Zoom lens and image capturing device

Abstract

To provide a zoom lens which offers a wide angle of view, a high zoom ratio, and high optical performance.SOLUTION: A zoom lens is provided, comprising a positive first lens group configured to be stationary while zooming, an intermediate group including at least three lens groups configured to move while zooming, and a positive final lens group configured to be stationary while zooming. The intermediate group includes at least one negative lens group, where a lens group with negative refractive power on the most object side among the at least one negative lens group includes at least one negative lens. The zoom lens satisfies: 2.02≤nn≤2.30, 20.0≤νn≤40.0, and 1.5≤f1 / fw≤7.7, where nn represents a refractive index of a negative lens on the most object side among the at least one negative lens, νn represents an Abbe number of the negative lens on the most object side, f1 represents a focal length of the first lens group, and fw represents a focal length of the zoom lens at the wide-angle end.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 positive refractive power is arranged on the most object side, Patent Documents 1 and 2 disclose zoom lenses composed of five or more lens groups. Patent Document 1 discloses a zoom lens having a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a fifth lens group with positive refractive power, which are arranged in order from the object side to the image side, and having a zoom ratio of about 23 times. Patent Document 2 discloses a zoom lens having a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a fifth lens group with positive refractive power, which are arranged in order from the object side to the image side, and having a zoom ratio of about 10 times.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the zoom lenses disclosed in Patent Documents 1 and 2, the refractive power arrangement and the optical material arrangement for each lens group are not appropriate, and it is difficult to satisfy all of wide angle of view, high zoom ratio, and high optical performance.

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

Means for Solving the Problems

[0006] As a zoom lens according to one aspect of the present invention, there are provided 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, an intermediate group including at least three lens groups that move during zooming, and a final lens group having a positive refractive power that does not move during zooming, and the interval between adjacent lens groups changes during zooming. The intermediate group includes at least one lens group having a negative refractive power, and the lens group having the most negative refractive power on the object side among the at least one lens group having a negative refractive power includes at least one negative lens. When the refractive index of the most object-side negative lens among the at least one negative lens on the d-line is nn, the Abbe number based on the d-line of the most object-side negative lens is νn, the focal length of the first lens group is f1, and the focal length at the wide-angle end of the zoom lens is fw, 2.02 ≦ nn ≦ 2.30 20.0 ≦ νn ≦ 40.0 1.5 ≦ f1 / fw ≦ 7.7 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.

Advantages of the Invention

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

Brief Description of the Drawings

[0008]

Figure 1

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Mode for Carrying Out the Invention

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

[0010] In a zoom lens, a lens group is a group of one or more lenses that move integrally during zooming (changing the magnification) between the wide-angle end and the 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 field angle (shortest focal length) and the minimum field angle (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 under control.

[0011] The zoom lenses of the embodiments are used in cameras for cinema, broadcast, video, surveillance, digital still cameras, cameras for silver halide film, etc.

[0012] The zoom lenses of the embodiments have a first lens group with positive refractive power, an intermediate group, and a final lens group with positive refractive power, which are arranged in order from the object side to the image side. The first lens group does not move during zooming. The intermediate group includes at least three lens groups that move during zooming. The final lens group does not move during zooming. The intermediate group includes at least one lens group with negative refractive power. The lens group with the most negative refractive power on the object side (hereinafter referred to as the object-side negative lens group) V among the at least one lens group with negative refractive power includes at least one negative lens.

[0013] Let nn be the refractive index of the most object-side negative lens among the at least one negative lens included in the object-side negative lens group V at the d-line, and let νn be the Abbe number based on the d-line of the most object-side negative lens. Also, let f1 be the focal length of the first lens group and fw be the focal length at the wide-angle end of the zoom lens. At this time, the conditions of the following formulas (1) to (3) are satisfied.

[0014] 2.02 ≦ nn ≦ 2.30 (1) 20.0 ≦ νn ≦ 40.0 (2) 1.5 ≦ f1 / fw ≦ 7.7 (3) The Abbe number ν at the d-line is calculated as follows: when the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer lines are Nd, NF, and NC, respectively, ν = (Nd - 1) / (NF - NC) It is represented by.

[0015] The conditions of formulas (1) and (2) indicate appropriate characteristics of the material of the most object-side negative lens among the object-side negative lens group V. By using a material that satisfies formulas (1) and (2), it is possible to achieve a refractive power distribution advantageous for wide-angle and high magnification, and it is also possible to suppress various aberrations. When nn exceeds the upper limit of formula (1), in existing materials, the dispersion becomes too large, making it difficult to correct chromatic aberration, so this is not preferable. When nn is below the lower limit of formula (1), it becomes difficult to achieve wide-angle and high magnification and to suppress various aberrations, so this is not preferable. When νn exceeds the upper limit of formula (2), in existing materials, the refractive index becomes too low, making it difficult to achieve wide-angle and high magnification and to suppress various aberrations, so this is not preferable. When νn is below the lower limit of formula (2), the dispersion becomes too large, making it difficult to correct chromatic aberration, so this is not preferable.

[0016] The condition of formula (3) indicates an appropriate relationship between the first lens group and the focal length at the wide-angle end of the zoom lens. By satisfying the condition of formula (1), it is possible to achieve both miniaturization and high optical performance of the zoom lens. When f1 / fw exceeds the upper limit of formula (1), the refractive power of the first lens group is weak and the lens diameter of the first lens group becomes large, making it difficult to miniaturize the zoom lens, so this is not preferable. When f1 / fw is below the lower limit of formula (1), the refractive power of the first lens group is strong and the curvature of the lenses constituting the first lens group becomes strong, making it difficult to achieve high optical performance, so this is not preferable.

[0017] Note that it is more preferable if the numerical ranges of formulas (1) to (3) are as follows.

[0018] 2.03 ≤ nn ≤ 2.25 (1a) 22.0 ≤ νn ≤ 35.0 (2a) 1.7 ≤ f1 / fw ≤ 7.5 (3a) Also, it is even more preferable if the numerical ranges of formulas (1) to (3) are as follows.

[0019] 2.04 ≤ nn ≤ 2.20 (1b) 24.0 ≤ νn ≤ 30.0 (2b) 1.9 ≤ f1 / fw ≤ 4.0 (3b) By satisfying the above-described configuration and conditions, a zoom lens having a wide angle of view, a high zoom ratio, and high optical performance over the entire zoom range can be realized.

[0020] The zoom lens of each embodiment preferably satisfies at least one of the conditions and configurations of the following formulas (4) to (9).

[0021] 0.7 ≦ fn / fV ≦ 2.0 (4) 0.63 ≦ θn + 0.00162 × νn ≦ 0.70 (5) 60 ≦ ν ≦ 100 (6) -0.0040 ≦ (θp ave -θn ave ) / (νp ave -νn ave ) < 0.0000 (7) -5.5 ≦ fV / fw ≦ -0.3 (8) 0.2 ≦ fw / IS ≦ 2.2 (9) In the above formulas (4) to (9), fn is the focal length of the most object-side negative lens in the object-side negative lens group V, and fV is the focal length of the lens group V. θn is the partial dispersion ratio between the g-line and the F-line of the most object-side negative lens in the lens group V. ν is the Abbe number based on the d-line of at least one negative lens included in the object-side negative lens group V. θp ave and νp ave are respectively the average value of the partial dispersion ratio between the g-line and the F-line and the average value of the Abbe number based on the d-line of all positive lenses included in the object-side negative lens group V. The partial dispersion ratio θ between the g-line and the F-line is given by θ = (Ng - NF) / (NF - NC) where Ng is the refractive index at the g-line (435.8 nm) of the Fraunhofer line.

[0022] Also, θn ave and νn aveThey are the average values of the partial dispersion ratios in the g-line and F-line of all the negative lenses included in the object-side negative lens group V and the average value of the Abbe number based on the d-line. Further, IS is the diagonal length of the effective imaging surface of the image sensor that performs imaging through the zoom lens. The effective imaging surface is the region that includes the pixels that output the signals used for generating the image data among the imaging surfaces of the image sensor.

[0023] The condition of Equation (4) shows an appropriate relationship between the focal length of the most object-side negative lens in the object-side negative lens group V and the focal length of the object-side negative lens group V. By satisfying the condition of Equation (4), it is possible to achieve wide-angle conversion and suppression of various aberrations. If fn / fV exceeds the upper limit of Equation (4), the refractive power of the most object-side negative lens becomes too weak, making it difficult to achieve wide-angle conversion, so it is not preferable. If fn / fV is below the lower limit of Equation (4), the refractive power of the most object-side negative lens becomes too strong, making it difficult to suppress various aberrations, so it is not preferable.

[0024] The condition of Equation (5) shows appropriate characteristics of the optical material of the most object-side negative lens in the object-side negative lens group V. By satisfying the condition of Equation (5), it is possible to achieve suppression of axial chromatic aberration and magnification chromatic aberration. If θn + 0.00162 × νn exceeds the upper limit of Equation (5), there is no existing optical material, so it is not preferable. If θn + 0.00162 × νn is below the lower limit of Equation (5), the correction of chromatic aberration becomes insufficient, so it is not preferable.

[0025] The condition of Equation (6) shows preferable characteristics of the optical materials of the negative lenses included in the object-side negative lens group V. By satisfying the condition of Equation (6), it is possible to correct the axial chromatic aberration well at the telephoto end. If ν exceeds the upper limit of Equation (6), there is no existing optical material, so it is not preferable. If ν is below the lower limit of Equation (6), it becomes difficult to correct the axial chromatic aberration well at the telephoto end, so it is not preferable.

[0026] The condition of Equation (7) shows an appropriate achromatic condition of the object-side negative lens group V. By satisfying the condition of Equation (7), an achromatic effect that can correct axial chromatic aberration and magnification chromatic aberration well can be obtained. (θp ave-θn ave ) / (νp ave -νn ave ) exceeds the upper limit of Equation (7), it becomes difficult to correct the axial chromatic aberration satisfactorily, which is not preferable. (θp ave -θn ave ) / (νp ave -νn ave ) is below the lower limit of Equation (7), it becomes difficult to correct the lateral chromatic aberration and the variation due to zooming of the lateral chromatic aberration satisfactorily. Therefore, it is not preferable.

[0027] The condition of Equation (8) shows an appropriate relationship between the focal length of the object-side negative lens group V and the focal length at the wide-angle end of the zoom lens. By satisfying the condition of Equation (8), a high zoom ratio can be achieved while suppressing various aberrations. If fV / fw exceeds the upper limit of Equation (8), the refractive power of the object-side negative lens group V becomes too weak, and the zoom lens becomes large in size to achieve a high zoom ratio, which is not preferable. If fV / fw is below the lower limit of Equation (8), the refractive power of the object-side negative lens group V becomes too strong, and it becomes difficult to suppress various aberrations, which is not preferable.

[0028] The condition of Equation (9) shows an appropriate relationship between the focal length at the wide-angle end of the zoom lens when the zoom lens of each embodiment is used in the imaging device and the diagonal length of the effective imaging surface of the imaging element. By satisfying the condition of Equation (9), an appropriate specification according to the imaging device can be realized. If fw / IS is below the lower limit of Equation (9), the zoom lens becomes overly wide-angle, and it becomes difficult to correct off-axis aberrations such as distortion aberration and lateral chromatic aberration, which is not preferable. If fw / IS exceeds the upper limit of Equation (9), the zoom lens becomes overly telephoto, and it becomes difficult to correct the axial chromatic aberration and other various aberrations at the telephoto end, which is not preferable.

[0029] Note that it is more preferable if the numerical ranges of Equations (4) to (9) are as follows.

[0030] 0.8 ≦ fn / fV ≦ 1.8 (4a) 0.635 ≦ θn + 0.00162 × νn ≦ 0.680 (5a) 62 ≦ ν ≦ 98 (6a) -0.0038 ≦ (θp ave - θn ave ) / (νp ave - νn ave ) ≦ -0.0005 (7a) -5.2 ≦ fV / fw ≦ -0.5 (8a) 0.3 ≦ fw / IS ≦ 2.1 (9a) When the numerical ranges of formulas (4) to (9) are as follows, it is more preferable.

[0031] 0.9 ≦ fn / fV ≦ 1.6 (4b) 0.640 ≦ θn + 0.00162 × νn ≦ 0.660 (5b) 64 ≦ ν ≦ 96 (6b) -0.0035 ≦ (θp ave - θn ave ) / (νp ave - νn ave ) ≦ -0.0010 (7b) -4.9 ≦ fV / fw ≦ -0.7 (8b) 0.35 ≦ fw / IS ≦ 2.0 (9b) Also, in each embodiment, it is preferable that the most object-side negative lens among at least one negative lens in the object-side negative lens group V is an aspherical lens. With this configuration, it becomes easy to suppress the variation of distortion aberration on the wide-angle side.

[0032] Also, in each embodiment, it is preferable that the object-side negative lens group V includes at least four lenses. With this configuration, it becomes easy to suppress various aberrations, particularly the variation of off-axis aberrations due to zooming on the wide-angle side.

[0033] Also, in each embodiment, it is preferable that a part of the first lens group (focus subgroup) moves for focusing. With this configuration, the movement amount of the focus subgroup can be made constant over the entire zoom range, and it is possible to prevent the variation of the zoom ratio associated with focusing on a close object.

[0034] Hereinafter, the zoom lenses of the respective embodiments will be specifically described. After the description of Embodiment 6, Numerical Examples 1 to 6 corresponding to each of Embodiments 1 to 6 are shown.

Embodiment

[0035] FIG. 1 shows a cross section at the wide-angle end in a state where the zoom lens 1a of Embodiment 1 (Numerical Example 1) is focused on an infinite object (hereinafter referred to as an infinite focus state). In this cross-sectional view and the cross-sectional views of other embodiments described later, the left side is the object side (front side) and the right side is the image side (rear side). Also, OA is the optical axis and I is the image plane. On the image plane I, an imaging surface (light-receiving surface) of an imaging element such as a CCD sensor or a CMOS sensor or a film surface (photosensitive surface) of a silver halide film is arranged.

[0036] The zoom lens 1a is composed of a first lens group L1 having a positive refractive power, a second lens group L2 having a negative refractive power, a third lens group L3 having a negative refractive power, a fourth lens group L4 having a positive refractive power, a fifth lens group L5 having a positive refractive power, an aperture stop SP, and a sixth lens group L6 having a positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move during zooming, and the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 that constitute the intermediate group move during zooming. The arrows in the figure indicate the movement trajectories of the lens groups that move during zooming from the wide-angle end to the telephoto end, and this is the same for the cross-sectional views of other embodiments described later. The sixth lens group L6 is the final lens group for imaging and does not move during zooming.

[0037] The first lens group L1 is composed of a first sub-lens group L11 having a negative refractive power, a second sub-lens group L12 having a positive refractive power, and a third sub-lens group L13 having a positive refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus subgroup that moves toward the image side during focusing from infinity to the closest distance, as indicated by the arrow (FOCUS) in the figure.

[0038] The second lens group L2 corresponds to the object-side negative lens group V and moves toward the image side when zooming from the wide-angle end to the telephoto end as a variator. The second lens group L2 is composed of four lenses (two of which form one cemented lens), and the negative lens closest to the object side is an aspherical lens. An optical unit such as an extender lens for focal length conversion may be inserted into the sixth lens group L6.

[0039] Fig. 2(A) shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the zoom lens 1a in the infinity focus state and at the wide-angle end. Fig. 2(B) shows the longitudinal aberrations of the zoom lens 1a in the infinity focus state and at the telephoto end. The solid line, two-dot chain line, one-dot chain line, and broken line in the spherical aberration diagram show the spherical aberration in the d-line, g-line, C-line, and F-line, respectively. The solid line and broken line in the astigmatism diagram show the astigmatism in the sagittal image plane (ΔS) and the meridional image plane (ΔM), respectively. The distortion diagram shows the distortion in the d-line. The two-dot chain line, one-dot chain line, and broken line in the chromatic aberration diagram show the lateral chromatic aberration in the g-line, C-line, and F-line, respectively. The astigmatism and lateral chromatic aberration show the aberration amount when the ray passing through the center of the light beam at the position of the aperture stop SP is taken as the chief ray. ω is the paraxial half field angle (°), and Fno is the F-number. The spherical aberration diagram is shown at a scale of 0.4 mm, the astigmatism diagram is shown at a scale of 0.4 mm, the distortion diagram is shown at a scale of 10%, and the chromatic aberration diagram is shown at a scale of 0.1 mm.

[0040] The explanations regarding the cross-sectional view and longitudinal aberration diagram of the zoom lens in this embodiment are the same in the following embodiments.

Embodiment

[0041] Fig. 3 shows a cross-section at the wide-angle end in the infinity focus state of the zoom lens 1b of Example 2 (numerical example 2).

[0042] The zoom lens 1b is composed of a first lens group L1 with a positive refractive power, a second lens group L2 with a negative refractive power, a third lens group L3 with a negative refractive power, a diaphragm SP, a fourth lens group L4 with a positive refractive power, and a fifth lens group L5 with a positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move during zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4 that constitute the intermediate group move during zooming. The fifth lens group L5 is the final lens group for imaging and does not move during zooming.

[0043] The first lens group L1 is composed of a first sub-lens group L11 with a negative refractive power, a second sub-lens group L12 with a positive refractive power, and a third sub-lens group L13 with a positive refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus subgroup that moves from the object side to the image side during focusing from infinity to the closest distance, as indicated by the arrow (FOCUS) in the figure.

[0044] The second lens group L2 corresponds to the object-side negative lens group V and moves to the image side during zooming from the wide-angle end to the telephoto end as a variator. The second lens group L2 is composed of four lenses (three of which form one cemented lens), and the negative lens closest to the object side is an aspherical lens. The fourth lens group L4 moves integrally with the diaphragm SP during zooming. An optical unit such as an extender lens may be inserted into the fifth lens group L5.

[0045] Figure 4(A) shows the longitudinal aberration of the zoom lens 1b in the infinite-focus state and at the wide-angle end, and Figure 4(B) shows the longitudinal aberration of the zoom lens 1b in the infinite-focus state and at the telephoto end.

Example

[0046] Figure 5 shows a cross-section at the wide-angle end of the zoom lens 1c in the infinite-focus state of Example 3 (numerical example 3).

[0047] The zoom lens 1c is composed of a first lens group L1 with a positive refractive power, a second lens group L2 with a negative refractive power, a third lens group L3 with a negative refractive power, a fourth lens group L4 with a positive refractive power, a fifth lens group L5 with a positive refractive power, a diaphragm SP, and a sixth lens group L6 with a positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move during zooming, and the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 that constitute the intermediate group move during zooming. The sixth lens group L6 is the final lens group for imaging and does not move for zooming.

[0048] The first lens group L1 is composed of a first sub-lens group L11 with a negative refractive power, a second sub-lens group L12 with a positive refractive power, a third sub-lens group L13 with a positive refractive power, a fourth sub-lens group L14 with a positive refractive power, and a fifth sub-lens group L15 with a positive refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12, the fourth sub-lens L14, and the fifth sub-lens group L15 are focus subgroups that move along different trajectories with respect to each other when focusing from infinity to the closest distance, as indicated by the arrow (FOCUS) in the figure.

[0049] The second lens group L2 corresponds to the object-side negative lens group V and moves toward the image side when zooming from the wide-angle end to the telephoto end as a variator. The second lens group L2 is composed of four lenses (two of which form a single cemented lens), and the negative lens closest to the object side is an aspherical lens. An optical unit such as an extender lens may be inserted into the sixth lens group L6.

[0050] Figure 6(A) shows the longitudinal aberration of the zoom lens 1c in the infinity focus state and at the wide-angle end, and Figure 6(B) shows the longitudinal aberration of the zoom lens 1b in the infinity focus state and at the telephoto end.

Example

[0051] Figure 7 shows a cross-section at the wide-angle end in the infinity focus state of the zoom lens 1d of Example 4 (numerical example 4).

[0052] The zoom lens 1d is composed of a first lens group L1 with a positive refractive power, a second lens group L2 with a negative refractive power, a third lens group L3 with a negative refractive power, an aperture stop SP, a fourth lens group L4 with a positive refractive power, and a fifth lens group L5 with a positive refractive power, which are arranged in order from the object side to the image side. The first lens group L1 does not move during zooming. The second lens group L2, the third lens group L3, and the fourth lens group L4, which constitute the intermediate group, move during zooming. The fifth lens group L5 is the final lens group for imaging and does not move during zooming.

[0053] The first lens group L1 is composed of a first sub-lens group L11 with a negative refractive power, a second sub-lens group L12 with a positive refractive power, and a third sub-lens group L13 with a positive refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus subgroup that moves from the object side to the image side during focusing from infinity to the closest distance, as indicated by the arrow (FOCUS) in the figure.

[0054] The second lens group L2 corresponds to the object-side negative lens group V and moves toward the image side during zooming from the wide-angle end to the telephoto end as a variator. The second lens group L2 is composed of four lenses (two of which form one cemented lens), and the most object-side negative lens is an aspherical lens. In this embodiment, the second lens group L2 corresponds to the object-side negative lens group V. The fourth lens group L4 moves integrally with the aperture stop SP during zooming. An optical unit such as an extender lens may be inserted into the fifth lens group L5.

[0055] FIG. 8(A) shows the longitudinal aberration of the zoom lens 1d in the infinity-focus state and at the wide-angle end, and FIG. 8(B) shows the longitudinal aberration of the zoom lens 1d in the infinity-focus state and at the telephoto end.

Example

[0056] FIG. 9 shows a cross-section at the wide-angle end in the infinity-focus state of the zoom lens 1e of Example 5 (numerical example 5).

[0057] The zoom lens 1e is composed of a first lens group L1 with a positive refractive power, a second lens group L2 with a negative refractive power, a third lens group L3 with a negative refractive power, an aperture stop SP, a fourth lens group L4 with a positive refractive power, a fifth lens group L5 with a positive refractive power, and a sixth lens group with a positive refractive power, which are arranged in order from the object side to the image side. G is an optical block such as a prism or an optical filter.

[0058] The first lens group L1 does not move during zooming. The second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 that constitute the intermediate group move during zooming. The sixth lens group L6 is the final lens group for imaging and does not move during zooming.

[0059] The first lens group L1 is composed of a first sub-lens group L11 with a negative refractive power, a second sub-lens group L12 with a positive refractive power, and a third sub-lens group L13 with a positive refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus subgroup that moves from the object side to the image side during focusing from infinity to the closest distance, as indicated by the arrow (FOCUS) in the figure.

[0060] The second lens group L2 corresponds to the object-side negative lens group V and moves toward the image side during zooming from the wide-angle end to the telephoto end as a variator. The second lens group L2 is composed of five lenses (two of which form a single cemented lens), and the negative lens closest to the object side is an aspherical lens. The fourth lens group L4 moves integrally with the aperture stop SP during zooming. An optical unit such as an extender lens may be inserted into the sixth lens group L6.

[0061] Figure 10(A) shows the longitudinal aberration of the zoom lens 1e in the infinity focus state and at the wide-angle end, and Figure 10(B) shows the longitudinal aberration of the zoom lens 1e in the infinity focus state and at the telephoto end.

Example

[0062] FIG. 11 shows a cross section at the wide-angle end in the infinity focus state of the zoom lens 1f of Example 6 (numerical example 6).

[0063] The zoom lens 1f is composed of a first lens group L1 having a positive refractive power, a second lens group L2 having a negative refractive power, a third lens group L3 having a negative refractive power, a fourth lens group L4 having a positive refractive power, an aperture stop SP, and a fifth lens group L5 having a positive refractive power, which are arranged in order from the object side to the image side. G is an optical block such as a prism or an optical filter.

[0064] The first lens group L1 does not move during zooming, and the second lens group L2, the third lens group L3, and the fourth lens group L4 that constitute the intermediate group move during zooming. The fifth lens group L5 is the final lens group for imaging and does not move during zooming.

[0065] The first lens group L1 is composed of a first sub-lens group L11 having a negative refractive power, a second sub-lens group L12 having a positive refractive power, and a third sub-lens group L13 having a positive refractive power, which are arranged in order from the object side to the image side. The second sub-lens group L12 is a focus subgroup that moves from the object side to the image side during focusing from infinity to the closest distance as indicated by the arrow (FOCUS) in the figure.

[0066] The second lens group L2 corresponds to the object-side negative lens group V and moves to the image side during zooming from the wide-angle end to the telephoto end as a variator. The second lens group L2 is composed of five lenses (two of which form one cemented lens), and the negative lens closest to the object side is an aspherical lens. An optical unit such as an extender lens may be inserted into the fifth lens group L5.

[0067] Hereinafter, numerical examples 1 to 6 are shown. In each numerical example, the surface number i is the order of the surfaces from the object side, r is the radius of curvature (mm) of the i-th surface, and d is the distance on the optical axis between the i-th surface and the (i + 1)-th surface (mm). The part where the interval d is (variable) changes during zooming, and a separate table shows the intervals corresponding to the focal lengths.

[0068] nd is the refractive index at the d-line of the optical material between the i-th surface and the (i + 1)-th surface (absolute refractive index at 1 atmosphere). 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. θgF is the partial dispersion ratio between the g-line and the F-line of the optical material between the i-th surface and the (i + 1)-th surface.

[0069] In addition, each numerical example shows the half field angle (°) of the zoom lens, in addition to specifications such as the focal length and F-number of the zoom lens. BF is the back focus, indicating the air-equivalent length from the most image-side surface (the final surface) of the zoom lens to the image plane. The overall lens length is the distance from the most object-side surface (the frontmost surface) of the zoom lens to the final surface plus the back focus.

[0070] The "*" attached to the surface number means that the surface has an aspherical shape. The aspherical shape is represented by the following formula 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 perpendicular to the optical axis, the light propagation direction is positive, R is the paraxial curvature radius, k is the conic constant, and A3 to A16 are the aspherical coefficients.

[0071]

Number

[0072] "e-X" in the conic constant and aspherical coefficients means "×10 -X ".

[0073] In addition, the lens group data shows the focal length of each lens group. Furthermore, the values of the above formulas (1) to (9) in each numerical example are summarized in Table 1. The zoom lenses in each numerical example satisfy all the conditions of formulas (1) to (9). [Numerical Example 1] Unit: mm Surface Data Surface Number r d nd νd θgF 1* ∞ 2.80 1.80100 35.0 0.5864 2 45.306 26.83 3 -76.888 2.00 1.64000 60.1 0.5370 4 130.776 1.31 5 139.162 8.49 1.95906 17.5 0.6598 6 -402.098 1.19 7 646.982 11.36 1.59522 67.7 0.5442 8* -82.754 5.15 9 514.992 9.73 1.43875 94.7 0.5340 10 -98.376 2.00 1.84666 23.8 0.6205 11 -275.863 0.20 12 194.597 7.32 1.49700 81.5 0.5375 13 -296.206 0.20 14 155.285 2.00 1.80518 25.4 0.6161 15 58.335 17.85 1.43875 94.7 0.5340 16 -162.863 0.20 17 131.230 10.48 1.76385 48.5 0.5589 18 -154.452 (variable) 19* 117.501 1.24 2.05090 26.9 0.6054 20 23.330 7.71 21 -33.594 0.85 1.49700 81.5 0.5375 22 35.319 5.34 1.85478 24.8 0.6122 23 -49.243 1.51 24 -28.530 1.00 1.88300 40.8 0.5667 25 -55.566 (variable) 26 -34.067 0.80 1.59522 67.7 0.5442 27 73.984 2.39 1.85896 22.7 0.6284 28 344.383 (Variable) 29* 73.879 5.01 1.89190 37.1 0.5780 30 -161.379 (Variable) 31 86.610 1.10 2.00069 25.5 0.6136 32 40.331 7.35 1.55200 70.7 0.5421 33 -124.178 (Variable) 34 (Aperture) ∞ 1.00 35 126.863 5.96 1.48749 70.2 0.5300 36 -61.210 0.25 37 -184.110 5.67 1.76182 26.5 0.6136 38 -32.960 1.10 2.00100 29.1 0.5997 39 533.450 41.06 40 -677.771 5.71 1.48749 70.2 0.5300 41 -37.548 2.04 42 49.952 7.10 1.80810 22.8 0.6307 43 -40.270 0.90 2.00100 29.1 0.5997 44 36.481 1.73 45 32.405 11.06 1.43875 94.7 0.5340 46 -23.422 1.00 1.88300 40.8 0.5667 47 191.906 0.50 48 52.888 7.16 1.48749 70.2 0.5300 49 -44.634 44.77 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 5.17853e-07 A 6= 5.27289e-10 A 8=-6.93652e-13 A10= 4.72801e-16 A12=-1.88957e-19 A14= 4.12626e-23 A16=-3.82327e-27 The 8th surface K = 0.00000e+00 A 4= 5.70451e-07 A 6= 8.31297e-11 A 8=-8.23396e-14 A10= 1.96459e-16 A12=-2.97759e-19 A14= 2.00949e-22 A16=-5.03199e-26 The 19th surface K = 0.00000e+00 A 4= 3.75208e-06 A 6=-2.79727e-09 A 8= 1.59700e-11 A10=-7.27063e-14 A12= 1.95147e-16 The 29th surface K = 0.00000e+00 A 4=-1.64984e-06 A 6= 5.45725e-10 A 8=-3.16916e-13 Various data Zoom ratio 8.22 Wide angle, medium, telephoto Focal length 15.08 58.04 124.02 F number 2.72 2.72 3.77 Half field angle (°) 44.46 14.30 6.81 Image height 14.80 14.80 14.80 Overall lens length 340.03 340.03 340.03 BF 44.77 44.77 44.77 d18 0.99 38.95 48.44 d25 33.07 2.45 2.31 d28 17.89 15.68 1.16 d30 6.17 2.39 1.50 d33 1.50 0.14 6.21 Lens group data Group start surface focal length 1 1 41.26 2 19 -26.27 3 26 -60.84 4 29 57.40 5 31 203.83 6 34 119.33 [Numerical example 2] Unit: mm Surface data Surface number r d nd νd θgF 1* 10000.000 2.58 1.80400 46.5 0.5577 2 32.590 14.26 3 93.927 1.65 1.88300 40.8 0.5667 4 44.959 18.42 5 -43.953 1.65 1.77250 49.6 0.5520 6 -71.542 5.77 7 565.785 7.99 1.89286 20.4 0.6393 8 -117.933 1.61 9 115.176 9.95 1.49700 81.5 0.5375 10* -159.676 11.65 11 -2566.642 9.34 1.43875 94.7 0.5340 12 -64.155 2.00 2.00100 29.1 0.5997 13 -74.025 0.20 14 104.797 1.84 1.96300 24.1 0.6212 15 47.782 11.71 1.49700 81.5 0.5375 16 -121.878 0.50 17 148.537 8.00 1.49700 81.5 0.5375 18 - 140.367 (variable) 19 * 107.996 1.20 2.05090 26.9 0.6054 20 28.944 5.00 21 - 82.229 0.83 1.49700 81.5 0.5375 22 28.282 4.39 1.85478 24.8 0.6122 23 - 296.990 0.83 1.76385 48.5 0.5589 24 103.912 (variable) 25 - 46.645 0.83 1.88300 40.8 0.5667 26 73.071 2.06 1.92286 18.9 0.6495 27 - 2265.947 (variable) 28 (aperture) ∞ 1.00 29 * 36.924 3.81 1.69680 55.5 0.5434 30 274.187 (variable) 31 92.171 1.11 2.00069 25.5 0.6136 32 35.401 5.63 1.51823 58.9 0.5457 33 - 87.881 35.00 34 87.968 4.90 1.49700 81.5 0.5375 35 - 46.509 0.37 36 416.555 3.77 1.92286 18.9 0.6495 37 - 49.455 0.83 1.91650 31.6 0.5911 38 262.820 10.00 39 51.195 6.72 1.43875 94.7 0.5340 40 - 26.203 0.92 2.00100 29.1 0.5997 41 82.576 0.65 42 38.677 6.56 1.48749 70.2 0.5300 43 -70.233 38.98 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 4.18291e-06 A 6=-2.97629e-09 A 8= 2.26460e-12 A10=-1.23261e-15 A12= 3.82334e-19 A14=-3.82317e-23 A16=-4.93139e-27 Tenth surface K = 0.00000e+00 A 4= 1.39531e-06 A 6=-2.83059e-10 A 8= 1.22795e-13 A10=-1.02418e-16 A12= 3.09917e-20 Nineteenth surface K = 0.00000e+00 A 4=-7.21477e-07 A 6=-2.32086e-09 A 8= 1.93226e-11 A10=-1.16522e-13 A12= 2.44693e-16 Twenty-ninth surface K = 0.00000e+00 A 4=-5.27893e-06 A 6= 9.60956e-10 A 8=-3.16459e-12 Various data Zoom ratio 4.00 Wide angle Middle Telephoto Focal length 12.50 27.91 49.99 F-number 2.69 2.69 3.09 Half field angle (°) 49.82 27.94 16.49 Image height 14.80 14.80 14.80 Overall lens length 291.28 291.28 291.28 BF 38.98 38.98 38.98 d18 0.50 26.13 37.11 d24 16.64 3.63 6.85 d27 19.96 13.83 1.29 d30 9.66 3.18 1.51 Lens group data Group start surface Focal length 1 1 27.64 2 19 -36.85 3 25 -55.68 4 28 60.84 5 31 70.49 [Numerical example 3] Unit: mm Surface data Surface number r d nd νd θgF 1 -298.726 1.60 1.89190 37.1 0.5780 2 147.923 2.01 3 158.765 4.92 1.98612 16.5 0.6657 4 287.958 2.39 5 280.011 11.22 1.49700 81.5 0.5375 6* -185.843 9.43 7 179.212 2.10 1.85478 24.8 0.6122 8 87.572 0.27 9 89.176 11.76 1.53775 74.7 0.5392 10 -747.731 7.19 11 106.075 8.53 1.53775 74.7 0.5392 12 2546.824 1.00 13 92.547 8.34 1.61800 63.3 0.5426 14 866.235 (Variable) 15* 412.405 1.20 2.05090 26.9 0.6054 16 24.508 7.25 17 -38.635 0.80 1.52841 76.5 0.5396 18 30.110 6.51 1.85478 24.8 0.6122 19 -42.813 2.20 20 -27.265 0.75 1.76385 48.5 0.5589 21 -239.767 (variable) 22 -55.914 0.90 1.88300 40.8 0.5667 23 94.395 3.48 1.85478 24.8 0.6122 24 -149.521 (variable) 25* 74.801 6.89 1.76385 48.5 0.5589 26 -98.208 (variable) 27 107.857 1.20 1.85478 24.8 0.6122 28 37.690 7.11 1.59522 67.7 0.5442 29 -361.701 (variable) 30 (aperture) ∞ 1.00 31 275.057 4.41 1.53775 74.7 0.5392 32 -132.095 7.31 33 -77.008 2.00 1.88300 40.8 0.5667 34 -216.738 43.69 35 76.510 6.85 1.55200 70.7 0.5421 36 -62.564 6.44 37 48.673 7.98 1.89286 20.4 0.6393 38 -37.719 1.00 2.05090 26.9 0.6054 39 37.396 2.76 40 97.544 7.35 1.48749 70.2 0.5300 41 -25.465 0.90 1.89190 37.1 0.5780 42 174.494 0.51 43 38.737 8.55 1.48749 70.2 0.5300 44 -35.456 0.95 2.00069 25.5 0.6136 45 -55.422 37.99 Image plane ∞ Aspherical data The 6th surface K = -5.68862e-01 A4 = 5.47754e-08 A6 = -1.24236e-12 A8 = -1.07816e-15 The 15th surface K = 1.92279e+00 A4 = 3.81337e-06 A6 = -2.75045e-09 A8 = 1.48101e-11 A10 = -4.33253e-14 A12 = 8.22883e-17 The 25th surface K = 2.00015e+00 A4 = -2.15756e-06 A6 = 1.15981e-10 A8 = -1.57896e-13 Various data Zoom ratio 11.51 Wide angle Middle Telephoto Focal length 24.92 89.42 286.96 F-number 2.73 2.73 4.18 Half field angle (°) 30.70 9.40 2.95 Image height 14.80 14.80 14.80 Overall lens length 318.17 318.17 318.17 BF 37.99 37.99 37.99 d14 1.00 38.59 54.70 d21 53.98 2.00 2.01 d24 7.03 21.18 1.16 d26 5.73 5.27 1.50 d29 1.72 2.42 10.09 Lens group data Group starting surface focal length 1 1 83.13 2 15 -19.43 3 22 -98.42 4 25 56.56 5 27 369.96 6 30 133.92 [Numerical example 4] Unit: mm Surface data Surface number r d nd νd θgF 1* 1000.000 2.60 1.78800 47.4 0.5559 2 32.299 23.71 3 -90.802 1.90 1.76385 48.5 0.5589 4 90.802 7.17 5 120.800 8.39 1.84666 23.8 0.6205 6 -305.584 1.50 7* 133.699 12.35 1.59522 67.7 0.5442 8 -82.940 10.44 9 1725.489 2.10 1.80518 25.4 0.6161 10 55.871 9.41 1.43875 94.7 0.5340 11 203.972 0.20 12 118.020 15.03 1.72916 54.7 0.5444 13 -67.209 (variable) 14* 205.547 1.25 2.05090 26.9 0.6054 15 48.364 4.59 16 -203.099 1.25 1.59522 67.7 0.5442 17 56.505 5.21 1.95906 17.5 0.6598 18 387.830 5.28 19 -43.707 1.25 1.88300 40.8 0.5667 20 -72.099 (Variable) 21 -103.496 1.40 1.43875 94.7 0.5340 22 1152.733 (Variable) 23 (Aperture) ∞ 1.00 24 74.231 6.01 1.80610 40.9 0.5713 25* -252.102 (Variable) 26 34.472 5.90 1.51633 64.1 0.5353 27 72.860 3.50 28 59.699 1.30 2.00100 29.1 0.5997 29 29.646 11.36 1.43875 94.7 0.5340 30 -70.883 0.45 31 134.895 9.65 1.80810 22.8 0.6307 32 -31.578 1.30 2.00100 29.1 0.5997 33 -190.743 0.91 34 84.793 1.20 2.00100 29.1 0.5997 35 23.466 7.31 1.49700 81.5 0.5375 36 71.932 2.10 37 35.085 5.57 1.49700 81.5 0.5375 38 92.149 51.99 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 3.58870e-06 A 6=-2.14135e-09 A 8= 1.47525e-12 A10=-8.12339e-16 A12= 3.46755e-19 A14=-1.00783e-22 A16= 1.44431e-26 The 7th side K = 0.00000e+00 A 4=-2.10391e-06 A 6= 7.90945e-10 A 8=-1.74703e-12 A10= 3.45388e-15 A12=-4.08574e-18 A14= 2.61795e-21 A16=-6.95832e-25 The 14th side K =-7.36061e-01 A 4= 7.22343e-08 A 6=-1.52191e-10 A 8= 1.09496e-12 A10=-2.08267e-15 A12= 1.14680e-18 The 25th side K = 0.00000e+00 A 4= 1.47861e-06 A 6= 2.63873e-10 A 8=-3.53362e-13 Various data Zoom ratio 2.50 Wide angle, medium, telephoto Focal length 20.00 35.00 49.99 F-number 2.30 2.30 2.30 Half field angle (°) 49.24 33.54 24.89 Image height 23.20 23.20 23.20 Overall lens length 286.93 286.93 286.93 BF 51.99 51.99 51.99 d13 1.40 36.36 53.55 d20 30.44 3.04 1.55 d22 3.26 10.42 3.26 d25 27.26 12.55 3.99 Lens group data Group, starting surface, focal length 1 1 51.49 2 14 -40.47 3 21 -216.38 4 23 71.73 5 26 91.86 [Numerical Example 5] Unit: mm Surface data Surface number r d nd νd θgF 1* 208.829 2.50 1.83481 42.7 0.5648 2 42.979 20.22 3* -146.676 2.00 1.89190 37.1 0.5780 4 133.898 0.15 5 89.888 5.94 1.95906 17.5 0.6598 6 396.326 3.12 7 285.020 9.53 1.59522 67.7 0.5442 8* -90.951 8.44 9 -124.552 5.54 1.43387 95.1 0.5373 10 -63.104 0.30 11 -62.877 1.70 1.80000 29.8 0.6017 12 -152.423 0.18 13 114.339 1.70 2.00100 29.1 0.5997 14 61.814 15.48 1.49700 81.5 0.5375 15 -121.372 0.20 16 356.300 10.87 1.43387 95.1 0.5373 17 -76.581 0.20 18 80.452 8.31 1.76385 48.5 0.5589 19 -12653.070 (Variable) 20* 72.226 0.70 2.05090 26.9 0.6054 21 16.800 4.06 22 -155.568 0.70 1.43875 94.7 0.5340 23 42.302 2.72 24 -146.175 5.36 1.85478 24.8 0.6122 25 -15.612 0.70 1.88300 40.8 0.5667 26 74.487 0.43 27 36.672 2.88 1.73800 32.3 0.5900 28 -220.003 (Variable) 29 -30.840 0.80 1.72916 54.7 0.5444 30 49.687 2.38 1.84666 23.8 0.6205 31 1984.632 (Variable) 32 (Aperture) ∞ 1.00 33* 118.953 5.04 1.89190 37.1 0.5780 34 -75.584 (Variable) 35 46.778 5.33 1.51742 52.4 0.5564 36 -98.699 1.00 1.83481 42.7 0.5648 37 105.890 (Variable) 38 56.779 1.00 1.95375 32.3 0.5905 39 24.833 5.63 1.51633 64.1 0.5353 40 -431.483 35.00 41 97.774 6.00 1.63980 34.5 0.5922 42 -44.117 0.80 43 -140.597 0.90 1.88300 40.8 0.5667 44 27.791 5.14 1.55200 70.7 0.5421 45 -178.218 0.50 46 43.965 6.20 1.43875 94.7 0.5340 47 -33.355 0.90 2.00100 29.1 0.5997 48 -64.288 0.50 49 301.737 2.31 1.48749 70.2 0.5300 50 -95.058 4.00 51 ∞ 33.00 1.60859 46.4 0.5664 52 ∞ 13.20 1.51680 64.2 0.5347 53 ∞ 7.45 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4=-7.47662e-06 A 6=-1.47215e-07 A 8=-2.46563e-10 A10= 4.11514e-13 A12= 1.22984e-16 A14=-1.08151e-19 A16=-5.20408e-24 A 3= 2.09871e-05 A 5= 1.42449e-06 A 7= 8.72980e-09 A 9=-2.02602e-12 A11=-1.32062e-14 A13= 3.20728e-18 A15= 1.23717e-21 Third surface K = 0.00000e+00 A 4= 1.01909e-05 A 6= 2.91856e-07 A 8= 2.33150e-09 A10= 6.11514e-12 A12= 2.38406e-15 A14=-1.91675e-18 A16=-2.08863e-22 A 3=-2.52129e-05 A 5=-2.14476e-06 A 7=-2.95677e-08 A 9=-1.40308e-10 A11=-1.75105e-13 A13= 2.93400e-17 A15= 3.29607e-20 Eighth surface K = 0.00000e+00 A 4= 3.94298e-06 A 6=-7.42330e-08 A 8=-1.93707e-09 A10 = -5.79331e-12, A12 = -3.06732e-15, A14 = -6.44985e-19, A16 = -8.11343e-23 A3 = -1.14993e-05, A5 = -1.55382e-07, A7 = 1.74480e-08, A9 = 1.31655e-10 A11 = 1.65574e-13, A13 = 4.17505e-17, A15 = 1.03987e-20 The 20th surface K = 1.55546e+00, A4 = 2.78255e-07, A6 = -4.73484e-10, A8 = -4.37626e-12 The 33rd surface K = -3.93401e+01, A4 = 1.76086e-06, A6 = -2.89485e-09, A8 = 2.28335e-12 Various data Zoom ratio 18.02 Wide angle, intermediate, telephoto Focal length 5.50, 21.02, 99.12 F-number 1.86, 1.86, 2.97 Half field angle (°) 45.00, 14.67, 3.18 Image height 5.50, 5.50, 5.50 Overall lens length 324.65, 324.65, 324.65 BF 7.45, 7.45, 7.45 d19 0.65, 36.44, 52.33 d28 35.32, 3.10, 16.62 d31 18.13, 21.19, 1.24 d34 17.56, 1.00, 1.00 d37 1.00, 10.92, 1.45 Lens group data Group, starting surface, focal length 1, 1, 40.24 2, 20, -18.35 3, 29, -46.09 4 32 52.46 5 35 2340.64 6 38 49.70 [Numerical Example 6] Unit: mm Surface data Surface number r d nd νd θgF 1* 1658.310 2.50 1.83481 42.7 0.5648 2 31.052 17.12 3* 165.877 2.00 1.83481 42.7 0.5648 4 86.855 9.99 5 -94.683 1.80 1.83481 42.7 0.5648 6 -532.838 0.15 7 94.232 4.27 1.92286 18.9 0.6495 8 357.216 1.71 9 166.608 8.24 1.60300 65.4 0.5401 10* -97.414 4.41 11 -603.969 7.95 1.43387 95.1 0.5373 12 -55.416 0.33 13 -53.264 1.70 1.80000 29.8 0.6017 14 -109.667 0.18 15 168.829 1.70 1.91650 31.6 0.5911 16 53.722 13.56 1.43875 94.7 0.5340 17 -120.939 0.40 18 978.223 9.10 1.43387 95.1 0.5373 19 -66.338 0.40 20 111.808 8.12 1.76385 48.5 0.5589 21 -168.562 (variable) 22* 135.706 0.70 2.05090 26.9 0.6054 23 17.909 3.93 24 -62.560 0.70 1.43875 94.7 0.5340 25 81.625 2.11 26 -164.446 5.71 1.85478 24.8 0.6122 27 -14.283 0.70 1.88300 40.8 0.5667 28 157.961 0.21 29 41.883 2.86 1.73800 32.3 0.5900 30 -191.791 (variable) 31 -32.514 0.80 1.72916 54.7 0.5444 32 45.779 2.59 1.84666 23.8 0.6205 33 2489.967 (variable) 34* 65.079 6.37 1.58913 61.1 0.5407 35 -53.660 (variable) 36 (aperture) ∞ 1.95 37 130.028 5.31 1.51742 52.4 0.5564 38 -45.807 1.00 1.83481 42.7 0.5648 39 -171.417 35.50 40 62.385 5.48 1.63980 34.5 0.5922 41 -50.700 1.53 42 -91.839 0.90 1.88300 40.8 0.5667 43 27.881 5.28 1.48749 70.2 0.5300 44 -140.321 0.20 45 61.712 7.86 1.43875 94.7 0.5340 46 -20.931 0.90 2.00100 29.1 0.5997 47 -54.391 0.13 48 143.444 5.38 1.48749 70.2 0.5300 49 -31.599 4.00 50 ∞ 33.00 1.60859 46.4 0.5664 51 ∞ 13.20 1.51680 64.2 0.5347 52 ∞ 7.45 Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 4.07369e-06 A 6= 1.07123e-08 A 8= 7.80444e-12 A10= 9.49529e-14 A12= 1.11177e-16 A14= 1.85178e-20 A16=-6.42205e-26 A 3= 1.27705e-05 A 5=-1.68113e-07 A 7=-3.07821e-10 A 9=-1.17404e-12 A11=-4.11434e-15 A13=-1.90018e-18 A15=-7.33161e-23 Third surface K = 0.00000e+00 A 4=-2.28149e-06 A 6=-7.50517e-08 A 8=-7.10699e-10 A10=-3.23653e-13 A12= 1.59720e-15 A14=-6.51703e-19 A16=-2.02837e-22 A 3=-1.08050e-05 A 5= 4.35381e-07 A 7= 9.13498e-09 A 9= 3.03383e-11 A11=-3.27445e-14 A13=-1.78369e-17 A15= 2.23156e-20 Tenth surface K = 0.00000e+00 A 4= 1.14792e-06 A 6= 1.37632e-08 A 8= 2.71470e-10 A10 = 2.08439e-13 A12 = -7.68942e-16 A14 = 1.05267e-18 A16 = 2.18868e-22 A3 = -3.26263e-06 A5 = -2.00722e-08 A7 = -2.66909e-09 A9 = -1.44185e-11 A11 = 1.68145e-14 A13 = -4.82496e-18 A15 = -2.63977e-20 The 22nd surface K = 3.26077e+01 A4 = 3.46197e-06 A6 = 4.66573e-08 A8 = -2.68025e-10 A10 = 2.62133e-12 A3 = -2.92893e-06 A5 = -7.62030e-07 A7 = 3.83578e-09 A9 = -3.83807e-11 The 34th surface K = -1.23593e+01 A4 = 1.51830e-06 A6 = -4.16722e-09 A8 = 2.26731e-12 Various data Zoom ratio 13.61 Wide angle, medium, telephoto Focal length 4.43, 15.50, 60.26 F-number 1.86, 1.86, 2.77 Half field angle (°) 51.16, 19.54, 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 d21 0.65, 35.73, 52.42 d30 41.36, 5.66, 4.62 d33 14.46, 17.85, 2.09 d35 7.81, 5.04, 5.15 Lens group data Group, starting surface, focal length 1 1 29.67 2 22 -20.17 3 31 -49.54 4 34 50.93 5 36 52.86

[0074]

Table 1

[0075] (Imaging device) FIG. 13 shows an imaging device using the zoom lens of each embodiment as an imaging optical system. In FIG. 13, 101 is a zoom lens of any one of Embodiments 1 to 6. 124 is 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.

[0076] The zoom lens 101 includes a first lens group F, a zoom unit LZ, and an imaging lens group R. The first lens group F includes a focus subgroup that moves during focusing.

[0077] The zoom unit LZ includes at least three or more lens groups that move during zooming. On the image side of the zoom unit 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.

[0078] 114 and 115 are respectively drive mechanisms for driving the first lens group F and the zoom unit LZ in the optical axis direction. 116 to 118 are respectively drive units including actuators for driving the drive mechanisms 114 and 115 and the aperture stop SP. 119 to 121 are respectively detection units 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 and 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 respectively CPUs as processing units (control units) in the camera body 124 and the zoom lens 101.

[0079] 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.

[0080] The above embodiments include the following configurations.

[0081] (Configuration 1) A zoom lens having a first lens group with a positive refractive power that does not move during zooming, an intermediate group including at least three lens groups that move during zooming, and a final lens group with a positive refractive power that does not move during zooming, arranged in order from the object side to the image side, and in which the interval between adjacent lens groups changes during zooming, The intermediate group includes at least one lens group with a negative refractive power, Among the at least one lens group with a negative refractive power, the lens group with the most negative refractive power on the object side includes at least one negative lens, When the refractive index of the most object-side negative lens among the at least one negative lens on the d-line is nn, the Abbe number based on the d-line of the most object-side negative lens is νn, the focal length of the first lens group is f1, and the focal length at the wide-angle end of the zoom lens is fw, 2.02 ≦ nn ≦ 2.30 20.0 ≦ νn ≦ 40.0 1.5 ≤ f1 / fw ≤ 7.7 A zoom lens characterized by satisfying the following condition. (Configuration 2) When the focal length of the most object-side negative lens is fn and the focal length of the lens group with the most object-side negative refractive power is fV, 0.7 ≤ fn / fV ≤ 2.0 The zoom lens according to Configuration 1, characterized by satisfying the following condition. (Configuration 3) When the partial dispersion ratio of the most object-side negative lens in the g-line and F-line is θn, 0.63 ≤ θn + 0.00162 × νn ≤ 0.70 The zoom lens according to Configuration 1 or 2, characterized by satisfying the following condition. (Configuration 4) The zoom lens according to any one of Configurations 1 to 3, characterized in that the most object-side negative lens is an aspherical lens. (Configuration 5) The zoom lens according to any one of Configurations 1 to 4, characterized in that the lens group with the most object-side negative refractive power has at least 4 lenses. (Configuration 6) When the at least one negative lens has an Abbe number ν based on the d-line, 60 ≤ ν ≤ 100 The zoom lens according to any one of Configurations 1 to 5, characterized by including a negative lens that satisfies the following condition. (Configuration 7) Let the average value of the Abbe number based on the d-line of at least one positive lens included in the lens group with the most object-side negative refractive power be νp ave , the average value of the partial dispersion ratio of the at least one positive lens in the g-line and F-line be θp ave , the average value of the Abbe number based on the d-line of the at least one negative lens be νn ave , and the average value of the partial dispersion ratio of the at least one negative lens in the g-line and F-line be θn ave When, -0.0040 ≤ (θp ave - θn ave ) / (νpave -νn ave )<0.0000 A zoom lens according to any one of Configurations 1 to 6, characterized by satisfying the condition. (Configuration 8) When the focal length of the lens group with the most negative refractive power on the object side is fV, -5.5 ≦ fV / fw ≦ -0.3 A zoom lens according to any one of Configurations 1 to 7, characterized by satisfying the condition. (Configuration 9) A zoom lens according to any one of Configurations 1 to 8, characterized in that a part of the first lens group moves for focusing. (Configuration 10) A zoom lens according to any one of Configurations 1 to 9, and An imaging device comprising an imaging element that images an object through the zoom lens. (Configuration 11) When the diagonal length of the effective imaging surface of the imaging element is IS, 0.2 ≦ fw / IS The imaging device according to Configuration 10, characterized by satisfying the condition.

[0082] 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.

Description of Reference Numerals

[0083] L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group L5 Fifth lens group L6 Sixth lens group

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, an intermediate group including at least three lens groups that move during zooming, and a final lens group with a positive refractive power that does not move during zooming, and in which the distance between adjacent lens groups changes during zooming, the intermediate group includes at least one lens group with a negative refractive power, among the at least one lens group with a negative refractive power, the lens group with the most negative refractive power on the object side includes at least one negative lens, when the refractive index of the most object-side negative lens among the at least one negative lens on the d-line is nn, the Abbe number based on the d-line of the most object-side negative lens is νn, the focal length of the first lens group is f1, and the focal length at the wide-angle end of the zoom lens is fw, 2.02 ≤ nn ≤ 2.30 20.0 ≤ νn ≤ 40.0 1.5 ≤ f1 / fw ≤ 7.7 A zoom lens characterized by satisfying the following conditions.

2. When the focal length of the most object-side negative lens is fn and the focal length of the lens group with the most negative refractive power on the object side is fV, 0.7 ≤ fn / fV ≤ 2.0 The zoom lens according to claim 1, characterized by satisfying the following conditions.

3. When the partial dispersion ratio of the most object-side negative lens on the g-line and F-line is θn, 0.63 ≤ θn + 0.00162 × νn ≤ 0.70 The zoom lens according to claim 1, characterized by satisfying the following conditions.

4. The zoom lens according to claim 1, characterized in that the most object-side negative lens is an aspherical lens.

5. The zoom lens according to claim 1, wherein the lens group having the most negative refractive power on the object side has at least four lenses.

6. When the Abbe number with respect to the d-line of the at least one negative lens is ν, 60 ≦ ν ≦ 100 The zoom lens according to claim 1, comprising a negative lens that satisfies the condition.

7. Let the average value of the Abbe number with respect to the d-line of at least one positive lens included in the lens group having the most negative refractive power on the object side be νp ａｖｅ , the average value of the partial dispersion ratios in the g-line and F-line of the at least one positive lens be θp ａｖｅ , the average value of the Abbe number with respect to the d-line of the at least one negative lens be νn ａｖｅ , the average value of the partial dispersion ratios in the g-line and F-line of the at least one negative lens be θn ａｖｅ When, −0.0040 ≦ (θp ａｖｅ −θn ａｖｅ ) / (νp ａｖｅ −νn ａｖｅ ) < 0.0000 The zoom lens according to claim 1, which satisfies the condition.

8. When the focal length of the lens group having the most negative refractive power on the object side is fV, −5.5 ≦ fV / fw ≦ −0.3 The zoom lens according to claim 1, which satisfies the condition.

9. The zoom lens according to claim 1, wherein a part of the first lens group moves for focusing.

10. The zoom lens according to claim 1, and An imaging device having an imaging element that images a subject through the zoom lens.

11. When the diagonal length of the effective imaging surface of the imaging element is IS, 0.2 ≤ fw / IS ≤ 2.2 The imaging device according to claim 10, characterized in that it satisfies the condition:

Images