Zoom lens and imaging device

Abstract

This provides a zoom lens with excellent focusing performance. [Solution] The zoom lens L0 has multiple lens groups, each consisting of a first lens group L1 with negative refractive power that is stationary during zooming and focusing and arranged sequentially from the object side to the image side, and at least five subsequent lens groups LR that move during zooming. The at least five subsequent lens groups include two focusing lens groups that move along different trajectories during focusing.

Description

[[Technical Field]]

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

[0002] As disclosed in Patent Document 1, some zoom lenses include, arranged in order from the object side to the image side, a first lens group having negative refractive power that remains stationary during zooming and focusing, and at least five subsequent lens groups that move during zooming. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Patent Laid-Open No. 2024-11103 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] The zoom lens described above is required to have good performance with respect to focusing. [[Means for Solving the Problem]]

[0005] A zoom lens according to one aspect of the present invention includes a plurality of lens groups including, arranged in order from the object side to the image side, a first lens group having negative refractive power that remains stationary during zooming and focusing, and at least five subsequent lens groups that move during zooming, wherein the distance between adjacent lens groups changes during zooming. The at least five subsequent lens groups are characterized by including two focus lens groups that move along different trajectories from each other during focusing. An imaging apparatus provided with the zoom lens described above also constitutes another aspect of the present invention. [[Effect of the Invention]]

[0006] This allows us to provide a zoom lens with excellent focusing performance. [Brief explanation of the drawing]

[0007] [Figure 1] Cross-sectional view of the zoom lens of Example 1 at infinity focus and wide-angle end. [Figure 2] Aberration diagrams of the zoom lens in the infinity focus state of Example 1 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. [Figure 3] Cross-sectional view of the zoom lens of Example 2 at infinity focus and wide-angle end. [Figure 4] Aberration diagrams of the zoom lens in the infinity focus state of Example 2, at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. [Figure 5] Cross-sectional view of the zoom lens of Example 3 at infinity focus and wide-angle end. [Figure 6] Aberration diagrams of the zoom lens in the infinity focus state of Example 3 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. [Figure 7] Cross-sectional view of the zoom lens of Example 4 at infinity focus and wide-angle end. [Figure 8] Aberration diagrams of the zoom lens in the infinity focus state of Example 4 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. [Figure 9] Cross-sectional view of the zoom lens of Example 5 at infinity focus and wide-angle end. [Figure 10] Aberration diagrams of the zoom lens in the infinity focus state of Example 5 at (A) the wide-angle end, (B) the intermediate zoom position, and (C) the telephoto end. [Figure 11] A diagram showing an imaging device equipped with a zoom lens according to Examples 1 to 5. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0009] Figures 1, 3, 5, 7, and 9 show the zoom lens L0 of Examples 1 to 5 in focus on an object at infinity (hereinafter referred to as the infinity focus state) and cross-section at the wide-angle end, respectively. Numerical examples 1 to 5 corresponding to Examples 1 to 5 are shown below.

[0010] The zoom lens L0 of each embodiment has multiple lens groups, each consisting of a negative first lens group L1 arranged sequentially from the object side to the image side, and at least five subsequent lens groups LR (R=2~8).

[0011] In a zoom lens, a lens group is a collection of one or more lenses that move together or remain stationary during zooming and focusing between the wide-angle and telephoto ends. That is, the distance between adjacent lens groups changes during zooming. A lens group may include an aperture diaphragm. The wide-angle and telephoto ends represent the zoom states at the maximum angle of view (shortest focal length) and minimum angle of view (longest focal length), respectively, when the lens group that moves during zooming is positioned at the ends of the range that is mechanically or controllly movable along the optical axis.

[0012] In each figure, a solid arrow indicates the trajectory of the lens group as it moves from the wide-angle end to the telephoto end during zooming. Similarly, a dashed arrow indicates the direction of movement of the lens group as it moves from infinity to near focus during focusing.

[0013] SP stands for aperture diaphragm, and IP stands for image plane. The image plane IP is where the imaging surface (light-receiving surface) of an image sensor such as a CCD sensor or CMOS sensor, or the film surface (photosensitive surface) of a silver halide film, is located.

[0014] Furthermore, in the zoom lens L0 of each embodiment, the first lens group L1 does not move (is immobile) during zooming and focusing. In addition, at least five subsequent lens groups LR include two focusing lens groups that move along different trajectories during focusing.

[0015] The zoom lens L0 of Example 1 is constituted, arranged in order from the object side to the image side, of a first lens group L1 having negative refractive power, a second lens group L2 having positive refractive power, a third lens group L3 having positive refractive power, a fourth lens group L4 having negative refractive power, a fifth lens group L5 having positive refractive power, a sixth lens group L6 having negative refractive power, a seventh lens group L7 having negative refractive power, and an eighth lens group L8 having positive refractive power. Note that an optical block having no refractive power, such as an optical filter (the ninth lens group in Numerical Example 1), is arranged between the eighth lens group L8 and the image plane IP.

[0016] Since the first lens group L1 has negative refractive power, a negative-lead power arrangement is achieved, which facilitates achieving a wide angle of view for the zoom lens L0.

[0017] Furthermore, in the zoom lens L0 of the present example, six lens groups from the second lens group L2 to the seventh lens group L7 move during zooming, and the eighth lens group remains stationary during zooming. When at least five subsequent lens groups move during zooming, it becomes easy to achieve a wide angle of view and a high zoom ratio for the zoom lens L0.

[0018] Furthermore, in the zoom lens L0 of the present example, the two focus lens groups L5 and L6 move along different trajectories from each other during focusing. By performing focusing by moving the two focus lens groups along different trajectories from each other in this manner, each focus lens group can be reduced in size and weight. Furthermore, fluctuations in spherical aberration, field curvature and the like during focusing can be suppressed, and fluctuations in the angle of view accompanying focusing can be suppressed.

[0019] Figures 2(A), (B), and (C) show the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lens L0 of numerical example 1 at infinity focus and at the wide-angle end, intermediate zoom position, and telephoto end, respectively. In the spherical aberration diagram, Fno indicates the F number, the solid line shows the spherical aberration at the d line (wavelength 587.6 nm), and the dashed line shows the spherical aberration at the g line (wavelength 435.8 nm). In the astigmatism diagram, the solid line S shows the astigmatism at the sagittal image plane, and the dashed line M shows the astigmatism at the meridional image plane. The distortion diagram shows the distortion at the d line. The chromatic aberration diagram shows the lateral chromatic aberration at the g line. ω is the half-angle of view (°). The explanation of the aberration diagrams above is the same for other numerical examples.

[0020] The zoom lens L0 of Example 2 is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, a fifth lens group L5 with positive refractive power, a sixth lens group L6 with negative refractive power, and a seventh lens group L7 with negative refractive power, arranged in order from the object side to the image side. An optical block without refractive power (the eighth lens group in Numerical Example 2) is placed between the seventh lens group L7 and the image plane IP.

[0021] In the zoom lens L0 of this embodiment, six lens groups, from the second lens group L2 to the seventh lens group L7, move during zooming. In addition, two focusing lens groups L5 and L6 move along different trajectories during focusing.

[0022] Figures 4(A), (B), and (C) show the longitudinal aberrations of the zoom lens L0 of numerical example 2 at infinity focus and at the wide-angle end, intermediate zoom position, and telephoto end, respectively.

[0023] The zoom lens L0 of Example 3 is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, a fifth lens group L5 with positive refractive power, a sixth lens group L6 with positive refractive power, and a seventh lens group L7 with negative refractive power, arranged in order from the object side to the image side. An optical block without refractive power (the eighth lens group in numerical example 3) is placed between the seventh lens group L7 and the image plane IP.

[0024] In the zoom lens L0 of this embodiment, six lens groups, from the second lens group L2 to the seventh lens group L7, move during zooming. The zoom lens L0 of this embodiment also has two focusing lens groups L5 and L6 that move along different trajectories during focusing.

[0025] Figures 6(A), (B), and (C) show the longitudinal aberrations of the zoom lens L0 of numerical example 3 at infinity focus and at the wide-angle end, intermediate zoom position, and telephoto end, respectively.

[0026] The zoom lens L0 of Example 4 is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, a fifth lens group L5 with positive refractive power, and a sixth lens group L6 with negative refractive power, arranged in order from the object side to the image side. An optical block without refractive power (the seventh lens group in numerical example 4) is placed between the sixth lens group L6 and the image plane IP.

[0027] In the zoom lens L0 of this embodiment, five lens groups, from the second lens group L2 to the sixth lens group L6, move during zooming. The zoom lens L0 of this embodiment also has two focusing lens groups L5 and L6, which move along different trajectories during focusing.

[0028] Figures 8(A), (B), and (C) show the longitudinal aberrations of the zoom lens L0 of numerical example 4 at infinity focus and at the wide-angle end, intermediate zoom position, and telephoto end, respectively.

[0029] The zoom lens L0 of Example 5 is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, a fifth lens group L5 with positive refractive power, a sixth lens group L6 with positive refractive power, and a seventh lens group L7 with negative refractive power, arranged in order from the object side to the image side. An optical block without refractive power (the eighth lens group in numerical example 5) is placed between the seventh lens group L7 and the image plane IP.

[0030] In the zoom lens L0 of this embodiment, five lens groups, from the second lens group L2 to the sixth lens group L6, move during zooming, while the seventh lens group L7 remains stationary during zooming. Furthermore, the zoom lens L0 of this embodiment has two focusing lens groups L3 and L6 that move along different trajectories during focusing.

[0031] Figures 10(A), (B), and (C) show the longitudinal aberrations of the zoom lens L0 of numerical example 5 at infinity focus and at the wide-angle end, intermediate zoom position, and telephoto end, respectively.

[0032] In the zoom lens L0 of each embodiment, it is preferable that the first lens group L1 has at least four lenses. This makes it easier to correct field curvature and distortion aberrations that occur during zooming. In the case of a cemented lens in which N lenses are joined together, the number of lenses is N.

[0033] Furthermore, it is preferable that the first lens group L1 includes at least two negative lenses arranged sequentially from the object side to the image side. This makes it easier to achieve both correction of field curvature at the wide-angle end and widening of the field of view.

[0034] Furthermore, it is preferable that the first focusing lens group, which has a shorter absolute focal length than the other two focusing lens groups, includes at least two lenses. This makes it easier to suppress variations in spherical aberration and field curvature during focusing.

[0035] Furthermore, of the two focusing lens groups, the first focusing lens group, which has a shorter absolute focal length, preferably has a positive refractive power and moves toward the object when focusing from infinity to close. This makes it easier to reduce the diameter of the subsequent lens group and also makes it easier to suppress fluctuations in spherical aberration and field curvature during focusing.

[0036] The zoom lens L0 of each embodiment preferably satisfies at least one of the following conditions (1) to (14). Here, the focal length of the first focus lens group, which has a shorter absolute value of focal length than the other two focus lens groups, is fF1, and the difference between the position of the first focus lens group at the wide-angle end and the position at the telephoto end (amount of movement during zooming) is mF1. The focal length of the first lens group L1 is f1, and the distance along the optical axis from the lens surface closest to the object to the image plane of the zoom lens L0 (total optical length) is L. The focal length of the second focus lens group, which has a longer absolute value of focal length than the other two focus lens groups, is fF2. The focal length of the lens group closest to the object (second lens group L2) among at least five subsequent lens groups is f2. Let ft be the focal length of zoom lens L0 at its telephoto end, fw be the focal length of zoom lens L0 at its wide-angle end, and skw be the air-equivalent distance along the optical axis from the image-side lens surface to the image plane at the wide-angle end. Let f1 be the focal length of the first lens group L1, and skw be the air-equivalent distance along the optical axis from the image-side lens surface to the image plane at the wide-angle end (back focus). Let fF1p be the focal length of the lens with the shortest absolute focal length among the multiple lenses included in the first focusing lens group, and fF1w be the focal length of the lens with the longest absolute focal length. Let β2t be the lateral magnification at the telephoto end of the lens group closest to the object (second lens group L2) among at least five subsequent lens groups, and let ωw be the half-angle of view at the wide-angle end of zoom lens L0.

[0037] 0.01 ≤ |mF1 / fF1| ≤ 0.60 (1) 0.10 ≤ |f1| / L ≤ 0.50 (2) 1.00 < |fF2 / fF1| ≤ 5.00 (3) -4.00 ≤ f2 / f1 ≤ -1.00 (4) 3.00 ≤ L / ft ≤ 5.00 (5) 0.50 ≤ fw / skw ≤ 2.50 (6) -5.00 ≤ f1 / skw ≤ -1.00 (7) 0.15 ≤ |fF1p / fF1w| ≤ 1.00 (8) 0.30 ≤ |fF1p / fF1| ≤ 2.50 (9) 0.10 ≤ |f1 / fF1| ≤ 0.90 (10) -2.00 ≤ ft / f1 ≤ -1.00 (11) 0.30 ≤ f² / |fF₁| ≤ 2.00 (12) -7.00 ≤ β2t ≤ 5.00 (13) 35.0≦ωw≦55.0 (14) The conditions in equation (1) indicate an appropriate relationship between the focal length of the first focus lens group and the amount of movement of the first focus lens group when zooming from the wide-angle end to the telephoto end. The amount of movement of the lens group is the difference between the position of the lens group at the wide-angle end and the position of the lens group at the telephoto end, and does not include the amount of movement back and forth. It is considered positive when the lens group is positioned closer to the image at the telephoto end compared to the wide-angle end. If the amount of movement of the first focus lens group when zooming from the wide-angle end to the telephoto end becomes large enough that |mF1 / fF1| exceeds the upper limit of equation (1), the zoom lens L0 becomes larger, which is undesirable. If the focal length of the first focus lens group becomes large enough that |mF1 / fF1| falls below the lower limit of equation (1), it becomes difficult to suppress fluctuations such as spherical aberration and field curvature during focusing, which is undesirable.

[0038] Furthermore, it is more preferable to set the lower limit of formula (1) to 0.02, 0.03, or 0.035. Also, it is more preferable to set the upper limit of formula (1) to 0.50, 0.48, 0.45, or 0.43.

[0039] The conditions in equation (2) indicate an appropriate relationship between the focal length of the first lens group L1 and the total optical length of the zoom lens L0. If the focal length of the first lens group L1 increases so that |f1| / L exceeds the upper limit of equation (2), it is undesirable because the first lens group L1 becomes larger when the angle of view is widened. If the total optical length of the zoom lens L0 increases so that |f1| / L falls below the lower limit of equation (2), it is undesirable because the subsequent lens group becomes larger.

[0040] Furthermore, it is more preferable to set the lower limit of equation (2) to 0.12, 0.13, 0.14, or 0.15. Also, it is more preferable to set the upper limit of equation (2) to 0.40, 0.30, or 0.20.

[0041] The conditions in equation (3) indicate an appropriate relationship between the focal length of the first focusing lens group and the focal length of the second focusing lens group. If |fF2 / fF1| exceeds the upper limit of equation (3), it becomes difficult to suppress fluctuations such as spherical aberration and field curvature during focusing, which is undesirable. If |fF2 / fF1| falls below the lower limit of equation (3), it becomes difficult to suppress changes in the angle of view associated with focusing, which is also undesirable.

[0042] Furthermore, it is more preferable to set the lower limit of equation (3) to 1.10, 1.20, or 1.25. Also, it is more preferable to set the upper limit of equation (3) to 4.00, 3.80, 3.60, or 3.30.

[0043] The conditions in equation (4) indicate an appropriate relationship between the focal length of the first lens group L1 and the focal length of the second lens group L2. If f2 / f1 exceeds the upper limit of equation (4), it becomes difficult to suppress the occurrence of field curvature and distortion at the wide-angle end, which is undesirable. If f2 / f1 falls below the lower limit of equation (4), it becomes difficult to suppress fluctuations in spherical aberration and field curvature during zooming, which is also undesirable.

[0044] Furthermore, it is more preferable to set the lower limit of equation (4) to -3.80, -3.60, -3.40, or -3.20. Also, it is more preferable to set the upper limit of equation (4) to -1.20, -1.30, -1.40, or -1.45.

[0045] The conditions in equation (5) indicate an appropriate relationship between the total optical length of the zoom lens L0 and the focal length at the telephoto end of the entire zoom lens L0 system. If L / ft exceeds the upper limit of equation (5), the subsequent lens group becomes larger, which is undesirable. If L / ft falls below the lower limit of equation (5), it becomes difficult to suppress the occurrence of spherical aberration at the telephoto end, which is also undesirable.

[0046] Furthermore, it is more preferable to set the lower limit of equation (5) to 3.10, 3.20, or 3.30. Also, it is more preferable to set the upper limit of equation (5) to 4.80, 4.50, 4.20, or 4.10.

[0047] The conditions in equation (6) indicate an appropriate relationship between the focal length at the wide-angle end and the back focus for the entire L0 zoom lens system. If fw / skw exceeds the upper limit of equation (6), widening the field of view becomes difficult, which is undesirable. If fw / skw falls below the lower limit of equation (6), it becomes difficult to suppress the occurrence of coma aberration and field curvature at the wide-angle end, which is also undesirable.

[0048] Furthermore, it is more preferable to set the lower limit of equation (6) to 0.60, 0.70, or 0.80. Also, it is more preferable to set the upper limit of equation (6) to 2.30, 2.20, 2.10, or 2.00.

[0049] The conditions in equation (7) indicate an appropriate relationship between the focal length of the first lens group L1 and the back focus of the zoom lens L0 at the wide-angle end. If f1 / skw exceeds the upper limit of equation (7), it becomes difficult to suppress field curvature when widening the field of view, which is undesirable. If f1 / skw falls below the lower limit of equation (7), the subsequent lens group becomes larger, which is also undesirable.

[0050] Furthermore, it is more preferable to set the lower limit of equation (7) to -4.50, -4.00, -3.50, or -3.00. Also, it is more preferable to set the upper limit of equation (7) to -1.20, -1.40, -1.50, or -1.60.

[0051] The condition in equation (8) indicates an appropriate relationship between the focal length of the lens with the shortest focal length and the focal length of the lens with the longest focal length among the multiple lenses in the first focusing lens group. If |fF1p / fF1w| exceeds the upper limit of equation (8), it becomes difficult to suppress fluctuations in spherical aberration during focusing, which is undesirable. If |fF1p / fF1w| falls below the lower limit of equation (8), the refractive power of the lens with the largest absolute value of focal length among the first focusing lens group becomes too small, making it difficult to suppress fluctuations in spherical aberration and field curvature during focusing, which is also undesirable.

[0052] Furthermore, it is more preferable to set the lower limit of equation (8) to 0.18, 0.20, 0.21, or 0.22. Also, it is more preferable to set the upper limit of equation (8) to 0.99, 0.98, or 0.97.

[0053] The condition in equation (9) indicates an appropriate relationship between the focal length of the lens with the shortest focal length among the multiple lenses in the first focusing lens group and the focal length of the first focusing lens group. If |fF1p / fF1| exceeds the upper limit of equation (9), the amount of movement of the first focusing lens group during focusing at the telephoto end becomes large, making it difficult to miniaturize the zoom lens L0, which is undesirable. If |fF1p / fF1| falls below the lower limit of equation (9), it becomes difficult to suppress fluctuations in axial chromatic aberration and lateral chromatic aberration during focusing at the telephoto end, which is also undesirable.

[0054] Furthermore, it is more preferable to set the lower limit of equation (9) to 0.35, 0.38, 0.40, or 0.43. Also, it is more preferable to set the upper limit of equation (9) to 2.40, 2.20, 2.00, or 1.95.

[0055] The conditions in equation (10) indicate an appropriate relationship between the focal length of the first lens group L1 and the focal length of the first focusing lens group. If |f1 / fF1| exceeds the upper limit of equation (10), it becomes difficult to suppress the change in the angle of view when focusing at the wide-angle end, which is undesirable. If |f1 / fF1| falls below the lower limit of equation (10), when the zoom lens L0 has a high magnification ratio, the amount of movement of the first focusing lens group when focusing at the telephoto end becomes large, making it difficult to miniaturize the zoom lens L, which is also undesirable.

[0056] Furthermore, it is more preferable to set the lower limit of equation (10) to 0.20, 0.22, 0.25, or 0.28. Also, it is more preferable to set the upper limit of equation (10) to 0.85, 0.80, 0.77, or 0.75.

[0057] The conditions in equation (11) indicate an appropriate relationship between the focal length of the zoom lens L0 at its telephoto end and the focal length of the first lens group L1. If ft / f1 exceeds the upper limit of equation (11), it is undesirable because the overall length of the zoom lens L0 increases when the zoom ratio is increased. If ft / f1 falls below the lower limit of equation (11), it is undesirable because the subsequent lens group becomes larger. Furthermore, it is undesirable because it becomes difficult to suppress spherical aberration at the telephoto end.

[0058] Furthermore, it is more preferable to set the lower limit of equation (11) to -1.90, -1.80, -1.75, or -1.70. Also, it is more preferable to set the upper limit of equation (11) to -1.10, -1.20, -1.30, or -1.35.

[0059] The conditions in equation (12) indicate an appropriate relationship between the focal length of the second lens group L2 and the focal length of the first focusing lens group. If f2 / |fF1| exceeds the upper limit of equation (12), it becomes difficult to suppress spherical aberration at the telephoto end, which is undesirable. It is also undesirable because the subsequent lens group becomes larger. If f2 / |fF1| falls below the lower limit of equation (12), the amount of movement of the first focusing lens group during focusing at the telephoto end becomes large, making it difficult to miniaturize the zoom lens L0, which is also undesirable.

[0060] Furthermore, it is more preferable to set the lower limit of formula (12) to 0.34, 0.37, 0.40, or 0.43. Also, it is more preferable to set the upper limit of formula (12) to 1.95, 1.90, 1.85, or 1.80.

[0061] The conditions in equation (13) indicate an appropriate range for the lateral magnification at the telephoto end of the second lens group L2. If β2t exceeds the upper limit of equation (13), it becomes difficult to correct spherical aberration and coma aberration at the telephoto end, which is undesirable. If β2t falls below the lower limit of equation (13), the subsequent lens group becomes larger, which is also undesirable.

[0062] Furthermore, it is more preferable to set the lower limit of equation (13) to -6.80, -6.50, -6.20, -5.90, or -5.70. Also, it is more preferable to set the upper limit of equation (13) to 4.80, 4.50, 4.20, 4.00, or 3.60.

[0063] The conditions in equation (14) indicate an appropriate range for the half-angle of view at the wide-angle end of the zoom lens L0. If ωw exceeds the upper limit of equation (14), it becomes difficult to suppress distortion and field curvature at the wide-angle end, which is undesirable. It also becomes difficult to increase the magnification ratio of the zoom lens L0, which is undesirable. If ωw falls below the lower limit of equation (14), it becomes difficult to widen the angle of view of the zoom lens L0, which is undesirable.

[0064] Furthermore, it is more preferable to set the lower limit of formula (14) to 38.0, 40.0, 42.0, 45.0, or 47.5. Also, it is more preferable to set the upper limit of formula (14) to 53.0, 51.0, 50, 49.0, or 48.0.

[0065] Numerical examples 1 to 5 are shown below. In each numerical example, the surface number i indicates the order of the surfaces when counted from the object side. r is the radius of curvature (mm) of the i-th surface from the object side, d is the lens thickness or air gap on the optical axis between the i-th and (i+1)-th surfaces (mm), and nd is the refractive index of the optical material at the d-line between the i-th and (i+1)-th surfaces. νd is the Abbe number with respect to the d-line of the optical material between the i-th and (i+1)-th surfaces. The Abbe number νd with respect to the d-line is expressed as νd = (Nd-1) / (NF-NC), where Nd, NF, and NC are the refractive indices at the Fraunhofer lines d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm). The effective diameter is the diameter (mm) of the region of the i-th lens surface through which the light rays contributing to image formation pass.

[0066] BF stands for back focus (mm). Back focus is the distance along the optical axis from the image-side lens surface (final surface) of a zoom lens to the paraxial image plane, expressed in terms of air-equivalent length. The total lens length is the distance along the optical axis from the object-side lens surface (frontmost surface) of a zoom lens to the image plane (or the distance along the optical axis from the frontmost surface to the final surface plus the back focus), and is also called the optical total length.

[0067] The asterisk (*) next to the surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following formula, where X is the displacement from the surface vertex in the optical axis direction, H is the height from the optical axis in the direction perpendicular to the optical axis, the direction of light propagation is positive, R is the radius of paraxial curvature, K is the cone constant, and A4, A6, A8, and A10 are aspherical coefficients. The cone constant and aspherical coefficients "e±x" are multiplied by 10⁻¹⁴. ±x It means...

[0068]

number

[0069] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd Effective diameter 1* 113.838 3.00 1.69350 53.2 80.28 2* 31.296 16.31 63.65 3 2000.000 3.00 1.58887 61.1 61.27 4* 86.374 5.74 55.01 5 154.019 2.00 1.72916 54.7 54.18 6 44.062 5.81 1.89286 20.4 51.20 7 82.116 (variable) 50.46 8 67.288 3.73 2.00069 25.5 45.57 9 152.093 0.30 45.66 10 63.662 8.08 1.62205 41.1 47.03 11 -150.231 1.50 1.85896 22.7 46.94 12 121.670 (Variable) 46.93 13* 69.092 4.72 1.62291 58.3 49.26 14 252.704 6.51 49.15 15 63.384 1.60 2.00069 25.5 49.27 16 31.280 14.05 1.72916 54.7 46.44 17 -183.297 (variable) 46.08 18 (aperture) ∞ 3.24 31.60 19 -119.920 1.10 1.73800 32.3 30.52 20 104.126 5.59 30.02 21 -34.301 1.25 2.00069 25.5 29.97 22 75.019 6.79 1.92286 20.9 32.87 23 -47.532 0.30 33.78 24 48.525 6.13 1.49782 82.6 35.42 25 -144.064 (variable) 35.24 26 35.342 3.60 1.59319 67.9 31.15 27 79.752 0.30 30.38 28 35.962 3.75 1.49782 82.6 30.69 29 96.076 (Variable) 30.36 30* 84.913 1.45 1.85108 40.1 29.87 31* 44.660 (variable) 28.51 32* -41.067 1.60 1.51680 64.1 29.64 33 -298.938 (variable) 32.21 34 1010.291 3.00 1.72916 54.7 38.82 35 -138.668 (variable) 39.25 36 ∞ 1.60 1.51680 64.1 50.00 37 ∞ (Variable) 50.00 Image plane ∞ Aspherical data Front page K = 0.00000e+00 A 4=-2.31736e-06 A 6= 2.15214e-09 A 8=-1.39023e-12 A10=5.30945e-16 A12=-7.80055e-20 2nd side K =-9.06407e-01 A 4=-1.75997e-06 A 6= 4.73966e-10 A 8= 5.18098e-14 A10=-1.69711e-15 A12= 9.91384e-19 Side 4 K = 0.00000e+00 A 4= 1.38443e-06 A 6= 1.18006e-09 A 8= 4.75133e-13 A10 = 4.22542e-16 Page 13 K = 0.00000e+00 A 4=-4.52426e-07 A 6=-5.89153e-11 A 8= 1.25872e-13 A10 = -1.31841e-16 Page 30 K = 0.00000e+00 A 4= 6.87600e-05 A 6=-2.77593e-07 A 8= 4.38645e-10 A10 = -1.61106e-13 Page 31 K = 0.00000e+00 A 4= 8.44607e-05 A 6=-2.32335e-07 A 8= 1.38583e-10 A10 = 6.41533e-13 Page 32 K = 0.00000e+00 A 4=-2.60736e-06 A 6= 3.37418e-08 A 8=-2.38845e-10 A10 = 4.98850e-13 Various data Zoom ratio 2.83 Wide-angle, Medium, Telephoto Focal length 20.59 34.99 58.20 F-number 2.10 2.10 2.10 Half-angle (°): 46.42, 31.73, 20.39 Image height 21.64 21.64 21.64 Lens length 205.83 205.83 205.83 BF 11.24 11.24 11.24 d 7 56.32 16.61 2.00 d12 3.47 17.21 4.71 d17 1.50 5.54 28.84 d25 7.18 16.06 9.93 d29 1.50 5.96 7.06 d31 9.16 9.16 9.18 d33 1.00 9.59 18.42 d35 9.18 9.18 9.18 d37 1.00 1.00 1.00 Entrance pupil position 38.27 40.20 51.30 Exit pupil position -59.03 -87.87 -98.39 Front principal point position 51.79 61.42 75.42 Back principal point position -19.59 -33.99 -57.20 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 -35.53 35.86 9.99 -16.80 2 8 95.77 13.60 -5.57 -12.74 3 13 60.32 26.89 7.55 -11.77 4 18 -273.71 24.40 -49.71 -84.26 5 26 54.85 7.65 -0.40 -5.38 6 30 -112.56 1.45 1.68 0.88 7 32 -92.31 1.60 -0.17 -1.23 8 34 167.41 3.00 1.53 -0.21 9 36 ∞ 1.60 0.53 -0.53 Single lens data Lens starting plane, focal length 1 1 -63.18 2 3 -153.39 3 5 -85.30 4 6 99.34 5 8 118.00 6 10 72.94 7 11 -78.06 8 13 151.16 9 15 -63.29 10 16 37.69 11 19 -75.36 12 21 -23.39 13 22 32.39 14 24 73.69 15 26 103.86 16 28 113.11 17 30 -112.56 18 32 -92.31 19 34 167.41 20 36 0.00 [Numerical Example 2] Unit: mm Surface data Face number rd nd νd Effective diameter 1* 99.167 3.00 1.69350 53.2 78.28 2* 30.876 15.03 61.88 3 246.709 3.00 1.58887 61.1 59.97 4* 64.439 5.70 54.14 5 149.611 2.00 1.72916 54.7 53.45 6 43.695 5.11 1.92286 18.9 50.27 7 72.696 (Variable) 49.50 8 61.487 6.02 1.90525 35.0 44.00 9 -791.942 3.04 44.14 10 -133.324 2.30 1.64769 33.8 44.30 11 -89.797 1.50 1.85896 22.7 44.57 12 -1017.581 (variable) 45.52 13* 60.906 5.53 1.62291 58.3 48.19 14 340.352 6.61 48.07 15 64.882 1.60 2.00069 25.5 47.65 16 29.674 13.91 1.72916 54.7 44.70 17 -172.079 (variable) 44.36 18 (aperture) ∞ 2.28 29.73 19 -485.056 1.10 1.90525 35.0 28.77 20 80.493 5.61 28.23 21 -32.138 1.25 2.00069 25.5 28.14 22 59.777 6.80 1.92286 20.9 30.98 23 -46.213 0.30 31.90 24 46.851 5.46 1.49782 82.6 33.48 25 -198.119 (variable) 33.33 26 38.806 3.18 1.59319 67.9 30.31 27 83.699 0.30 30.32 28 35.858 3.74 1.49782 82.6 30.89 29 93.092 (Variable) 30.64 30 132.513 2.75 1.49782 82.6 30.52 31 -268.638 0.30 30.33 32* 628.981 1.45 1.85108 40.1 29.86 33* 67.169 (variable) 28.89 34* -30.011 1.60 1.51680 64.1 30.56 35 -56.307 (variable) 32.77 36 ∞ 1.60 1.51680 64.1 50.00 37 ∞ (Variable) 50.00 Image plane ∞ Aspherical data Front page K = 0.00000e+00 A 4=-1.71297e-06 A 6= 1.10441e-09 A 8=-8.50148e-13 A10=3.94661e-16 A12=-6.49879e-20 2nd side K =-8.80032e-01 A 4=-7.25014e-08 A 6= 3.20193e-10 A 8=-2.68635e-13 A10=-2.46967e-15 A12= 1.46151e-18 Side 4 K = 0.00000e+00 A 4=-4.42265e-08 A 6= 6.74492e-10 A 8= 7.96378e-13 A10 = 7.86576e-16 Page 13 K = 0.00000e+00 A 4=-4.64159e-07 A 6= 1.29682e-11 A 8= 1.87905e-13 A10 = -1.76659e-16 Page 32 K = 0.00000e+00 A 4= 5.88945e-05 A 6=-2.69244e-07 A 8= 4.43387e-10 A10 = -1.59878e-13 Page 33 K = 0.00000e+00 A 4= 7.47779e-05 A 6=-2.20232e-07 A 8= 1.85949e-10 A10 = 4.44226e-13 Page 34 K = 0.00000e+00 A 4= 3.09753e-06 A 6= 4.30531e-08 A 8=-2.31604e-10 A10 = 4.36843e-13 Various data Zoom ratio 2.83 Wide-angle, Medium, Telephoto Focal length 20.58 34.99 58.21 F-number 2.10 2.10 2.10 Half-angle (°): 46.43, 31.73, 20.39 Image height 21.64 21.64 21.64 Lens length 197.62 197.62 197.62 BF 10.61 19.17 26.44 d 7 53.73 14.51 1.99 d12 1.50 15.05 1.57 d17 1.50 6.15 29.97 d25 8.02 15:31 9.87 d29 1.88 7.66 8.63 d33 9.92 9.32 8.70 d35 8.56 17.11 24.38 d37 1.00 1.00 1.00 Entrance pupil position 37.97 39.98 52.96 Exit pupil position -50.64 -67.25 -69.20 Front principal point position 50.35 57.03 62.90 Back principal point position -19.58 -33.99 -57.21 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 -34.74 33.84 10.55 -14.65 2 8 99.34 12.86 -3.70 -11.73 3 13 56.76 27.64 7.29 -12.71 4 18 -175.86 22.80 -28.48 -55.08 5 26 58.96 7.22 -0.45 -5.16 6 30 -180.03 4.50 5.51 2.52 7 34 -126.98 1.60 -1.23 -2.31 8 36 ∞ 1.60 0.53 -0.53 Single lens data Lens starting plane, focal length 1 1 -65.83 2 3 -149.02 3 5 -85.33 4 6 109.42 5 8 63.24 6 10 416.03 7 11 -114.75 8 13 118.19 9 15 -55.92 10 16 35.75 11 19 -76.19 12 21 -20.75 13 22 29.14 14 24 76.68 15 26 118.84 16 28 114.67 17 30 178.66 18 32 -88.46 19 34 -126.98 20 36 0.00 [Numerical Example 3] Unit: mm Surface data Face number rd nd νd Effective diameter 1* 520.550 2.60 1.69350 53.2 76.19 2* 35.522 9.86 59.55 3 85.322 2.00 1.72916 54.7 58.22 4 48.429 10.87 54.22 5 -568.433 2.00 1.59245 66.9 53.45 6 41.296 7.57 2.00100 29.1 51.03 7 98.291 (Variable) 50.10 8* 60.625 4.90 1.59245 66.9 43.72 9* 3971.538 2.56 43.53 10 -127.896 1.60 1.84666 23.8 43.48 11 -139.315 (variable) 43.63 12 ∞ 11.62 43.20 13 88.629 1.50 2.00069 25.5 46.92 14 43.619 10.26 1.59319 67.9 46.37 15 -211.123 0.30 46.79 16 68.851 9.51 1.43700 95.1 47.75 17 -89.098 (variable) 47.53 18 (aperture) ∞ 2.00 31.31 19 1259.149 1.50 1.81600 46.6 30.43 20 57.001 3.64 29.62 21 -67.553 1.20 1.85478 24.8 29.62 22 48.802 3.57 1.94594 18.0 30.72 23 328.490 0.30 30.95 24 45.365 4.59 1.91812 32.6 32.15 25 -550.726 (variable) 31.93 26 61.031 1.28 1.59319 67.9 28.73 27 79.020 0.30 28.79 28 31.675 3.53 1.49782 82.6 29.66 29 75.967 (Variable) 29.48 30 -369.985 8.41 1.49782 82.6 29.45 31 -20.829 1.30 2.00069 25.5 29.49 32 -29.224 0.30 30.90 33* -288.804 1.50 1.85108 40.1 29.92 34* 308.204 (variable) 29.78 35* -20.976 1.60 1.62291 58.3 31.60 36 -36.017 (variable) 34.41 37 ∞ 1.60 1.51680 64.1 47.16 38 ∞ (variable) 47.16 Image plane ∞ Aspherical data Front page K = 0.00000e+00 A 4= 1.37786e-06 A 6=-1.55813e-09 A 8= 1.13578e-12 A10=-3.59744e-16 A12= 4.38698e-20 2nd side K =-8.59311e-01 A 4= 7.61570e-07 A 6=-1.18580e-09 A 8= 1.55417e-12 A10=-2.42873e-15 A12= 3.28966e-18 A14=-1.06806e-21 Side 8 K = 0.00000e+00 A 4=-1.49232e-06 A 6= 4.43568e-10 A 8=-1.06499e-12 A10 = 1.94505e-15 9th page K = 0.00000e+00 A 4= 8.17107e-07 A 6= 5.33731e-10 A 8=-1.10567e-12 A10 = 2.14744e-15 Page 33 K = 0.00000e+00 A 4=-3.91120e-05 A 6= 1.19380e-07 A 8=-1.47255e-11 A10 = -1.20231e-13 Page 34 K = 0.00000e+00 A 4=-2.82126e-05 A 6= 1.31379e-07 A 8=-7.40689e-11 A10 = 2.97094e-14 Page 35 K = 0.00000e+00 A 4= 1.22438e-05 A 6=-5.17517e-09 A 8= 4.38497e-11 A10 = -7.67557e-14 Various data Zoom ratio 2.37 Wide-angle, Medium, Telephoto Focal length 20.50 35.00 48.60 F-number 2.10 2.10 2.10 Half-angle (°): 46.54, 31.72, 24.00 Image height 21.64 21.64 21.64 Lens length 198.31 198.31 198.31 BF 10.49 20.64 25.86 d 7 37.55 13.04 2.45 d11 10.08 10.20 2.00 d17 1.50 21.12 35.18 d25 7.35 8.47 6.93 d29 3.24 4.56 5.60 d34 15.95 8.14 8.14 d36 8.44 18.58 23.81 d38 1.00 1.00 1.00 Entrance pupil position 34.56 38.93 44.82 Exit pupil position -47.87 -56.95 -61.39 Front principal point position 46.46 52.79 55.57 Back principal point position -19.50 -34.00 -47.60 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 -35.20 34.90 6.69 -19.39 2 8 109.93 9.06 0.21 -6.33 3 12 64.88 33.19 19.96 -6.20 4 18 -279.81 16.80 -22.49 -37.45 5 26 85.97 5.11 -0.96 -4.34 6 30 279.01 11.51 11.72 4.53 7 35 -84.06 1.60 -1.43 -2.46 8 37 ∞ 1.60 0.53 -0.53 Single lens data Lens starting plane, focal length 1 1 -55.09 2 3 -157.19 3 5 -64.90 4 6 66.72 5 8 103.87 6 10 -1969.49 7 13 -87.28 8 14 61.87 9 16 90.53 10 19 -73.21 11 21 -32.99 12 22 60.22 13 24 45.82 14 26 440.27 15 28 106.32 16 30 43.98 17 31 -78.53 18 33 -174.98 19 35 -84.06 20 37 0.00 [Numerical Example 4] Unit: mm Surface data Face number rd nd νd Effective diameter 1* 64.631 3.00 1.69350 53.2 72.42 2* 24.767 18.89 56.32 3 -501.254 3.00 1.58887 61.1 52.81 4* 92.768 4.62 47.73 5 320.328 2.00 1.48749 70.2 47.21 6 41.745 4.35 1.84666 23.8 44.79 7 69.784 (Variable) 44.10 8 64.269 3.55 2.00069 25.5 39.35 9 193.232 0.75 39.09 10 112.331 6.77 1.61216 37.2 39.55 11 -60.958 1.50 1.84666 23.8 39.64 12 -531.279 (variable) 40.23 13* 56.209 3.83 1.62291 58.3 42.11 14 130.333 3.35 41.83 15 67.389 1.60 2.00069 25.5 41.27 16 28.744 11.76 1.67972 57.0 39.03 17 -98.624 (variable) 38.76 18 (aperture) ∞ 4.28 26.67 19 -49.280 1.10 1.85478 24.8 25.36 20 134.458 1.41 25.34 21 -163.282 1.25 2.00069 25.5 25.39 22 37.796 4.65 1.92286 18.9 26.01 23 -139.593 11.05 26.34 24 100.381 5.37 1.49782 82.6 28.77 25 -67.226 (variable) 28.85 26 36.781 5.48 1.59319 67.9 37.45 27 136.735 0.30 37.22 28 46.787 4.69 1.59319 67.9 37.04 29 245.280 (variable) 36.49 30* 64.852 1.45 1.85108 40.1 32.29 31* 27.720 (variable) 30.66 32 ∞ 1.60 1.51680 64.1 50.00 33 ∞ (Variable) 50.00 Image plane ∞ Aspherical data Front page K = 0.00000e+00 A 4=-4.16953e-06 A 6= 2.96619e-09 A 8=-2.07716e-12 A10=9.52043e-16 A12=-1.70706e-19 2nd side K =-7.37114e-01 A 4=-2.68323e-06 A 6= 2.47910e-10 A 8= 5.83834e-13 A10=-5.11133e-15 A12= 2.35029e-18 Side 4 K = 0.00000e+00 A 4= 1.49881e-06 A 6= 2.03865e-09 A 8=-6.55376e-13 A10 = 4.91448e-15 Page 13 K = 0.00000e+00 A 4=-1.19843e-07 A 6= 9.33404e-12 A 8=-2.28678e-13 A10 = 3.38883e-16 Page 30 K = 0.00000e+00 A 4=-8.58944e-06 A 6=-1.42332e-08 A 8= 5.07485e-11 A10 = -4.00284e-14 Page 31 K = 0.00000e+00 A 4=-4.53252e-07 A 6=-1.55697e-08 A 8= 5.09732e-11 A10 = 8.23426e-16 Various data Zoom ratio 2.36 Wide-angle, Medium, Telephoto Focal length 20.56 35.00 48.51 F-number 2.10 2.10 2.10 Half-angle (°): 46.46, 31.72, 24.04 Image height 21.64 21.64 21.64 Lens length 192.96 192.96 192.96 BF 25.04 29.21 30.11 d 7 50.68 11.11 1.99 d12 1.50 13.47 5.95 d17 1.50 6.52 22.34 d25 2.73 14.59 14.52 d29 1.50 8.05 8.04 d31 22.99 27.16 28.05 d33 1.00 1.00 1.00 Entrance pupil position 36.05 38.04 45.34 Exit pupil position -66.76 -88.54 -89.32 Front principal point position 50.37 59.36 67.80 Back principal point position -19.56 -34.00 -47.51 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 -33.24 35.86 10.49 -17.14 2 8 72.72 12.57 -0.67 -8.13 3 13 62.19 20.54 5.88 -8.40 4 18 -146.17 29.11 -30.01 -70.00 5 26 45.76 10.48 0.76 -5.93 6 30 -57.92 1.45 1.39 0.60 7 32 ∞ 1.60 0.53 -0.53 Single lens data Lens starting plane, focal length 1 1 -59.74 2 3 -132.69 3 5 -98.70 4 6 114.56 5 8 94.93 6 10 65.52 7 11 -81.45 8 13 155.58 9 15 -51.15 10 16 34.02 11 19 -42.07 12 21 -30.58 13 22 32.64 14 24 81.75 15 26 83.12 16 28 96.61 17 30 -57.92 18 32 0.00 [Numerical Example 5] Unit: mm Surface data Face number rd nd νd Effective diameter 1* 137.119 3.00 1.69350 53.2 75.73 2* 29.429 20.75 59.75 3 -99.018 3.00 1.69350 53.2 55.18 4* 232.189 2.74 50.31 5 183.999 2.00 1.72916 54.7 50.08 6 67.875 4.04 1.84666 23.8 49.06 7 146.261 (variable) 48.70 8 101.324 2.82 1.95375 32.3 40.45 9 317.051 0.30 40.77 10 50.976 10.19 1.48749 70.2 43.43 11 -71.163 (variable) 43.52 12 -63.879 1.50 1.90525 35.0 42.36 13 -101.510 (variable) 42.93 14* 139.550 3.29 1.62291 58.3 42.93 15 -1307.375 11.03 42.93 16 -238.843 1.60 1.85451 25.2 42.74 17 169.982 9.10 1.56873 63.1 43.02 18 -42.779 (variable) 43.27 19 (aperture) ∞ 5.15 29.37 20 -43.132 1.10 2.00069 25.5 27.94 21 51.047 3.80 1.49782 82.6 28.53 22 -730.277 5.97 29.10 23 283.085 3.60 1.94594 18.0 32.47 24 -83.103 0.30 32.77 25 66.265 5.48 1.49782 82.6 32.81 26 -77.466 (variable) 32.54 27 58.514 5.97 1.59319 67.9 29.80 28 -49.430 1.30 1.73800 32.3 29.74 29 -282.288 (variable) 29.82 30* -234.083 1.45 1.85108 40.1 29.44 31 54.836 (Variable) 30.04 32 ∞ 1.60 1.51680 64.1 50.00 33 ∞ (Variable) 50.00 Image plane ∞ Aspherical data Front page K = 0.00000e+00 A 4=-3.40422e-07 A 6= 2.05356e-09 A 8=-2.14648e-12 A10=9.81586e-16 A12=-1.73380e-19 2nd side K =-2.48608e-01 A 4=-3.32698e-06 A 6=-1.25281e-09 A 8= 3.70091e-12 A10=-9.19159e-15 A12= 1.30747e-19 Side 4 K = 0.00000e+00 A 4= 2.42366e-06 A 6= 1.98186e-09 A 8=-1.98532e-12 A10 = 5.27103e-15 Page 14 K = 0.00000e+00 A 4=-2.80024e-06 A 6=-1.13290e-09 A 8=-1.05754e-12 A10 = 2.71365e-16 Page 30 K = 0.00000e+00 A 4=-9.56006e-06 A 6= 1.61527e-08 A 8=-7.76834e-11 A10 = 1.26695e-13 Various data Zoom ratio 2.35 Wide-angle, Medium, Telephoto Focal length 20.62 35.01 48.49 F-number 2.10 2.10 2.10 Half-angle (°): 46.38, 31.72, 24.05 Image height 21.64 21.64 21.64 Lens length 193.21 193.21 193.21 BF 17.80 17.80 17.80 d 7 49.73 15.04 2.00 d11 2.04 3.70 4.89 d13 2.78 11.35 1.49 d18 1.50 1.50 21.56 d26 3.33 27.41 25.20 d29 6.54 6.94 10.79 d31 15.75 15.75 15.75 d33 1.00 1.00 1.00 Entrance pupil position 35.15 37.04 44.13 Exit pupil position -46.25 -56.10 -55.56 Front principal point position 46.77 50.59 51.04 Back principal point position -19.62 -34.01 -47.49 Lens group data Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 -30.58 35.53 9.30 -18.04 2 8 45.75 13.31 3.23 -5.68 3 12 -194.03 1.50 -1.36 -2.16 4 14 80.36 25.02 15.97 -5.22 5 19 166.81 25.39 59.24 59.43 6 27 101.83 7.27 0.08 -4.43 7 30 -52.08 1.45 0.63 -0.15 8 32 ∞ 1.60 0.53 -0.53 Single lens data Lens starting plane, focal length 1 1 -54.65 2 3 -99.72 3 5 -148.58 4 6 146.14 5 8 155.15 6 10 62.64 7 12 -194.03 8 14 202.60 9 16 -116.01 10 17 61.04 11 20 -23.23 12 21 96.00 13 23 68.24 14 25 72.66 15 27 46.12 16 28 -81.39 17 30 -52.08 18 32 0.00 Table 1 summarizes the values ​​related to equations (1) to (14) mentioned above for numerical examples 1 to 5. The zoom lens L0 in each numerical example satisfies all the conditions of equations (1) to (14).

[0070] [Table 1]

[0071] [Imaging device] Figure 11 shows a digital still camera 10 as an imaging device using the zoom lens L0 of each embodiment as the imaging optical system. 11 is the imaging optical system composed of the zoom lens L0 of any of Embodiments 1 to 5. 12 is a solid-state image sensor such as a CCD sensor or CMOS sensor that converts the optical image (subject image) formed by the imaging optical system 21 into photoelectric data, that is, captures the subject image via the imaging optical system 11.

[0072] By using the zoom lens L0 of each embodiment, a compact camera with a wide angle of view and high optical performance can be obtained. The camera may be a single-lens reflex camera with a quick-turn mirror, or a mirrorless camera without a quick-turn mirror.

[0073] The above embodiments include the following configuration.

[0074] (Composition 1) A zoom lens comprising a plurality of lens groups including, in order from an object side to an image side: a first lens group having negative refractive power that remains stationary during zooming and focusing; and at least five subsequent lens groups that move during zooming, wherein the distance between adjacent lens groups changes during zooming, wherein the at least five subsequent lens groups include two focus lens groups that move along different trajectories from each other during focusing. (Configuration 2) The zoom lens according to Configuration 1, wherein the two focus lens groups move along different trajectories from each other during zooming. (Configuration 3) Among the two focus lens groups, a first focus lens group having a shorter absolute value of focal length moves during zooming, when a focal length of the first focus lens group is fF1, and a difference between a position of the first focus lens group at a wide-angle end and a position thereof at a telephoto end is mF1, then, 0.01≦|mF1 / fF1|≦0.60 The zoom lens according to Configuration 1 or 2, which satisfies the following condition. (Configuration 4) when a focal length of the first lens group is f1, and a distance on an optical axis from a lens surface closest to an object side of the zoom lens to an image plane is L, 0.10≦|f1| / L≦0.50 An optical system according to any one of Configurations 1 to 3, which satisfies the following condition. (Configuration 5) when a focal length of a first focus lens group having a shorter absolute value of focal length among the two focus lens groups is fF1, and a focal length of a second focus lens group having a longer absolute value of focal length is fF2, 1.00<|fF2 / fF1|≦5.00 The zoom lens according to any one of Configurations 1 to 4, which satisfies the following condition. (Configuration 6) When the focal length of the first lens group is denoted as f1, and the focal length of the lens group closest to the object side among the at least five subsequent lens groups is denoted as f2, -4.00≦f2 / f1≦-1.00 The zoom lens according to any one of configurations 1 to 5, which satisfies the above condition. (Configuration 7) When the distance on the optical axis from the lens surface closest to the object side of the zoom lens to the image plane is denoted as L, and the focal length of the zoom lens at the telephoto end is denoted as ft, 3.00≦L / ft≦5.00 The zoom lens according to any one of configurations 1 to 6, which satisfies the above condition. (Configuration 8) When the focal length of the zoom lens at the wide-angle end is denoted as fw, and the air-equivalent distance on the optical axis from the lens surface closest to the image side of the zoom lens to the image plane at the wide-angle end is denoted as skw, 0.50≦fw / skw≦2.50 The zoom lens according to any one of configurations 1 to 7, which satisfies the above condition. (Configuration 9) When the focal length of the first lens group is denoted as f1, and the air-equivalent distance on the optical axis from the lens surface closest to the image side of the zoom lens to the image plane at the wide-angle end is denoted as skw, -5.00≦f1 / skw≦-1.20 The zoom lens according to any one of configurations 1 to 8, which satisfies the above condition. (Configuration 10) Among the two focus lens groups, the first focus lens group having a smaller absolute value of focal length includes a plurality of lenses, when the focal length of the lens having the smallest absolute value of focal length among the plurality of lenses is denoted as fF1p, and the focal length of the lens having the largest absolute value of focal length among the plurality of lenses is denoted as fF1w, 0.15≦|fF1p / fF1w|≦1.00 The zoom lens according to any one of configurations 1 to 9, which satisfies the above condition. (Configuration 11) Of the two focusing lens groups, the first focusing lens group, which has a shorter absolute focal length, includes multiple lenses, and when the focal length of the lens with the shortest absolute focal length among these multiple lenses is fF1p, and the focal length of the first focusing lens group is fF1, 0.30 ≤ |fF1p / fF1| ≤ 2.50 A zoom lens according to any one of configurations 1 to 10, characterized by satisfying the following conditions. (Composition 12) When the focal length of the first lens group is f1, and the focal length of the first focusing lens group with the shorter absolute value of focal length among the two focusing lens groups is fF1, 0.10 ≤ |f1 / fF1| ≤ 0.90 A zoom lens according to any one of configurations 1 to 11, characterized by satisfying the following conditions. (Composition 13) When the focal length of the first lens group is f1 and the focal length of the zoom lens at its telephoto end is ft, -2.00 ≤ ft / f1 ≤ -1.00 A zoom lens according to any one of configurations 1 to 12, characterized by satisfying the following conditions. (Composition 14) When the focal length of the lens group closest to the object among the at least five subsequent lens groups is f2, and the focal length of the first focusing lens group, which has a shorter absolute value of focal length among the two focusing lens groups, is fF1, 0.30 ≤ f² / |fF1| ≤ 2.00 A zoom lens according to any one of configurations 1 to 13, characterized by satisfying the following conditions. (Composition 15) When β2t is the lateral magnification at the telephoto end of the lens group closest to the object among the five successor lens groups mentioned above, -7.00 ≤ β2t ≤ 5.00 A zoom lens according to any one of configurations 1 to 14, characterized by satisfying the following conditions. (Composition 16) When the half-angle of view at the wide-angle end of the aforementioned zoom lens is ωw, 35.0 ≤ ωw ≤ 55.0 A zoom lens according to any one of configurations 1 to 15, characterized by satisfying the following conditions. (Composition 17) The zoom lens according to any one of configurations 1 to 16, characterized in that the first lens group includes at least four lenses. (Composition 18) The zoom lens according to any one of configurations 1 to 17, characterized in that the first lens group includes at least two negative lenses. (Composition 19) The zoom lens according to any one of configurations 1 to 8, characterized in that the first focus lens group, of the two focus lens groups, has a shorter absolute focal length, and includes at least two lenses. (Composition 20) The zoom lens according to any one of configurations 1 to 19, characterized in that the first focusing lens group, of the two focusing lens groups, has a shorter absolute focal length, has a positive refractive power, and moves toward the object when focusing from infinity to close. (Composition 21) A zoom lens comprising a first lens group with negative refractive power that is fixed during zooming and focusing and arranged sequentially from the object side to the image side, and at least three subsequent lens groups that move during zooming, wherein the spacing between adjacent lens groups changes during zooming, A zoom lens characterized in that, of the at least three subsequent lens groups, at least two lens groups have positive refractive power and at least one lens group has negative refractive power. (Composition 22) A zoom lens described in any one of configurations 1 to 21, An imaging device characterized by having an image sensor that captures an image of a subject through the zoom lens.

[0075] 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]

[0076] L0 Zoom lens L1 First lens unit LR(L2~L8) Subsequent lens unit

Claims

1. The system has multiple lens groups, each consisting of a first lens group with negative refractive power that remains stationary during zooming and focusing, arranged sequentially from the object side to the image side, and at least five subsequent lens groups that move during zooming, wherein the spacing between adjacent lens groups changes during zooming. The zoom lens is characterized in that the at least five subsequent lens groups include two focusing lens groups that move along different trajectories during focusing.

2. The zoom lens according to claim 1, characterized in that the two groups of focus lenses move along different trajectories when zooming.

3. Of the two focusing lens groups, the first focusing lens group, which has a shorter absolute focal length, moves during zooming. When the focal length of the first focusing lens group is fF1, and the difference between the position of the first focusing lens group at the wide-angle end and the position at the telephoto end is mF1, In that case, 0.01≦|mF1 / fF1|≦0.60 The zoom lens according to claim 1, characterized by satisfying the following conditions.

4. When the focal length of the first lens group is f1, and the distance along the optical axis from the lens surface closest to the object to the image plane of the zoom lens is L, 0.10≦|f1| / L≦0.50 The optical system according to claim 1, characterized in that it satisfies the following conditions.

5. When the focal length of the first focusing lens group, which has a shorter absolute focal length, is fF1, and the focal length of the second focusing lens group, which has a longer absolute focal length, is fF2, 1.00<|fF2 / fF1|≦5.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

6. When the focal length of the first lens group is f1, and the focal length of the lens group closest to the object among the at least five subsequent lens groups is f2, -4.00 ≤ f² / f¹ ≤ -1.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

7. When L is the distance along the optical axis from the lens surface closest to the object to the image plane of the zoom lens, and ft is the focal length at the telephoto end of the zoom lens, 3.00 ≤ L / ft ≤ 5.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

8. When the focal length of the zoom lens at its wide-angle end is fw, and the air-equivalent distance along the optical axis from the lens surface closest to the image plane to the image plane at the wide-angle end of the zoom lens is skw, 0.50 ≤ fw / skw ≤ 2.50 The zoom lens according to claim 1, characterized by satisfying the following conditions.

9. When the focal length of the first lens group is f1, and the air-equivalent distance on the optical axis from the image-side lens surface to the image plane of the zoom lens at the wide-angle end is skw, -5.00 ≤ f1 / skw ≤ -1.20 The zoom lens according to claim 1, characterized by satisfying the following conditions.

10. Of the two groups of focusing lenses, the first group of focusing lenses, which has a shorter absolute focal length, includes multiple lenses. When the focal length of the lens with the shortest absolute focal length among these multiple lenses is fF1p, and the focal length of the lens with the largest absolute focal length is fF1w, 0.15≦|fF1p / fF1w|≦1.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

11. Of the two focusing lens groups, the first focusing lens group, which has a shorter absolute focal length, includes multiple lenses, and when the focal length of the lens with the shortest absolute focal length among these multiple lenses is fF1p, and the focal length of the first focusing lens group is fF1, 0.30≦|fF1p / fF1|≦2.50 The zoom lens according to claim 1, characterized by satisfying the following conditions.

12. When the focal length of the first lens group is f1, and the focal length of the first focusing lens group with the shorter absolute value of focal length among the two focusing lens groups is fF1, 0.10≦|f1 / fF1|≦0.90 The zoom lens according to claim 1, characterized by satisfying the following conditions.

13. When the focal length of the first lens group is f1 and the focal length of the zoom lens at its telephoto end is ft, -2.00 ≤ ft / f1 ≤ -1.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

14. When the focal length of the lens group closest to the object among the at least five subsequent lens groups is f2, and the focal length of the first focusing lens group, which has a shorter absolute value of focal length among the two focusing lens groups, is fF1, 0.30≦f2 / |fF1|≦2.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

15. When the lateral magnification at the telephoto end of the lens group closest to the object among the five successor lens groups is β2t, -7.00 ≤ β2t ≤ 5.00 The zoom lens according to claim 1, characterized by satisfying the following conditions.

16. When the half-angle of view at the wide-angle end of the aforementioned zoom lens is denoted as ωw, 35.0 ≤ ωw ≤ 55.0 The zoom lens according to claim 1, characterized by satisfying the following conditions.

17. The zoom lens according to claim 1, characterized in that the first lens group includes at least four lenses.

18. The zoom lens according to claim 1, characterized in that the first lens group includes at least two negative lenses.

19. The zoom lens according to claim 1, characterized in that the first focus lens group, of the two focus lens groups, which has a shorter absolute value of focal length, includes at least two lenses.

20. The zoom lens according to claim 1, characterized in that the first focusing lens group, of the two focusing lens groups, which has a shorter absolute focal length, has a positive refractive power and moves toward the object when focusing from infinity to close.

21. A zoom lens comprising a first lens group with negative refractive power that is fixed during zooming and focusing, arranged sequentially from the object side to the image side, and at least three subsequent lens groups that move during zooming, wherein the spacing between adjacent lens groups changes during zooming, A zoom lens characterized in that, of the at least three subsequent lens groups, at least two lens groups have positive refractive power and at least one lens group has negative refractive power.

22. A zoom lens according to any one of claims 1 to 21, An imaging device characterized by having an image sensor that captures an image of a subject through the zoom lens.

Images