Zoom lens and imaging device having the same

Abstract

To provide a zoom lens that is small and has an excellent optical characteristic, and an imaging device and an imaging system having the zoom lens.SOLUTION: A zoom lens L0 includes: a first lens group L1 with a negative refractive force; a second lens group L2 with a positive refractive force; and a subsequent group LR including at least one lens group, which are sequentially arranged in a direction from an object side to an image side. The subsequent group includes a focus lens group LP with a positive refractive force, the focus lens group moving in a direction from an image side to an object side at the time of focusing from infinity to close range. The focal distance fLP of the focus lens group, the focal distance fL1 of the first lens group, and the focal distance fL2 of the second lens group satisfy a predetermined conditional expression.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a zoom lens and is suitable for imaging devices that use solid-state image sensors, such as digital still cameras, digital video cameras, broadcast cameras, and surveillance cameras, or imaging devices that use silver halide photographic film. [Background technology]

[0002] Zoom lenses used in imaging devices are required to have a wide field of view, be compact, and possess good optical characteristics. As a wide-angle zoom lens, the so-called negative lead type zoom lens is known, in which the lens group with negative refractive power is positioned closest to the object.

[0003] Negative-lead zoom lenses, in which the lens group with negative refractive power precedes the other lens group, have the advantage of being able to achieve a wide angle of view relatively easily and a long back focus easily. However, because negative-lead zoom lenses tend to have an asymmetrical lens configuration with respect to the aperture, it is difficult to correct various aberrations, and for example, it is difficult to suppress aberration fluctuations during focusing, making it very difficult to obtain high optical performance. In particular, in the inner-focus system, where focusing is performed by the lens group positioned closer to the image than the first lens group L1, it is easy to make the focusing lens group smaller and lighter and to perform high-speed focusing, but aberration fluctuations during focusing tend to increase. In order to achieve good optical performance while making the focusing lens group smaller and lighter, it is important to appropriately set the power distribution of each lens group, including the focusing lens group.

[0004] Patent Document 1 discloses a zoom lens comprising a first lens group with negative refractive power, a second lens group with positive refractive power, a third lens group with negative refractive power, and a fourth lens group with positive refractive power, arranged in order from the object side to the image side. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-040029 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, while the zoom lens described in Patent Document 1 achieved miniaturization of the focusing lens group, its optical performance was insufficient.

[0007] The present invention provides a compact zoom lens with excellent optical properties, and an imaging device and imaging system having the same. [Means for solving the problem]

[0008] A zoom lens as one aspect of the present invention comprises a first lens group with negative refractive power, a second lens group with positive refractive power, and a rear group including one or more lens groups, arranged sequentially from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming, and the rear group includes a focusing lens group with positive refractive power that moves from the image side to the object side during focusing from infinity to close distance, and when the focal length of the focusing lens group is fLP, the focal length of the first lens group is fL1, and the focal length of the second lens group is fL2, 1.20 <fLP / fL2<3.20 -3.00 <fL1 / fL2<-0.85 It is characterized by satisfying the following conditional expression.

[0009] Other objects and features of the present invention are described in the following embodiments. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a zoom lens that is compact and has good optical properties, as well as an imaging device and imaging system having the same. [Brief explanation of the drawing]

[0011] [Figure 1] It is a lens cross-sectional view of the zoom lens of Example 1. [Figure 2] It is an aberration diagram of the zoom lens of Example 1. [Figure 3] It is a lens cross-sectional view of the zoom lens of Example 2. [Figure 4] It is an aberration diagram of the zoom lens of Example 2. [Figure 5] It is a lens cross-sectional view of the zoom lens of Example 3. [Figure 6] It is an aberration diagram of the zoom lens of Example 3. [Figure 7] It is a lens cross-sectional view of the zoom lens of Example 4. [Figure 8] It is an aberration diagram of the zoom lens of Example 4. [Figure 9] It is a lens cross-sectional view of the zoom lens of Example 5. [Figure 10] It is an aberration diagram of the zoom lens of Example 5. [Figure 11] It is a lens cross-sectional view of the zoom lens of Example 6. [Figure 12] It is an aberration diagram of the zoom lens of Example 6. [Figure 13] It is a schematic diagram of an imaging device.

Mode for Carrying Out the Invention

[0012] Hereinafter, examples of the zoom lens of the present invention and an imaging device having the same will be described based on the accompanying drawings.

[0013] FIG. 1, FIG. 3, FIG. 5, FIG. 7, FIG. 9, and FIG. 11 are lens cross-sectional views in a state of being focused at infinity (infinity focus state) at the wide-angle end of the zoom lens L0 of Examples 1 to 6, respectively. The zoom lens L0 of each example is used in an imaging device such as a digital video camera, a digital still camera, a broadcast camera, a silver halide film camera, a surveillance camera, or an optical device including an interchangeable lens.

[0014] In each lens cross-sectional view, the left side is the object side and the right side is the image side. The zoom lens L0 of each embodiment is composed of multiple lens groups. In this specification, a lens group is a component of the zoom lens L0 consisting of one lens or multiple lenses. The lens group may include an aperture diaphragm and a flare cut diaphragm. In the zoom lens L0 of each embodiment, the spacing between adjacent lens groups changes when zooming from the wide-angle end to the telephoto end.

[0015] In each lens cross-sectional view, Li represents the i-th lens group (where i is a natural number) from the object side among the lens groups included in the zoom lens L0. SP is the aperture diaphragm. FP is the flare cut diaphragm, which cuts out unwanted light. IP is the image plane, and when the zoom lens L0 of each embodiment is used as the shooting optical system of a digital still camera or digital video camera, the image plane of a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor is placed on it. When the zoom lens L0 of each embodiment is used as the shooting optical system of a silver halide film camera, a photosensitive surface corresponding to the film plane is placed on the image plane IP.

[0016] The solid arrows shown in each lens cross-sectional view represent a simplified representation of the movement trajectory of each lens group when zooming from the wide-angle end to the telephoto end. In this specification, the wide-angle end and telephoto end refer to the zoom positions when each lens group is located at the ends of the range in which it can move along the optical axis mechanically. The dashed arrows shown in each lens cross-sectional view represent a simplified representation of the movement trajectory of the lens group when focusing from infinity to close range.

[0017] Figures 2, 4, 6, 8, 10, and 12 are aberration diagrams of the zoom lens L0 of Examples 1 to 6, respectively. Each aberration diagram represents the case when the lens is focused at infinity, with (A) being the aberration diagram at the wide-angle end, (B) being the aberration diagram at the intermediate zoom position, and (C) being the aberration diagram at the telephoto end.

[0018] In the spherical aberration diagram, Fno is the F-number and indicates the amount of spherical aberration for the d-line (wavelength 587.6 nm) and the g-line (wavelength 435.8 nm). In the astigmatism diagram, ΔS indicates the amount of astigmatism at the sagittal image plane, and ΔM indicates the amount of astigmatism at the meridional image plane. In the distortion diagram, the amount of distortion for the d-line is shown. In the chromatic aberration diagram, the amount of chromatic aberration at the g-line is shown. ω is the half-angle of view (°) and is the angle of view calculated paraxially.

[0019] Next, we will describe the characteristic configuration of the zoom lens L0 in each embodiment.

[0020] The zoom lens L0 in each embodiment consists of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, and a rear group LR including one or more lens groups, arranged in order from the object side to the image side. The rear group LR consists of all lens groups arranged closer to the image side than the second lens group L2. The zoom lens L0 is a zoom lens in which the spacing between adjacent lens groups changes during zooming. The rear group LR includes a lens group LP (focus lens group) with positive refractive power that moves from the image side to the object side during focusing from infinity to close distance.

[0021] In addition, in the zoom lens L0 of each embodiment, it is preferable that the first lens group L1 includes a negative lens G1 (first negative lens) and a negative lens G2 (second negative lens) arranged in order from the object side to the image side.

[0022] In an inner focusing system, where focusing is performed by a lens group positioned closer to the image than the first lens group L1, the focusing lens group can be made smaller and lighter, and high-speed focusing is easily achieved. However, this system tends to increase aberration fluctuations during focusing. To achieve good optical performance while making the focusing lens group smaller and lighter, it is important to appropriately set the power distribution of each lens group, including the focusing lens group.

[0023] Therefore, in the zoom lens L0 of each embodiment, the focal length of each lens group is appropriately set. Specifically, the zoom lens L0 of each embodiment satisfies the following conditions (1) and (2).

[0024] 1.20 <fLP / fL2<3.20 ···(1) -3.00 <fL1 / fL2<-0.85 ···(2) Here, fLP is the focal length of lens group LP, fL1 is the focal length of the first lens group L1, and fL2 is the focal length of the second lens group L2.

[0025] Condition (1) relates to the ratio of the focal length fLP of lens group LP to the focal length fL2 of lens group L2. If the value falls below the lower limit of condition (1), the refractive power of lens group LP becomes strong, making it difficult to suppress fluctuations in various aberrations, including spherical aberration, associated with focusing. On the other hand, if the value exceeds the upper limit of condition (1), the refractive power of lens group LP becomes weak, and the amount of movement associated with focusing becomes longer.

[0026] Condition (2) relates to the ratio of the focal length fL1 of the first lens group L1 to the focal length fL2 of the second lens group L2. If the value falls below the lower limit of condition (2), the refractive power of the first lens group L1 becomes too weak, making it difficult to miniaturize the zoom lens. On the other hand, if the value exceeds the upper limit of condition (2), the negative refractive power of the first lens group L1 becomes too strong, increasing off-axis aberrations such as coma and field curvature occurring in the first lens group L1, making it difficult to adequately correct them.

[0027] With the above configuration, a compact zoom lens with excellent optical characteristics can be obtained.

[0028] Furthermore, it is more preferable to set the numerical ranges of the above-mentioned conditional expressions (1) and (2) to the ranges of the following conditional expressions (1a) and (2a).

[0029] 1.30 <fLP / fL2<3.10 ···(1a) -2.50 <fL1 / fL2<-0.90 ···(2a) Furthermore, it is even more preferable that the numerical ranges of conditional expressions (1a) and (2a) be within the ranges of the following conditional expressions (1b) and (2b).

[0030] 1.40 <fLP / fL2<3.05 ···(1b) -2.00 <fL1 / fL2<-0.95 ···(2b) Here, the zoom lens L0 in each embodiment is designed to tolerate distortion. Assuming the use of electronic aberration correction technology due to recent technological advancements, image distortion caused by distortion can be corrected by this image processing technology. Therefore, the imaging optical system having these zoom lenses L0 has a design value for the amount of distortion that the zoom lens L0 possesses. The electronic image captured using this imaging optical system is corrected by image processing in an arbitrary image processing unit (for example, a CPU attached to an imaging device such as a camera body) using the design value for the amount of distortion.

[0031] In zoom lenses that tolerate distortion, a separate lens for correcting distortion is unnecessary, making it easier to miniaturize and lighten the zoom lens. In particular, by making the effective imaging area (effective image circle diameter) of the image sensor at the wide-angle end smaller than the effective imaging area (effective image circle diameter) at the telephoto end, and correcting the distortion, it contributes to reducing the diameter of the front element.

[0032] In the zoom lens L0 of each embodiment, some lenses or some lens groups may be made to function as an image-stabilizing optical system by parallel eccentricity (movement) in a direction that includes a component perpendicular to the optical axis (preferably perpendicular to the optical axis) when correcting image shake. Alternatively, a parallel plate with substantially no refractive power, such as a low-pass filter or an infrared cut filter, may be placed between the lens positioned closest to the image and the imaging plane.

[0033] Next, we will describe the conditions that are preferable to satisfy in the zoom lens L0 of each embodiment.

[0034] The zoom lens L0 of each embodiment preferably satisfies one or more of the following conditional expressions (3) to (12).

[0035] 0.25 <DSPw / TLw<0.53 ···(3) 1.40 <ndG1<1.69 ···(4) 45 < νdG1 < 95 ... (5) 1.40 <ndLPP<1.65 ···(6) 45 < νdLPP < 95 ... (7) 1.60 <ndL1P<2.10 ···(8) 15 < νdL1P < 45 ... (9) 0.50 <MLP / ML2<1.50 ···(10) 0 <fG1 / fG2<0.42 ···(11) -3.00<(G1R2+G1R1) / (G1R2-G1R1)<-0.10 ···(12) Here, DSPw is the distance along the optical axis from the aperture diaphragm SP to the image plane IP at the wide-angle end. TLw is the total lens length of the zoom lens L0 at the wide-angle end. ndG1 is the refractive index of the negative lens G1 with respect to the d line, and νdG1 is the Abbe number of the negative lens G1 with respect to the d line. ndLPP is the refractive index of the positive lens LPP, which has the strongest refractive power (largest refractive power value) among the positive lenses included in lens group LP, with respect to the d line. Here, refractive power is expressed as the reciprocal of the focal length, and strong refractive power means that the value of the reciprocal of the focal length is large (the value of the focal length is small). νdLPP is the Abbe number of the positive lens LPP, which has the strongest refractive power (largest refractive power value) among the positive lenses included in lens group LP, with respect to the d line. ndL1P is the refractive index of the positive lens L1P, which has the strongest refractive power (largest refractive power value) among the positive lenses included in the first lens group L1, with respect to the d line. νdL1P is the Abbe number on the d line of the positive lens L1P, which has the strongest refractive power (largest refractive power value) among the positive lenses included in the first lens group L1. MLP is the amount of movement of lens group LP when zooming from the wide-angle end to the telephoto end when focused at infinity. The sign of the amount of movement is negative when lens group LP is located on the object side at the telephoto end compared to the wide-angle end, and positive when it is located on the image side. ML2 is the amount of movement of the second lens group L2 when zooming from the wide-angle end to the telephoto end. The sign of the amount of movement is negative when lens group L2 is located on the object side at the telephoto end compared to the wide-angle end, and positive when it is located on the image side. fG1 is the focal length of negative lens G1, and fG2 is the focal length of negative lens G2. G1R2 is the radius of curvature of the image-side lens surface of negative lens G1, and G1R1 is the radius of curvature of the object-side lens surface of negative lens G1.

[0036] Conditional equation (3) relates to the ratio of the distance DSPw on the optical axis from the aperture diaphragm SP to the image plane IP at the wide-angle end to the total lens length TLw at the wide-angle end. By positioning the aperture diaphragm SP appropriately, it becomes easy to reduce the diameter of the aperture diaphragm SP while miniaturizing the zoom lens L0. If the value falls below the lower limit of conditional equation (3), and the distance from the aperture diaphragm SP to the image plane IP becomes too short, the outer diameter of the lens positioned closer to the object than the aperture diaphragm SP tends to become larger. Therefore, miniaturization of the zoom lens L0 becomes difficult and undesirable. On the other hand, if the value exceeds the upper limit of conditional equation (3), and the distance from the aperture diaphragm SP to the image plane IP becomes too long, the light beam diverged in the first lens group L1 enters the aperture diaphragm SP without being converged. Therefore, it becomes difficult to reduce the diameter of the aperture diaphragm SP, and miniaturization of the zoom lens L0 becomes difficult and undesirable.

[0037] Conditional equation (4) relates to the refractive index ndG1 of the negative lens G1. If the value falls below the lower limit of conditional equation (4), the refractive index becomes low, and there is a tendency for many glass materials to have a low specific gravity. Therefore, although this is effective for reducing the weight of the zoom lens L0, the refractive power becomes weaker, making miniaturization difficult and thus undesirable. If the value exceeds the upper limit of conditional equation (4), the specific gravity of the lens becomes high, making weight reduction difficult and thus undesirable.

[0038] Conditional equation (5) relates to the Abbe number νdG1 of the negative lens G1 with respect to the d line. If the value falls below the lower limit of conditional equation (5), it becomes difficult to correct chromatic aberration, which is undesirable. Conversely, if the value exceeds the upper limit of conditional equation (5), the correction of chromatic aberration becomes excessive, which is also undesirable.

[0039] Conditional equation (6) relates to the refractive index ndLPP of the positive lens LPP, which has the strongest refractive power among the positive lenses included in the lens group LP, with respect to the d line. If the value falls below the lower limit of conditional equation (6), the refractive index of the positive lens LPP becomes too low, and the radius of curvature of the lens surface becomes small in order to obtain the appropriate refractive power. This is undesirable because it makes it difficult to correct various aberrations, including spherical aberration. On the other hand, if the value exceeds the upper limit of conditional equation (6), the specific gravity of the positive lens LPP tends to increase, making weight reduction difficult, which is also undesirable.

[0040] Conditional equation (7) relates to the Abbe number νdLPP for the d line of the positive lens LPP, which has the strongest refractive power among the positive lenses included in lens group LP. If the value falls below the lower limit of conditional equation (7), it becomes difficult to correct lateral chromatic aberration and axial chromatic aberration, which is undesirable. If the value exceeds the upper limit of conditional equation (7), the correction of lateral chromatic aberration and axial chromatic aberration becomes excessive, which is also undesirable.

[0041] Conditional equation (8) relates to the refractive index ndL1P of the positive lens L1P, which has the strongest refractive power among the positive lenses included in the first lens group L1, with respect to the d line. If the refractive index of positive lens L1P exceeds the upper limit of conditional equation (8) and becomes high, the Petzval sum of the entire lens system becomes too small, making it difficult to correct field curvature, which is undesirable. On the other hand, if the refractive index of positive lens L1P falls below the lower limit of conditional equation (8) and becomes low, the Petzval sum of the entire lens system becomes large, making it difficult to correct field curvature, which is also undesirable. Furthermore, in order to obtain appropriate refractive power, the radius of curvature of the lens surface becomes small, making it difficult to correct off-axis aberrations such as coma aberration, which is also undesirable.

[0042] Conditional equation (9) relates to the Abbe number νdL1P for the d line of the positive lens L1P, which has the strongest refractive power among the positive lenses included in the first lens group L1. If the value falls below the lower limit of conditional equation (9), it is undesirable because it becomes difficult to correct lateral chromatic aberration. On the other hand, if it exceeds the upper limit of conditional equation (9), it is undesirable because the correction of lateral chromatic aberration and axial chromatic aberration is insufficient.

[0043] Conditional equation (10) relates to the ratio of the amount of movement MLP of lens group LP when zooming from the wide-angle end to the telephoto end while focused at infinity, to the amount of movement ML2 of the second lens group L2 when zooming from the wide-angle end to the telephoto end. If the value falls below the lower limit of conditional equation (10), the amount of movement of the second lens group L2 increases, which is undesirable because it increases the overall length of the lens at the wide-angle end. On the other hand, if the value exceeds the upper limit of conditional equation (10), the amount of movement of the second lens group L2 decreases, and the refractive power of the second lens group L2 increases in order to obtain the desired zoom ratio. Therefore, it becomes difficult to suppress fluctuations in various aberrations, including spherical aberration, that accompany zooming, which is undesirable.

[0044] Conditional equation (11) relates to the ratio of the focal length fG1 of negative lens G1 to the focal length fG2 of negative lens G2. If the value falls below the lower limit of conditional equation (11), either negative lens G1 or negative lens G2 will become a positive lens, making wide-angle correction difficult, which is undesirable. Furthermore, if the absolute value of the focal length of negative lens G1 becomes excessively small compared to the focal length of negative lens G2, it may become difficult to achieve both wide-angle correction and high performance. Therefore, as described below, it is also preferable to set a value greater than 0 as the lower limit of conditional equation (11). If the value exceeds the upper limit of conditional equation (11), the refractive power of negative lens G1 will weaken, making it difficult to miniaturize the zoom lens L0, which is undesirable. Alternatively, the refractive power of negative lens G2 will become stronger, making it difficult to correct off-axis aberrations such as field curvature, which is also undesirable.

[0045] Condition (12) relates to the shape of the negative lens G1. If the value falls below the lower limit of condition (12), the negative lens G1 has a negative refractive power, resulting in a meniscus shape that is convex towards the object and has weak refractive power. In this case, sufficient refractive power cannot be obtained from the negative lens G1, so the refractive power of the lens on the image side of the negative lens G1 becomes stronger, making it difficult to correct off-axis aberrations such as field curvature, which is undesirable. On the other hand, if the value exceeds the upper limit of condition (12), the negative lens G1 becomes a biconcave shape or a meniscus shape that is convex towards the image side, and the radius of curvature of the object-side surface of the negative lens G1 becomes smaller. In this case, the occurrence of off-axis aberrations such as field curvature occurring on the object-side surface of the negative lens G1 increases and becomes difficult to correct, which is undesirable. Alternatively, the negative lens G1 has a shape with weak refractive power, making it difficult to correct off-axis aberrations such as field curvature, which is undesirable.

[0046] Furthermore, it is more preferable to use the numerical ranges of the following conditional expressions (3a) to (12a) instead of the numerical ranges of conditional expressions (3a) to (12a).

[0047] 0.28 <DSPw / TLw<0.51 ···(3a) 1.50 <ndG1<1.67 ···(4a) 50 < νdG1 < 85 ···(5a) 1.45 <ndLPP<1.63 ···(6a) 55 < νdLPP < 90 ···(7a) 1.65 <ndL1P<2.05 ···(8a) 18<νdL1P<40 ···(9a) 0.60 <MLP / ML2<1.40 ···(10a) 0.05 <fG1 / fG2<0.41 ···(11a) -2.50<(G1R2+G1R1) / (G1R2-G1R1)<-0.30 (12a) Furthermore, it is even more preferable that the numerical ranges of conditional expressions (3) to (12) be the numerical ranges of the following conditional expressions (3b) to (12b).

[0048] 0.30 <DSPw / TLw<0.50 ···(3b) 1.55 <ndG1<1.65 ···(4b) 55 < νdG1 < 75 ···(5b) 1.48 <ndLPP<1.61 ···(6b) 65 < νdLPP < 85 ···(7b) 1.68 <ndL1P<2.01 ···(8b) 20 < νdL1P < 35 ···(9b) 0.70 <MLP / ML2<1.30 ···(10b) 0.09 <fG1 / fG2<0.40 ···(11b) -2.00<(G1R2+G1R1) / (G1R2-G1R1)<-0.50 (12b) Next, we will describe the preferred configurations for the zoom lens L0 of each embodiment.

[0049] The first lens group L1 preferably consists of a negative lens G1, a negative lens G2, and a positive lens L1P, arranged in order from the object side to the image side. This makes it easier to correct off-axis aberrations such as field curvature at the wide-angle end.

[0050] Preferably, at least one of the object-side and image-side lens surfaces of the negative lens G2 has an aspherical shape. This facilitates the correction of off-axis aberrations such as coma and field curvature at the wide-angle end.

[0051] The negative lens G2 is preferably made of a resin material. By using a resin material for the negative lens G2, which tends to have a large outer diameter, it becomes easier to reduce the weight of the zoom lens L0.

[0052] It is preferable that negative lenses G1 and G2 have an air gap on the optical axis. This facilitates the correction of off-axis aberrations such as coma and field curvature.

[0053] When correcting image blur, it is preferable to move the second lens group L2 in a parallel eccentricity (movement) in a direction that includes a component perpendicular to the optical axis (preferably perpendicular to the optical axis). By using the second lens group L2, in which the light beam converges, as the lens group for image blur correction, it becomes easier to miniaturize the lens group for image blur correction.

[0054] The second lens group L2 is preferably composed of three or fewer lenses. This facilitates weight reduction of the zoom lens L0.

[0055] The second lens group L2 preferably includes an aperture diaphragm SP, and the aperture diaphragm SP is positioned on the image side of the second lens group L2. Since the light beam converges on the image side of the second lens L2, it is easy to miniaturize the aperture diaphragm SP.

[0056] It is preferable that the positive refractive power lens group LP, included in the rear group LR, moves from the image side to the object side to perform focusing from infinity to close distance. Axial rays converge on the image side from the second lens group L2. This makes it easier to suppress fluctuations in various aberrations, including spherical aberration, during focusing.

[0057] The lens group LP preferably consists of a single positive lens element with a meniscus shape and a concave surface facing the object. Here, the single lens element is either a single lens or a cemented lens. By making the object-side lens surface of the lens group LP concave, the angle of incidence of off-axis light rays to the lens surface can be reduced, making it easier to suppress fluctuations in off-axis aberrations such as field curvature during focusing.

[0058] Next, we will describe the zoom lens L0 of each embodiment in detail.

[0059] The zoom lens L0 in Examples 1 and 2 consists of a first lens group L1, a second lens group L2, a third lens group L3 with positive refractive power, and a fourth lens group L4 with negative refractive power. In the zoom lens L0 of Examples 1 and 2, the third lens group L3 and the fourth lens group L4 correspond to the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves in a convex trajectory toward the image side, while the second lens group L2, the third lens group L3, and the fourth lens group L4 move monotonically toward the object side. In the zoom lens L0 of Examples 1 and 2, the second lens group L2 and the fourth lens group L4 move together (in the same trajectory) during zooming. Furthermore, the third lens group L3 corresponds to the lens group LP with positive refractive power, and by moving the third lens group L3 along the optical axis, focusing is achieved from an object point at infinity to an object point at close range.

[0060] The zoom lens L0 of Example 3 consists of a first lens group L1, a second lens group L2, a third lens group L3 with positive refractive power, and a fourth lens group L4 with positive refractive power. In the zoom lens L0 of Example 3, the third lens group L3 and the fourth lens group L4 correspond to the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves in a convex trajectory toward the image side, while the second lens group L2, the third lens group L3, and the fourth lens group L4 move monotonically toward the object side. In the zoom lens L0 of Example 3, the second lens group L2 and the fourth lens group L4 move together (in the same trajectory) when zooming. Furthermore, the third lens group L3 corresponds to the lens group LP with positive refractive power, and by moving the third lens group L3 along the optical axis, focusing is achieved from an object point at infinity to an object point at close range.

[0061] The zoom lens L0 of Example 4 consists of a first lens group L1, a second lens group L2, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, and a fifth lens group L5 with positive refractive power. In the zoom lens L0 of Example 4, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 correspond to the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves in a convex trajectory toward the image side, the second lens group L2, the third lens group L3, and the fourth lens group L4 move monotonically toward the object side, and the fifth lens group L5 moves monotonically toward the image side. In the zoom lens L0 of Example 4, the second lens group L2 and the fourth lens group L4 move together (in the same trajectory) when zooming. Furthermore, the third lens group L3 corresponds to the lens group LP with positive refractive power, and by moving the third lens group L3 along the optical axis, focusing is achieved from an object point at infinity to an object point at close range.

[0062] The zoom lens L0 of Example 5 consists of a first lens group L1, a second lens group L2, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, and a fifth lens group L5 with negative refractive power. In the zoom lens L0 of Example 5, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 correspond to the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves in a convex trajectory toward the image side, while the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move monotonically toward the object side. In the zoom lens L0 of Example 5, the second lens group L2 and the fifth lens group L5 move together (in the same trajectory) when zooming. Furthermore, the fourth lens group L4 corresponds to the positive refractive power lens group LP, and by moving the fourth lens group L4 along the optical axis, focusing is achieved from an object point at infinity to an object point at close range.

[0063] The zoom lens L0 of Example 6 consists of a first lens group L1, a second lens group L2, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, a fifth lens group L5 with negative refractive power, and a sixth lens group L6 with positive refractive power. In the zoom lens L0 of Example 6, the third lens group L3, fourth lens group L4, fifth lens group L5, and sixth lens group L6 correspond to the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves in a convex trajectory toward the image side, while the second lens group L2, third lens group L3, fourth lens group L4, fifth lens group L5, and sixth lens group L6 move monotonically toward the object side. In the zoom lens L0 of Example 6, the second lens group L2 and fifth lens group L5 move together (in the same trajectory) when zooming. Furthermore, the fourth lens group L4 corresponds to the positive refractive power lens group LP, and by moving the fourth lens group L4 along the optical axis, focusing is achieved from an object point at infinity to an object point at close range.

[0064] The numerical values ​​corresponding to Examples 1 to 6 are shown below.

[0065] In the surface data for each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the on-axial spacing (distance along the optical axis) between the m-th surface and the (m+1)-th surface. Here, m is the surface number counted from the light incident side. Also, nd represents the refractive index of each optical element with respect to the d line, and νd represents the Abbe number of the optical element. Note that the Abbe number νd of a certain material is given by Nd, NF, and NC, respectively, when the refractive indices at the Fraunhofer lines d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) are Nd, NF, and NC. νd = (Nd-1) / (NF-NC) It is represented as follows.

[0066] In each numerical example, d, focal length (mm), F-number, and half angle of view (°) are all values when the zoom lens L0 of each example is focused on an object at infinity. "Back focus" is the distance on the optical axis from the final lens surface (the lens surface closest to the image side) to the paraxial image plane, expressed in terms of the air-equivalent length. "Overall lens length" is the length obtained by adding the back focus to the distance on the optical axis from the frontmost surface (the lens surface closest to the object side) to the final surface of the zoom lens L0. "Lens group" shall include not only cases composed of a plurality of lenses but also cases composed of a single lens.

[0067] When the optical surface is an aspherical surface, an asterisk (*) is attached to the right side of the surface number. The aspherical shape is expressed as follows when X is the displacement amount from the vertex of the surface in the optical axis direction, h is the height from the optical axis in the direction perpendicular to the optical axis, R is the paraxial curvature radius, K is the conic constant, and A4, A6, A8, A10, A12 are the aspherical coefficients of each order: 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 Here, "e±XX" in each aspherical coefficient means "×10± XX ". [Numerical Example 1] Unit: mm Surface Data Surface Number r d nd νd 1 238.756 1.40 1.63854 55.4 2 18.479 7.21 3* 994.673 3.70 1.53110 55.9 4 56.399 0.30 5 28.004 3.60 1.69895 30.1 6 65.231 (Variable) 7 21.644 3.00 1.90366 31.3 8 -709.102 2.60 9 -102.707 0.70 1.84666 23.9 10 16.164 0.37 11 26.583 2.05 1.77250 49.6 12 -76.939 2.00 13 (aperture) ∞ 6.15 14 ∞ (Variable) 15 -65.961 2.95 1.48749 70.2 16 -21.205 (variable) 17* -90.404 3.50 1.53110 55.9 18* -1111.779 (variable) Image plane ∞ Aspherical data 3rd page K = 0.00000e+000 A 4= 2.06228e-006 A 6=-3.09541e-009 A 8= 7.24904e-011 A10=-3.07809e-013 A12= 9.19241e-016 Page 17 K = 0.00000e+000 A 4=-1.01775e-004 A 6= 1.71677e-007 A 8= 1.83977e-010 A10=-1.16025e-011 A12= 2.80092e-014 Side 18 K = 0.00000e+000 A 4=-9.00719e-005 A 6= 2.07355e-007 A 8=-1.21619e-010 A10=-4.95038e-012 A12= 1.35424e-014 Various data Zoom ratio 1.96 Wide-angle, Medium, Telephoto Focal length 24.71 35.01 48.53 F-numbers 4.63 5.66 6.48 Half-angle (°): 36.23, 29.55, 23.08 Image height 18.10 19.85 20.68 Lens length: 105.60 mm, 98.52 mm, 99.03 mm BF 16.94 25.84 37.19 d 6 27.85 11.87 1.02 d14 10.04 10.38 10.30 d16 11.24 10.91 10.98 d18 16.94 25.84 37.19 Zoom lens group data Group starting plane focal length 1 1 -40.14 2 7 39.51 3 15 62.75 4 17 -185.51 [Numerical Example 2] Unit: mm Surface data Face number rd nd νd 1 194.836 1.40 1.63854 55.4 2 19.216 7.45 3* 97.731 3.30 1.53110 55.9 4 50.481 0.15 5 25.378 3.36 1.74077 27.8 6 40.484 (variable) 7 28.994 1.78 1.95375 32.3 8 -2837.037 4.32 9 -36.870 0.55 1.80810 22.8 10 26.363 0.35 11 61.033 1.82 1.85150 40.8 12 -30.900 2.06 13 (aperture) ∞ (variable) 14 ∞ 9.45 15 -87.219 2.77 1.48749 70.2 16 -22.880 (variable) 17* -140.744 3.55 1.53110 55.9 18* 244.765 (variable) Image plane ∞ Aspherical data 3rd page K = 0.00000e+000 A 4= 1.74257e-006 A 6=-2.46696e-009 A 8= 7.75729e-011 A10=-3.31377e-013 A12= 8.09051e-016 Page 17 K = 0.00000e+000 A 4=-8.76708e-005 A 6= 1.10417e-007 A 8= 2.08926e-009 A10=-3.00779e-011 A12= 1.05365e-013 Side 18 K = 0.00000e+000 A 4=-8.05410e-005 A 6= 2.07802e-007 A 8= 2.03128e-010 A10=-8.66422e-012 A12= 2.90115e-014 Various data Zoom ratio 1.96 Wide-angle, Medium, Telephoto Focal length 24.72 36.55 48.52 F-numbers: 4.64, 5.88, 6.49 Half-angle (°): 36.09, 28.56, 23.01 Image height 18.02 19.90 20.61 Lens length: 108.53 x 98.64 x 98.06 BF 16.96 26.55 36.14 d 6 30.74 11.26 1.09 d13 7.26 7.81 8.06 d16 11.25 10.70 10.44 d18 16.96 26.55 36.14 Zoom lens group data Group starting plane focal length 1 1 -44.09 2 7 41.43 3 14 62.74 4 17 -167.72 [Numerical Example 3] Unit: mm Surface data Face number rd nd νd 1 232.845 1.40 1.62299 58.2 2 19.941 7.96 3* 111.062 3.30 1.53110 55.9 4 51.120 0.15 5 27.285 3.28 1.85026 32.3 6 42.225 (variable) 7 21.725 3.96 1.95375 32.3 8 1131.357 2.85 9 -46.823 0.55 1.80810 22.8 10 20.233 0.51 11 60.580 1.70 1.80400 46.5 12 -36.758 1.68 13 (aperture) ∞ (variable) 14 ∞ 5.20 15 -49.571 2.22 1.49700 81.5 16 -27.201 (variable) 17* 39.782 3.43 1.53110 55.9 18* 50.673 (variable) Image plane ∞ Aspherical data 3rd page K = 0.00000e+000 A 4= 1.84216e-006 A 6= 8.01311e-010 A 8= 5.12283e-011 A10=-2.30863e-013 A12= 5.59343e-016 Page 17 K = 0.00000e+000 A 4=-4.36850e-005 A 6=-1.04709e-007 A 8= 1.10943e-009 A10=-6.81115e-012 A12= 1.19305e-014 Side 18 K = 0.00000e+000 A 4=-4.39901e-005 A 6=-9.00326e-008 A 8= 9.46107e-010 A10=-5.28840e-012 A12= 9.00245e-015 Various data Zoom ratio 1.96 Wide-angle, Medium, Telephoto Focal length 24.71 36.32 48.52 F-numbers: 4.64, 5.88, 6.49 Half-angle (°): 36.10, 28.72, 23.02 Image height 18.02 19.90 20.62 Lens length: 111.00 99.87 98.01 BF 16.96 26.97 36.98 d 6 34.02 12.88 1.01 d13 14.34 17.31 17.82 d16 7.48 4.50 3.99 d18 16.96 26.97 36.98 Zoom lens group data Group starting plane focal length 1 1 -46.24 2 7 38.99 3 14 117.40 4 17 314.18 [Numerical Example 4] Unit: mm Surface data Face number rd nd νd 1 -1120.940 1.40 1.63854 55.4 2 29.481 9.39 3* -105.871 3.30 1.53110 55.9 4* -390.341 0.15 5 37.169 5.61 2.00100 29.1 6 55.239 (variable) 7 22.578 3.84 1.85150 40.8 8 -4398.814 3.78 9 -49.047 3.04 1.76182 26.5 10 19.940 0.38 11 38.988 1.70 1.77250 49.6 12 -50.780 1.49 13 (aperture) ∞ (variable) 14 ∞ 8.31 15 -60.430 2.44 1.53775 74.7 16 -28.373 (variable) 17* 27.547 3.42 1.53110 55.9 18* 19.381 (variable) 19 -476.759 2.53 1.98612 16.5 20 -139.384 (variable) Image plane ∞ Aspherical data 3rd page K = 0.00000e+000 A 4= 1.73506e-005 A 6=-5.81504e-008 A 8= 2.33643e-010 A10=-4.73065e-013 A12= 3.72284e-016 Side 4 K = 2.78976e+002 A 4= 1.77155e-005 A 6=-5.73090e-008 A 8= 2.47146e-010 A10=-5.30598e-013 A12= 4.44306e-016 Page 17 K = 0.00000e+000 A 4=-1.15240e-004 A 6= 1.08980e-007 A 8= 1.09284e-009 A10=-9.51817e-012 A12= 2.49887e-014 Side 18 K = 0.00000e+000 A 4=-1.42130e-004 A 6= 2.49994e-007 A 8= 5.94173e-011 A10=-4.17813e-012 A12= 1.06545e-014 Various data Zoom ratio 2.07 Wide-angle, Medium, Telephoto Focal length 26.52 40.09 55.00 F-numbers: 4.63, 5.88, 6.49 Half-angle (°): 34.19, 26.40, 20.54 Image height 18.02 19.90 20.61 Lens length: 130.02 x 109.61 x 101.49 BF 11.57 11.28 11.00 d 6 47.80 18.28 1.05 d13 12.86 15.19 14.62 d16 4.53 2.19 2.76 d18 2.50 11.89 21.29 d20 11.57 11.28 11.00 Zoom lens group data Group starting plane focal length 1 1 -66.85 2 7 42.89 3 14 96.88 4 17 -144.01 5 19 199.00 [Numerical Example 5] Unit: mm Surface data Face number rd nd νd 1 80.208 1.40 1.63854 55.4 2 19.361 14.61 3* -164.348 2.80 1.53110 55.9 4* 253.136 0.15 5 38.801 2.51 1.92286 20.9 6 55.307 (variable) 7 21.105 4.44 1.91082 35.3 8 -157.113 0.10 9 -95.832 4.01 1.85451 25.2 10 15.464 0.27 11 20.249 2.55 1.63930 44.9 12 -54.619 1.98 13 (aperture) ∞ (variable) 14 -20.018 0.80 1.83481 42.7 15 -24.304 (variable) 16 ∞ 5.38 17 -79.509 2.82 1.49700 81.5 18 -23.407 (variable) 19* 106.844 3.57 1.53110 55.9 20 * 35.485 (variable) Image plane ∞ Aspherical data 3rd page K = 0.00000e+000 A 4= 8.19088e-006 A 6=-4.23962e-008 A 8= 4.87158e-011 A10=2.63400e-013 A12=-6.28278e-016 Side 4 K =-1.79037e+002 A 4= 6.17666e-006 A 6=-5.09905e-008 A 8= 3.25197e-011 A10=3.67841e-013 A12=-9.82139e-016 Page 19 K = 0.00000e+000 A 4=-1.33629e-004 A 6= 9.73781e-008 A 8= 1.70352e-009 A10=-1.81236e-011 A12= 4.81540e-014 Page 20 K = 0.00000e+000 A 4=-1.31273e-004 A 6= 3.10386e-007 A 8= 7.12932e-012 A10=-5.06314e-012 A12= 1.39234e-014 Various data Zoom ratio 2.35 Wide-angle, Medium, Telephoto Focal length 20.61 33.70 48.50 F-numbers: 4.63, 5.88, 6.49 Half-angle (°): 41.17 30.56 23.03 Image height 18.02 19.90 20.61 Lens length: 120.00 x 104.38 x 100.66 BF 10.49 20.91 31.34 d 6 41.21 15.16 1.01 d13 4.86 6.13 7.40 d15 6.56 8.20 6.82 d18 9.48 6.58 6.69 d20 10.49 20.91 31.34 Zoom lens group data Group starting plane focal length 1 1 -45.32 2 7 32.92 3 14 -148.57 4 16 65.65 5 19 -101.81 [Numerical Example 6] Unit: mm Surface data Face number rd nd νd 1 91.050 1.40 1.63854 55.4 2 22.276 17.49 3* -59.262 2.80 1.53110 55.9 4* -858.745 0.15 5 46.234 3.30 1.92286 20.9 6 79.048 (Variable) 7 21.043 4.64 1.80400 46.5 8 172.624 2.15 9 -5060.863 4.00 1.73037 32.2 10 13.782 0.37 11 17.389 4.12 1.75500 52.3 12 -278.333 1.71 13 (aperture) ∞ (variable) 14* -66.256 1.20 1.82165 24.0 15 -282.440 3.65 16 ∞ (Variable) 17 -129.496 4.64 1.59522 67.7 18 -13.532 1.00 1.72916 54.7 19 -22.824 (variable) 20* 110.948 2.98 1.53110 55.9 21 * 29.174 (variable) 22 154.476 2.41 1.98612 16.5 23 -14900.415 (variable) Image plane ∞ Aspherical data 3rd page K = 0.00000e+000 A 4= 2.47198e-005 A 6=-8.08847e-008 A 8= 1.65476e-010 A10=-1.37297e-013 A12= 3.16753e-017 Side 4 K =-8.61713e+003 A 4= 1.91654e-005 A 6=-6.74993e-008 A 8= 7.58767e-011 A10= 1.07307e-013 A12=-2.66741e-016 Side 14 K = 0.00000e+000 A 4=-9.45333e-006 A 6= 1.17313e-007 A 8=-6.37183e-012 A10= 2.95045e-011 A12= 0.00000e+000 Page 20 K = 0.00000e+000 A 4=-1.23685e-004 A 6= 4.03138e-007 A 8= 6.98371e-010 A10=-1.74137e-011 A12= 5.43473e-014 Page 21 K = 0.00000e+000 A 4=-1.34776e-004 A 6= 5.78897e-007 A 8=-1.36238e-009 A10=-2.66916e-012 A12= 1.50537e-014 Various data Zoom ratio 2.84 Wide-angle, Medium, Telephoto Focal length 20.61 39.47 58.50 F-numbers: 4.64, 5.88, 6.49 Half-angle (°): 41.17, 26.75, 19.41 Image height 18.02 19.90 20.61 Lens length: 135.00, 120.11, 125.50 BF 10.49 11.09 11.70 d 6 46.04 13.39 1.02 d13 2.30 4.06 5.83 d16 7.15 9.97 10.76 d19 9.71 5.12 2.57 d21 1.30 18.46 35.61 d23 10.49 11.09 11.70 Zoom lens group data Group starting plane focal length 1 1 -47.50 2 7 34.88 3 14 -105.62 4 17 55.50 5 20 -75.48 6 22 155.06 The various values ​​in each numerical example are summarized in Table 1 below.

[0068] [Table 1]

[0069] [Imaging device] Next, an embodiment of a digital camera (imaging device) using the zoom lens L0 of the present invention as an imaging optical system will be described with reference to Figure 13. Figure 13 is a schematic diagram of the imaging device (digital still camera) 10 of this embodiment. The imaging device 10 comprises a camera body 13, a zoom lens 11 which is the same as in any of the embodiments 1 to 6 described above, and a light-receiving element (image sensor) 12 which is built into the camera body 13 and converts the optical image formed by the zoom lens 11 into photoelectricity. The camera body 13 may be a so-called single-lens reflex camera with a quick-turn mirror, or a so-called mirrorless camera without a quick-turn mirror.

[0070] The imaging device 10 of this embodiment has a zoom lens 11 that is compact and has good optical characteristics, so it can obtain high-quality images.

[0071] Furthermore, an image sensor such as a CCD or CMOS sensor can be used as the light-receiving element 12. In this case, the output image can be made higher quality by electrically correcting various aberrations such as distortion and chromatic aberration of the image acquired by the light-receiving element 12.

[0072] Furthermore, the zoom lens L0 in each of the above embodiments can be applied not only to the digital still camera shown in Figure 13, but also to various optical instruments such as silver halide film cameras, video cameras, and telescopes. [Imaging System] Furthermore, an imaging system (surveillance camera system) may be configured that includes the zoom lens L0 of each embodiment and a control unit that controls the zoom lens L0. In this case, the control unit can control the zoom lens L0 so that each lens group moves as described above during zooming, focusing, and image blur correction. At this time, the control unit does not need to be integrally configured with the zoom lens L0, and the control unit may be configured separately from the zoom lens L0. For example, a configuration may be adopted in which a control unit (control device) located far away from the drive unit that drives each lens of the zoom lens L0 has a transmission unit that sends control signals (commands) for controlling the zoom lens L0. With such a control unit, the zoom lens L0 can be remotely operated.

[0073] Alternatively, the control unit may be equipped with an operating section such as a controller or buttons for remotely controlling the zoom lens L0, thereby enabling a configuration that controls the zoom lens L0 in response to user input to the operating section. For example, the operating section may include a zoom-in button and a zoom-out button. In this case, the control unit should be configured to send a signal to the drive unit of the zoom lens L0 so that when the user presses the zoom-in button, the magnification of the zoom lens L0 increases, and when the user presses the zoom-out button, the magnification of the zoom lens L0 decreases.

[0074] Furthermore, the imaging system may have a display unit, such as an LCD panel, that displays information (movement status) related to the zoom of the zoom lens L0. This information could include, for example, the zoom magnification (zoom status) or the amount of movement of each lens group (movement status). In this case, the user can remotely operate the zoom lens L0 via the control unit while viewing the zoom information of the zoom lens L0 displayed on the display unit. In this case, the display unit and the control unit may be integrated by, for example, using a touch panel.

[0075] Although preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of its gist. [Explanation of symbols]

[0076] L0 Zoom Lens L1 First lens group L2 Second lens group LR rear group LP Focus Lens Group

Claims

1. A zoom lens comprising, in order from an object side to an image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a rear group including one or more lens groups, in which the spacing between adjacent lens groups changes during zooming, the first lens group includes a first negative lens and a second negative lens arranged in this order from the object side to the image side, the rear group includes a focus lens group having positive refractive power that moves from the image side to the object side during focusing from infinity to a close distance, When the focal length of the focus lens group is fLP, the focal length of the first lens group is fL1, the focal length of the second lens group is fL2, the focal length of the first negative lens is fG1, and the focal length of the second negative lens is fG2, 1.20<fLP / fL2<3.20 -3.00<fL1 / fL2<-0.85 0<fG1 / fG2<0.42 A zoom lens characterized by satisfying the following conditional expressions:

2. When the distance on the optical axis from the aperture stop to the image plane at the wide-angle end is DSPw, and the total lens length of the zoom lens at the wide-angle end is TLw, 0.25<DSPw / TLw<0.53 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. the first lens group includes a first negative lens and a second negative lens arranged in this order from the object side to the image side, When the refractive index of the first negative lens is ndG1, 1.40<ndG1<1.69 3. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. the first lens group includes a first negative lens and a second negative lens arranged in this order from the object side to the image side, When the Abbe number of the first negative lens is νdG1, 45<νdG1<95 4. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the refractive index of the positive lens having the largest refractive power among the positive lenses included in the focus lens group is denoted by ndLPP, 1.40<ndLPP<1.65 5. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. When the Abbe number of the positive lens having the largest refractive power among the positive lenses included in the focus lens group is νdLPP, 45<νdLPP<95 6. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. When the refractive index of the positive lens having the largest refractive power among the positive lenses included in the first lens group is denoted by ndL1P, 1.60<ndL1P<2.10 7. The zoom lens according to claim 1, wherein the following condition is satisfied:

8. When the Abbe number of the positive lens having the largest refractive power among the positive lenses included in the first lens group is νdL1P, 15<νdL1P<45 8. The zoom lens according to claim 1, wherein the following condition is satisfied:

9. the first lens group includes a first negative lens and a second negative lens arranged in this order from the object side to the image side, 9. The zoom lens according to claim 1, wherein the first negative lens and the second negative lens have an air gap on the optical axis.

10. When the amount of movement of the focus lens group during zooming from the wide-angle end to the telephoto end in a state where the focus is focused on infinity is MLP, and the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end is ML2, 0.50<MLP / ML2<1.50 10. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. the first lens group includes a first negative lens and a second negative lens arranged in this order from the object side to the image side, When the radius of curvature of the lens surface on the image side of the first negative lens is G1R2 and the radius of curvature of the lens surface on the object side of the first negative lens is G1R1, -3.00<(G1R2+G1R1) / (G1R2-G1R1)<-0.10 11. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. 12. The zoom lens according to claim 1, wherein the first lens group consists of a first negative lens, a second negative lens, and a positive lens, arranged in this order from the object side to the image side.

13. the first lens group includes a first negative lens and a second negative lens arranged in this order from the object side to the image side, 13. The zoom lens according to claim 1, wherein the second negative lens is made of a resin material.

14. the first lens group includes a first negative lens and a second negative lens arranged in this order from the object side to the image side, 14. The zoom lens according to claim 1, wherein at least one of the object-side and image-side lens surfaces of the second negative lens has an aspheric shape.

15. the second lens group includes an aperture stop; 15. The zoom lens according to claim 1, wherein the aperture diaphragm is disposed closest to the image side of the second lens group.

16. 16. The zoom lens according to claim 1, wherein the number of lenses in the second lens group is three or less.

17. 17. The zoom lens according to claim 1, wherein the focus lens group is composed of one positive lens element having a meniscus shape with a concave surface facing the object side.

18. 18. The zoom lens according to claim 1, wherein the second lens group moves in a direction including a component perpendicular to an optical axis during image blur correction.

19. The rear group includes at least one aspheric lens, 19. The zoom lens according to claim 1, wherein at least one of an object side lens surface and an image side lens surface of the aspherical lens is an aspherical surface having an inflection point.

20. A zoom lens as described in any one of claims 1 to 19, characterized in that the first lens group moves in a trajectory that is convex toward the image side when zooming from the wide-angle end to the telephoto end.

21. 21. The zoom lens according to claim 1, wherein the rear group consists of a third lens group having a positive refractive power and a fourth lens group having a negative refractive power, arranged in this order from the object side to the image side.

22. 21. The zoom lens according to claim 1, wherein the rear group consists of a third lens group having a positive refractive power and a fourth lens group having a positive refractive power, arranged in this order from the object side to the image side.

23. 21. The zoom lens according to claim 1, wherein the rear group consists of, arranged in order from the object side to the image side, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power.

24. 21. The zoom lens according to claim 1, wherein the rear group consists of, arranged in order from the object side to the image side, a third lens group having negative refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power.

25. 21. The zoom lens according to claim 1, wherein the rear group consists of, arranged in order from the object side to the image side, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group having positive refractive power.

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

27. 27. The image pickup apparatus according to claim 26, wherein an effective image circle diameter of said image pickup element at a wide-angle end is smaller than an effective image circle diameter at a telephoto end.

28. 28. An imaging system comprising: a zoom lens according to claim 1; and a control unit that controls the zoom lens during zooming.

29. 29. The imaging system according to claim 28, wherein the control unit is configured as a separate unit from the zoom lens, and includes a transmission unit that transmits a control signal for controlling the zoom lens.

30. 30. The imaging system according to claim 28, wherein the control unit is configured as a separate unit from the zoom lens, and has an operation unit for operating the zoom lens.

31. 31. The imaging system according to claim 28, further comprising a display unit that displays information related to the zoom of the zoom lens.

Images