Zoom lens and image capturing device

Abstract

To provide a wide-angle, compact, and light-weight zoom lens which offers high optical performance.SOLUTION: A zoom lens is provided, comprising a positive first lens group configured to be stationary while zooming, at least one negative lens group configured to move toward the image side while zooming from the wide-angle end to the telephoto end, an intermediate group, and a positive final lens group located on the most image side and configured to be stationary while zooming. The intermediate group includes a negative lens group, a positive a-th lens group, and a positive or negative b-th lens group, each being configured to move while zooming. The final lens group includes four or more lenses. A focal length f1 of the first lens group, a focal length fw of the zoom lens at the wide-angle end, and focal lengths fa, fb of the a-th lens group and the b-th lens group, respectively, satisfy conditions expressed as: 1.0≤f1 / fw≤8.5 and -0.5≤fa / fb≤0.9.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a zoom lens used for imaging.

Background Art

[0002] As a positive lead type zoom lens in which a lens group with a positive refractive power is arranged closest to the object side, Patent Documents 1 and 2 disclose zoom lenses composed of four or more lens groups. The zoom lens of Patent Document 1 (Example 5) is composed of a first lens group with a positive refractive power that does not move during zooming, a second lens group to a fourth lens group that move during zooming, and a fifth lens group with a positive refractive power that does not move during zooming, which are arranged in order from the object side to the image side. Further, the zoom lens of Patent Document 2 is composed of a first lens group with a positive refractive power arranged closest to the object side, a second lens group to a fourth lens group that move during zooming, and a relay lens group as a fifth lens group arranged closest to the image side and that does not move during zooming. The relay lens group includes an aberration adjustment group that can move in the optical axis direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a positive lead type zoom lens, in order to achieve high optical performance, wide angle of view, and miniaturization, it is important to appropriately set the focal length of the first lens group and the focal length of the lens group that moves during zooming. However, in the zoom lens of Patent Document 1, since the L3B group constituting the third lens group has a weaker refractive power compared to the fourth lens group, the fourth lens group and the aperture become larger. Further, in the zoom lens of Patent Document 2, the refractive power of the first lens group is weak, and it is difficult to miniaturize the first lens group due to wide angle of view.

[0005] The present invention provides a zoom lens having a wide angle of view, being small and lightweight, and having high optical performance over the entire zoom range.

Means for Solving the Problems

[0006] The zoom lens according to one aspect of the present invention includes a first lens group having a positive refractive power that does not move during zooming, arranged in order from the object side to the image side, at least one lens group having a negative refractive power that moves toward the image side during zooming from the wide angle end to the telephoto end, an intermediate group, and a final lens group having a positive refractive power that does not move during zooming and is arranged closest to the image side. The interval between adjacent lens groups changes during zooming. The intermediate group includes a lens group having a negative refractive power that moves during zooming, a first a lens group having a positive refractive power, and a first b lens group having a positive or negative refractive power. The final lens group includes four or more lenses. When the focal length of the first lens group is f1, the focal length at the wide angle end of the zoom lens is fw, and the focal lengths of the first a lens group and the first b lens group are fa and fb respectively, 1.0 ≦ f1 / fw ≦ 8.5 -0.5 ≦ fa / fb ≦ 0.9 It is characterized by satisfying the following conditions. Note that an imaging device including the above zoom lens also constitutes another aspect of the present invention.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a zoom lens having a wide angle of view, being small and lightweight, and having high optical performance over the entire zoom range.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Best Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, prior to the specific description of Embodiments 1 to 6, matters common to each embodiment will be described.

[0010] In a zoom lens, a lens group is a group of one or more lenses that move integrally during zooming (variation) between a wide-angle end and a telephoto end. That is, the distance between adjacent lens groups changes during zooming. The lens group may include an aperture stop. Also, the wide-angle end and the telephoto end respectively indicate the zoom states of the maximum angle of view (shortest focal length) and the minimum angle of view (longest focal length) when the lens group that moves during zooming is located at both ends of the range where it can move on the optical axis mechanically or controllably.

[0011] The zoom lenses of the respective embodiments are used in, for example, a cinema camera, a broadcast camera, a video camera, a surveillance camera, a digital still camera, and a silver halide film camera.

[0012] The zoom lenses of the respective embodiments have, in order from the object side to the image side, a first lens group with a positive refractive power that does not move during zooming, at least one lens group with a negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end, an intermediate group, and a final lens group with a positive refractive power that does not move during zooming and is arranged on the most image side. The intermediate group includes a lens group with a negative refractive power that moves during zooming, a first a lens group with a positive refractive power, and a first b lens group with a positive or negative refractive power. Also, the final lens group includes four or more lenses.

[0013] FIG. 13 shows the optical path diagrams of the zoom lens of Example 1 at (a) the wide-angle end, (b) the intermediate zoom position (focal length: 84.59 mm), and (c) the telephoto end and focused on an infinite object (hereinafter referred to as the infinitely focused state). The zoom lens of each example moves at least four lens groups during zooming from the wide-angle end to the telephoto end, and moves the first lens group and the second lens group included in the intermediate group along separate trajectories, thereby correcting coma aberration and field curvature in the intermediate zoom range well. Further, by configuring the final lens group with four or more lenses, axial chromatic aberration and lateral chromatic aberration at the wide-angle end are corrected.

[0014] When the focal length of the first lens group is f1, the focal length of the zoom lens at the wide-angle end is fw, and the focal lengths of the first lens group and the second lens group are fa and fb, respectively, the zoom lens of each example sets each focal length so as to satisfy the following formulas (1) and (2).

[0015] 1.0 ≦ f1 / fw ≦ 8.5 (1) -0.5 ≦ fa / fb ≦ 0.9 (2) The condition of Equation (1) shows an appropriate relationship between the focal length of the first lens group and the focal length at the wide-angle end of the zoom lens. By satisfying the condition of Equation (1), it is possible to achieve both miniaturization and high optical performance of the zoom lens. If f1 / fw exceeds the upper limit of Equation (1), the refractive power of the first lens group is too weak, the diameter of the first lens group becomes large, and it becomes difficult to miniaturize the zoom lens, which is not preferable. If f1 / fw is below the lower limit of Equation (1), the refractive power of the first lens group is too strong, the curvature of the lenses constituting the first lens group becomes strong, and it becomes difficult to obtain high optical performance, which is not preferable. The condition of Equation (2) shows an appropriate relationship between the focal lengths of the a-th lens group and the b-th lens group that constitute the intermediate group. By satisfying the condition of Equation (2), it is possible to achieve both miniaturization of the lens groups after the b-th lens group and high optical performance. If fa / fb exceeds the upper limit of Equation (2), the positive refractive power of the a-th lens group becomes too weak, the diameter of the lens groups after the b-th lens group becomes large, and it becomes difficult to miniaturize the zoom lens, which is not preferable. If fa / fb is below the lower limit of Equation (2), the refractive power of the a-th lens group becomes too strong, and it becomes difficult to correct coma aberration and field curvature in the intermediate zoom range, and it becomes difficult to obtain high optical performance, which is not preferable.

[0016] Note that it is more preferable to set the numerical ranges of Equations (1) and (2) as follows.

[0017] 1.5 ≦ f1 / fw ≦ 8.5 (1a) -0.4 ≦ fa / fb ≦ 0.7 (2a) Also, it is even more preferable to set the numerical ranges of Equations (1) and (2) as follows.

[0018] 1.8 ≦ f1 / fw ≦ 8.5 (1b) -0.3 ≦ fa / fb ≦ 0.5 (2b) By satisfying the above configuration and conditions, it is possible to realize a zoom lens that has a wide angle of view, is small and lightweight, and has high optical performance over the entire zoom range.

[0019] Also, the zoom lens of each embodiment preferably satisfies at least one of the conditions and configurations of the following formulas (3) to (9).

[0020] When the distance on the optical axis between the most image-side lens surface in the b-th lens group at the telephoto end and the most object-side lens surface in the final lens group is L, and the thickness on the optical axis (group thickness) of the final lens group is LN, the zoom lens of each embodiment preferably satisfies the condition of the following formula (3).

[0021] 0 < L / LN ≤ 0.5 (3) By satisfying the condition of formula (3), it becomes possible to favorably correct spherical aberration and axial chromatic aberration at the wide-angle end. If L / LN exceeds the upper limit of formula (3), the distance between the b-th lens group and the final lens group through which the axial light beam passes at a height away from the optical axis becomes too wide, making it difficult to correct spherical aberration and axial chromatic aberration at the wide-angle end, so it is not preferable. If L / LN is below the lower limit of formula (3), the b-th lens group and the final lens group interfere with each other, so it is not preferable.

[0022] Note that it is more preferable if the numerical range of formula (3) is as follows.

[0023] 0 < L / LN ≤ 0.2 (3a) Also, it is even more preferable if the numerical range of formula (3) is as follows.

[0024] 0 < L / LN ≤ 0.12 (3b) When the lateral magnification of the final lens group at the wide-angle end when a light beam is incident from infinity is βN, the zoom lens of each embodiment preferably satisfies the condition of the following formula (4).

[0025] -0.5 ≤ βN ≤ 0.5 (4) By satisfying the conditions of Equation (4), high optical performance at the wide-angle end and miniaturization of the final lens group can be achieved. When βN exceeds the upper limit of Equation (4), the convergence of the incident light beam to the final lens group becomes strong, and the refractive powers of the a-th lens group and the b-th lens group become too strong, making it difficult to obtain high optical performance at the wide-angle end, so this is not preferable. When βN is below the lower limit of Equation (4), the divergence of the incident light beam to the final lens group becomes too strong, making it difficult to miniaturize the final lens group, so this is not preferable.

[0026] In addition, it is more preferable if the numerical range of Equation (4) is as follows.

[0027] -0.20 ≦ βN ≦ 0.46 (4a) Also, it is more preferable if the numerical range of Equation (4) is as follows.

[0028] -0.01 ≦ βN ≦ 0.44 (4b) When the intervals between the a-th lens group and the b-th lens group at the wide-angle end and the telephoto end are Lw and Lt respectively, it is preferable to satisfy the conditions of the following Equation (5).

[0029] 0.2 ≦ Lw / Lt ≦ 20.0 (5) By satisfying the conditions of Equation (5), high optical performance at the telephoto end and miniaturization of the zoom lens can be achieved. When Lw / Lt exceeds the upper limit of Equation (5), the change in the interval between the a-th lens group and the b-th lens group from the wide-angle end to the telephoto end becomes too large, making it impossible to correct the aberration variation due to zooming, and it becomes difficult to obtain high optical performance, so this is not preferable. When Lw / Lt is below the lower limit of Equation (5), the interval between the a-th lens group and the b-th lens group at the telephoto end becomes too wide, making it difficult to miniaturize the zoom lens, so this is not preferable.

[0030] In addition, it is more preferable if the numerical range of Equation (5) is as follows.

[0031] 0.3 ≦ Lw / Lt ≦ 15.0 (5a) Also, it is even more preferable if the numerical range of Equation (5) is as follows.

[0032] 0.5 ≦ Lw / Lt ≦ 11.0 (5b) For the zoom lens of each embodiment, let the focal length at the wide-angle end of the entire zoom lens system be fw, the zoom ratio of the zoom lens be Z, and the focal length fm = fw × Z 0.5 When the distance between the a-th lens group and the b-th lens group is Lm, it is preferable to satisfy the condition of the following formula (6).

[0033] 0.2 ≦ Lm / Lt ≦ 10.0 (6) By satisfying the condition of formula (6), high optical performance in the intermediate zoom range can be achieved. When Lm / Lt exceeds the upper limit of formula (6), the change in the distance between the a-th lens group and the b-th lens group from the focal length fm to the telephoto end becomes too large, and it becomes difficult to correct the aberration variation due to zooming, making it difficult to obtain high optical performance, so this is not preferable. When Lm / Lt is below the lower limit of formula (6), the change in the distance between the a-th lens group and the b-th lens group at the focal length fm and the telephoto end becomes too small, resulting in insufficient correction of optical performance in the intermediate zoom range, so this is not preferable.

[0034] Note that it is more preferable if the numerical range of formula (6) is as follows.

[0035] 0.3 ≦ Lm / Lt ≦ 6.0 (6a) Also, it is even more preferable if the numerical range of formula (6) is as follows.

[0036] 0.5 ≦ Lm / Lt ≦ 4.0 (6b) The zoom lens of each embodiment is preferably composed of the above-mentioned first lens group arranged in order from the object side to the image side, a second lens group with a negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end, a third lens group with a negative refractive power that moves during zooming, a fourth lens group as the a-th lens group, a fifth lens group as the b-th lens group, an intermediate group composed of these, and a sixth lens group as the final lens group.

[0037] The zoom lens of each embodiment is preferably composed of the first lens group arranged in order from the object side to the image side, a second lens group with positive or negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end, and a third lens group with negative refractive power, a fourth lens group with negative refractive power that moves during zooming, a fifth lens group as the a-th lens group, and a sixth lens group as the b-th lens group that form an intermediate group, and a seventh lens group as the final lens group.

[0038] When the focal lengths of the second lens group and the third lens group are f2 and f3 respectively, and the focal length of the a-th lens group is fa, the zoom lens of each embodiment preferably satisfies the conditions of the following formulas (7) to (9).

[0039] 0.1 ≦ f2 / f3 ≦ 2.0 (7) 0.2 ≦ f1 / fa ≦ 5.0 (8) -2.0 ≦ f2 / fa ≦ -0.1 (9) By satisfying the conditions of formulas (7), (8), and (9), high optical performance and miniaturization can be achieved. If f2 / f3 exceeds the upper limit of formula (7), the refractive power of the second lens group becomes too strong, making it difficult to correct distortion aberration at the wide-angle end and spherical aberration at the telephoto end, which is not preferable. If f2 / f3 is below the lower limit of formula (7), the refractive power of the second lens group becomes too weak, and the movement amount of the second lens group during zooming becomes too large, making it difficult to miniaturize the zoom lens, which is not preferable.

[0040] If f1 / fa exceeds the upper limit of formula (8), the refractive power of the first lens group becomes too weak with respect to the a-th lens group, making it difficult to widen the angle of view of the zoom lens, which is not preferable. If f1 / fa is below the lower limit of formula (8), the refractive power of the first lens group becomes too strong, making it difficult to obtain high optical performance, which is not preferable. If f2 / fa exceeds the upper limit of formula (9), the refractive power of the a-th lens group becomes too weak, making it difficult to miniaturize the final lens group, which is not preferable. If f2 / fa is below the lower limit of formula (9), the refractive power of the a-th lens group becomes too strong, making it difficult to correct the optical performance in the intermediate zoom range, which is not preferable.

[0041] In addition, it is more preferable that the numerical ranges of formulas (7) to (9) are as follows.

[0042] 0.1 ≦ f2 / f3 ≦ 1.5 (7a) 0.3 ≦ f1 / fa ≦ 4.0 (8a) -1.5 ≦ f2 / fa ≦ -0.2 (9a) Also, it is even more preferable that the numerical ranges of formulas (7) to (9) are as follows.

[0043] 0.15 ≦ f2 / f3 ≦ 1.35 (7b) 0.5 ≦ f1 / fa ≦ 2.3 (8b) -1.1 ≦ f2 / fa ≦ -0.3 (9b) In the zoom lens of each embodiment, it is preferable that the b-th lens group has a positive refractive power. By making the b-th lens group a positive lens group, it becomes possible to miniaturize the final lens group.

[0044] In the zoom lens of each embodiment, it is preferable that the a-th lens group is composed of one positive lens, and the b-th lens group includes at least one positive lens and at least one negative lens. By configuring the a-th lens group with a strong refractive power using one positive lens and arranging positive and negative lenses in the b-th lens group with a weak refractive power for achromatism, it is possible to effectively correct chromatic aberration while reducing the number of lenses constituting the a-th lens group and the b-th lens group.

[0045] Hereinafter, the zoom lens of each embodiment will be specifically described. After the description of Example 6, Numerical Examples 1 to 6 corresponding to each of Examples 1 to 6 are shown.

Example

[0046] FIG. 1 shows a cross section of the wide-angle end of the zoom lens according to Example 1 (numerical example 1) in an infinitely focused state. In this cross-sectional view and the cross-sectional views of other examples described later, the left side is the object side (front side) and the right side is the image side (rear side). Also, SP is the aperture stop, and I is the image plane. On the image plane I, the imaging surface (light-receiving surface) of an imaging device such as a CCD sensor or a CMOS sensor or the film surface (photosensitive surface) of a silver halide film is disposed.

[0047] The zoom lens of this example includes, in order from the object side to the image side, a first lens group L1 having a positive refractive power with a part moving during focusing, a second lens group L2 having a negative refractive power that moves monotonically toward the image side during zooming from the wide-angle end to the telephoto end, and a third lens group L3 having a negative refractive power and a fourth lens group having a positive refractive power that each move during zooming.

[0048] The zoom lens of this example also has a fifth lens group L5 having a positive refractive power that moves along with the movement of the second lens group L2, the third lens group L3, and the fourth lens group L4 to correct the image plane fluctuation associated with zooming. The third lens group L3, the fourth lens group L4, and the fifth lens group L5 constitute an intermediate group, and the fourth lens group L4 and the fifth lens group L5 correspond to the a-th lens group and the b-th lens group, respectively. In this example, the second lens group L2 to the fifth lens group L5 constitute a zooming system. Further, the zoom lens of this example has a sixth lens group L6 as a final lens group having a positive refractive power for imaging that does not move during zooming. The aperture stop SP is disposed on the most object side in the sixth lens group L6.

[0049] Note that in FIG. 1, the movement trajectories of the lens groups that move during zooming from the wide-angle end to the telephoto end are indicated by arrows. Also, the movement direction during focusing from an infinitely distant object to a close object of the partial group that moves during focusing in the first lens group L1 is indicated by an arrow marked (FOCUS). This is the same for other figures showing cross sections of the zoom lenses of other examples.

[0050] The first lens group L1 corresponds to the first surface to the fourteenth surface in Numerical Example 1. The second lens group L2 corresponds to the fifteenth surface to the twenty-first surface, the third lens group L3 corresponds to the twenty-second surface to the twenty-fourth surface, and the fourth lens group L4 corresponds to the twenty-fifth surface to the twenty-sixth surface respectively. The fifth lens group L5 corresponds to the twenty-seventh surface to the twenty-ninth surface, and the sixth lens group L6 corresponds to the thirtieth surface to the forty-fifth surface respectively.

[0051] The fourth lens group L4 is composed of one biconvex lens. The fifth lens group L5 is composed of a cemented lens of a meniscus concave lens convex on the object side and a biconvex lens. The sixth lens group L6 is composed of a total of nine lenses including a convex lens and a concave lens.

[0052] In the numerical example, the surface number i indicates the order of the surface when counted from the object side. r is the radius of curvature (mm) of the i-th surface counted from the object side, d is the lens thickness or air interval (mm) on the optical axis between the i-th surface and the (i + 1)-th surface, and nd is the refractive index at the d-line of the optical material between the i-th surface and the (i + 1)-th surface. νd is the Abbe number based on the d-line of the optical material between the i-th surface and the (i + 1)-th surface.

[0053] The Abbe number νd based on the d-line is expressed as νd=(Nd - 1) / (NF - NC), where Nd, NF, and NC are the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer lines respectively. The effective diameter is the radius (mm) of the region through which the light rays contributing to imaging pass among the i-th lens surfaces.

[0054] BF represents the back focus (mm). The back focus is expressed as the distance on the optical axis from the final surface (the lens surface closest to the image side) of the zoom lens to the paraxial image plane in terms of the air-equivalent length. The overall length of the lens is the length obtained by adding the back focus to the distance on the optical axis from the frontmost surface (the lens surface closest to the object side) of the zoom lens to the final surface.

[0055] An asterisk (*) attached to the surface number means that the surface has an aspherical shape. The aspherical shape is represented by the following equation when X is the displacement amount from the surface vertex in the optical axis direction, H is the height from the optical axis in the direction orthogonal to the optical axis, the direction of light propagation is defined as positive, R is the paraxial curvature radius, k is the conic constant, and A3 to A16 are the aspherical coefficients. The "e-Z" of the conic constant and the aspherical coefficient means "×10 -Z ".

[0056]

Number

[0057] The values of formulas (1) to (9) in this example (numerical example 1) are summarized in Table 1. Numerical example 1 satisfies the conditions of formulas (1) to (9).

[0058] Figs. 2(a), (b), and (c) show the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) at the wide-angle end, focal length of 84.59 mm, and telephoto end in the infinity-focus state of the zoom lens of numerical example 1, respectively.

[0059] In the spherical aberration diagram, Fno indicates the F-number. The solid line represents the spherical aberration with respect to the e-line (wavelength 546.1 nm), and the two-dot chain line represents the spherical aberration with respect to the g-line (wavelength 435.8 nm). In the astigmatism diagram, the solid line S represents the astigmatism at the sagittal image plane, and the broken line M represents the astigmatism at the meridional image plane. The distortion aberration diagram shows the distortion aberration at the e-line. The chromatic aberration diagram shows the lateral chromatic aberration at the g-line. ω is the half field angle (°). The spherical aberration diagram is drawn on a scale of 0.4 mm, the astigmatism diagram is drawn on a scale of 0.4 mm, the distortion aberration diagram is drawn on a scale of 10%, and the chromatic aberration diagram is drawn on a scale of 0.1 mm. The explanations regarding the aberration diagrams are the same for other examples.

Example

[0060] Fig. 3 shows a cross-section of the zoom lens of Example 2 (numerical example 2) at the wide-angle end and in the infinity-focus state.

[0061] The zoom lens of this embodiment includes a first lens group L1 with a positive refractive power, a part of which moves during focusing, arranged in order from the object side to the image side, a second lens group L2 with a negative refractive power that moves monotonically toward the image side during zooming from the wide-angle end to the telephoto end, and a third lens group L3 with a negative refractive power and a fourth lens group with a positive refractive power that move during zooming respectively.

[0062] Also, the zoom lens of this embodiment has a fifth lens group L5 with a positive refractive power that moves along with the movement of the second lens group L2, the third lens group L3, and the fourth lens group L4 to correct the image plane fluctuation associated with zooming. The third lens group L3, the fourth lens group L4, and the fifth lens group L5 constitute an intermediate group, and the fourth lens group L4 and the fifth lens group L5 correspond to the a-th lens group and the b-th lens group respectively. In this embodiment, the second lens group L2 to the fifth lens group L5 constitute a variable magnification system.

[0063] Furthermore, the zoom lens of this embodiment has a sixth lens group L6 as the final lens group with a positive refractive power for imaging that does not move during zooming. The aperture stop SP is arranged on the most object side in the sixth lens group L6.

[0064] The first lens group L1 corresponds to the first surface to the eighteenth surface. The second lens group L2 corresponds to the nineteenth surface to the twenty-fifth surface, the third lens group L3 corresponds to the twenty-sixth surface to the twenty-eighth surface, the fourth lens group L4 corresponds to the twenty-ninth surface to the thirtieth surface respectively. The fifth lens group L5 corresponds to the thirty-first surface to the thirty-third surface, and the sixth lens group L6 corresponds to the thirty-fourth surface to the forty-ninth surface respectively.

[0065] The fourth lens group L4 is composed of one biconvex lens. The fifth lens group L5 is composed of a cemented lens of a meniscus concave lens convex on the object side and a biconvex lens. The sixth lens group L6 is composed of a total of nine lenses including a convex lens and a concave lens.

[0066] The values of formulas (1) to (9) of this embodiment (numerical example 2) are summarized in Table 1. Numerical example 2 satisfies the conditions of formulas (1) to (9).

[0067] Figs. 4(a), 4(b), and 4(c) show the longitudinal aberration at the wide-angle end, at a focal length of 43.26 mm, and at the telephoto end, respectively, in the infinity-focus state of the zoom lens of Numerical Example 2.

Example

[0068] Fig. 5 shows a cross section at the wide-angle end and in the infinity-focus state of the zoom lens of Example 3 (Numerical Example 3).

[0069] The zoom lens of this example includes a first lens group L1 with a positive refractive power, part of which moves during focusing, arranged in order from the object side to the image side, a second lens group L2 with a negative refractive power that moves monotonically toward the image side during zooming from the wide-angle end to the telephoto end, and a third lens group L3 with a negative refractive power, and a fourth lens group L4 with a negative refractive power and a fifth lens group with a positive refractive power that move during zooming, respectively.

[0070] The zoom lens of this example also has a sixth lens group L6 with a positive refractive power that moves with the movement of the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 to correct the image plane fluctuation associated with zooming. The fourth lens group L4, the fifth lens group L5, and the sixth lens group L6 form an intermediate group, and the fifth lens group L5 and the sixth lens group L6 correspond to the first a lens group and the first b lens group, respectively. In this example, the second lens group L2 to the sixth lens group L6 constitute a variable magnification system.

[0071] Furthermore, the zoom lens of this example has a seventh lens group L7 as a final lens group with a positive refractive power for imaging that does not move during zooming. The aperture stop SP is arranged closest to the object side in the seventh lens group L7.

[0072] The first lens group L1 corresponds to the first surface to the twelfth surface. The second lens group L2 corresponds to the thirteenth surface to the seventeenth surface, the third lens group L3 corresponds to the eighteenth surface to the nineteenth surface, and the fourth lens group L4 corresponds to the twentieth surface to the twenty-fourth surface respectively. The fifth lens group L5 corresponds to the twenty-fifth surface to the twenty-sixth surface, the sixth lens group L6 corresponds to the twenty-seventh surface to the thirty-first surface, and the seventh lens group L7 corresponds to the thirty-second surface to the forty-fifth surface respectively.

[0073] The fifth lens group L5 is composed of one biconvex lens. The sixth lens group L6 is composed of a biconvex lens and a cemented lens of a biconvex lens and a biconcave lens. The seventh lens group L7 is composed of eight lenses including a convex lens and a concave lens.

[0074] The values of formulas (1) to (9) of this embodiment (numerical example 3) are summarized in Table 1. Numerical example 3 satisfies the conditions of formulas (1) to (9).

[0075] Figs. 6(a), (b), and (c) show the longitudinal chromatic aberration at the wide-angle end, the focal length of 191.75 mm, and the telephoto end in the infinity focus state of the zoom lens of numerical example 3, respectively.

Embodiment

[0076] Fig. 7 shows a cross-section of the zoom lens of Example 4 (numerical example 4) at the wide-angle end and in the infinity focus state.

[0077] The zoom lens of this embodiment includes a first lens group L1 with a positive refractive power that moves partially during focusing, arranged in order from the object side to the image side, and a second lens group L2 with a negative refractive power that moves monotonically to the image side during zooming from the wide-angle end to the telephoto end. It has a third lens group L3 with a negative refractive power and a fourth lens group with a positive refractive power that move during zooming, respectively. Further, the zoom lens of this embodiment has a fifth lens group L5 with a positive refractive power that moves along with the movement of the second lens group L2, the third lens group L3, and the fourth lens group L4 to correct the image plane fluctuation associated with zooming. The third lens group L3, the fourth lens group L4, and the fifth lens group L5 constitute an intermediate group, and the fourth lens group L4 and the fifth lens group L5 correspond to the a-th lens group and the b-th lens group, respectively. In this embodiment, the second lens group L2 to the fifth lens group L5 constitute a variable magnification system. The aperture stop SP is disposed on the most object side in the fifth lens group L5.

[0078] Furthermore, the zoom lens of this embodiment has a sixth lens group L6 as a final lens group with a positive refractive power for imaging that does not move during zooming.

[0079] The first lens group L1 corresponds to the first surface to the fifteenth surface. The second lens group L2 corresponds to the sixteenth surface to the twenty-second surface, the third lens group L3 corresponds to the twenty-third surface to the twenty-fourth surface, and the fourth lens group L4 corresponds to the twenty-fifth surface to the twenty-sixth surface, respectively. The fifth lens group L5 corresponds to the twenty-seventh surface to the thirtieth surface, and the sixth lens group L6 corresponds to the thirty-first surface to the forty-third surface, respectively.

[0080] The fourth lens group L4 is composed of one biconvex lens. The fifth lens group L5 is composed of a cemented lens of a biconvex lens and a meniscus lens convex on the image side. The sixth lens group L6 is composed of a total of eight lenses including a convex lens and a concave lens.

[0081] The values of formulas (1) to (9) of this embodiment (numerical example 4) are summarized in Table 1. Numerical example 4 satisfies the conditions of formulas (1) to (9).

[0082] Figs. 8(a), (b), and (c) show the longitudinal chromatic aberration at the wide-angle end, a focal length of 33.16 mm, and the telephoto end, respectively, in the infinity focus state of the zoom lens of numerical example 4.

Embodiment

[0083] FIG. 9 shows a cross section at the wide-angle end and in the infinity focus state of the zoom lens of Example 5 (numerical example 5).

[0084] The zoom lens of this example includes a first lens group L1 having a positive refractive power, a part of which moves during focusing, arranged in order from the object side to the image side, a second lens group L2 having a positive refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end, a third lens group L3 having a negative refractive power that moves monotonically toward the image side, a fourth lens group L4 having a negative refractive power that moves during zooming, and a fifth lens group L5 having a positive refractive power.

[0085] The zoom lens of this example further includes a sixth lens group L6 having a positive refractive power that moves along with the movement of the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 to correct the image plane fluctuation associated with zooming. The fourth lens group L4, the fifth lens group L5, and the sixth lens group L6 constitute an intermediate group, and the fifth lens group L5 and the sixth lens group L6 correspond to the a-th lens group and the b-th lens group, respectively. In this example, the second lens group L2 to the sixth lens group L6 constitute a variable magnification system. The aperture stop SP is arranged on the most object side in the fifth lens group L5.

[0086] Furthermore, the zoom lens of this example includes a seventh lens group L7 as a final lens group having a positive refractive power for imaging that does not move during zooming. P is a glass block such as a color separation prism or an optical filter, and the same applies to Example 6 below.

[0087] The first lens group L1 corresponds to the first surface to the 19th surface. The second lens group L2 corresponds to the 20th surface to the 21st surface, the third lens group L3 corresponds to the 22nd surface to the 30th surface, the fourth lens group L4 corresponds to the 31st surface to the 33rd surface, the fifth lens group L5 corresponds to the 34th surface to the 36th surface, the sixth lens group L6 corresponds to the 37th surface to the 39th surface, and the seventh lens group L7 corresponds to the 40th surface to the 52nd surface, respectively.

[0088] The fifth lens group L5 is composed of one biconvex lens. The sixth lens group L6 is composed of a cemented lens of a biconvex lens and a biconcave lens, and the seventh lens group L7 is composed of 11 lenses combining a convex lens and a concave lens.

[0089] The values of formulas (1) to (9) of this example (numerical example 5) are summarized in Table 1. Numerical example 5 satisfies the conditions of formulas (1) to (6) and (8), and does not satisfy the conditions of formulas (7) and (9).

[0090] Figs. 10(a), (b), and (c) show the longitudinal chromatic aberration at the wide-angle end, the focal length of 16.34 mm, and the telephoto end in the infinity focus state of the zoom lens of numerical example 5, respectively.

Example

[0091] Fig. 11 shows a cross-section of the zoom lens of Example 6 (numerical example 6) at the wide-angle end and in the infinity focus state.

[0092] The zoom lens of this example includes a first lens group L1 with a positive refractive power that moves partially during focusing, arranged in order from the object side to the image side, a second lens group L2 with a negative refractive power that moves monotonically to the image side during zooming from the wide-angle end to the telephoto end, and a third lens group L3 with a negative refractive power and a fourth lens group with a positive refractive power that move during zooming, respectively. The aperture stop SP is arranged on the most object side in the fourth lens group L4.

[0093] Also, the zoom lens of this example has a fifth lens group L5 with a positive refractive power that moves with the movement of the second lens group L2, the third lens group L3, and the fourth lens group L4 to correct the image plane fluctuation associated with zooming. The third lens group L3, the fourth lens group L4, and the fifth lens group L5 constitute an intermediate group, and the fourth lens group L4 and the fifth lens group L5 correspond to the a-th lens group and the b-th lens group, respectively. In this example, the second lens group L2 to the fifth lens group L5 constitute a variable magnification system.

[0094] Furthermore, the zoom lens of the present embodiment has a sixth lens group L6 as a final lens group with a positive refractive power for imaging that does not move during zooming.

[0095] The first lens group L1 corresponds to the first surface to the 19th surface. The second lens group L2 corresponds to the 20th surface to the 28th surface, the third lens group L3 corresponds to the 29th surface to the 31st surface, the fourth lens group L4 corresponds to the 32nd surface to the 34th surface, respectively. The fifth lens group L5 corresponds to the 35th surface to the 37th surface, and the sixth lens group L6 corresponds to the 38th surface to the 50th surface, respectively.

[0096] The fourth lens group L4 is composed of a single biconvex lens. The fifth lens group L5 is composed of a cemented lens of a meniscus convex lens concave on the image side and a meniscus concave lens convex on the object side.

[0097] The values of formulas (1) to (9) of this embodiment (numerical example 6) are summarized in Table 1. Numerical example 6 satisfies the conditions of formulas (1) to (9).

[0098] Figs. 12(a), (b), and (c) show the longitudinal chromatic aberration at the wide-angle end, focal length of 22.08 mm, and telephoto end in the infinity focus state of the zoom lens of numerical example 6, respectively. [Numerical Example 1] Unit: mm Surface data Surface number r d nd νd Effective diameter 1 -298.726 1.60 1.89190 37.1 96.01 2 147.923 2.01 90.99 3 158.765 4.92 1.98612 16.5 90.73 4 287.958 2.39 90.02 5 280.011 11.22 1.49700 81.5 88.93 6* -185.843 9.43 87.86 7 179.212 2.10 1.85478 24.8 79.05 8 87.572 0.27 77.29 9 89.176 11.76 1.53775 74.7 77.33 10 -747.731 7.19 77.22 11 106.075 8.53 1.53775 74.7 76.13 12 2546.824 1.00 75.53 13 92.547 8.34 1.61800 63.3 71.10 14 866.235 (Variable) 70.03 15* 412.405 1.20 2.05090 26.9 31.62 16 24.508 7.25 27.12 17 -38.635 0.80 1.52841 76.5 26.67 18 30.110 6.51 1.85478 24.8 26.09 19 -42.813 2.20 25.71 20 -27.265 0.75 1.76385 48.5 25.16 21 -239.767 (Variable) 26.03 22 -55.914 0.90 1.88300 40.8 29.34 23 94.395 3.48 1.85478 24.8 31.13 24 -149.521 (Variable) 31.73 25* 74.801 6.89 1.76385 48.5 39.00 26 -98.208 (Variable) 39.37 27 107.857 1.20 1.85478 24.8 38.82 28 37.690 7.11 1.59522 67.7 37.92 29 -361.701 (Variable) 37.85 30 (Aperture) ∞ 1.00 37.01 31 275.057 4.41 1.53775 74.7 36.80 32 -132.095 7.31 36.46 33 -77.008 2.00 1.88300 40.8 34.05 34 -216.738 43.69 34.14 35 76.510 6.85 1.55200 70.7 38.01 36 -62.564 6.44 37.94 37 48.673 7.98 1.89286 20.4 32.53 38 -37.719 1.00 2.05090 26.9 31.55 39 37.396 2.76 28.41 40 97.544 7.35 1.48749 70.2 28.37 41 -25.465 0.90 1.89190 37.1 28.12 42 174.357 0.51 29.19 43 38.737 8.55 1.48749 70.2 30.81 44 -35.456 0.95 2.00069 25.5 30.88 45 -55.422 38.00 31.48 Image plane ∞ Aspherical data The 6th surface K =-5.68862e-01 A 4= 5.47754e-08 A 6=-1.24236e-12 A 8=-1.07816e-15 The 15th surface K = 1.92279e+00 A 4= 3.81337e-06 A 6=-2.75045e-09 A 8= 1.48101e-11 A10=-4.33253e-14 A12= 8.22883e-17 The 25th surface K = 2.00015e+00 A 4=-2.15756e-06 A 6= 1.15981e-10 A 8=-1.57896e-13 Various data Zoom ratio 11.51 Wide angle Middle Telephoto Focal length 24.93 84.59 287.01 F-number 2.73 2.73 4.18 Half angle of view (°) 30.70 9.92 2.95 Image height 14.80 14.80 14.80 Overall lens length 318.18 318.18 318.18 BF 38.00 38.00 38.00 d14 1.00 37.20 54.70 d21 53.98 2.16 2.01 d24 7.03 21.60 1.16 d26 5.73 5.64 1.50 d29 1.72 2.86 10.09 Entrance pupil position 73.57 207.71 573.71 Exit pupil position -93.90 -93.90 -93.90 Front principal point position 93.79 238.05 236.23 Rear principal point position 13.07 -46.59 -249.01 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 83.13 70.75 45.08 -1.55 2 15 -19.43 18.70 2.78 -10.27 3 22 -98.42 4.38 -1.31 -3.72 4 25 56.56 6.89 1.72 -2.25 5 27 369.96 8.31 1.47 -3.67 6 30 133.96 101.68 33.65 -48.97 [Numerical example 2] Unit mm Surface data Surface number r d nd νd Effective diameter 1* -10026.850 2.80 1.80100 35.0 90.67 2 45.635 26.96 70.86 3 -75.769 2.00 1.64000 60.1 70.30 4 131.059 1.22 73.25 5 138.336 8.64 1.95906 17.5 74.05 6 -387.683 1.20 74.17 7 678.908 11.60 1.59522 67.7 73.98 8* -81.148 5.14 73.77 9 742.065 9.83 1.43875 94.7 68.59 10 -89.601 2.00 1.84666 23.8 68.69 11 -242.798 0.20 70.07 12 207.450 7.21 1.49700 81.5 70.98 13 -293.498 0.20 70.96 14 151.548 2.00 1.80518 25.4 70.12 15 58.631 17.84 1.43875 94.7 68.47 16 -164.554 0.20 68.91 17 127.297 10.56 1.76385 48.5 69.02 18 -158.835 (variable) 68.53 19* 122.817 1.24 2.00100 29.1 30.17 20 23.093 7.25 26.10 21 -39.480 0.85 1.53775 74.7 25.41 22 32.473 5.06 1.85478 24.8 25.11 23 -68.896 2.10 25.22 24 -27.450 1.00 1.80400 46.5 25.18 25 - 47.504 (variable) 25.99 26 - 34.368 0.80 1.59522 67.7 26.23 27 85.625 2.28 1.85896 22.7 28.16 28 486.122 (variable) 28.56 29* 72.197 5.08 1.89190 37.1 36.30 30 - 162.017 (variable) 36.51 31 86.169 1.10 2.00069 25.5 36.50 32 40.202 7.43 1.55200 70.7 35.78 33 - 122.707 (variable) 35.79 34 (aperture) ∞ 1.00 35.00 35 122.613 5.92 1.48749 70.2 34.66 36 - 60.937 0.25 34.21 37 - 192.679 5.72 1.76182 26.5 32.95 38 - 32.830 1.10 2.00100 29.1 32.38 39 451.147 41.06 31.87 40 - 425.965 5.97 1.48749 70.2 32.46 41 - 36.618 2.04 32.90 42 51.505 7.36 1.80810 22.8 31.04 43 - 36.352 0.90 2.00100 29.1 30.38 44 37.996 1.30 28.54 45 32.673 10.95 1.43875 94.7 29.11 46 - 23.525 1.00 1.88300 40.8 28.82 47 199.695 0.50 30.61 48 52.412 7.14 1.48749 70.2 32.32 49 - 45.144 44.83 32.64 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A4 = 5.29771e-07 A6 = 5.19999e-10 A8 = -6.99339e-13 A10 = 4.88456e-16 A12 = -2.01744e-19 A14 = 4.61660e-23 A16 = -4.55966e-27 Eighth surface K = 0.00000e+00 A4 = 5.49631e-07 A6 = 7.86753e-11 A8 = -7.44163e-14 A10 = 1.84541e-16 A12 = -2.88502e-19 A14 = 1.98622e-22 A16 = -5.05112e-26 Nineteenth surface K = 0.00000e+00 A4 = 3.66276e-06 A6 = -2.97465e-09 A8 = 1.47231e-11 A10 = -6.80963e-14 A12 = 1.79673e-16 Twenty-ninth surface K = 0.00000e+00 A4 = -1.75609e-06 A6 = 5.87222e-10 A8 = -3.23480e-13 Various data Zoom ratio 8.22 Wide angle Medium Telephoto Focal length 15.08 43.26 124.02 F-number 2.72 2.72 3.77 Half field angle (°) 44.46 18.89 6.81 Image height 14.80 14.80 14.80 Overall lens length 340.04 340.04 340.04 BF 44.83 44.83 44.83 d18 0.99 32.59 48.53 d25 33.42 3.30 2.08 d28 16.74 18.36 1.17 d30 6.58 3.41 1.50 d33 1.50 1.57 5.97 Entrance pupil position 43.46 72.83 135.08 Exit pupil position -126.29 -126.29 -126.29 Front principal point position 57.21 105.15 169.22 Rear principal point position 29.75 1.57 -79.20 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 41.22 109.59 54.85 36.92 2 19 -25.36 17.50 1.59 -11.86 3 26 -62.40 3.08 0.09 -1.63 4 29 56.57 5.08 0.84 -1.88 5 31 200.72 8.53 3.62 -1.79 6 34 119.06 92.20 54.86 -24.55 [Numerical example 3] Unit: mm Surface data Surface number r d nd νd Effective diameter 1 177.551 14.36 1.48749 70.2 123.02 2 -5090.548 0.20 121.40 3 239.752 4.00 1.77250 49.6 115.00 4 115.939 3.91 108.55 5 123.400 18.28 1.43387 95.1 108.23 6 -447.553 3.90 107.56 7 -259.024 3.20 1.72916 54.7 106.78 8 640.500 18.50 105.77 9 224.557 13.41 1.43387 95.1 104.99 10 -295.915 0.15 104.61 11 178.031 5.35 1.49700 81.5 100.00 12 332.878 (Variable) 99.14 13* 172.752 1.20 1.76385 48.5 45.29 14 36.660 10.24 40.26 15 -64.616 1.00 1.43875 94.7 39.55 16 59.109 5.92 1.85478 24.8 38.06 17 -229.863 (Variable) 37.43 18 -53.088 1.20 1.76385 48.5 36.08 19 2179.036 (Variable) 35.78 20 -240.822 1.00 1.77250 49.6 29.80 21 109.454 2.63 1.89286 20.4 30.15 22 -1109.622 2.00 30.32 23 -70.761 1.20 1.88300 40.8 30.41 24 -589.464 (Variable) 31.21 25* 267.759 4.49 1.76385 48.5 40.20 26 -105.131 (Variable) 40.75 27 68.731 8.04 1.59522 67.7 42.13 28 -82.093 0.20 41.89 29 126.641 5.49 1.43875 94.7 39.47 30 -138.967 1.20 1.95375 32.3 38.23 31 78.762 (variable) 36.98 32 (aperture) ∞ 1.50 35.24 33 43.037 5.66 1.49700 81.5 34.96 34 3328.939 31.89 34.31 35 -70.095 1.20 2.00069 25.5 19.86 36 25.357 4.46 1.80810 22.8 20.10 37 -158.714 38.00 20.42 38 73.093 2.95 1.51742 52.4 27.75 39 262.589 1.00 27.72 40 321.462 5.97 1.85478 24.8 27.76 41 -27.988 1.00 1.88300 40.8 27.71 42 40.470 2.00 27.68 43 40.041 8.46 1.58144 40.8 29.38 44 -31.971 1.00 1.95906 17.5 29.60 45 -52.676 52.00 30.29 Image plane ∞ Aspherical data 13th surface K = -1.83072e+02 A4 = 5.21288e-06 A6 = -1.30348e-08 A8 = 4.13637e-11 A10 = -1.04472e-13 A12 = 1.71504e-16 A14 = -1.53944e-19 A16 = 5.63699e-23 25th surface K = -8.62985e+01 A4 = -6.71236e-07 A6 = -4.13236e-10 A8 = -4.86348e-14 Various data Zoom ratio 29.98 Wide-angle telephoto Focal length 35.01 191.75 1049.66 F-number 4.70 4.70 9.13 Half field angle (°) 22.92 4.41 0.81 Image height 14.80 14.80 14.80 Overall lens length 467.14 467.14 467.14 BF 52.00 52.00 52.00 d12 1.00 103.97 147.17 d17 4.14 6.78 12.65 d19 146.02 14.19 3.81 d24 13.31 29.75 2.38 d26 2.27 1.94 3.61 d31 12.22 22.33 9.35 Entrance pupil position 138.93 697.14 3141.20 Exit pupil position -161.16 -161.16 -161.16 Front principal point position 168.19 716.40 -977.77 Rear principal point position 16.99 -139.74 -997.66 Lens group data Group Starting surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 223.37 85.26 41.36 -31.03 2 13 -88.01 18.35 -4.38 -20.43 3 18 -67.83 1.20 0.02 -0.66 4 20 -81.00 6.83 3.25 -1.31 5 25 99.35 4.49 1.84 -0.72 6 27 196.89 14.94 -18.21 -25.31 7 32 203.57 105.10 46.93 -100.17 [Numerical Example 4] Unit: mm Surface data Surface number r d nd νd Effective diameter 1* 187.897 2.80 1.83481 42.7 82.22 2 37.089 13.64 63.16 3 98.539 2.00 1.76385 48.5 62.48 4 55.065 15.52 58.96 5 -94.236 1.70 1.59522 67.7 58.47 6 94.438 4.16 59.75 7 104.850 8.10 1.85478 24.8 62.34 8 -1666.387 1.50 62.78 9* 90.656 14.49 1.53775 74.7 65.93 10 -92.722 5.33 66.80 11 151.914 2.00 1.85478 24.8 65.54 12 52.157 19.17 1.43875 94.7 63.28 13 -159.720 0.20 63.90 14 130.565 14.86 1.59522 67.7 63.84 15 -77.398 (Variable) 63.03 16 401.053 1.20 1.76385 48.5 33.95 17 32.077 6.57 32.04 18 -130.131 1.00 1.49700 81.5 32.31 19 33.718 5.30 2.00100 29.1 33.77 20 195.728 4.37 33.57 21 -54.448 1.10 1.76385 48.5 33.48 22 -93.524 (Variable) 33.97 23 -60.403 1.10 1.59522 67.7 34.44 24 147.785 (Variable) 35.83 25* 63.154 6.97 1.76385 48.5 37.83 26 -67.354 (Variable) 37.98 27 (Aperture) ∞ 1.50 36.74 28 414.572 6.67 1.48749 70.2 36.18 29 -36.552 1.10 1.89190 37.1 35.82 30 -224.353 (Variable) 36.18 31 138.259 3.30 1.77250 49.6 35.92 32 -253.937 0.20 35.74 33 199.955 1.10 1.95375 32.3 35.22 34 36.400 3.59 1.48749 70.2 34.06 35 69.383 0.20 34.09 36 38.292 7.54 1.59349 67.0 36.58 37 -123.759 10.49 36.66 38 153.850 6.74 1.95906 17.5 35.48 39 -44.210 1.10 1.85478 24.8 35.14 40 77.366 2.00 33.66 41 73.581 11.21 1.49700 81.5 33.59 42 -23.955 1.10 2.00069 25.5 33.12 43 -74.296 40.59 35.03 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 1.86243e-06 A 6=-8.14032e-10 A 8= 4.12454e-13 A10 = -1.24101e-16, A12 = 1.75055e-20 The 9th surface K = 0.00000e+00, A4 = -1.97663e-06, A6 = 3.31608e-10, A8 = -7.12315e-14 The 25th surface K = 0.00000e+00, A4 = -1.61157e-06, A6 = 5.42350e-10, A8 = -3.68567e-14 Various data Zoom ratio 2.27 Wide angle, middle, telephoto Focal length 22.00, 33.16, 49.99 F-number 2.22, 2.22, 2.22 Half field angle (°) 44.52, 33.12, 23.40 Image height 21.64, 21.64, 21.64 Overall lens length 278.98, 278.98, 278.98 BF 40.59, 40.59, 40.59 d15 1.00, 20.42, 34.41 d22 6.36, 2.00, 4.91 d24 13.67, 9.45, 1.30 d26 1.50, 1.71, 1.86 d30 24.95, 13.89, 5.00 Entrance pupil position 37.40, 44.77, 54.44 Exit pupil position -74.87, -54.00, -41.86 Front principal point position 55.21, 66.31, 74.12 Rear principal point position 18.59, 7.43, -9.40 Lens group data Group, start surface, focal length, lens configuration length, front principal point position, rear principal point position 1, 1, 40.13, 105.47, 54.52, 53.04 2 16 -45.23 19.55 2.63 -12.18 3 23 -71.90 1.10 0.20 -0.49 4 25 43.68 6.97 1.96 -2.09 5 27 -170.87 9.27 6.52 -0.08 6 31 79.02 48.56 -4.54 -34.41 [Numerical Example 5] Unit: mm Surface data Surface number r d nd νd Effective diameter 1* 1224.730 2.50 1.83481 42.7 78.53 2 29.276 20.71 53.73 3* -317.380 2.00 1.83481 42.7 52.84 4 486.501 3.94 52.01 5 -266.838 1.80 1.83481 42.7 51.54 6 214.788 0.15 51.37 7 83.555 3.69 1.92286 18.9 51.73 8 193.579 2.66 51.42 9 175.147 6.65 1.60300 65.4 50.84 10* -130.878 4.47 50.37 11 688.747 8.03 1.43387 95.1 50.96 12 -64.974 0.30 51.68 13 -62.220 1.70 1.80000 29.8 51.69 14 -108.005 0.18 53.48 15 214.553 1.70 1.91650 31.6 55.66 16 60.031 14.33 1.43875 94.7 56.20 17 -91.075 0.40 57.57 18 408.291 10.29 1.43387 95.1 60.30 19 -67.083 (variable) 60.78 20 160.427 8.03 1.76385 48.5 59.92 21 -131.900 (variable) 59.55 22 168.261 0.70 2.00100 29.1 21.50 23 19.097 3.58 19.31 24 -89.372 0.70 1.43875 94.7 19.16 25 64.066 2.10 18.84 26 -415.702 5.16 1.85478 24.8 18.71 27 -16.810 0.70 1.88300 40.8 18.62 28 75.626 0.34 18.54 29 34.928 2.89 1.64769 33.8 19.07 30 -276.902 (variable) 19.23 31 -32.498 0.80 1.72916 54.7 19.62 32 42.251 2.45 1.84666 23.8 20.87 33 360.852 (variable) 21.24 34 (aperture) ∞ 1.00 26.35 35* 120.516 4.81 1.89190 37.1 27.38 36 -82.437 (variable) 27.99 37 104.532 3.20 1.51742 52.4 28.27 38 -696.788 1.00 1.83481 42.7 28.19 39 545.030 (variable) 28.16 40 79.909 1.00 1.95375 32.3 28.17 41 31.355 5.17 1.51742 52.4 27.65 42 -210.143 35.00 27.74 43 57.222 6.00 1.63980 34.5 28.47 44 -51.827 0.67 28.04 45 -440.566 0.90 1.88300 40.8 26.24 46 25.855 4.96 1.48749 70.2 25.20 47 -2670.548 0.50 25.20 48 75.548 7.51 1.43875 94.7 25.20 49 -21.043 0.90 2.00100 29.1 24.95 50 -55.450 0.50 26.08 51 199.152 5.12 1.48749 70.2 26.52 52 -31.817 4.00 26.65 53 ∞ 33.00 1.60859 46.4 40.00 54 ∞ 13.20 1.51680 64.2 40.00 55 ∞ 7.45 40.00 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A4 = 4.41408e-06 A6 = -4.65049e-08 A8 = -1.93941e-10 A10 = 4.20928e-14 A12 = 1.81592e-16 A14 = 2.64005e-21 A16 = -2.41021e-24 A3 = 1.06509e-05 A5 = 1.90056e-07 A7 = 4.09260e-09 A9 = 4.27158e-12 A11 = -5.92471e-15 A13 = -2.45436e-18 A15 = 3.01854e-22 Third surface K = 0.00000e+00 A 4=-4.47149e-06 A 6=-6.66270e-08 A 8= 3.56356e-10 A10= 2.99312e-12 A12= 2.08692e-15 A14=-3.63149e-18 A16=-9.26190e-22 A 3=-3.88396e-06 A 5= 6.30987e-07 A 7= 2.07657e-09 A 9=-4.90746e-11 A11=-1.10055e-13 A13= 3.40263e-17 A15= 9.67115e-20 The 10th surface K = 0.00000e+00 A 4=-1.87256e-06 A 6=-1.41825e-07 A 8=-8.68219e-10 A10=-1.50660e-12 A12=-1.93867e-15 A14= 2.86996e-18 A16= 7.53015e-22 A 3= 1.71318e-06 A 5= 9.02040e-07 A 7= 1.39153e-08 A 9= 3.75962e-11 A11= 6.67935e-14 A13=-1.23136e-17 A15=-8.04554e-20 The 35th surface K =-5.10384e+01 A 4= 1.78702e-06 A 6=-4.69354e-09 A 8= 4.28013e-12 Various data Zoom ratio 13.61 Wide angle, medium, telephoto Focal length 4.43, 16.34, 60.24 F-number 1.86, 1.86, 2.77 Half field angle (°) 51.17, 18.60, 5.22 Image height 5.50, 5.50, 5.50 Overall lens length 315.65, 315.65, 315.65 BF 7.45, 7.45, 7.45 d19 0.50 2.27 3.00 d21 0.65 36.92 51.92 d30 33.20 4.58 8.35 d33 14.96 16.89 1.40 d36 3.45 0.99 1.00 d39 14.03 5.14 1.13 Entrance pupil position 28.36 49.52 100.45 Exit pupil position 114.87 214.73 314.38 Front principal point position 32.97 67.15 172.51 Rear principal point position 3.02 -8.89 -52.79 Lens group data Group Start surface Focal length Lens configuration length Front principal point position Rear principal point position 1 1 129.64 85.50 104.43 208.24 2 20 95.90 8.03 2.53 -2.08 3 22 -19.74 16.17 -0.15 -12.61 4 31 -45.33 3.25 0.13 -1.65 5 34 55.51 5.81 2.53 -1.04 6 37 334.77 4.20 -1.68 -4.32 7 40 50.62 118.44 50.47 -43.64 [Numerical example 6] Unit: mm Surface data Surface number r d nd νd Effective diameter 1* 492.061 2.50 1.83481 42.7 83.99 2 40.721 19.65 63.41 3* -170.055 2.00 1.83481 42.7 62.41 4 153.657 0.15 61.25 5 85.133 4.88 1.92286 18.9 61.52 6 215.750 1.53 61.11 7 133.633 9.83 1.59522 67.7 60.23 8* -105.059 6.84 59.43 9 -177.182 5.29 1.43387 95.1 55.39 10 -74.604 0.30 55.09 11 -76.485 1.70 1.80000 29.8 54.81 12 -247.725 0.18 56.76 13 89.989 1.70 1.91650 31.6 60.45 14 53.384 14.91 1.43875 94.7 59.93 15 -154.720 0.20 60.90 16 -865.308 8.96 1.43387 95.1 61.81 17 -67.519 0.20 62.30 18 93.423 8.08 1.76385 48.5 61.36 19 -417.698 (variable) 60.75 20 117.598 0.70 2.00100 29.1 21.69 21 17.102 3.72 19.07 22 -119.533 0.70 1.43875 94.7 18.89 23 66.085 2.38 18.49 24 -96.904 4.76 1.85478 24.8 18.23 25 -16.434 0.70 1.88300 40.8 18.18 26 100.237 0.26 18.16 27 34.396 2.80 1.64769 33.8 18.34 28 -264.424 (variable) 18.21 29 -33.374 0.80 1.72916 54.7 18.51 30 34.134 2.47 1.84666 23.8 19.74 31 174.853 (Variable) 20.09 32 (Aperture) ∞ 1.00 25.59 33* 675.282 4.76 1.89190 37.1 26.28 34 -52.918 (Variable) 27.21 35 38.752 4.36 1.51742 52.4 27.98 36 268.994 1.00 1.83481 42.7 27.61 37 81.192 (Variable) 27.32 38 45.098 1.00 1.95375 32.3 27.13 39 21.921 5.64 1.51633 64.1 26.13 40 474.334 35.00 26.14 41 122.800 6.00 1.63980 34.5 27.74 42 -40.806 0.50 27.57 43 -159.212 0.90 1.88300 40.8 26.09 44 29.108 5.19 1.48749 70.2 25.08 45 -123.924 0.50 25.01 46 44.032 6.50 1.43875 94.7 25.20 47 -30.701 0.90 2.00100 29.1 24.92 48 -63.156 0.50 25.27 49 353.920 2.79 1.48749 70.2 25.06 50 -66.262 4.00 24.93 51 ∞ 33.00 1.60859 46.4 40.00 52 ∞ 13.20 1.51680 64.2 40.00 53 ∞ 7.45 40.00 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4=-7.78903e-06 A 6=-1.88452e-07 A 8=-3.82996e-10 A10= 3.64015e-13 A12= 1.24868e-16 A14=-1.13713e-19 A16=-5.53432e-24 A 3= 2.43646e-05 A 5= 1.73726e-06 A 7= 1.17722e-08 A 9= 1.58042e-12 A11=-1.31366e-14 A13= 3.38166e-18 A15= 1.30488e-21 Third surface K = 0.00000e+00 A 4= 1.05466e-05 A 6= 2.78278e-07 A 8= 1.99500e-09 A10= 5.59398e-12 A12= 3.10924e-15 A14=-2.04657e-18 A16=-2.93424e-22 A 3=-2.75954e-05 A 5=-2.18469e-06 A 7=-2.63045e-08 A 9=-1.20971e-10 A11=-1.79745e-13 A13= 1.43822e-17 A15= 4.13794e-20 Eighth surface K = 0.00000e+00 A 4= 5.15532e-06 A 6=-5.04035e-08 A 8=-1.78563e-09 A10=-5.59055e-12 A12=-3.02027e-15 A14=-3.27059e-19 A16=-3.06914e-23 A 3=-1.35872e-05 A 5=-3.46732e-07 A 7= 1.52759e-08 A 9= 1.24401e-10 A11 = 1.63178e-13 A13 = 3.51644e-17 A15 = 3.88119e-21 Page 33 K = -4.40624e+03 A4 = 2.17690e-07 A6 = -4.76702e-09 A8 = 7.83209e-12 Various data Zoom ratio 18.02 Wide angle, medium, telephoto Focal length 5.20, 22.08, 93.68 F-number 1.86, 1.86, 2.95 Half field angle (°) 46.61, 13.99, 3.36 Image height 5.50, 5.50, 5.50 Overall lens length 314.65, 314.65, 314.65 BF 7.45, 7.45, 7.45 d19 0.65, 43.15, 60.90 d28 37.47, 2.00, 8.38 d31 11.61, 16.16, 1.51 d34 10.79, 1.15, 1.00 d37 11.78, 9.84, 0.50 Entrance pupil position 37.65, 83.11, 231.56 Exit pupil position 86.94, 138.45, 278.87 Front principal point position 43.19, 108.91, 357.58 Rear principal point position 2.25, -14.63, -86.23 Lens group data Group, start surface, focal length, lens configuration length, front principal point position, rear principal point position 1, 1, 44.17, 88.89, 52.01, 35.72 2, 20, -17.72, 16.02, 0.09, -12.45 3, 29, -42.77, 3.27, 0.30, -1.48 4, 32, 55.19, 5.76, 3.34, -0.18 5 35 213.67 5.36 -6.78 -9.88 6 38 49.11 115.61 49.63 -41.99

[0099]

Table 1

[0100] (Imaging device) FIG. 14 shows an imaging device using the zoom lens of each example as an imaging optical system. In FIG. 14, reference numeral 101 denotes a zoom lens of any one of Examples 1 to 6. Reference numeral 124 denotes a camera body. The imaging device 125 is configured by detachably attaching the zoom lens 101 to the camera body 124. However, an imaging device in which the zoom lens 101 is integrally provided with the camera body 124 may also be used.

[0101] The zoom lens 101 includes a first lens group F, a zoom section LZ, and an imaging lens group R. The first lens group F includes a focus subgroup that moves during focusing.

[0102] The zoom section LZ includes at least three or more lens groups that move during zooming. On the image side of the zoom section LZ, an aperture stop SP, a lens group R1, and a lens group R2 are arranged. The imaging device 125 also has a lens unit IE that can be inserted into the optical path between the lens group R1 and the lens group R2. By inserting the lens unit IE, the range of the overall focal length of the zoom lens 101 can be changed.

[0103] 114 and 115 are each a drive mechanism for driving the first lens group F and the zoom unit LZ in the optical axis direction. 116 to 118 are each a drive unit including an actuator for driving the drive mechanisms 114 and 115 and the aperture stop SP. 119 to 121 are each a detection unit for detecting the position on the optical axis of the focus subgroup, the position on the optical axis of the zoom unit LZ, and the aperture diameter of the aperture stop SP. In the camera body 124, 109 is a glass block including an optical filter or the like, and 110 is an imaging element such as a CCD sensor or a CMOS sensor that photoelectrically converts (images) the subject image formed by the zoom lens 101. 111 and 122 are each a CPU as a processing unit (control unit) in the camera body 124 and the zoom lens 101.

[0104] By using the zoom lens of each embodiment as an imaging optical system, it is possible to obtain a photographed image with good image quality over the entire zoom range with a wide angle of view and a high zoom ratio.

[0105] The above embodiments include the following configurations.

[0106] (Configuration 1) A zoom lens having, in order from the object side to the image side, a first lens group with a positive refractive power that does not move during zooming, at least one lens group with a negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end, an intermediate group, and a final lens group with a positive refractive power that does not move during zooming and is disposed closest to the image side, and in which the interval between adjacent lens groups changes during zooming, The intermediate group includes a lens group with a negative refractive power that moves during zooming, a first a lens group with a positive refractive power, and a first b lens group with a positive or negative refractive power, respectively, The final lens group includes four or more lenses, When the focal length of the first lens group is f1, the focal length at the wide-angle end of the zoom lens is fw, and the focal lengths of the first a lens group and the first b lens group are fa and fb, respectively, 1.0 ≦ f1 / fw ≦ 8.5 -0.5 ≦ fa / fb ≦ 0.9 A zoom lens characterized by satisfying the following conditions. (Configuration 2) When the distance on the optical axis between the most image-side lens surface in the b-th lens group at the telephoto end and the most object-side lens surface in the final lens group is L, and the thickness on the optical axis of the final lens group is LN, 0 < L / LN ≤ 0.5 The zoom lens according to Configuration 1, characterized by satisfying the following conditions. (Configuration 3) When the lateral magnification of the final lens group at the wide-angle end when a light beam is incident from infinity is βN, -0.5 ≤ βN ≤ 0.5 The zoom lens according to Configuration 1 or 2, characterized by satisfying the following conditions. (Configuration 4) When the distances on the optical axis between the a-th lens group and the b-th lens group at the wide-angle end and the telephoto end are Lw and Lt, respectively, 0.2 ≤ Lw / Lt ≤ 20.0 The zoom lens according to any one of Configurations 1 to 3, characterized by satisfying the following conditions. (Configuration 5) When the zoom ratio of the zoom lens is Z and the focal length fm of the zoom lens is fm = fw × Z 0.5 and the distance on the optical axis between the a-th lens group and the b-th lens group at the focal length fm is Lm, and the distance on the optical axis between the a-th lens group and the b-th lens group at the telephoto end is Lt, 0.2 ≤ Lm / Lt ≤ 10.0 The zoom lens according to any one of Configurations 1 to 4, characterized by satisfying the following conditions. (Configuration 6) A zoom lens according to any one of Configurations 1 to 5, comprising: a first lens group arranged in order from the object side to the image side; a second lens group having a negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end; a third lens group having a negative refractive power that moves during zooming; an intermediate group composed of a fourth lens group as the a-th lens group and a fifth lens group as the b-th lens group; and a sixth lens group as the final lens group. (Configuration 7) A zoom lens according to any one of Configurations 1 to 5, comprising: a first lens group arranged in order from the object side to the image side; a second lens group having a positive or negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end and a third lens group having a negative refractive power; a fourth lens group having a negative refractive power that moves during zooming; an intermediate group composed of a fifth lens group as the a-th lens group and a sixth lens group as the b-th lens group; and a seventh lens group as the final lens group. (Configuration 8) When the focal lengths of the second lens group and the third lens group are f2 and f3, respectively, and the focal length of the a-th lens group is fa, 0.1 ≦ f2 / f3 ≦ 2.0 0.2 ≦ f1 / fa ≦ 5.0 -2.0 ≦ f2 / fa ≦ -0.1 A zoom lens according to Configuration 6 or 7, satisfying the following conditions. (Configuration 9) The zoom lens according to any one of Configurations 1 to 8, wherein the b-th lens group has a positive refractive power. (Configuration 10) The a-th lens group is composed of one positive lens, The zoom lens according to any one of Configurations 1 to 9, wherein the b-th lens group includes at least one positive lens and at least one negative lens. (Configuration 11) A zoom lens according to any one of Configurations 1 to 10, and An imaging device comprising an imaging element that images a subject through the zoom lens.

[0107] Each of the embodiments described above is merely a representative example, and various modifications and changes can be made to each embodiment when implementing the present invention.

Explanation of Reference Numerals

[0108] L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group L5 Fifth lens group L6 Sixth lens group L7 Seventh lens group SP Aperture stop I Image plane

Claims

1. A zoom lens having, in order from the object side to the image side, a first lens group with a positive refractive power that does not move during zooming, at least one lens group with a negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end, an intermediate group, and a final lens group with a positive refractive power that does not move during zooming and is disposed closest to the image side, and in which the interval between adjacent lens groups changes during zooming, the intermediate group includes a lens group with a negative refractive power that moves during zooming, a first a lens group with a positive refractive power, and a second b lens group with a positive or negative refractive power, the final lens group includes four or more lenses, when the focal length of the first lens group is f1, the focal length of the zoom lens at the wide-angle end is fw, and the focal lengths of the first a lens group and the second b lens group are fa and fb, respectively, 1.0 ≤ f1 / fw ≤ 8.5 -0.5 ≤ fa / fb ≤ 0.9 A zoom lens characterized by satisfying the following conditions.

2. When the interval on the optical axis between the most image-side lens surface in the second b lens group at the telephoto end and the most object-side lens surface in the final lens group is L, and the thickness on the optical axis of the final lens group is LN, 0 < L / LN ≤ 0.5 The zoom lens according to claim 1, characterized by satisfying the following conditions.

3. When the lateral magnification of the final lens group at the wide-angle end when light beams are incident from infinity is βN, -0.5 ≤ βN ≤ 0.5 The zoom lens according to claim 1, characterized by satisfying the following conditions.

4. When the intervals on the optical axis between the first a lens group and the second b lens group at the wide-angle end and the telephoto end are Lw and Lt, respectively, 0.2 ≤ Lw / Lt ≤ 20.0 The zoom lens according to claim 1, characterized by satisfying the following conditions.

5. Let the zoom ratio of the zoom lens be Z, and the focal length fm of the zoom lens be fm = fw × Z ０．５ When the on-axis distance between the first lens group and the second lens group at the focal length fm is Lm, and the on-axis distance between the first lens group and the second lens group at the telephoto end is Lt, 0.2 ≤ Lm / Lt ≤ 10.0 The zoom lens according to claim 1, characterized by satisfying the condition.

6. The zoom lens according to claim 1, comprising, in order from the object side to the image side, the first lens group, a second lens group having a negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end, a third lens group having a negative refractive power that moves during zooming, a fourth lens group as the first lens group, and a fifth lens group as the second lens group, and a sixth lens group as the final lens group.

7. The zoom lens according to claim 1, comprising, in order from the object side to the image side, the first lens group, a second lens group having a positive or negative refractive power that moves toward the image side during zooming from the wide-angle end to the telephoto end and a third lens group having a negative refractive power, a fourth lens group having a negative refractive power that moves during zooming, a fifth lens group as the first lens group, and a sixth lens group as the second lens group, and a seventh lens group as the final lens group.

8. When the focal lengths of the second lens group and the third lens group are f2 and f3 respectively, and the focal length of the first lens group is fa, 0.1 ≤ f2 / f3 ≤ 2.0 0.2 ≤ f1 / fa ≤ 5.0 -2.0 ≤ f2 / fa ≤ -0.1 The zoom lens according to claim 6 or 7, characterized by satisfying the condition.

9. The zoom lens according to claim 1, wherein the b-th lens group has a positive refractive power.

10. The a-th lens group is composed of one positive lens, The zoom lens according to claim 1, wherein the b-th lens group includes at least one positive lens and at least one negative lens.

11. The zoom lens according to claim 1, An imaging device, comprising: the zoom lens; and an imaging element that images a subject through the zoom lens.

Images