Zoom lens and imaging device having the same

The zoom lens design addresses the challenge of achieving compactness and high optical performance by optimizing refractive power and lens group spacing, particularly in the third lens group, resulting in a lightweight lens with improved aberration correction across the zoom range.

JP7757510B2Active Publication Date: 2025-10-21CANON KK
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Patent Information

Application Number
JP2024219519
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Filing Date
2024-12-16
Publication Date
2025-10-21
Estimated Expiration
2041-01-07

AI Technical Summary

Technical Problem

Existing zoom lenses face challenges in achieving a compact and lightweight design while maintaining high optical performance across the entire zoom range due to inappropriate refractive power and lens configuration, particularly in the third lens group, leading to significant aberration fluctuations during zooming.

Method used

A zoom lens configuration with specific refractive power arrangements and lens group spacing changes during zooming, including a third lens group composed of a positive and negative meniscus lens, along with conditional expressions to optimize lens dimensions and materials, ensuring a telephoto-type power arrangement at the telephoto end.

Benefits of technology

The solution enables a small, lightweight zoom lens with excellent optical performance throughout the entire zoom range by effectively correcting various aberrations, including spherical and chromatic aberrations.

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Patent Text Reader

Abstract

To provide a small and lightweight zoom lens which has high optical performance over the entire zoom range.SOLUTION: A zoom lens (1a) has a first lens group (L1) of positive refractive power, a second lens group (L2) of negative refractive power, a third lens group (L3) of positive refractive power, a fourth lens group (L4) of the positive refractive power, and a fifth lens group of the negative refractive power that are arranged from an object side to an image side, and a gap between adjacent lens groups changes when zooming from a wide angle end to a telephoto end. In zooming from the wide angle end to the telephoto end, the gap between the first lens group and the second lens group widens, a gap between the second lens group and the third lens group narrows, and a gap between the third lens group and the fourth lens group narrows. The third lens group comprises a positive lens and a negative lens arranged from the object side to the image side in order. An entire optical length TLt of the zoom lens at the telephoto end, a focus distance ft of the zoom lens at the telephoto end, and a focus distance f3 of the third lens group satisfy a prescribed conditional expression.SELECTED DRAWING: Figure 1
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Description

[Technical Field]

[0001] The present invention relates to an optical system, and more particularly to a zoom lens for a silver halide film camera, a digital still camera, a video camera, a digital video camera, or the like, and an imaging device having the same. [Background technology]

[0002] In recent years, imaging devices such as digital cameras and video cameras have adopted high-pixel imaging elements. The optical systems used in such imaging devices are required to have excellent correction of various aberrations, high optical performance across the entire image field, and to be small and lightweight.

[0003] 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 positive refractive power, a fourth lens group with positive refractive power, a fifth lens group with negative refractive power, and a sixth lens group with positive refractive power. In this zoom lens, the third lens group is composed of two lenses: a positive lens and a negative meniscus lens that is convex toward the image side.

[0004] 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 negative refractive power. In this zoom lens, the third lens group is composed of two lenses: a positive lens and a negative meniscus lens that is convex toward the object side. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-209347 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-97322 Summary of the Invention [Problem to be solved by the invention]

[0006] In general, to reduce the size of a zoom lens, it is effective to adopt a telephoto-type power arrangement at the telephoto end, strengthening the positive refractive power on the object side and the negative refractive power on the image side. However, strengthening the refractive power of each lens group increases the fluctuations in various aberrations that occur during zooming, making it difficult to effectively correct various aberrations with a small number of lens elements. For this reason, to achieve both a compact and lightweight optical system, it is important to appropriately set the refractive power and lens configuration of each lens group.

[0007] However, in the zoom lenses disclosed in Patent Documents 1 and 2, the refractive power and lens configuration of the third lens group are inappropriate, making it difficult to realize a small and lightweight zoom lens.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a small, lightweight zoom lens and an imaging device that have high optical performance over the entire zoom range. [Means for solving the problem]

[0009] A zoom lens according to one aspect of the present invention has, arranged in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power, and the distance between adjacent lens groups changes during zooming from the wide-angle end to the telephoto end, and during zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the distance between the third lens group and the fourth lens group decreases. ,before the third lens group comprises a positive lens and a negative lens arranged in this order from the object side to the image side, the negative lens has a meniscus shape convex toward the image side, The total optical length TLt of the zoom lens at the telephoto end, the focal length ft of the zoom lens at the telephoto end, and the focal length f3 of the third lens group , the radii of curvature Rpf and Rpr of the object-side lens surface and the image-side lens surface of the negative lens satisfies a predetermined conditional expression.

[0010] Other objects and features of the present invention are illustrated in the following examples. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a small, lightweight zoom lens and an imaging device that have high optical performance over the entire zoom range. [Brief explanation of the drawings]

[0012] [Figure 1] 1A and 1B are cross-sectional views of a zoom lens according to a first embodiment at a wide-angle end and a telephoto end. [Figure 2] 3A to 3C are longitudinal aberration diagrams of the zoom lens in Example 1 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 3] 10A and 10B are cross-sectional views of a zoom lens according to a second embodiment at a wide-angle end and a telephoto end. [Figure 4] 10A to 10C are longitudinal aberration diagrams of the zoom lens in Example 2 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 5] 10A and 10B are cross-sectional views of a zoom lens according to a third embodiment at a wide-angle end and a telephoto end. [Figure 6] 10A to 10C are longitudinal aberration diagrams of the zoom lens in Example 3 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 7] 10A and 10B are cross-sectional views of a zoom lens according to a fourth embodiment at a wide-angle end and a telephoto end. [Figure 8] 10A to 10C are longitudinal aberration diagrams of the zoom lens in Example 4 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 9] 10A and 10B are cross-sectional views of a zoom lens at a wide-angle end and a telephoto end in a fifth embodiment. [Figure 10] 10A to 10C are longitudinal aberration diagrams of the zoom lens in Example 5 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 11] 13A and 13B are cross-sectional views of a zoom lens according to a sixth embodiment at a wide-angle end and a telephoto end. [Figure 12] 13A to 13C are longitudinal aberration diagrams of the zoom lens in Example 6 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 13]FIG. 10 is a diagram showing the relationship between the Abbe number and the partial dispersion ratio in each example. [Figure 14] 1 is a schematic diagram of an imaging device equipped with a zoom lens in each embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0014] 1, 3, 5, 7, 9, and 11 are cross-sectional views of zoom lenses (optical systems) 1a to 1f of Examples 1 to 6, respectively, when focused at infinity (infinity focused state). The zoom lenses of each Example are imaging optical systems used in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, silver halide film cameras, and surveillance cameras, as well as optical instruments including interchangeable lenses.

[0015] In each cross-sectional view, the left side is the object side (front) and the right side is the image side (rear). The zoom lens of each embodiment is composed of multiple lens groups. In each embodiment, a lens group is a group of lenses that move together or are stationary during zooming. In the zoom lens of each embodiment, the spacing between adjacent lens groups changes when the lens is zoomed from the wide-angle end to the telephoto end. The wide-angle end and the telephoto end are zoom states when the lens group that moves during zooming is located at both ends of the range of movement along the optical axis OA (optical axis direction) due to its mechanism. Note that the lens group may be composed of one lens or multiple lenses. The lens group may also include an aperture stop.

[0016] In each cross-sectional view, i (a natural number) indicates the order counted from the object side, and Li indicates the ith lens group. SP is an aperture stop. IP is an image plane, and when the zoom lenses 1a to 1f of each embodiment are used as imaging optical systems for digital video cameras or digital still cameras, the imaging surface of a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor is disposed on the image plane IP. When the optical systems 1a to 1f of each embodiment are used as imaging optical systems for silver halide film cameras, the photosensitive surface of the film is disposed on the image plane IP. In the zoom lenses 1a to 1f of each embodiment, when zooming from the wide-angle end to the telephoto end, each lens group moves as shown by the solid arrow in each cross-sectional view.

[0017] 2, 4, 6, 8, 10, and 12 are longitudinal aberration diagrams of the zoom lenses 1a to 1f of Examples 1 to 6, respectively. In each aberration diagram, (A) shows the longitudinal aberration diagram at the wide-angle end and in a state where the focus is on infinity, (B) shows the longitudinal aberration diagram at the intermediate zoom position and in a state where the focus is on infinity, and (C) shows the longitudinal aberration diagram at the telephoto end and in a state where the focus is on infinity.

[0018] In the spherical aberration diagram, Fno is the F-number, and the amount of spherical aberration for the d-line (wavelength 587.6 nm) and g-line (wavelength 435.8 nm) is shown by the solid line and the two-dot chain line, respectively. In the astigmatism diagram, ΔS is the amount of astigmatism on the sagittal image plane (solid line), and ΔM is the amount of astigmatism on the meridional image plane (dashed line). In the distortion diagram, the amount of distortion for the d-line is shown. In the chromatic aberration diagram, the amount of chromatic aberration for the g-line is shown. ω is the half angle of view (°).

[0019] Next, the characteristic configuration and conditions of the zoom lens of each embodiment will be described. The zoom lens of each embodiment has, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and one or more lens groups (rear group LR). When zooming from the wide-angle end to the telephoto end, the distance between the first lens group L1 and the second lens group L2 increases, the distance between the second lens group L2 and the third lens group L3 decreases, and the distance between the third lens group L3 and the fourth lens group L4 decreases, and the rear group LR moves along the optical axis. This configuration results in a telephoto-type power arrangement at the telephoto end when zooming from the wide-angle end to the telephoto end, allowing the overall optical length at the telephoto end (the distance from the object-side surface to the image plane IP) to be reduced. The third lens group L3 is composed of two lenses, a positive lens and a negative lens, arranged in that order from the object side to the image side, which makes it possible to reduce the weight of the third lens group L3 and the entire zoom lens system.

[0020] In each embodiment, in order to obtain a small, lightweight lens with excellent optical performance, it is necessary to satisfy the following conditional expressions (1) and (2).

[0021] 0.50 <TLt / ft<0.69 ···(1) 0.10 <f3 / ft<0.58 ···(2) In conditional expression (1), TLt is the total optical length of the entire zoom lens system at the telephoto end (the distance from the surface closest to the object to the image plane IP), and ft is the focal length of the entire zoom lens system at the telephoto end. In conditional expression (2), f3 is the focal length of the third lens unit L3.

[0022] Conditional expression (1) indicates the ratio (telephoto ratio) between the total optical length and focal length of the zoom lens at the telephoto end. Conditional expression (1) is a conditional expression for achieving a compact, lightweight zoom lens while also achieving good optical performance. If the upper limit of conditional expression (1) is exceeded and the refractive power of the first lens unit L1 becomes weak, the zoom lens becomes large. On the other hand, if the lower limit of conditional expression (1) is exceeded and the refractive power of the first lens unit L1 becomes strong, chromatic aberration becomes noticeable at the telephoto end, making it difficult to maintain optical performance.

[0023] Preferably, the numerical range of conditional expression (1) is set as in the following conditional expression (1a).

[0024] 0.55 <TLt / ft<0.69 ···(1a) Conditional expression (2) represents the ratio between the focal length of the third lens group L3 and the focal length of the zoom lens at the telephoto end. Conditional expression (2) is a conditional expression for appropriately controlling the refractive index of the third lens group L3. If the upper limit of conditional expression (2) is exceeded and the refractive power of the third lens group L3 becomes weak, the zoom lens becomes large. On the other hand, if the lower limit of conditional expression (2) is exceeded and the refractive power of the third lens group L3 becomes strong, spherical aberration becomes large at the wide-angle end, making it difficult to maintain optical performance.

[0025] Preferably, the numerical range of conditional expression (2) is set as in the following conditional expression (2a).

[0026] 0.20 <f3 / ft<0.50 ···(2a) According to each embodiment, by configuring the lens so that conditional expressions (1) and (2) are satisfied, it is possible to realize a small, lightweight telephoto zoom lens that exhibits excellent optical performance throughout the entire zoom range.

[0027] In each embodiment, in order to obtain a more compact, lightweight lens with favorably controlled optical performance, it is preferable to satisfy the following conditional expression (3).

[0028] 0.25 <D3 / LT3<1.00 ···(3) In conditional expression (3), D3 is the distance between the positive lens and the negative lens in the third lens unit L3, and LT3 is the total thickness of the third lens unit L3. Conditional expression (3) is a conditional expression for appropriately setting the distance D3 between the positive lens and the negative lens in the third lens unit L3. If the upper limit of conditional expression (3) is exceeded, it is not possible to physically arrange the positive lens and the negative lens in the third lens unit L3. On the other hand, if the lower limit of conditional expression (3) is exceeded, spherical aberration becomes correctable, making it difficult to maintain optical performance with a two-lens configuration.

[0029] More preferably, the numerical range of conditional expression (3) is set as in the following conditional expression (3a).

[0030] 0.25 <D3 / LT3<0.90 ···(3a) In each embodiment, in order to obtain a more compact, lightweight lens with favorably controlled optical performance, it is preferable to satisfy the following conditional expression (4), where νdp is the Abbe number of the positive lens that constitutes the third lens unit L3.

[0031] νdp>65 (4) Conditional expression (4) indicates the material that has an appropriate Abbe number for the positive lens that constitutes the third lens group L3. Here, the Abbe number νd of a certain material can be expressed as follows, 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:

[0032] νd=(Nd-1) / (NF-NC) (a) If the lower limit of conditional expression (4) is exceeded, achromatism becomes insufficient, making it difficult to correct chromatic aberration.

[0033] More preferably, the numerical range of conditional expression (4) is set as in the following conditional expression (4a).

[0034] νdp>70 (4a) In each embodiment, in order to obtain an even smaller, lighter lens with better controlled optical performance, it is preferable to satisfy the following conditional expression (5), where Ndn is the refractive index at the d-line of the negative lens constituting the third lens unit L3:

[0035] Ndn>1.80 (5) If the lower limit of condition (5) is exceeded, the Petzval sum will become too large in the negative direction, which is undesirable because it will increase off-axis aberrations such as curvature of field.

[0036] More preferably, the numerical range of conditional expression (5) is set as shown in the following conditional expression (5).

[0037] Ndn>1.85 (5a) In each embodiment, in order to obtain an even smaller, lighter lens with better controlled optical performance, it is preferable to satisfy the following conditional expression (6), where νdn is the Abbe number of the negative lens constituting the third lens unit L3 and θgFn is the partial dispersion ratio:

[0038] 25<νdn<45 (6) θgFn-0.6438+0.001682×νdn<0.02 (7) Here, the partial dispersion ratio θgF of a certain material can be expressed as follows, where the refractive indices of the material for the g-line (435.8 nm), F-line (486.1 nm), and C-line (656.3 nm) are Ng, NF, and NC, respectively:

[0039] θgF=(Ng-NF) / (NF-NC) ···(b) Figure 13 is a graph showing the relationship between the Abbe number vd and the partial dispersion ratio θgF. In Figure 13, the horizontal axis represents the Abbe number vd, and the vertical axis represents the partial dispersion ratio θgF. Figure 13 also shows two Ohara Inc. products: PBM2 (vd = 36.26, θgF = 0.5828) and NSL7 (vd = 60.49, θgF = 0.5436). The line connecting these two points is the reference line. For low-dispersion glass, using glass that is located above the reference line is effective for correcting secondary spectra, and the correction effect increases the further away from the reference line.

[0040] Conditions (6) and (7) indicate the material for the negative lens constituting the third lens unit L3 that provides appropriate values ​​for the Abbe number νdn and partial dispersion ratio θgF. Lens materials that have high dispersion but also anomalous dispersion are not effective in correcting chromatic aberration. Lens materials that satisfy conditions (6) and (7) have high dispersion but suppressed anomalous dispersion, and are therefore effective in correcting chromatic aberration.

[0041] If the upper limit of conditional expression (6) is exceeded, the achromatism will be insufficient with a two-lens configuration, making it difficult to correct axial chromatic aberration. On the other hand, if the lower limit of conditional expression (6) is exceeded, the achromatism will be correctable with a two-lens configuration, making it difficult to correct axial chromatic aberration. If the upper limit of conditional expression (7) is exceeded, the anomalous dispersion of the material of the negative lens will increase, making it difficult to correct the secondary spectrum of chromatic aberration with a two-lens configuration.

[0042] More preferably, the numerical ranges of the conditional expressions (6) and (7) are set as shown in the following conditional expressions (6a) and (7a), respectively.

[0043] 25<νdn<35 (6a) θgFn-0.6438+0.001682×νdn<0.01 (7a) In each embodiment, to obtain an even smaller, lighter lens with better optical performance, it is preferable that the negative lens constituting the third lens unit L3 has a meniscus shape convex toward the image side and satisfies the following conditional expression (8):

[0044] -10.0<(Rpf+Rpr) / (Rpf-Rpr)<-1.0 ···(8) In conditional expression (8), Rpf and Rpr are the radii of curvature on the object side and image side, respectively, of the negative lens constituting the third lens unit L3. Conditional expression (8) is a shape factor that indicates the meniscus shape of the negative lens constituting the third lens unit L3. If the upper limit of conditional expression (8) is exceeded, the radius of curvature on the object side of the negative lens becomes small, spherical aberration becomes over-corrected, and it becomes difficult to maintain optical performance. On the other hand, if the lower limit of conditional expression (8) is exceeded, the radius of curvature on the object side of the negative lens becomes large, spherical aberration becomes under-corrected, and it becomes difficult to maintain optical performance.

[0045] More preferably, the numerical range of conditional expression (8) is set as in the following conditional expression (8a).

[0046] -5.0<(Rpf+Rpr) / (Rpf-Rpr)<-1.1 (8a) In each embodiment, to achieve a smaller size and higher optical performance, it is preferable that the fourth lens unit L4 consists of two lenses, arranged in order from the object side to the image side: a positive lens and a positive or negative lens. This configuration makes it possible to reduce the weight of the fourth lens unit L4 and the entire zoom lens system.

[0047] In each embodiment, to achieve a smaller size and higher optical performance, it is preferable that the lens (positive or negative lens) located on the image side of the fourth lens group L4 has an aspherical surface. By locating the aspherical surface in this position, it is possible to reduce fluctuations in spherical aberration during zooming, and to achieve good optical performance even at the periphery of the image.

[0048] In each embodiment, to achieve a smaller size and higher optical performance, it is preferable that the second lens group L2 be a cemented lens consisting of a negative lens and a positive lens arranged in that order from the object side to the image side. This configuration allows the chromatic aberration of the second lens group L2 to be appropriately controlled, correcting the chromatic aberration and achieving good optical performance. Furthermore, by moving the second lens group L2 in a direction that includes a component perpendicular to the optical axis OA, fluctuations in chromatic aberration can be suppressed during image stabilization.

[0049] In each embodiment, to achieve even smaller size and higher optical performance, it is preferable that the rear group LR include a fifth lens unit L5 with negative refractive power. With this configuration, when a telephoto type power arrangement is adopted at the telephoto end, the negative refractive power on the image side can be strengthened, and the overall optical length can be reduced.

[0050] In each embodiment, to achieve even smaller size and higher optical performance, it is preferable that the fifth lens unit L5 with negative refractive power in the rear group LR performs focusing from infinity to a close distance. By using a lens unit behind (on the image side of) the aperture stop SP, which has a small magnification change effect, as the focus lens unit, it is possible to reduce the change in image magnification when focusing from infinity to a close distance. This is particularly suitable for video shooting, as it reduces the change in the angle of view when the subject changes from infinity to a close distance.

[0051] The image-side positive or negative lens in the fourth lens group L4 is a resin lens. Specific examples of such optical materials include cycloolefin polymer-based thermoplastic resins. Resin lenses have a lower specific gravity than glass lenses, which reduces the weight of the zoom lens. However, the material is not limited to these, and any material with a lower specific gravity than glass lenses can be used.

[0052] With the above-described configuration, it is possible to obtain a small, lightweight zoom lens that exhibits excellent optical performance throughout the entire zoom range in a telephoto optical system. The zoom lenses of each embodiment will be described in detail below. [Example]

[0053] First, a zoom lens 1a according to a first embodiment of the present invention will be described with reference to Figures 1 and 2. The zoom lens 1a is composed of, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a rear group LR. The rear group LR is composed of, arranged in order from the object side to the image side, a fifth lens group L5 and a sixth lens group L6, both of which have negative refractive power.

[0054] The first lens group L1 is composed of, arranged in order from the object side to the image side, a positive lens L11 and a cemented lens of a negative lens L12 and a positive lens L13. The second lens group L2 is composed of, arranged in order from the object side to the image side, a cemented lens of a negative lens L21 and a positive lens L22. The third lens group L3 is composed of, arranged in order from the object side to the image side, an aperture stop SP, a positive lens L31, and a negative meniscus lens L32 convex toward the image side. The fourth lens group L4 is composed of, arranged in order from the object side to the image side, a positive lens L41 and a negative meniscus lens L42. The negative meniscus lens L42 is made of a resin material.

[0055] The fifth lens group L5 is composed of a cemented lens consisting of a positive lens L51 and a negative lens L52, arranged in this order from the object side to the image side. The sixth lens group L6 is composed of a flat lens with no refractive power. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group L1 and the second lens group L2 increases, the distance between the second lens group L2 and the third lens group L3 decreases, and the distance between the third lens group L3 and the fourth lens group L4 decreases, and the rear group LR moves along the optical axis. During focusing from infinity to a close distance, the fifth lens group L5 moves toward the image side along the optical axis.

[0056] As is clear from each aberration diagram, various aberrations are well corrected in this embodiment. [Example]

[0057] Next, a zoom lens 1b according to a second embodiment of the present invention will be described with reference to Figures 3 and 4. The zoom lens 1b is composed of, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a rear group LR. The rear group LR is composed of, arranged in order from the object side to the image side, a fifth lens group L5 and a sixth lens group L6, both of which have negative refractive power.

[0058] The first lens group L1 is composed of, arranged in order from the object side to the image side, a positive lens L11 and a cemented lens of a negative lens L12 and a positive lens L13. The second lens group L2 is composed of, arranged in order from the object side to the image side, a cemented lens of a negative lens L21 and a positive lens L22. The third lens group L3 is composed of, arranged in order from the object side to the image side, an aperture stop SP, a positive lens L31, and a negative meniscus lens L32 convex toward the image side. The fourth lens group L4 is composed of, arranged in order from the object side to the image side, a positive lens L41 and a negative meniscus lens L42. The negative meniscus lens L42 is made of a resin material.

[0059] The fifth lens group L5 is composed of a cemented lens consisting of a positive lens L51 and a negative lens L52, arranged in this order from the object side to the image side. The sixth lens group L6 is composed of a flat lens with no refractive power. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group L1 and the second lens group L2 increases, the distance between the second lens group L2 and the third lens group L3 decreases, and the distance between the third lens group L3 and the fourth lens group L4 decreases, and the rear group LR moves along the optical axis. During focusing from infinity to a close distance, the fifth lens group L5 moves toward the image side along the optical axis.

[0060] As is clear from each aberration diagram, various aberrations are well corrected in this embodiment. [Example]

[0061] Next, a zoom lens 1c according to a third embodiment of the present invention will be described with reference to Figures 5 and 6. The zoom lens 1c is composed of, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a rear group LR. The rear group LR is composed of, arranged in order from the object side to the image side, a fifth lens group L5 with negative refractive power and a sixth lens group L6 with negative refractive power.

[0062] The first lens group L1 is composed of, arranged in order from the object side to the image side, a positive lens L11 and a cemented lens of a negative lens L12 and a positive lens L13. The second lens group L2 is composed of, arranged in order from the object side to the image side, a cemented lens of a negative lens L21 and a positive lens L22. The third lens group L3 is composed of, arranged in order from the object side to the image side, an aperture stop SP, a positive lens L31, and a negative meniscus lens L32 convex toward the image side. The fourth lens group L4 is composed of, arranged in order from the object side to the image side, a positive lens L41 and a positive meniscus lens L42. The positive meniscus lens L42 is made of a resin material.

[0063] The fifth lens group L5 is composed of a cemented lens consisting of a positive lens L51 and a negative lens L52, arranged in this order from the object side to the image side. The sixth lens group L6 is composed of a negative lens. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group L1 and the second lens group L2 increases, the distance between the second lens group L2 and the third lens group L3 decreases, and the distance between the third lens group L3 and the fourth lens group L4 decreases, and the rear group LR moves along the optical axis. During focusing from infinity to a close distance, the fifth lens group L5 moves toward the image side along the optical axis.

[0064] As is clear from each aberration diagram, various aberrations are well corrected in this embodiment. [Example]

[0065] Next, a zoom lens 1d according to a fourth embodiment of the present invention will be described with reference to Figures 7 and 8. The zoom lens 1d is composed of, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a rear group LR. The rear group LR is composed of, arranged in order from the object side to the image side, a fifth lens group L5 and a sixth lens group L6, both of which have negative refractive power.

[0066] The first lens group L1 is composed of, arranged in order from the object side to the image side, a positive lens L11 and a cemented lens of a negative lens L12 and a positive lens L13. The second lens group L2 is composed of, arranged in order from the object side to the image side, a cemented lens of a negative lens L21 and a positive lens L22. The third lens group L3 is composed of, arranged in order from the object side to the image side, an aperture stop SP, a positive lens L31, and a negative meniscus lens L32 convex toward the image side. The fourth lens group L4 is composed of, arranged in order from the object side to the image side, a positive lens L41 and a negative meniscus lens L42. The negative meniscus lens L42 is made of a resin material.

[0067] The fifth lens group L5 is composed of a cemented lens consisting of a positive lens L51 and a negative lens L52, arranged in this order from the object side to the image side. The sixth lens group L6 is composed of a flat lens with no refractive power. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group L1 and the second lens group L2 increases, the distance between the second lens group L2 and the third lens group L3 decreases, and the distance between the third lens group L3 and the fourth lens group L4 decreases, and the rear group LR moves along the optical axis. During focusing from infinity to a close distance, the fifth lens group L5 moves toward the image side along the optical axis.

[0068] As is clear from each aberration diagram, various aberrations are well corrected in this embodiment. [Example]

[0069] Next, a zoom lens 1e according to a fifth embodiment of the present invention will be described with reference to Figures 9 and 10. The zoom lens 1e is composed of, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a rear group LR. The rear group LR is composed of, arranged in order from the object side to the image side, a fifth lens group L5 and a sixth lens group L6, both of which have negative refractive power.

[0070] The first lens group L1 is composed of, arranged in order from the object side to the image side, a positive lens L11 and a cemented lens of a negative lens L12 and a positive lens L13. The second lens group L2 is composed of, arranged in order from the object side to the image side, a cemented lens of a negative lens L21 and a positive lens L22. The third lens group L3 is composed of, arranged in order from the object side to the image side, an aperture stop SP, a positive lens L31, and a negative meniscus lens L32 convex toward the image side. The fourth lens group L4 is composed of, arranged in order from the object side to the image side, a positive lens L41 and a positive meniscus lens L42. The positive meniscus lens L42 is made of a resin material.

[0071] The fifth lens group L5 is composed of a cemented lens consisting of a positive lens L51 and a negative lens L52, arranged in this order from the object side to the image side. The sixth lens group L6 is composed of a flat lens with no refractive power. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group L1 and the second lens group L2 increases, the distance between the second lens group L2 and the third lens group L3 decreases, and the distance between the third lens group L3 and the fourth lens group L4 decreases, and the rear group LR moves along the optical axis. During focusing from infinity to a close distance, the fifth lens group L5 moves toward the image side along the optical axis.

[0072] As is clear from each aberration diagram, various aberrations are well corrected in this embodiment. [Example]

[0073] Next, a zoom lens 1f according to a sixth embodiment of the present invention will be described with reference to Figures 11 and 12. The zoom lens 1f is composed of, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a rear group LR. The rear group LR is composed of, arranged in order from the object side to the image side, a fifth lens group L5 and a sixth lens group L6, both of which have negative refractive power.

[0074] The first lens group L1 is composed of, arranged in order from the object side to the image side, a positive lens L11 and a cemented lens of a negative lens L12 and a positive lens L13. The second lens group L2 is composed of, arranged in order from the object side to the image side, a cemented lens of a negative lens L21 and a positive lens L22. The third lens group L3 is composed of, arranged in order from the object side to the image side, an aperture stop SP, a positive lens L31, and a negative meniscus lens L32 convex toward the image side. The fourth lens group L4 is composed of, arranged in order from the object side to the image side, a positive lens L41 and a positive meniscus lens L42. The positive meniscus lens L42 is made of a resin material.

[0075] The fifth lens group L5 is composed of a cemented lens consisting of a positive lens L51 and a negative lens L52, arranged in this order from the object side to the image side. The sixth lens group L6 is composed of a flat lens with no refractive power. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group L1 and the second lens group L2 increases, the distance between the second lens group L2 and the third lens group L3 decreases, and the distance between the third lens group L3 and the fourth lens group L4 decreases, and the rear group LR moves along the optical axis. During focusing from infinity to a close distance, the fifth lens group L5 moves toward the image side along the optical axis.

[0076] As is clear from each aberration diagram, various aberrations are well corrected in this embodiment.

[0077] Numerical Examples 1 to 6 corresponding to Examples 1 to 6, respectively, are shown below. In each numerical example, each surface of the optical system is assigned a surface number i (i is a natural number) from the object side. r is the radius of curvature of each surface (mm), d is the lens thickness or distance (air gap) (mm) on the optical axis between the surface with surface number i and the surface with surface number (i+1), nd is the refractive index for the d-line of the material of the optical element that comprises each surface, and νd is the Abbe number for the d-line of the material of the optical element that comprises each surface.

[0078] The focal length (mm), F-number, and half angle of view (°) are values ​​when the optical system is focused on an object at infinity. The total lens length is the distance on the optical axis from the front surface of the optical system (the lens surface closest to the object) to the last surface (the lens surface closest to the image) plus the back focal length (BF). The back focal length (BF) is the distance from the last surface of the optical system to the image plane (the distance from the last lens surface to the paraxial image plane in air equivalent).

[0079] An "*" next to a surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following formula, where x is the displacement from the vertex of the surface in the optical axis direction, h is the height from the optical axis in a direction perpendicular to the optical axis, the direction of light travel is positive, R is the paraxial radius of curvature, k is the conic constant, and A4, A6, A8, A10, and A12 are aspherical coefficients. The aspherical coefficient "e-xx" is 10 -xx means.

[0080] x=(h 2 / R) / [1+{1-(1+k)(h / R) 2} 1 / 2 +A4×h 4 +A6×h 6 +A8×h 8 +A10×h 10 +A12×h 12 Values ​​corresponding to conditional expressions (1) to (8) in Numerical Examples 1 to 6 are summarized in Table 1.

[0081] (Numerical Example 1) Unit: mm Surface Data Surface number rd nd νd 1 96.848 4.58 1.48749 70.2 2 -1538.934 0.15 3 97.960 2.00 1.61340 44.3 4 43.522 6.43 1.49700 81.5 5 122.959 (variable) 6 -98.396 1.20 1.77250 49.6 7 27.696 3.01 2.05090 26.9 8 53.328 (variable) 9 (Aperture) ∞ 0.80 10 30.325 5.23 1.48749 70.2 11 -50.245 5.50 12 -29.430 1.50 2.00100 29.1 13 -70.595 (variable) 14 452.936 4.17 1.48749 70.2 15 -28.599 3.32 16* 41.480 3.00 1.53110 55.9 17* 40.012 (variable) 18 -1288.012 3.06 1.84666 23.8 19 -42.793 1.20 1.80400 46.5 20 38.589 (variable) 21 ∞ 1.30 1.51633 64.1 22 ∞ (variable) Image plane ∞ Aspheric data Page 16 K = 0.00000e+000 A 4=-3.78070e-005 A 6=-1.21129e-007 A 8=-3.09634e-010 A10= 1.17462e-012 Page 17 K = 0.00000e+000 A 4=-3.20663e-005 A 6=-1.15972e-007 A 8=-3.95696e-010 A10= 2.43533e-012 Various data Zoom ratio 3.77 Wide-angle Mid-range Telephoto Focal length 103.00 216.56 387.89 F-number 5.82 7.39 8.24 Half angle of view 11.86 5.71 3.19 Image height 21.64 21.64 21.64 Lens total length 183.21 227.16 258.38 BF 39.88 62.29 81.93 d 5 19.55 63.50 94.72 d 8 37.55 21.22 3.53 d13 12.00 5.91 3.97 d17 19.44 12.20 2.73 d20 8.34 15.59 25.05 d22 39.88 62.29 81.93 Zoom lens group data Group starting plane focal length 1 1 194.23 2 6 -57.17 3 9 107.61 4 14 54.31 5 18 -48.75 6 21 ∞ (Numerical Example 2) Unit: mm Surface Data Surface number rd nd νd 1 98.773 4.60 1.48749 70.2 2 -1094.378 0.15 3 90.004 2.00 1.61340 44.3 4 42.540 6.20 1.49700 81.5 5 104.085 (variable) 6 -116.344 1.20 1.72916 54.7 7 28.368 2.85 2.05090 26.9 8 48.728 (variable) 9 (Aperture) ∞ 0.80 10 27.951 5.54 1.48749 70.2 11 -42.619 2.83 12 -32.957 1.50 1.95375 32.3 13 -455.880 (variable) 14 75.047 4.52 1.60311 60.6 15 -35.048 2.09 16* 45.908 3.00 1.53110 55.9 17* 31.890 (variable) 18 241.496 2.68 1.92286 20.9 19 -69.765 1.20 1.88300 40.8 20 36.813 (variable) 21 ∞ 1.30 1.51633 64.1 22 ∞ (variable) Image plane ∞ Aspheric data Page 16 K = 0.00000e+000 A 4=-5.20282e-005 A 6=-5.28393e-008 A 8=-2.17741e-010 A10= 1.66219e-012 Page 17 K = 0.00000e+000 A 4=-4.74670e-005 A 6=-3.41109e-008 A 8=-3.26561e-010 A10= 2.58840e-012 Various data Zoom ratio 3.77 Wide-angle Mid-range Telephoto Focal length 103.00 222.89 387.85 F-number 5.75 7.45 8.24 Half angle of view 11.86 5.54 3.19 Image height 21.64 21.64 21.64 Lens total length 190.00 233.89 265.06 BF 44.04 68.34 88.09 d 5 22.44 66.33 97.50 d 8 40.90 21.15 3.61 d13 12.22 7.67 5.46 d17 19.62 12.37 2.71 d20 8.34 15.59 25.25 d22 44.04 68.34 88.09 Zoom lens group data Group starting plane focal length 1 1 200.48 2 6 -61.04 3 9 193.61 4 14 46.93 5 18 -51.54 6 21 ∞ (Numerical Example 3) Unit: mm Surface Data Surface number rd nd νd 1 102.804 4.52 1.48749 70.2 2 -942.943 0.15 3 110.795 2.00 1.61340 44.3 4 45.741 6.53 1.49700 81.5 5 152.786 (variable) 6 -102.315 1.20 1.75500 52.3 7 28.676 2.93 2.05090 26.9 8 54.067 (variable) 9 (Aperture) ∞ 0.80 10 32.923 4.85 1.48749 70.2 11 -63.730 4.82 12 -35.426 1.50 2.05090 26.9 13 -108.572 (variable) 14 91.027 4.54 1.53996 59.5 15 -32.480 1.46 16* 49.783 3.00 1.53110 55.9 17* 43.243 (variable) 18 147.917 2.93 1.92286 20.9 19 -82.245 1.20 1.88300 40.8 20 34.470 (variable) 21 -147.758 1.30 1.59522 67.7 22 -320.037 (variable) Image plane ∞ Aspheric data Page 16 K = 0.00000e+000 A 4=-2.40666e-005 A 6=-7.97212e-008 A 8=-1.93457e-010 A10= 6.17436e-013 Page 17 K = 0.00000e+000 A 4=-1.61994e-005 A 6=-7.78080e-008 A 8=-2.63557e-010 A10= 1.13396e-012 Various data Zoom ratio 3.75 Wide-angle Mid-range Telephoto Focal length 103.35 214.26 387.77 F-number 5.82 7.31 8.24 Half angle of view 11.82 5.77 3.19 Image height 21.64 21.64 21.64 Lens total length 190.00 234.02 265.09 BF 45.79 66.46 86.74 d 5 20.07 64.09 95.15 d 8 41.89 25.82 7.45 d13 10.27 5.67 3.77 d17 19.59 12.29 2.46 d20 8.66 15.96 25.79 d22 45.79 66.46 86.74 Zoom lens group data Group starting plane focal length 1 1 192.76 2 6 -60.75 3 9 191.67 4 14 46.49 5 18 -53.93 6 21 -462.45 (Numerical Example 4) Unit: mm Surface Data Surface number rd nd νd 1 97.979 4.64 1.48749 70.2 2 -1008.913 0.15 3 94.241 2.00 1.61340 44.3 4 42.618 6.40 1.49700 81.5 5 114.681 (variable) 6 -106.744 1.20 1.75500 52.3 7 28.414 2.98 2.05090 26.9 8 52.202 (variable) 9 (Aperture) ∞ 0.80 10 29.270 5.67 1.48749 70.2 11 -42.436 3.68 12 -30.096 1.50 1.85025 30.1 13 -152.213 (variable) 14 221.981 4.31 1.51823 58.9 15 -30.408 3.51 16* 51.871 3.00 1.53110 55.9 17* 44.691 (variable) 18 515.868 2.71 1.92286 20.9 19 -60.058 1.20 1.88300 40.8 20 38.657 (variable) 21 ∞ 1.30 1.51633 64.1 22 ∞ (variable) Image plane ∞ Aspheric data Page 16 K = 0.00000e+000 A 4=-5.46707e-005 A 6=-1.12893e-007 A 8=-7.42004e-011 A10= 1.56469e-012 Page 17 K = 0.00000e+000 A 4=-5.09007e-005 A 6=-9.82769e-008 A 8= 1.32982e-011 A10= 1.90268e-012 Various data Zoom ratio 3.76 Wide-angle Mid-range Telephoto Focal length 103.00 214.71 387.77 F-number 5.79 7.32 8.24 Half angle of view 11.86 5.75 3.19 Image height 21.64 21.64 21.64 Lens total length 185.00 228.69 260.16 BF 42.31 64.98 86.46 d 5 16.44 60.13 91.60 d 8 40.00 22.73 3.59 d13 13.89 8.49 6.14 d17 19.12 11.87 2.27 d20 8.21 15.46 25.07 d22 42.31 64.98 86.46 Zoom lens group data Group starting plane focal length 1 1 193.10 2 6 -59.74 3 9 118.31 4 14 54.32 5 18 -49.27 6 21 ∞ (Numerical Example 5) Unit: mm Surface Data Surface number rd nd νd 1 132.654 5.69 1.48749 70.2 2 -1033.578 0.20 3 144.804 2.50 1.61340 44.3 4 59.816 7.26 1.49700 81.5 5 200.000 (variable) 6 -106.658 1.80 1.77250 49.6 7 35.060 4.56 2.05090 26.9 8 68.942 (variable) 9 (Aperture) ∞ 1.19 10 33.537 6.03 1.48749 70.2 11 -79.649 9.25 12 -35.795 2.00 2.00100 29.1 13 -91.179 (variable) 14 -77.084 3.28 1.48749 70.2 15 -30.018 10.26 16* 129.613 4.00 1.53110 55.9 17* -1769.683 (variable) 18 -8365.787 3.19 1.84666 23.8 19 -58.604 1.80 1.80400 46.5 20 51.522 (variable) 21 ∞ 1.93 1.51633 64.1 22 ∞ (variable) Image plane ∞ Aspheric data Page 16 K = 0.00000e+000 A 4=-4.03529e-005 A 6=-1.04123e-007 A 8= 2.67850e-012 A10=-3.15135e-013 Page 17 K = 0.00000e+000 A 4=-3.68960e-005 A 6=-8.74780e-008 A 8= 1.03207e-010 A10=-1.72503e-013 Various data Zoom ratio 3.80 Wide-angle Mid-range Telephoto Focal length 153.00 328.55 581.90 F-number 8.00 10.26 11.31 Half angle of view 8.05 3.77 2.13 Image height 21.64 21.64 21.64 Lens total length 274.81 319.32 354.89 BF 68.40 102.29 126.51 d 5 44.31 88.82 124.39 d 8 58.14 27.89 3.39 d13 10.52 6.88 7.16 d17 20.02 14.46 2.49 d20 8.47 14.04 26.00 d22 68.40 102.29 126.51 Zoom lens group data Group starting plane focal length 1 1 244.96 2 6 -68.62 3 9 133.19 4 14 70.76 5 18 -66.79 6 21 ∞ (Numerical Example 6) Unit: mm Surface Data Surface number rd nd νd 1 137.987 5.46 1.48749 70.2 2 -1546.758 0.20 3 193.562 2.50 1.61340 44.3 4 67.305 7.64 1.49700 81.5 5 500.000 (variable) 6 -101.769 1.80 1.77250 49.6 7 31.879 3.89 2.05090 26.9 8 61.953 (variable) 9 (Aperture) ∞ 1.19 10 33.593 5.72 1.48749 70.2 11 -114.082 9.82 12 -38.356 2.00 2.00100 29.1 13 -120.188 (variable) 14 -158.725 3.68 1.51633 64.1 15 -32.193 12.03 16* 141.213 4.00 1.53110 55.9 17* -559.264 (variable) 18 1037.884 3.06 1.92286 20.9 19 -73.351 1.80 1.88300 40.8 20 53.111 (variable) 21 ∞ 1.93 1.51633 64.1 22 ∞ (variable) Image plane ∞ Aspheric data Page 16 K = 0.00000e+000 A 4=-4.64647e-005 A 6=-1.28525e-007 A 8= 2.52244e-011 A10=-6.53496e-013 Page 17 K = 0.00000e+000 A 4=-4.37120e-005 A 6=-1.05428e-007 A 8= 1.36931e-010 A10=-3.04580e-013 Various data Zoom ratio 3.80 Wide-angle Mid-range Telephoto Focal length 153.00 330.53 581.87 F-number 8.00 10.50 11.31 Half angle of view 8.05 3.74 2.13 Image height 21.64 21.64 21.64 Lens total length 285.00 320.05 360.14 BF 72.60 108.49 124.92 d 5 48.74 83.79 123.89 d 8 58.99 25.57 8.57 d13 9.45 6.99 7.55 d17 20.30 18.25 2.49 d20 8.19 10.25 26.00 d22 72.60 108.49 124.92 Zoom lens group data Group starting plane focal length 1 1 230.43 2 6 -63.11 3 9 199.38 4 14 59.21 5 18 -66.02 6 21 ∞

[0082] [Table 1]

[0083] Next, an imaging device will be described with reference to Fig. 14. Fig. 14 is a schematic diagram of an imaging device (single-lens reflex camera system) 100 that uses any one of the zoom lenses 1a to 1f of Examples 1 to 6 as an imaging optical system.

[0084] In FIG. 14, reference numeral 10 denotes a camera body, and 11 denotes an interchangeable lens (image pickup optical system) constituted by any of the zoom lenses 1a to 1f of Examples 1 to 6. Reference numeral 12 denotes a recording means such as a film or an image sensor that records the subject image formed by the interchangeable lens 11. The recording means 12 receives the image formed by the image pickup optical system. Reference numeral 13 denotes a finder optical system that observes the subject image from the interchangeable lens 11. Reference numeral 14 denotes a quick-return mirror that rotates to selectively transmit the subject image formed by the interchangeable lens 11 to either the recording means 12 or the finder optical system 13. When observing the subject image through the viewfinder, the subject image formed on the focusing screen 15 via the quick-return mirror 14 is first made into an erect image by a pentaprism 16, and then enlarged and observed by an eyepiece optical system 17. When taking a photograph, the quick-return mirror 14 rotates in the direction of the arrow, and the subject image is formed on the recording means 12 and recorded. Reference numeral 18 denotes a sub-mirror, and reference numeral 19 denotes a focus detection device.

[0085] In this way, by applying the zoom lens of each embodiment to an imaging device such as an interchangeable lens for a single-lens reflex camera, an imaging device with high optical performance can be realized. The imaging device may also be a mirrorless imaging device that does not have a quick-return mirror 14, or may be an integrated lens imaging device that does not have an interchangeable lens.

[0086] According to each embodiment, it is possible to provide a small, lightweight zoom lens and an imaging device that have high optical performance over the entire zoom range.

[0087] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0088] 1a-1f zoom lens L1 First lens group L2 Second lens group L3: Third lens group L4 4th lens group

Claims

1. A zoom lens having, arranged in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power, wherein the spacing between adjacent lens groups changes during zooming from a wide-angle end to a telephoto end, During zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the distance between the third lens group and the fourth lens group decreases, the third lens group includes a positive lens and a negative lens arranged in this order from the object side to the image side, and the negative lens has a meniscus shape convex toward the image side; When the total optical length of the zoom lens at the telephoto end is TLt, the focal length of the zoom lens at the telephoto end is ft, the focal length of the third lens group is f3, and the radii of curvature of the object-side lens surface and the image-side lens surface of the negative lens are Rpf and Rpr, respectively, 0.50 <TLt / ft<0.69 0.10< f3 / ft<0.58 -10.0<(Rpf+Rpr) / (Rpf-Rpr)<-1.0 A zoom lens characterized by satisfying the following conditional expressions:

2. When the distance between the positive lens and the negative lens in the third lens group is D3 and the total thickness of the third lens group is LT3, 0.25<D3 / LT3<1.00 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. When the Abbe number of the material of the positive lens in the third lens group is νdp, νdp>65 3. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. When the refractive index at the d-line of the material of the negative lens in the third lens group is Ndn, Ndn>1.80 4. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the Abbe number of the material of the negative lens in the third lens group is νdn and the partial dispersion ratio is θgFn, 25<νdn<45 θgFn-0.6438+0.001682×νdn<0.02 5. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. 6. The zoom lens according to claim 1, wherein the fourth lens group is composed of two lenses, a positive lens and a positive or negative lens, arranged in this order from the object side to the image side.

7. 7. The zoom lens according to claim 1, wherein the positive lens or the negative lens provided on the image side of the fourth lens group has an aspherical surface.

8. 8. The zoom lens according to claim 1, wherein the second lens group is made up of a cemented lens of a negative lens and a positive lens arranged in this order from the object side to the image side.

9. 9. The zoom lens according to claim 1, further comprising a sixth lens group arranged closer to the image side than the fifth lens group.

10. 10. The zoom lens according to claim 1, wherein the fifth lens group is a focus lens group that performs focusing from infinity to a close distance.

11. 11. An imaging device comprising: the zoom lens according to claim 1; and an imaging element that receives an image formed by the zoom lens.

Citation Information

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