.1×10-3≤(θgFp-θgFn) / (νdp-νdn)≤-1.0×10-3, 3.6≤ft / f1≤7.0, and 35≤ft / fw≤70.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] As a zoom lens to be attached to a camera equipped with a large image sensor, a positive-lead zoom lens having a lens group with positive refractive power closest to the object is known as a zoom lens that is small, lightweight, has a wide angle of view, a high zoom ratio, and high optical performance. Patent Document 1 discloses a zoom lens having, in order from the object side to the image side, a first lens group with positive refractive power that does not move for zooming, an intermediate lens group that moves for zooming, and a final lens group that also does not move for zooming. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-203916 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to achieve a small, lightweight, wide-angle lens with a high zoom ratio and excellent optical performance throughout the entire zoom range, it is necessary for the intermediate lens group that moves for zooming to have an appropriate configuration. In the zoom lens of Patent Document 1, if the half angle of view at the wide-angle end is set larger and the zoom ratio is further increased, chromatic aberration increases throughout the entire zoom range.

[0005] The present invention provides a zoom lens having a high zoom ratio and high optical performance over the entire zoom range. [Means for solving the problem]

[0006] A zoom lens according to one aspect of the present invention includes lens groups arranged in order from the object side to the image side: a first lens group with positive refractive power that does not move for zooming; multiple intermediate lens groups that move for zooming; and a final lens group that is positioned closest to the image side and does not move for zooming; the spacing between adjacent lens groups changes during zooming. The intermediate lens groups include at least one lens group with negative refractive power and at least one lens group with positive refractive power. All of the lens groups with positive refractive power included in the intermediate lens groups move toward the object side during zooming from the wide-angle end to the telephoto end. The Nth lens group, which has the strongest negative refractive power among the at least one lens group with negative refractive power in the intermediate lens groups, includes at least two negative lenses and at least one positive lens.

[0007] In the Nth lens group, let the average Abbe number of at least one positive lens referenced to the d-line be νdp, the average partial dispersion ratio of at least one positive lens referenced to the g-line and the F-line be θgFp, the average Abbe number of at least two negative lenses referenced to the d-line be νdn, the average partial dispersion ratio of at least two negative lenses referenced to the g-line and the F-line be θgFn, the focal length of the zoom lens at the wide-angle end be fw, the focal length of the zoom lens at the telephoto end be ft, and the focal length of the first lens group be f1. -3.1×10 -3 ≦(θgFp-θgFn) / (νdp-νdn)≦-1.0×10 -3 3.6≦ft / f1≦7.0 35≦ft / fw≦70 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 having a high zoom ratio and 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] 3A and 3B are aberration diagrams of the zoom lens of Example 1 at infinity focus and at the wide-angle end and the telephoto end, respectively. [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 and 10B are aberration diagrams of the zoom lens of Example 2 at infinity focus and at the wide-angle end and the telephoto end, respectively. [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 and 10B are aberration diagrams of the zoom lens of Example 3 at infinity focus and at the wide-angle end and the telephoto end, respectively. [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 and 10B are aberration diagrams of the zoom lens of Example 4 at infinity focus and at the wide-angle end and the telephoto end, respectively. [Figure 9] FIG. 1 is a schematic diagram of an imaging device equipped with a zoom lens according to any one of Examples 1 to 4. 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, and 7 show cross sections of the zoom lenses of Examples 1 to 4 at the wide-angle end and in a state where the lens is focused on an object at infinity (hereinafter referred to as the infinity focused state), respectively. Before specifically describing Examples 1 to 4, matters common to all Examples will be described.

[0012] The zoom lens of each embodiment is used as an imaging optical system in imaging devices such as broadcast cameras, cinema cameras, general-purpose video cameras, surveillance cameras, digital still cameras, etc. In each figure, the left side is the object side (front side) and the right side is the image side (rear side).

[0013] The zoom lens of each embodiment is configured with lens groups arranged in order from the object side to the image side: a first lens group L1 with positive refractive power that does not move for zooming, a plurality of intermediate lens groups (L2 to L4 or L5) that move for zooming, and a final lens group (L5 or L6) that is arranged closest to the image side and does not move for 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 and telephoto ends. That is, the spacing between adjacent lens groups changes during zooming. The lens group may include an aperture stop. The wide-angle and telephoto ends 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] In each figure, SP is the aperture stop and IP is the image plane, 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 each zoom lens embodiment, the intermediate lens group includes at least one lens group with negative refractive power and at least one lens group with positive refractive power. All of the lens groups with positive refractive power included in the intermediate lens group move toward the object side during zooming from the wide-angle end to the telephoto end. Furthermore, the Nth lens group, which has the strongest negative refractive power among the at least one lens group with negative refractive power in the intermediate lens group, includes at least two negative lenses and at least one positive lens. Note that for a cemented lens in which m lenses are cemented together, the number of lenses is represented as m.

[0017] Let vdp be the average Abbe number of at least one positive lens in the Nth lens group referenced to the d-line, and θgFp be the average partial dispersion ratio of the at least one positive lens at the g-line and the F-line. Let vdn be the average Abbe number of at least two negative lenses in the Nth lens group referenced to the d-line, and θgFn be the average partial dispersion ratio of the at least two negative lenses at the g-line and the F-line. Let fw be the focal length of the zoom lens at the wide-angle end, ft be the focal length of the zoom lens at the telephoto end, and f1 be the focal length of the first lens group L1. In this case, the zoom lens of each embodiment satisfies the conditions of the following expressions (1) to (3).

[0018] -3.1×10 -3 ≦(θgFp-θgFn) / (νdp-νdn)≦-1.0×10 -3 (1) 3.6≦ft / f1≦7.0 (2) 35≦ft / fw≦70 (3) The conditions of formulas (1) to (3) indicate the appropriate characteristics of the Nth lens group. By satisfying these conditions, it is possible to realize a zoom lens that is small, lightweight, and has a wide angle of view, a high zoom ratio, and excellent optical performance throughout the entire zoom range.

[0019] If (θgFp-θgFn) / (νdp-νdn) is below the lower limit of formula (1), it becomes difficult to properly correct axial chromatic aberration at the telephoto end, which is undesirable. If (θgFp-θgFn) / (νdp-νdn) is above the upper limit of formula (1), it becomes difficult to properly correct lateral chromatic aberration at the telephoto end, which is undesirable.

[0020] If ft / f1 is below the lower limit of formula (2), the focal length of the first lens group L1 becomes too short, making it difficult to achieve the desired zoom ratio, which is undesirable.If ft / f1 is above the upper limit of formula (2), the focal length of the first lens group L1 becomes too long, making the sensitivity of the first lens group L1 to the optical performance of the zoom lens too high, which is also undesirable.

[0021] If ft / fw is below the lower limit of equation (3), it becomes difficult to achieve the desired zoom ratio, which is undesirable.If ft / fw is above the upper limit of equation (3), the overall length of the zoom lens becomes long, which makes it difficult to achieve compactness, which is also undesirable.

[0022] It is more preferable that the numerical ranges of the formulas (1) to (3) are as follows:

[0023] -3.0×10 -3 ≦(θgFp-θgFn) / (νdp-νdn)≦-2.0×10 -3 (1a) 3.8≦ft / f1≦6.0 (2a) 40≦ft / fw≦65 (3a) Furthermore, it is more preferable to set the numerical ranges of the formulas (1) to (3) as follows:

[0024] -2.9×10 -3 ≦(θgFp-θgFn) / (νdp-νdn)≦-2.4×10 -3 (1b) 3.9≦ft / f1≦5.1 (2b) 42≦ft / fw≦58 (3b) The following describes the conditions and configurations that the zoom lens of each embodiment preferably satisfies.

[0025] It is preferable that the zoom lens of each embodiment satisfies the condition of the following formula (4), where fn is the focal length of the Nth lens unit.

[0026] 5.0≦|f1 / fn|≦9.0 (4) If |f1 / fn| is below the lower limit of equation (4), the focal length of the Nth lens group becomes too long, making it difficult to achieve a desired zoom ratio, which is undesirable.If |f1 / fn| is above the upper limit of equation (4), the focal length of the Nth lens group becomes too short, making it difficult to achieve high optical performance over the entire zoom range, which is undesirable.

[0027] The zoom lens of each embodiment preferably satisfies the condition of the following formula (5), where the lateral magnifications of the Nth lens unit at the wide-angle end and the telephoto end are βNw and βNt, respectively, and the zoom ratio of the zoom lens is Zwt.

[0028] 0.1≦(βNt / βNw) / Zwt≦0.5 (5) If (βNt / βNw) / Zwt exceeds the lower limit of formula (5), the magnification ratio of the lens groups after the Nth lens group, which have a relatively simple configuration, increases, making it difficult to achieve high optical performance, which is undesirable.If (βNt / βNw) / Zwt exceeds the upper limit of formula (5), the magnification ratio of the Nth lens group becomes too large, making it difficult to suppress aberration fluctuations due to movement of the Nth lens group, which is undesirable.

[0029] It is preferable that the zoom lens of each embodiment satisfies the condition of the following expression (6), where f11 is the focal length of the lens closest to the object in the first lens unit L1.

[0030] -1.0≦f11 / f1≦-3.0 (6) If f11 / f1 is below the lower limit of equation (6), it is difficult to achieve the desired zoom ratio, which is undesirable.If f11 / f1 is above the upper limit of equation (6), it is difficult to achieve a wide angle of view and compactness of the zoom lens, which is undesirable.

[0031] It is preferable that the zoom lens of each embodiment satisfies the condition of the following formula (7), where Ndn is the average of the refractive indices for the d-line of all the positive lenses included in the Nth lens group.

[0032] 1.83≦Ndn≦2.20 (7) If Ndn is below the lower limit of formula (7), the average refractive index of all the positive lenses in the Nth lens group becomes too small, making it difficult to achieve a desired zoom ratio, which is undesirable.If Ndn is above the upper limit of formula (7), the average refractive index of all the positive lenses in the Nth lens group becomes too large, making the movement of the Nth lens group too sensitive to the optical performance of the zoom lens, which is also undesirable.

[0033] It is more preferable to set the numerical ranges of the formulas (4) to (7) as follows:

[0034] 6.0≦|f1 / fn|≦9.0 (4a) 0.15≦(βNt / βNw) / Zwt≦0.35 (5a) -1.2≦f11 / f1≦-2.0 (6a) 1.84≦Ndn≦2.00 (7a) Furthermore, it is more preferable to set the numerical ranges of the formulas (4) to (7) as follows.

[0035] 7.0≦|f1 / fn|≦8.9 (4b) 0.20≦(βNt / βNw) / Zwt≦0.25 (5b) -1.4≦f11 / f1≦-1.7 (6b) 1.84≦Ndn≦1.87 (7b) In the zoom lens of each condition, it is preferable that the Nth lens group be composed of, in order from the object side to the image side, one negative lens, one positive lens, two negative lenses, one positive lens, and one negative lens, which makes it possible to achieve a wide angle of view and a high zoom ratio at the wide-angle end while preventing the overall length of the zoom lens from increasing.

[0036] Next, the zoom lenses of Examples 1 to 4 will be specifically described. [Example]

[0037] 1 is composed of, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power that does not move for zooming, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, and a fourth lens group L4 with positive refractive power that each move for zooming, an aperture stop SP, and a fifth lens group (final lens group) L5 with positive refractive power for imaging that does not move for zooming. The second, third, and fourth lens groups L2 to L4 correspond to intermediate lens groups.

[0038] During zooming from the wide-angle end to the telephoto end, the second lens unit L2 serving as a variator lens unit moves monotonically toward the image side, the third lens unit L3 moves sequentially toward the object side, the image side, and then the object side, and the fourth lens unit L4 moves toward the object side.

[0039] The lens closest to the object side in the first lens group L1 is a negative lens. The second lens group L2 corresponds to the Nth lens group and is composed of, arranged in order from the object side to the image side, a negative lens, a cemented lens of a positive lens and a negative lens, a cemented lens of a negative lens and a positive lens, and a negative lens. [Example]

[0040] 3 is composed of, arranged in order from the object side to the image side, a first lens unit L1 with positive refractive power that does not move for zooming, a second lens unit L2 with negative refractive power, a third lens unit L3 with positive refractive power, a fourth lens unit L4 with negative refractive power, and a fifth lens unit L5 with positive refractive power that each move for zooming, an aperture stop SP, and a sixth lens unit (final lens unit) L6 with positive refractive power that does not move for zooming. The second, third, fourth, and fifth lens units L2 to L5 correspond to intermediate lens units.

[0041] During zooming from the wide-angle end to the telephoto end, the second lens unit L2 serving as a variator lens unit moves monotonically toward the image side, the third lens unit L3 and the fourth lens unit L4 move sequentially toward the object side, the image side, and then the object side, and the fifth lens unit L5 moves toward the object side.

[0042] The lens closest to the object side in the first lens group L1 is a negative lens. The second lens group L2 corresponds to the Nth lens group and is composed of a positive lens and a negative lens arranged in this order from the object side to the image side. [Example]

[0043] The zoom lens of Example 3 shown in Figure 5 is composed of, arranged in order from the object side to the image side, a first lens unit L1 with positive refractive power that does not move for zooming, a second lens unit L2 with negative refractive power, a third lens unit L3 with positive refractive power, and a fourth lens unit L4 with positive refractive power that each move for zooming, an aperture stop SP, and a fifth lens unit (final lens unit) L5 with negative refractive power for imaging that does not move for zooming. The second, third, and fourth lens units L2 to L4 correspond to intermediate lens units.

[0044] During zooming from the wide-angle end to the telephoto end, the second lens unit L2 serving as a variator lens unit moves monotonically toward the image side, the third lens unit L3 moves sequentially toward the object side, the image side, and then the object side, and the fourth lens unit L4 moves toward the object side.

[0045] The lens closest to the object side in the first lens group L1 is a negative lens. The second lens group L2 corresponds to the Nth lens group and is composed of, arranged in order from the object side to the image side, a negative lens, a cemented lens of a negative lens and a positive lens, and a cemented lens of a negative lens and a positive lens. [Example]

[0046] 7 is composed of, arranged in order from the object side to the image side, a first lens unit L1 with positive refractive power that does not move for zooming, a second lens unit L2 with negative refractive power, a third lens unit L3 with positive refractive power, and a fourth lens unit L4 with positive refractive power that each move for zooming, an aperture stop SP, and a fifth lens unit (final lens unit) L5 with positive refractive power for imaging that does not move for zooming. The second, third, and fourth lens units L2 to L4 correspond to intermediate lens units.

[0047] During zooming from the wide-angle end to the telephoto end, the second lens unit L2 serving as a variator lens unit moves monotonically toward the image side, the third lens unit L3 moves sequentially toward the object side, the image side, and then the object side, and the fourth lens unit L4 moves toward the object side.

[0048] The lens closest to the object side in the first lens group L1 is a negative lens. The second lens group L2 corresponds to the Nth lens group and is composed of, arranged in order from the object side to the image side, a negative lens, a cemented lens of a positive lens and a negative lens, a cemented lens of a negative lens and a positive lens, and a negative lens.

[0049] Numerical Examples 1 to 4 corresponding to Examples 1 to 4, respectively, are shown below. In each numerical example, surface number i indicates the order of the surface when counted from the object side. r indicates the radius of curvature (mm) of the ith surface from the object side, and d indicates the lens thickness or air gap (mm) on the optical axis between the ith and (i+1)th surfaces. nd indicates the refractive index at the d-line of the optical material between the ith and (i+1)th surfaces. νd indicates the Abbe number based on the d-line of the optical material between the ith and (i+1)th surfaces. The Abbe number based on the d-line, νd, is given by Nd, NF, and NC, respectively, when 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 are Nd, NF, and NC, respectively. νd=(Nd-1) / (NF-NC) θgF represents the partial dispersion ratio between the g-line and F-line of the optical material between the ith surface and the (i+1)th surface, and when the refractive index at the g-line (wavelength 435.8 nm) is Ng, θgF=(Ng-NF) / (NF-NC) It is expressed as:

[0050] BF stands for back focal length (mm). Back focal length is the distance on the optical axis from the lens surface closest to the image (the final surface) of a zoom lens to the paraxial image plane, expressed as an air-equivalent length. The total lens length is the distance on the optical axis from the lens surface closest to the object (the frontmost surface) to the final surface, plus the back focal length.

[0051] 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.

[0052]

number

[0053] The "e±x" of the conic constant and aspherical coefficient is x10 ±x means.

[0054] Moreover, values ​​corresponding to the conditions of the above-mentioned expressions (1) to (7) in Numerical Examples 1 to 4 are summarized in Table 1. The zoom lens of each Numerical Example satisfies all of the conditions of expressions (1) to (7).

[0055] 2, 4, 6, and 8 respectively show longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) at (A) the wide-angle end and (B) the telephoto end when the zoom lenses of Numerical Examples 1 to 4 are focused at infinity. In the spherical aberration diagrams, Fno indicates the F-number. The solid line shows spherical aberration at the d-line (wavelength 587.6 nm), the two-dot chain line shows spherical aberration at the g-line (wavelength 435.8 nm), the one-dot chain line shows spherical aberration at the C-line (wavelength 656.3 nm), and the dashed line shows spherical aberration at the F-line (wavelength 486.1 nm).

[0056] 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 represents distortion at the d-line. In the chromatic aberration diagram, the two-dot chain line represents lateral chromatic aberration at the g-line, the one-dot chain line represents lateral chromatic aberration at the C-line, and the dashed line represents lateral chromatic aberration at the F-line. ω is the half angle of view (°).

[0057] The scales are as follows: spherical aberration 0.2mm, astigmatism 0.2mm, distortion 5%, and lateral chromatic aberration 0.05mm. [Numerical example 1] Unit: mm Surface Data Surface number rd nd νd θgF 1 -2949.662 6.00 1.83481 42.7 0.5648 2 357.074 1.50 3 349.213 24.64 1.43387 95.1 0.5373 4 -867.827 0.20 5 539.137 14.30 1.43387 95.1 0.5373 6 -1804.945 25.83 7 454.299 13.59 1.43387 95.1 0.5373 8 -77722.572 0.25 9 376.558 17.19 1.43387 95.1 0.5373 10 -2713.647 1.60 11 173.336 16.38 1.43387 95.1 0.5373 12 375.209 (variable) 13* 1257.361 2.20 1.89190 37.1 0.5780 14 47.781 11.60 15 -103.021 5.90 1.78880 28.4 0.6009 16 -46.226 1.60 1.95375 32.3 0.5905 17 -308.422 3.86 18 -71.439 1.50 1.76385 48.5 0.5589 19 106.851 11.43 1.85478 24.8 0.6122 20 -49.840 1.17 21 -45.134 1.65 1.77250 49.6 0.5520 22 -139.896 (variable) 23 111.685 13.29 1.76385 48.5 0.5589 24* -1005.803 (variable) 25 131.516 15.51 1.43875 94.7 0.5340 26 -164.110 0.49 27 298.353 2.50 1.78880 28.4 0.6009 28 77.164 (variable) 29 79.856 13.41 1.43875 94.7 0.5340 30 -633.825 2.40 1.78880 28.4 0.6009 31 527.937 0.17 32* 174.166 9.51 1.49700 81.5 0.5375 33 -189.536 (variable) 34 (Aperture) ∞ 5.03 35 -376.035 1.40 1.88300 40.8 0.5667 36 57.889 0.50 37 36.077 3.82 1.89286 20.4 0.6393 38 70.713 4.02 39 -186.251 1.50 1.88300 40.8 0.5667 40 71.853 10.26 41 201.222 1.50 2.00100 29.1 0.5997 42 30.134 6.11 1.77830 23.9 0.6248 43 96.796 0.20 44 35.387 1.50 1.88300 40.8 0.5667 45 26.637 14.36 1.49700 81.5 0.5375 46 -120.806 6.95 47 1717.236 4.81 1.53172 48.8 0.5631 48 -49.890 0.20 49 168.626 1.50 1.89190 37.1 0.5780 50 50.388 0.50 51 36.990 9.25 1.58913 61.1 0.5407 52 43.297 1.24 53 56.586 4.45 1.54814 45.8 0.5686 54 779.358 11.07 55 -32.048 1.20 1.76385 48.5 0.5589 56 47.767 6.88 1.85478 24.8 0.6122 57 -71.150 0.36 58 59.802 8.17 1.56732 42.8 0.5731 59 -39.515 1.20 1.95906 17.5 0.6598 60 -123.388 53.95 Image plane ∞ Aspheric data Page 13 K = 2.00000e+00 A 4= 4.15986e-07 A 6= 2.31467e-11 A 8=-1.81134e-13 A10=-3.95949e-17 A12= 7.76617e-19 A14=-9.79554e-22 A16= 3.96698e-25 Page 24 K = 2.00000e+00 A 4= 3.10238e-07 A 6=-3.61734e-12 A 8= 4.99908e-15 A10=-5.55220e-19 A12=-6.72946e-23 Page 32 K = 1.22230e+00 A 4=-3.49489e-07 A 6=-4.65996e-11 A 8=-1.61820e-14 A10=2.69342e-17 A12=-9.10437e-21 Various data Zoom ratio 47.94 Focal length 23.89 149.47 1145.35 F-number 2.90 2.90 5.98 Half angle of view (°) 31.78 5.65 0.74 Image height 14.80 14.80 14.80 Lens total length 673.99 673.99 673.99 BF 53.95 53.95 53.95 d12 3.16 134.35 182.87 d22 250.96 102.23 2.00 d28 29.03 14.27 11.31 d33 2.89 35.20 89.87 d60 53.95 53.95 53.95 Lens group data Group starting plane focal length 1 1 256.04 2 13 -31.12 3 23 143.61 4 29 116.09 5 34 1382.82 [Numerical example 2] Unit: mm Surface Data Surface number rd nd νd θgF 1 -2949.791 4.50 1.83481 42.7 0.5648 2 352.957 1.30 3 347.294 24.35 1.43387 95.1 0.5373 4 -897.579 0.20 5 571.959 13.48 1.43387 95.1 0.5373 6 -2023.134 23.09 7 407.594 14.59 1.43387 95.1 0.5373 8 25837.750 0.25 9 384.716 17.03 1.43387 95.1 0.5373 10 -2508.051 1.60 11 178.124 15.97 1.43387 95.1 0.5373 12 379.711 (variable) 13* 877.444 2.00 1.88300 40.8 0.5667 14 45.513 11.57 15 -106.695 3.27 1.85478 24.8 0.6122 16 -73.368 1.60 2.00100 29.1 0.5997 17 -273.528 4.30 18 -61.583 1.50 1.76385 48.5 0.5589 19 96.635 11.32 1.85478 24.8 0.6122 20 -49.408 1.35 21 -43.793 1.65 1.75500 52.3 0.5474 22 -161.420 (variable) 23 112.270 12.47 1.76385 48.5 0.5589 24* -4681.476 (variable) 25 116.048 16.47 1.43875 94.7 0.5340 26 -171.368 0.50 27 222.294 2.50 1.78880 28.4 0.6009 28 71.781 (variable) 29 70.420 14.82 1.43875 94.7 0.5340 30 -819.275 2.30 1.78880 28.4 0.6009 31 453.819 0.20 32* 160.030 9.39 1.49700 81.5 0.5375 33 -187.647 (variable) 34 (Aperture) ∞ 5.70 35 1703.727 1.40 1.88300 40.8 0.5667 36 52.137 0.96 37 35.787 3.68 1.89286 20.4 0.6393 38 67.046 3.94 39 -217.530 1.50 1.88300 40.8 0.5667 40 72.829 10.12 41 200.183 1.50 2.00100 29.1 0.5997 42 29.918 5.55 1.77830 23.9 0.6248 43 87.244 0.68 44 36.113 1.50 1.88300 40.8 0.5667 45 27.938 14.44 1.49700 81.5 0.5375 46 -139.041 6.95 47 223.491 5.71 1.53172 48.8 0.5631 48 -50.188 0.20 49 392.667 1.50 1.89190 37.1 0.5780 50 41.568 0.20 51 34.900 11.51 1.58913 61.1 0.5407 52 44.105 1.24 53 53.802 4.45 1.54814 45.8 0.5686 54 24161.728 4.03 55 -29.985 1.20 1.76385 48.5 0.5589 56 50.220 7.13 1.85478 24.8 0.6122 57 -57.929 4.34 58 70.502 8.53 1.56732 42.8 0.5731 59 -35.342 1.20 1.95906 17.5 0.6598 60 -83.794 51.96 Image plane ∞ Aspheric data Page 13 K = 2.00000e+00 A 4= 4.02568e-07 A 6= 2.18372e-11 A 8=-1.59954e-13 A10= 2.16400e-17 A12= 5.42209e-19 A14=-7.27782e-22 A16= 3.11984e-25 Page 24 K = 2.00000e+00 A 4= 2.74196e-07 A 6= 3.26329e-12 A 8= 2.84445e-15 A10=3.97003e-20 A12=-1.26556e-22 Page 32 K =-2.30668e-01 A 4=-4.68840e-07 A 6=-6.54710e-11 A 8= 1.04820e-14 A10=3.74249e-18 A12=-2.10842e-21 Various data Zoom ratio 57.54 Focal length 22.88 156.83 1316.54 F-number 2.90 2.90 6.86 Half angle of view (°) 32.90 5.39 0.64 Image height 14.80 14.80 14.80 Lens total length 666.58 666.58 666.58 BF 51.96 51.96 51.96 d12 3.05 140.44 191.25 d22 253.16 96.22 2.00 d24 8.14 7.12 6.40 d28 25.36 12.62 2.70 d33 2.20 35.51 89.56 d60 51.96 51.96 51.96 Lens group data Group starting plane focal length 1 1 261.40 2 13 -29.50 3 23 143.70 4 25 -1393.58 5 29 105.98 6 34 585.55 [Numerical example 3] Unit: mm Surface Data Surface number rd nd νd θgF 1 -62638.944 6.00 1.80610 40.9 0.5701 2 344.092 1.50 3 334.151 22.66 1.43387 95.1 0.5373 4 -1787.131 0.20 5 532.116 16.28 1.43387 95.1 0.5373 6 -1217.565 27.34 7 431.474 12.48 1.43387 95.1 0.5373 8 2804.559 0.25 9 338.404 15.72 1.43387 95.1 0.5373 10 3719.344 1.60 11 182.427 17.90 1.43387 95.1 0.5373 12 468.476 (variable) 13* 17876.618 2.20 1.95375 32.3 0.5905 14 45.568 14.28 15 -60.138 1.60 1.83481 42.7 0.5642 16 72.462 10.07 1.85896 22.7 0.6284 17 -69.693 3.86 18 -48.207 1.50 1.77250 49.6 0.5520 19 -381.106 3.97 1.85478 24.8 0.6122 20 -126.570 (variable) 21 114.071 11.45 1.65160 58.5 0.5390 22* -7159.613 (variable) 23 106.817 19.38 1.49700 81.5 0.5375 24 -198.198 0.49 25 184.625 2.50 1.80440 39.6 0.5762 26 69.690 (variable) 27 75.019 17.84 1.49700 81.5 0.5375 28 -270.765 2.40 1.96300 24.1 0.6212 29 1410.187 1.19 30* 282.109 9.11 1.48749 70.2 0.5300 31 -139.643 (variable) 32 (Aperture) ∞ 5.03 33 -376.035 1.40 1.88300 40.8 0.5667 34 57.889 0.50 35 36.077 3.82 1.89286 20.4 0.6393 36 70.713 4.02 37 -186.251 1.50 1.88300 40.8 0.5667 38 71.853 10.26 39 201.222 1.50 2.00100 29.1 0.5997 40 30.134 6.11 1.77830 23.9 0.6248 41 96.796 0.20 42 35.387 1.50 1.88300 40.8 0.5667 43 26.637 14.36 1.49700 81.5 0.5375 44 -120.806 6.95 45 1717.236 4.81 1.53172 48.8 0.5631 46 -49.890 0.20 47 63.436 1.50 1.85026 32.3 0.5929 48 38.224 2.01 49 30.920 3.52 1.55200 70.7 0.5421 50 46.394 1.99 51 106.568 3.17 1.51823 58.9 0.5457 52 1158.905 8.73 53 -42.136 1.20 1.83481 42.7 0.5648 54 95.752 6.75 1.85478 24.8 0.6122 55 -94.636 0.30 56 97.836 10.17 1.72151 29.2 0.6053 57 -30.989 1.20 1.96300 24.1 0.6212 58 -253.983 53.96 Image plane ∞ Aspheric data Page 13 K =-1.30998e+06 A 4= 8.24555e-07 A 6=-1.99590e-10 A 8=-3.39131e-14 A10=-2.57862e-16 A12= 1.00254e-18 A14=-1.05371e-21 A16= 3.68636e-25 Page 22 K =-1.90943e+04 A 4= 2.98500e-07 A 6= 9.98231e-12 A 8= 2.16198e-15 A10=-1.75329e-19 A12= 1.02455e-23 Page 30 K =-1.08530e+01 A 4=-4.32548e-07 A 6=-2.48004e-11 A 8=-1.52486e-14 A10= 1.92128e-17 A12=-5.56616e-21 Various data Zoom ratio 54.32 Focal length 23.89 152.90 1297.69 F-number 2.90 2.90 6.57 Half angle of view (°) 31.78 5.53 0.65 Image height 14.80 14.80 14.80 Lens total length 667.54 667.54 667.54 BF 53.96 53.96 53.96 d12 3.31 134.50 183.02 d20 253.78 105.04 4.82 d26 25.54 12.46 4.98 d31 2.50 33.13 92.31 d58 53.96 53.96 53.96 Lens group data Group starting plane focal length 1 1 258.23 2 13 -29.51 3 21 149.48 4 27 110.69 5 32 -280.78 [Numerical example 4] Unit: mm Surface Data Surface number rd nd νd θgF 1 -1652.488 6.00 1.83481 42.7 0.5648 2 409.439 1.50 3 398.411 29.03 1.43387 95.1 0.5373 4 -453.106 0.20 5 853.366 8.69 1.43387 95.1 0.5373 6 -5767.646 26.10 7 377.178 11.05 1.43387 95.1 0.5373 8 1351.608 0.25 9 332.399 17.12 1.43387 95.1 0.5373 10 -2708.385 1.60 11 179.758 14.59 1.43387 95.1 0.5373 12 399.463 (variable) 13* -2063.243 2.20 1.95375 32.3 0.5905 14 51.250 11.00 15 -123.149 9.61 1.78880 28.4 0.6009 16 -35.469 1.60 1.95375 32.3 0.5905 17 -198.669 3.86 18 -67.376 1.50 1.76385 48.5 0.5589 19 265.868 8.32 1.89286 20.4 0.6393 20 -68.974 1.17 21 -60.192 1.65 1.77250 49.6 0.5520 22 -103.942 (variable) 23 87.661 16.51 1.83400 37.2 0.5776 24* -885.373 2.17 25 125.357 14.56 1.49700 81.5 0.5375 26 -161.835 0.49 27 -2498.577 2.50 1.80518 25.4 0.6161 28 64.516 (variable) 29 102.843 10.68 1.49700 81.5 0.5375 30 -284.330 2.40 1.84666 23.8 0.6205 31 133.012 0.17 32* 85.877 11.38 1.73800 32.3 0.5900 33 -191.192 (variable) 34 (Aperture) ∞ 5.03 35 -376.035 1.40 1.88300 40.8 0.5667 36 57.889 0.50 37 36.077 3.82 1.89286 20.4 0.6393 38 70.713 4.02 39 -186.251 1.50 1.88300 40.8 0.5667 40 71.853 10.26 41 201.222 1.50 2.00100 29.1 0.5997 42 30.134 6.11 1.77830 23.9 0.6248 43 96.796 0.20 44 35.387 1.50 1.88300 40.8 0.5667 45 26.637 14.36 1.49700 81.5 0.5375 46 -120.806 6.95 47 -197.791 4.19 1.53172 48.8 0.5631 48 -47.189 0.20 49 172.215 1.50 1.88300 40.8 0.5667 50 65.484 1.14 51 70.469 7.88 1.43875 94.7 0.5340 52 50.144 1.24 53 41.628 6.42 1.63930 44.9 0.5683 54 -262.016 11.07 55 -39.176 1.20 1.81600 46.6 0.5568 56 262.557 3.25 1.85478 24.8 0.6122 57 -181.046 0.36 58 96.608 5.36 1.65160 58.5 0.5390 59 -66.597 1.20 1.96300 24.1 0.6212 60 -155.607 53.90 Image plane ∞ Aspheric data Page 13 K = 4.30239e+03 A 4= 6.20793e-07 A 6=-9.40835e-11 A 8= 7.03740e-13 A10=-3.02315e-15 A12= 6.32142e-18 A14=-6.18214e-21 A16= 2.36462e-24 Page 24 K =-3.28257e+02 A 4= 3.82357e-07 A 6= 2.97637e-12 A 8= 8.37892e-15 A10=-5.08823e-19 A12=-1.36837e-22 Page 32 K = 5.40392e-01 A 4=-4.07004e-07 A 6=-1.02411e-10 A 8= 7.92656e-15 A10=2.22076e-17 A12=-1.06401e-20 Various data Zoom ratio 42.62 Focal length 23.89 144.27 1018.31 F-number 2.90 2.90 5.68 Half angle of view (°) 31.78 5.86 0.83 Image height 14.80 14.80 14.80 Lens total length 656.36 656.36 656.36 BF 53.90 53.90 53.90 d12 5.55 136.74 185.27 d22 252.09 103.36 3.13 d28 22.26 9.99 5.03 d33 2.50 32.32 88.98 d60 53.90 53.90 53.90 Lens group data Group starting plane focal length 1 1 259.22 2 13 -33.86 3 23 144.36 4 29 106.91 5 34 3230.64

[0058] [Table 1]

[0059] [Imaging device] FIG. 9 shows the configuration of an imaging device (television camera system) that uses the zoom lens of each embodiment as an imaging optical system. In FIG. 9, 101 is an imaging optical system that is a zoom lens of any of embodiments 1 to 4. 124 is a camera body. The imaging optical system 101 is detachable from the camera body 124. However, the imaging optical system 101 may also be provided integrally with the camera body 124.

[0060] The imaging optical system 101 has a first lens group F, a zoom section LZ, and a final lens group R for imaging. The first lens group F includes a sub-lens group that moves during focusing.

[0061] The zoom unit LZ includes multiple 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 lens groups that make up the zoom unit LZ in the optical axis direction, respectively. Reference numerals 116 to 118 denote motors that drive the drive mechanisms 114 and 115 and the aperture diaphragm SP. Reference numerals 119 to 121 denote detectors such as encoders, potentiometers, or photosensors that detect the positions of the first lens group F and the lens groups that make up the zoom unit LZ in the optical axis direction, and the aperture diameter of the aperture diaphragm SP.

[0062] The camera body 124 includes a glass block 109 that corresponds to an optical filter or a color separation optical system, and an imaging element 110 such as a CCD sensor or CMOS sensor that photoelectrically converts the subject image formed by the imaging optical system 101 (capturing the subject through the imaging optical system 101).

[0063] Reference numerals 111 and 122 denote control units such as a CPU that control the driving of the camera body 124 and the imaging optical system 101 .

[0064] 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.

[0065] The above embodiment includes the following configurations.

[0066] (Configuration 1) A zoom lens in which the lens groups arranged in order from the object side to the image side are composed of a first lens group with positive refractive power that does not move for zooming, a plurality of intermediate lens groups that move for zooming, and a final lens group that is arranged closest to the image side and does not move for zooming, and in which the spacing between adjacent lens groups changes during zooming, the intermediate lens group includes at least one lens group having a negative refractive power and at least one lens group having a positive refractive power; all of the lens units having positive refractive power included in the intermediate lens unit move toward the object side during zooming from the wide-angle end to the telephoto end, the Nth lens group, which has the strongest negative refractive power among the intermediate lens groups, includes at least two negative lenses and at least one positive lens; In the Nth lens group, when the average Abbe number of the at least one positive lens referenced to the d-line is vdp, the average partial dispersion ratio of the at least one positive lens at the g-line and the F-line is θgFp, the average Abbe number of the at least two negative lenses referenced to the d-line is vdn, the average partial dispersion ratio of the at least two negative lenses at the g-line and the F-line is θgFn, the focal length of the zoom lens at the wide-angle end is fw, the focal length of the zoom lens at the telephoto end is ft, and the focal length of the first lens group is f1, -3.1×10 -3 ≦(θgFp-θgFn) / (νdp-νdn)≦-1.0×10 -3 3.6≦ft / f1≦7.0 35≦ft / fw≦70 A zoom lens characterized by satisfying the following conditions: (Configuration 2) When the focal length of the Nth lens group is fn, 5.0≦|f1 / fn|≦9.0 The zoom lens according to configuration 1, characterized in that the following condition is satisfied: (Configuration 3) When the lateral magnifications of the N lens group at the wide-angle end and the telephoto end are βNw and βNt, respectively, and the zoom ratio of the zoom lens is Zwt, 0.1≦(βNt / βNw) / Zwt≦0.5 3. The zoom lens according to configuration 1 or 2, characterized in that the following conditions are satisfied: (Configuration 4) the lens closest to the object in the first lens group is a negative lens; When the focal length of the negative lens is f11, -1.0≦f11 / f1≦-3.0 4. The zoom lens according to any one of configurations 1 to 3, wherein the following condition is satisfied: (Configuration 5) When the average refractive index at the d-line of all the positive lenses included in the Nth lens group is Ndn, 1.83≦Ndn≦2.20 5. The zoom lens according to any one of configurations 1 to 4, wherein the following condition is satisfied: (Configuration 6) The zoom lens according to any one of configurations 1 to 5, wherein the Nth lens group is composed of, arranged in order from the object side to the image side, one negative lens, one positive lens, two negative lenses, one positive lens, and one negative lens. (Configuration 7) The zoom lens according to any one of configurations 1 to 6, characterized in that the lens groups arranged in order from the object side to the image side comprise the first lens group, a second lens group with negative refractive power that moves for zooming, a third lens group with positive refractive power that moves for zooming, a fourth lens group with positive refractive power that moves for zooming, and a fifth lens group with positive refractive power as the final lens group. (Configuration 8) The zoom lens according to any one of configurations 1 to 6, characterized in that the lens groups arranged in order from the object side to the image side comprise the first lens group, a second lens group with negative refractive power that moves for zooming, a third lens group with positive refractive power that moves for zooming, a fourth lens group with negative refractive power that moves for zooming, a fifth lens group with positive refractive power that moves for zooming, and a sixth lens group with negative refractive power as the final lens group. (Configuration 9) The zoom lens according to any one of configurations 1 to 6, characterized in that the lens groups arranged in order from the object side to the image side comprise the first lens group, a second lens group with negative refractive power that moves for zooming, a third lens group with positive refractive power that moves for zooming, a fourth lens group with positive refractive power that moves for zooming, and a fifth lens group with negative refractive power as the final lens group. (Configuration 10) The zoom lens according to any one of configurations 1 to 9, and an image sensor for capturing an image of a subject through the zoom lens.

[0067] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of symbols]

[0068] L1 First lens group L2 Second lens group L3: Third lens group L4 4th lens group L5 Fifth lens group L6 6th lens group SP aperture stop

Claims

1. A zoom lens in which lens groups arranged in order from the object side to the image side include a first lens group having positive refractive power that does not move for zooming, a plurality of intermediate lens groups that move for zooming, and a final lens group that is arranged closest to the image side and does not move for zooming, and in which the spacing between adjacent lens groups changes during zooming, the intermediate lens group includes at least one lens group having a negative refractive power and at least one lens group having a positive refractive power; all of the lens units having positive refractive power included in the intermediate lens unit move toward the object side during zooming from the wide-angle end to the telephoto end, the Nth lens group, which has the strongest negative refractive power among the intermediate lens groups, includes at least two negative lenses and at least one positive lens; In the Nth lens group, when the average Abbe number of the at least one positive lens referenced to the d-line is vdp, the average partial dispersion ratio of the at least one positive lens at the g-line and the F-line is θgFp, the average Abbe number of the at least two negative lenses referenced to the d-line is vdn, the average partial dispersion ratio of the at least two negative lenses at the g-line and the F-line is θgFn, the focal length of the zoom lens at the wide-angle end is fw, the focal length of the zoom lens at the telephoto end is ft, and the focal length of the first lens group is f1, -3.1×10 －３ ≦(θgFp-θgFn) / (νdp-νdn)≦-1.0×10 －３ 3.6≦ft / f1≦7.0 35≦ft / fw≦70 A zoom lens characterized by satisfying the following conditions:

2. When the focal length of the Nth lens group is fn, 5.0≦|f1 / fn|≦9.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. When the lateral magnifications of the Nth lens group at the wide-angle end and the telephoto end are βNw and βNt, respectively, and the zoom ratio of the zoom lens is Zwt, 0.1≦(βNt / βNw) / Zwt≦0.5 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. the lens closest to the object side in the first lens group is a negative lens; When the focal length of the negative lens is f11, -1.0≦f11 / f1≦-3.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the average of the refractive indices at the d-line of all the positive lenses included in the Nth lens group is Ndn, 1.83≦Ndn≦2.20 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. 2. The zoom lens according to claim 1, wherein the Nth lens group consists of, arranged in order from the object side to the image side, one negative lens, one positive lens, two negative lenses, one positive lens, and one negative lens.

7. 2. The zoom lens according to claim 1, wherein the lens groups arranged in order from the object side to the image side comprise the first lens group, a second lens group having negative refractive power that moves for zooming, a third lens group having positive refractive power that moves for zooming, a fourth lens group having positive refractive power that moves for zooming, and a fifth lens group having positive refractive power as the final lens group.

8. 2. The zoom lens according to claim 1, wherein the lens groups arranged in order from the object side to the image side comprise the first lens group, a second lens group having negative refractive power that moves for zooming, a third lens group having positive refractive power that moves for zooming, a fourth lens group having negative refractive power that moves for zooming, a fifth lens group having positive refractive power that moves for zooming, and a sixth lens group having negative refractive power as the final lens group.

9. 2. The zoom lens according to claim 1, wherein the lens groups arranged in order from the object side to the image side comprise the first lens group, a second lens group with negative refractive power that moves for zooming, a third lens group with positive refractive power that moves for zooming, a fourth lens group with positive refractive power that moves for zooming, and a fifth lens group with negative refractive power as the final lens group.

10. The zoom lens according to any one of claims 1 to 9; and an image sensor for capturing an image of a subject through the zoom lens.

Images