Zoom lens and imaging device

Abstract

To provide a zoom lens which offers a reduced size and higher magnification and is advantageous in terms of autofocusing, and to provide an image capturing device having the same.SOLUTION: A zoom lens is provided, comprising, in order from the object side, a first lens group having positive refractive power, an intermediate group comprising multiple lens groups configured to alter distances between adjacent lens groups thereof when zooming, and a final lens group. A focusing group configured to move while focusing is located in the intermediate group. The zoom lens satisfies predefined conditional expressions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology of the present disclosure relates to a zoom lens and an imaging device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, as zoom lenses applicable to imaging devices such as digital cameras and video cameras, lens systems described in, for example, Patent Documents 1 and 2 below are known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 116563 [Patent Document 2] International Publication No. 2019 / 116565 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for a zoom lens that is compact, has a high magnification, and is advantageous for autofocus.

[0005] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a zoom lens that is compact, has a high magnification, and is advantageous for autofocusing, and an imaging device equipped with this zoom lens. [Means for solving the problem]

[0006] A zoom lens according to a first aspect of the present disclosure comprises, in order from the object side to the image side, a first lens group having positive refractive power, an intermediate group including a plurality of lens groups whose spacing between adjacent lens groups changes during zooming, and a final lens group, wherein a focusing group that moves during focusing is disposed within the intermediate group, and assuming that DF is the difference in the optical axis direction between the position of the focusing group when focused on an object at infinity at the telephoto end and the position of the focusing group when the lateral magnification of the entire system at the telephoto end is -0.1 times, and ft is the focal length of the entire system when focused on an object at infinity at the telephoto end, then: 0.04 <DF / ft<0.4 (1) The conditional expression (1) expressed by the following formula is satisfied.

[0007] The zoom lens according to the first aspect of the present invention comprises: 0.05 <DF / ft<0.2 (1-1) It is preferable that conditional formula (1-1) represented by the following formula (1-1) is satisfied.

[0008] In the zoom lens according to the first aspect described above, when the difference in the optical axis direction between the position of each lens group in the middle group when focused on an object at infinity at the wide-angle end and the position of each lens group in the middle group when focused on an object at infinity at the telephoto end is defined as the zoom movement amount, the zoom movement amount of the lens group in the middle group with the largest zoom movement amount is defined as DV, and the focal length of the entire system when focused on an object at infinity at the wide-angle end is defined as fw, 2 <DV / fw<18 (2) It is preferable to satisfy conditional expression (2) expressed as follows:

[0009] A zoom lens according to a second aspect of the present disclosure includes, in order from the object side to the image side, a first lens group having positive refractive power, an intermediate group including a plurality of lens groups whose spacing between adjacent lens groups changes during magnification change, and a final lens group, wherein a focusing group that moves during focusing is disposed within the intermediate group, and when the difference in the optical axis direction between the position of each lens group of the intermediate group when focused on an object at infinity at the wide-angle end and the position of each lens group when focused on an object at infinity at the telephoto end is defined as the zoom movement amount, DV is the zoom movement amount of the lens group in the intermediate group that has the largest zoom movement amount, and fw is the focal length of the entire system when focused on an object at infinity at the wide-angle end, 2 <DV / fw<18 (2) The condition (2) expressed by the following formula (2) is satisfied.

[0010] The zoom lens according to the second aspect of the present invention has 3.5 <DV / fw<15 (2-1) It is preferable that conditional formula (2-1) expressed by the following formula (2-1) is satisfied.

[0011] In the following description, the zoom lenses according to the first and second aspects will be collectively referred to as the zoom lenses according to the above aspects. If the lateral magnification of the focusing group when focused on an object at infinity at the telephoto end is βFt, and the combined lateral magnification of all lenses on the image side of the focusing group when focused on an object at infinity at the telephoto end is βRt, the zoom lenses according to the above aspects are 0.5<(1-βFt 2 ) × βRt 2 <5 (3) It is preferable to satisfy conditional expression (3) expressed as follows:

[0012] It is preferable that the intermediate group includes at least one negative moving lens group, which is a lens group that has negative refractive power and moves during magnification change. In a configuration in which the zoom lens of the above aspect includes at least one negative moving lens group, when a plurality of negative moving lens groups are arranged in succession in the intermediate group, the composite lateral magnification of the plurality of negative moving lens groups arranged in succession in a state focused on an object at infinity at the wide-angle end is βMnw, and the composite lateral magnification of the plurality of negative moving lens groups arranged in succession in a state focused on an object at infinity at the telephoto end is βMnt, and when a plurality of negative moving lens groups are not arranged in succession in the intermediate group, the lateral magnification of any one of the negative moving lens groups in a state focused on an object at infinity at the wide-angle end is βMnw, and the lateral magnification of any one of the negative moving lens groups in a state focused on an object at infinity at the telephoto end is βMnt, and the focal length of the negative moving lens group with the strongest refractive power among the negative moving lens groups of the intermediate group is fMn1, and the focal length of the final lens group is fE, the zoom lens of the above aspect is as follows. -0.5<βMnw<-0.05 (4) -24<βMnt<-2 (5) 0.02<|fMn1 / fE|<0.2 (6) It is preferable to satisfy the following conditional expressions (4), (5), and (6):

[0013] If the focal length of the focusing group is fF and the focal length of the final lens group is fE, then the zoom lens of the above embodiment is 0.04<|fF / fE|<0.4 (7) It is preferable to satisfy conditional expression (7) expressed as follows:

[0014] It is preferable that the intermediate group includes at least one negative moving lens group, which is a lens group that has negative refractive power and moves during magnification change. In the configuration in which the zoom lens of the above aspect includes at least one negative moving lens group, when a plurality of negative moving lens groups are arranged in succession in the intermediate group, the composite lateral magnification of the plurality of negative moving lens groups arranged in succession in a state focused on an infinite object at the wide-angle end is βMnw, and the composite lateral magnification of the plurality of negative moving lens groups arranged in succession in a state focused on an infinite object at the telephoto end is βMnt, and when a plurality of negative moving lens groups are not arranged in succession in the intermediate group, the lateral magnification of any one of the negative moving lens groups in a state focused on an infinite object at the wide-angle end is βMnw, and the lateral magnification of any one of the negative moving lens groups in a state focused on an infinite object at the telephoto end is βMnt, the focal length of the focusing group is fF, and the focal length of the final lens group is fE, the zoom lens of the above aspect is -0.5<βMnw<-0.05 (4) -24<βMnt<-2 (5) 0.04<|fF / fE|<0.4 (7) It is preferable to satisfy the following conditional expressions (4), (5), and (7):

[0015] When the sum of the distance on the optical axis from the lens surface of the first lens group closest to the object to the lens surface of the final lens group closest to the image when focused on an object at infinity at the telephoto end and the back focus of the entire system in air equivalent distance is defined as TTL, and the focal length of the entire system when focused on an object at infinity at the telephoto end is defined as ft. The zoom lens of the above embodiment has the following characteristics: 0.5 <TTL / ft<3 (8) It is preferable to satisfy conditional expression (8) expressed as follows:

[0016] In the zoom lens of the above aspect, it is preferable that the first lens group is fixed with respect to the image plane during zooming.

[0017] In the zoom lens of the above aspect, it is preferable that the first lens group includes at least two positive lenses.

[0018] The zoom lens of the above aspect is described by taking the difference in the optical axis direction between the position of each lens group in the middle group when focused on an object at infinity at the wide-angle end and the position of each lens group in the middle group when focused on an object at infinity at the telephoto end as the zoom movement amount, the zoom movement amount of the lens group in the middle group with the largest zoom movement amount as DV, the maximum image height as Ymax, the focal length of the entire system when focused on an object at infinity at the telephoto end as ft, and the focal length of the entire system when focused on an object at infinity at the wide-angle end as fw. 5 <DV / {Ymax×log(ft / fw)}<15 (9) It is preferable to satisfy conditional expression (9) expressed as follows:

[0019] If the difference in the optical axis direction between the position of the focusing group when focused on an object at infinity at the telephoto end and the position of the focusing group when the lateral magnification of the entire system at the telephoto end is -0.1 times is DF and the focal length of the focusing group is fF, then the zoom lens of the above embodiment is 0.1<|DF / fF|<1 (10) It is preferable to satisfy conditional expression (10) expressed as follows:

[0020] In the zoom lens of the above aspect, it is preferable that the focusing group is disposed closest to the image side within the intermediate group.

[0021] In the zoom lens of the above aspect, the lens group that moves during magnification change is defined as a moving lens group, and the moving lens group closest to the object among the moving lens groups in the intermediate group is defined as the leading moving lens group. When the intermediate group includes a moving lens group train consisting of a plurality of moving lens groups arranged in succession including the leading moving lens group, the composite focal length of the moving lens group train in a state focused on an object at infinity at the wide-angle end is defined as fMVw, and when the intermediate group does not include a moving lens group train, the focal length of the leading moving lens group is defined as fMVw and the focal length of the first lens group is defined as f1, the zoom lens of the above aspect is as follows: -0.4 <fMVw / f1<-0.03 (11) It is preferable to satisfy conditional expression (11) expressed as follows:

[0022] In the zoom lens of the above aspect, the lens group that moves during magnification change is defined as a moving lens group, and the moving lens group closest to the object among the moving lens groups in the intermediate group is defined as the leading moving lens group. When the intermediate group includes a moving lens group train consisting of a plurality of moving lens groups arranged in succession including the leading moving lens group, the combined lateral magnification of the moving lens group train in a state focused on an object at infinity at the telephoto end is defined as βMVt, and when the intermediate group does not include a moving lens group train, the lateral magnification of the leading moving lens group in a state focused on an object at infinity at the telephoto end is defined as βMVt. -20<βMVt<-1.1 (12) It is preferable to satisfy conditional expression (12) expressed as follows:

[0023] It is preferable that the intermediate group includes at least one fixed lens group, which is a lens group that is fixed with respect to the image plane during zooming. In the zoom lens of the above embodiment including at least one fixed lens group, if the lateral magnification of the final lens group at the telephoto end in a state where it is focused on an object at infinity, is βE, and the lateral magnification of the fixed lens group closest to the image side among the fixed lens groups in the intermediate group at the telephoto end in a state where it is focused on an object at infinity, is βMS, the zoom lens of the above embodiment is 1<βE<2 (13) -1.8<1 / βMS<1.4 (14) It is preferable to satisfy the following conditional expressions (13) and (14):

[0024] The lateral magnification of the focusing group when focused on an object at infinity at the wide-angle end is βFw, and the combined lateral magnification of all lenses on the image side of the focusing group when focused on an object at infinity at the wide-angle end is βRw, and γ = (1-βFw 2 ) × βRw 2 Let fF be the focal length of the focusing group, fRw be the composite focal length of all lenses on the image side of the focusing group when focused on an object at infinity at the wide-angle end, De be the distance from the exit pupil position to the image plane when focused on an object at infinity at the wide-angle end, the sign of De is positive if the exit pupil position is closer to the object side than the image plane and negative if the exit pupil position is closer to the image side than the image plane, and the maximum image height is Ymax, then the zoom lens of the above aspect is -0.1<{βFw / (fF×γ)-1 / (βRw×fRw)-(1 / De)}×Ymax<0.1 (15) It is preferable to satisfy conditional expression (15) expressed as follows:

[0025] An imaging device according to another aspect of the present disclosure includes the zoom lens according to the above aspect of the present disclosure.

[0026] In addition, in this specification, "consisting of" and "consisting of" are intended to mean that, in addition to the listed components, the following may be included: a lens that has substantially no refractive power, optical elements other than lenses such as an aperture, a filter, and a cover glass, and mechanical parts such as a lens flange, a lens barrel, an image sensor, and an image stabilization mechanism.

[0027] In this specification, "a group having positive refractive power" means that the group as a whole has positive refractive power. Similarly, "a group having negative refractive power" means that the group as a whole has negative refractive power. "A lens having positive refractive power" and "a positive lens" are synonymous. "A lens having negative refractive power" and "a negative lens" are synonymous. Each "lens group" and "focusing group" in this specification is not limited to a configuration consisting of multiple lenses, and may be a configuration consisting of only one lens.

[0028] A compound aspherical lens (a lens that is constructed by integrating a spherical lens with an aspherical film formed on the spherical lens, and functions as a single aspherical lens as a whole) is not considered a cemented lens, but is treated as a single lens. The sign of the refractive power of a lens that includes an aspherical surface is that of the paraxial region, unless otherwise specified.

[0029] In this specification, "whole system" refers to a zoom lens. "Back focus" is the distance on the optical axis from the lens surface closest to the image side of the zoom lens to the image plane. "Focal length" used in the conditional expressions is the paraxial focal length. Unless otherwise specified, the values ​​used in the conditional expressions are values ​​based on the d-line.

[0030] The terms "d-line," "C-line," "F-line," and "g-line" used in this specification are emission lines, and the wavelength of the d-line is 587.56 nm (nanometers), the wavelength of the C-line is 656.27 nm (nanometers), the wavelength of the F-line is 486.13 nm (nanometers), and the wavelength of the g-line is 435.84 nm (nanometers). Effect of the Invention

[0031] According to the present disclosure, it is possible to provide a zoom lens that is compact, has a high magnification, and is advantageous for autofocus, and an imaging device equipped with this zoom lens. [Brief description of the drawings]

[0032] [Figure 1] 1A and 1B correspond to the zoom lens of Example 1 and are diagrams showing a cross-sectional view of the configuration of a zoom lens according to an embodiment and a movement locus thereof. [Diagram 2] 2A to 2C are diagrams illustrating the configuration and light beams in each state of the zoom lens in FIG. [Diagram 3] 3A to 3C are diagrams showing various aberrations of the zoom lens of Example 1. [Figure 4] 11A and 11B are diagrams illustrating a cross-sectional view of the configuration of a zoom lens according to a second embodiment and a movement locus thereof. [Diagram 5] 6A to 6C are diagrams showing various aberrations of the zoom lens of Example 2. [Figure 6] 11A and 11B are diagrams illustrating a cross-sectional view of the configuration of a zoom lens according to a third embodiment and a movement locus thereof. [Figure 7] 11A to 11C are diagrams showing various aberrations of the zoom lens of Example 3. [Figure 8] 11A and 11B are diagrams illustrating a cross-sectional view of the configuration of a zoom lens according to a fourth embodiment and a movement locus thereof. [Figure 9] 11A to 11C are diagrams illustrating configurations and light beams in each state of a zoom lens according to a fourth embodiment. [Figure 10] 11A to 11C are diagrams showing various aberrations of the zoom lens of Example 4. [Figure 11] 13A and 13B are diagrams illustrating a cross-sectional view of the configuration of a zoom lens according to a fifth embodiment and a movement locus thereof. [Figure 12] 13A to 13C are diagrams showing various aberrations of the zoom lens of Example 5. [Figure 13] 13A and 13B are diagrams illustrating a cross-sectional view of the configuration of a zoom lens according to a sixth embodiment and a movement locus thereof. [Figure 14] 13A to 13C are diagrams showing various aberrations of the zoom lens of Example 6. [Figure 15] 13A and 13B are diagrams illustrating a cross-sectional view and a movement locus of a zoom lens according to a seventh embodiment. [Figure 16] 13A to 13C are diagrams showing various aberrations of the zoom lens of Example 7. [Figure 17] 13A and 13B are diagrams illustrating a cross-sectional view of the configuration of a zoom lens according to an eighth embodiment and a movement locus thereof. [Figure 18] 13A to 13C are diagrams illustrating configurations and light beams in each state of a zoom lens according to an eighth embodiment. [Figure 19] 13A to 13C are diagrams showing various aberrations of the zoom lens of Example 8. [Figure 20] 13A and 13B are diagrams illustrating a cross-sectional view and a movement locus of a zoom lens according to a ninth embodiment. [Figure 21] 13A to 13C are diagrams showing various aberrations of the zoom lens of Example 9. [Figure 22] 1 is a diagram illustrating a schematic configuration of an imaging device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0034] FIG. 1 shows a cross-sectional view of the configuration and the movement trajectory of the zoom lens according to an embodiment of the present disclosure at the wide-angle end. FIG. 2 shows cross-sectional views of the configuration and the light beams in each state of the zoom lens in FIG. 1. In FIG. 2, the upper row labeled "WIDE" shows a state in which an object at infinity is focused at the wide-angle end, the middle row labeled "TELE" shows a state in which an object at infinity is focused at the telephoto end, and the lower row labeled "TELE, β=-0.1" shows a state in which the lateral magnification of the zoom lens at the telephoto end is -0.1 times. In FIG. 2, the upper row shows the axial light beam wa and the light beam wb at the maximum image height, the middle row shows the axial light beam ta and the light beam tb at the maximum image height, and the lower row shows the axial light beam ta1 and the light beam tb1 at the maximum image height. The examples shown in FIG. 1 and FIG. 2 correspond to the zoom lens of Example 1 described later. In FIG. 1 and FIG. 2, the left side is the object side, and the right side is the image side. A zoom lens according to an embodiment of the present disclosure will be described below mainly with reference to FIG.

[0035] In FIG. 1, assuming that the zoom lens is applied to an imaging device, an example is shown in which an optical member PP with parallel entrance and exit surfaces is disposed between the zoom lens and an image plane Sim. The optical member PP is a member assuming a protective cover glass, various filters according to the use of the imaging device, a prism, and the like. The various filters are, for example, a low-pass filter, an infrared cut filter, and a filter that cuts a specific wavelength range. The optical member PP is a member that does not have a refractive power. It is also possible to configure the imaging device without the optical member PP.

[0036] The zoom lens according to this embodiment is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a middle group GM, and a final lens group GE. By making the first lens group G1, which is the closest to the object side, a lens group having positive refractive power, it is advantageous for shortening the overall length of the lens system. When varying the magnification, the distance between the first lens group G1 and the middle group GM changes, and the distance between the middle group GM and the final lens group GE changes.

[0037] The intermediate group GM includes a plurality of lens groups whose spacing between adjacent lens groups changes when the magnification is changed. In this specification, the term "lens group" refers to a component of a zoom lens, which is a portion including at least one lens and separated by an air gap that changes when the magnification is changed. When the magnification is changed, each lens group is moved or fixed, and the spacing between lenses in one lens group does not change. In other words, in this specification, one lens group is defined as a group whose spacing between adjacent groups changes when the magnification is changed, but the total spacing between adjacent lenses does not change within itself.

[0038] As an example, the zoom lens in Fig. 1 is composed of, in order from the object side to the image side, a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6. In the example in Fig. 1, the middle group GM is composed of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5.

[0039] As an example, each lens group in the example of FIG. 1 is composed of the lenses described below. The first lens group G1 is composed of three lenses, L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of one lens, L21. The third lens group G3 is composed of four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 is composed of an aperture stop St and five lenses, L41 to L45, in order from the object side to the image side. The fifth lens group G5 is composed of three lenses, L51 to L53, in order from the object side to the image side. The sixth lens group G6 is composed of two lenses, L61 to L62, in order from the object side to the image side. The aperture stop St in FIG. 1 does not indicate the shape or size, but indicates the position in the optical axis direction.

[0040] In the example of Fig. 1, during zooming, the first lens group G1, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image plane Sim, and the second lens group G2, the third lens group G3, and the fifth lens group G5 move along the optical axis Z while changing the intervals between adjacent lens groups. In Fig. 1, during zooming from the wide-angle end to the telephoto end, a curved arrow is shown below each moving lens group to indicate its approximate movement trajectory, and a ground symbol is shown below each lens group that is fixed with respect to the image plane Sim.

[0041] As shown in the example of FIG. 1, it is preferable that the first lens group G1 is fixed relative to the image plane Sim when the magnification is changed. In this case, the overall length of the lens system does not change even when the magnification is changed, so that the change in the center of gravity when the magnification is changed can be suppressed. This is particularly effective when the zoom lens is mounted on a gimbal, since it can suppress the change in the center of gravity when the magnification is changed. In this case, it is also preferable that the lens group closest to the object in the intermediate group GM moves when the magnification is changed.

[0042] In the zoom lens according to this embodiment, the focusing group that moves during focusing is disposed in the middle group GM. The focusing group includes at least one lens and performs focusing by moving along the optical axis Z. By disposing the focusing group in the middle group GM closer to the image side than the first lens group G1, the effective diameter of the focusing group can be made smaller, which is advantageous for miniaturization. In the example of FIG. 1, the focusing group is made up of the fifth lens group G5. The brackets and horizontal arrow below the fifth lens group G5 in FIG. 1 indicate that the fifth lens group G5 is the focusing group.

[0043] Next, preferred and possible configurations regarding the conditional expressions of the zoom lens of the present disclosure will be described. In the following, a lens group that moves during magnification change will be called a "moving lens group," and a lens group that is fixed relative to the image plane Sim during magnification change will be called a "fixed lens group." In addition, in the following description of preferred and possible configurations, the "zoom lens of the present disclosure" will also be simply called a "zoom lens" to avoid redundancy.

[0044] Regarding the amount of movement of the focusing group, it is preferable that the zoom lens satisfies the following conditional formula (1). Here, DF is the difference in the optical axis direction between the position of the focusing group when focused on an object at infinity at the telephoto end and the position of the focusing group when the lateral magnification of the entire system at the telephoto end is -0.1 times. Also, ft is the focal length of the entire system when focused on an object at infinity at the telephoto end. As an example, DF is shown in FIG. 2. By making the corresponding value of conditional formula (1) not equal to or less than the lower limit, it is possible to suppress aberration fluctuations during focusing, making it easy to achieve both high optical performance and high magnification. By making the corresponding value of conditional formula (1) not equal to or more than the upper limit, it is possible to suppress an increase in the overall length of the lens system, making it easy to achieve both high magnification and small size and light weight. Also, by making the corresponding value of conditional formula (1) not equal to or more than the upper limit, it is possible to make the lens system advantageous for autofocus. In order to obtain better characteristics, it is more preferable that the zoom lens satisfies the following conditional expression (1-1), and it is even more preferable that the zoom lens satisfies the following conditional expression (1-2). 0.04 <DF / ft<0.4 (1) 0.05 <DF / ft<0.2 (1-1) 0.05 <DF / ft<0.15 (1-2)

[0045] When the difference in the optical axis direction between the position of each lens group in the middle group GM when it is focused on an object at infinity at the wide-angle end and the position of each lens group in the telephoto end when it is focused on an object at infinity is taken as the zoom movement amount, it is preferable that the zoom lens satisfies the following conditional formula (2). Here, the zoom movement amount of the lens group with the largest zoom movement amount among the lens groups in the middle group GM is taken as DV. Also, the focal length of the entire system when it is focused on an object at infinity at the wide-angle end is taken as fw. In the example of FIG. 1, the lens group with the largest zoom movement amount is the third lens group. As an example, FIG. 2 shows DV. By making the corresponding value of conditional formula (2) not smaller than the lower limit, the refractive power of the moving lens group in the middle group GM does not become too strong, so that it is easy to achieve both suppression of aberration fluctuations such as field curvature, distortion, and chromatic aberration of magnification during zooming and high magnification. Furthermore, by ensuring that the corresponding value of conditional expression (2) is not below the lower limit, it is advantageous to reduce the lens diameter of the focusing group, and a lens system that is advantageous for autofocusing can be obtained. By ensuring that the corresponding value of conditional expression (2) is not above the upper limit, the zoom movement amount of the moving lens group can be suppressed, which is advantageous to shorten the overall length of the lens system and makes it easier to make it compact. In order to obtain better characteristics, it is more preferable for the zoom lens to satisfy the following conditional expression (2-1), and it is even more preferable for the zoom lens to satisfy the following conditional expression (2-2). 2 <DV / fw<18 (2) 3.5 <DV / fw<15 (2-1) 5 <DV / fw<12 (2-2)

[0046] If the lateral magnification of the focusing group when focused on an object at infinity at the telephoto end is βFt, and the combined lateral magnification of all lenses on the image side of the focusing group when focused on an object at infinity at the telephoto end is βRt, it is preferable that the zoom lens satisfy the following conditional expression (3): (1-βFt 2 ) × βRt 2is the ratio of the amount of movement of the image plane to the unit amount of movement of the focusing group when focused on an object at infinity at the telephoto end, that is, the so-called backlash magnification. By ensuring that the corresponding value of conditional expression (3) is not below the lower limit, the overall length of the lens system can be prevented from increasing, making it easy to achieve a compact and lightweight lens system. By ensuring that the corresponding value of conditional expression (3) is not above the upper limit, aberration fluctuations during focusing can be suppressed, making it easy to achieve both high optical performance and high magnification. In order to obtain better characteristics, it is more preferable for the zoom lens to satisfy the following conditional expression (3-1), and it is even more preferable for the zoom lens to satisfy the following conditional expression (3-2). 0.5<(1-βFt 2 ) × βRt 2 <5 (3) 0.6<(1-βFt 2 ) × βRt 2 <3 (3-1) 0.7<(1-βFt 2 ) × βRt 2 <2 (3-2)

[0047] It is preferable that the middle group GM includes at least one moving lens group having negative refractive power. Hereinafter, the moving lens group having negative refractive power is referred to as the "negative moving lens group". In a configuration in which the middle group GM includes at least one negative moving lens group, it is preferable that the zoom lens satisfies the following conditional expression (4). Here, βMnw is defined as follows depending on the case. When a plurality of negative moving lens groups are consecutively arranged in the middle group GM, the combined lateral magnification of the consecutively arranged plurality of negative moving lens groups in a state in which the lens is focused on an object at infinity at the wide-angle end is βMnw. When a plurality of negative moving lens groups are not consecutively arranged in the middle group GM, the lateral magnification of any one of the negative moving lens groups in a state in which the lens is focused on an object at infinity at the wide-angle end is βMnw. That is, when a plurality of negative moving lens groups are not consecutively arranged in the middle group GM, it is preferable that at least one negative moving lens group in the middle group GM satisfies the conditional expression (4). By ensuring that the corresponding value of conditional expression (4) does not fall below the lower limit, the amount of movement of the negative moving lens group during magnification change with respect to conditional expression (4) can be suppressed, which is advantageous for shortening the overall length of the lens system and facilitating size reduction. By ensuring that the corresponding value of conditional expression (4) does not fall above the upper limit, correction of distortion aberration and lateral chromatic aberration at the wide-angle end, etc. is facilitated. In order to obtain better characteristics, it is more preferable for the zoom lens to satisfy the following conditional expression (4-1), and even more preferable for it to satisfy the following conditional expression (4-2). -0.5<βMnw<-0.05 (4) -0.4<βMnw<-0.1 (4-1) -0.3<βMnw<-0.15 (4-2)

[0048] For example, in the example of FIG. 1, the negative moving lens group in the middle group GM is only the third lens group G3, and there are no multiple negative moving lens groups arranged consecutively in the middle group GM. Therefore, in the example of FIG. 1, the lateral magnification of the third lens group G3 in a state focused on an object at infinity at the wide-angle end is βMnw. On the other hand, in Example 4 described later, the negative moving lens groups in the middle group GM are the second lens group G2 and the third lens group G3, and these two lens groups are arranged consecutively. Therefore, in Example 4, the combined lateral magnification of the second lens group G2 and the third lens group G3 in a state focused on an object at infinity at the wide-angle end is βMnw. The same can be considered for βMnt in conditional formula (5) described next.

[0049] In a configuration in which the middle group GM includes at least one negative moving lens group, it is preferable that the zoom lens satisfies the following conditional formula (5). Here, βMnt is defined as follows depending on the case. When multiple negative moving lens groups are arranged in succession in the middle group GM, the composite lateral magnification of the multiple negative moving lens groups arranged in succession in a state in which an object at infinity is focused at the telephoto end is defined as βMnt. When multiple negative moving lens groups are not arranged in succession in the middle group GM, the lateral magnification of any one of the negative moving lens groups in a state in which an object at infinity is focused at the telephoto end is defined as βMnt. In other words, when multiple negative moving lens groups are not arranged in succession in the middle group GM, it is preferable that at least one negative moving lens group in the middle group GM satisfies conditional formula (5). By making the corresponding value of conditional formula (5) not equal to or less than the lower limit, the amount of movement of the negative moving lens group during magnification change related to conditional formula (5) can be suppressed, which is advantageous for shortening the overall length of the lens system and facilitating miniaturization. By making sure that the corresponding value of conditional expression (5) is not equal to or greater than the upper limit, the zoom magnification carried by the negative moving lens group regarding conditional expression (5) does not become too large, and the refractive power of the negative moving lens group regarding conditional expression (5) does not become too strong. This makes it easier to correct spherical aberration and axial chromatic aberration, particularly at the telephoto end. To obtain better characteristics, it is more preferable for the zoom lens to satisfy the following conditional expression (5-1), and even more preferable for it to satisfy the following conditional expression (5-2). -24<βMnt<-2 (5) -18<βMnt<-2.5 (5-1) -12<βMnt<-3.3 (5-2)

[0050] In a configuration in which the middle group GM includes at least one negative moving lens group, it is preferable that the zoom lens satisfies the following conditional formula (6). Here, the focal length of the negative moving lens group with the strongest refractive power among the negative moving lens groups of the middle group GM is fMn1. Also, the focal length of the final lens group GE is fE. By making the corresponding value of the conditional formula (6) not smaller than the lower limit, the refractive power of the final lens group GE does not become too weak, so that the correction of distortion aberration and lateral chromatic aberration is easy. By making the corresponding value of the conditional formula (6) not larger than the upper limit, the movement amount of the negative moving lens group with the strongest refractive power among the negative moving lens groups of the middle group GM during magnification change can be suppressed, which is advantageous for shortening the overall length of the lens system and facilitating miniaturization. In order to obtain better characteristics, it is more preferable that the zoom lens satisfies the following conditional formula (6-1), and it is even more preferable that the zoom lens satisfies the following conditional formula (6-2). 0.02<|fMn1 / fE|<0.2 (6) 0.025<|fMn1 / fE|<0.15 (6-1) 0.03<|fMn1 / fE|<0.1 (6-2)

[0051] It is preferable that the zoom lens simultaneously satisfies conditional expressions (4), (5), and (6).It is even more preferable that the zoom lens simultaneously satisfies conditional expressions (4), (5), and (6), and further satisfies at least one of conditional expressions (4-1), (4-2), (5-1), (5-2), (6-1), and (6-2).

[0052] If the focal length of the focusing group is fF and the focal length of the final lens group GE is fE, it is preferable that the zoom lens satisfies the following conditional expression (7). By making sure that the corresponding value of conditional expression (7) is not below the lower limit, the refractive power of the final lens group GE does not become too weak, making it easy to correct distortion and lateral chromatic aberration. By making sure that the corresponding value of conditional expression (7) is not above the upper limit, it is possible to suppress the amount of movement of the focusing group during focusing, which is advantageous for shortening the overall length of the lens system and facilitating miniaturization. In order to obtain better characteristics, it is more preferable that the zoom lens satisfies the following conditional expression (7-1), and it is even more preferable that the zoom lens satisfies the following conditional expression (7-2). 0.04<|fF / fE|<0.4 (7) 0.05<|fF / fE|<0.3 (7-1) 0.07<|fF / fE|<0.2 (7-2)

[0053] It is preferable that the zoom lens simultaneously satisfies conditional expressions (4), (5), and (7).It is even more preferable that the zoom lens simultaneously satisfies conditional expressions (4), (5), and (7), and further satisfies at least one of conditional expressions (4-1), (4-2), (5-1), (5-2), (7-1), and (7-2).

[0054] It is preferable that the zoom lens satisfies the following conditional expression (8) with respect to the total length of the lens system. Here, TTL is the sum of the distance on the optical axis from the lens surface of the first lens group G1 closest to the object to the lens surface of the final lens group GE closest to the image when the lens is focused on an object at infinity at the telephoto end, and the back focus of the entire system in air equivalent distance. Also, ft is the focal length of the entire system when the lens is focused on an object at infinity at the telephoto end. By making the corresponding value of conditional expression (8) not equal to or less than the lower limit, it is possible to suppress an increase in curvature of field, and therefore it is easy to achieve both suppression of aberration fluctuations during zooming and compactness and weight reduction. By making the corresponding value of conditional expression (8) not equal to or more than the upper limit, it is possible to suppress an increase in the total length of the lens system, and therefore it is easy to achieve both high magnification and compactness and weight reduction. In order to obtain better characteristics, it is more preferable that the zoom lens satisfies the following conditional expression (8-1), and it is even more preferable that the zoom lens satisfies the following conditional expression (8-2). 0.5 <TTL / ft<3 (8) 0.5 <TTL / ft<1.8 (8-1) 0.5 <TTL / ft<1.2 (8-2)

[0055] When the difference in the optical axis direction between the position of each lens group of the middle group GM when it is focused on an object at infinity at the wide-angle end and the position of each lens group of the middle group GM when it is focused on an object at infinity at the telephoto end is taken as the zoom movement amount, it is preferable that the zoom lens satisfies the following conditional expression (9). Here, the zoom movement amount of the lens group of the middle group GM with the largest zoom movement amount is taken as DV, and the maximum image height is taken as Ymax. In addition, the focal length of the entire system when it is focused on an object at infinity at the telephoto end is taken as ft, and the focal length of the entire system when it is focused on an object at infinity at the wide-angle end is taken as fw. ft / fw corresponds to the maximum zoom magnification. By making sure that the corresponding value of conditional expression (9) is not below the lower limit, the refractive power of the lens group of the middle group GM with the largest zoom movement amount does not become too strong, making it easy to suppress aberration fluctuations such as field curvature, distortion, and chromatic aberration of magnification during magnification change. By ensuring that the corresponding value of conditional expression (9) is not equal to or greater than the upper limit, the amount of zoom movement of the lens group having the largest amount of zoom movement among the lens groups in the middle group GM can be suppressed, which is advantageous for shortening the overall length of the lens system and facilitating size reduction. In order to obtain better characteristics, it is more preferable for the zoom lens to satisfy the following conditional expression (9-1), and it is even more preferable for it to satisfy the following conditional expression (9-2). 5 <DV / {Ymax×log(ft / fw)}<15 (9) 5.5 <DV / {Ymax×log(ft / fw)}<12 (9-1) 6 <DV / {Ymax×log(ft / fw)}<10 (9-2)

[0056] Regarding the amount of movement of the focusing group, it is preferable that the zoom lens satisfies the following conditional expression (10). Here, DF is the difference in the optical axis direction between the position of the focusing group when focused on an object at infinity at the telephoto end and the position of the focusing group when the lateral magnification of the entire system at the telephoto end is -0.1 times. Also, fF is the focal length of the focusing group. By making sure that the corresponding value of conditional expression (10) is not below the lower limit, the refractive power of the focusing group does not become too weak, which is advantageous for miniaturization, since it is possible to suppress an increase in the amount of movement of the focusing group when the object distance changes, particularly at the telephoto end. By making sure that the corresponding value of conditional expression (10) is not above the upper limit, the refractive power of the focusing group does not become too strong, which is advantageous for high magnification, since it is possible to suppress fluctuations in spherical aberration and field curvature when the object distance changes, particularly at the telephoto end. Alternatively, by making the corresponding value of conditional expression (10) not equal to or greater than the upper limit, the amount of movement of the focusing group when the object distance changes at the telephoto end does not become too large, which is advantageous for size reduction. Note that in this specification, "object distance" refers to the distance on the optical axis between the object that is the subject of the zoom lens and the zoom lens. To obtain better characteristics, it is more preferable for the zoom lens to satisfy the following conditional expression (10-1), and even more preferable for it to satisfy the following conditional expression (10-2). 0.1<|DF / fF|<1 (10) 0.12<|DF / fF|<0.9 (10-1) 0.15<|DF / fF|<0.8 (10-2)

[0057] When the moving lens group closest to the object among the moving lens groups in the middle group GM is the leading moving lens group, it is preferable that the zoom lens satisfies the following conditional expression (11). Here, the focal length of the first lens group G1 is f1. In addition, fMVw is defined as follows depending on the case. When the middle group GM includes a moving lens group train consisting of a plurality of moving lens groups arranged in succession including the leading moving lens group, the composite focal length of the moving lens group train in a state focused on an object at infinity at the wide-angle end is fMVw. When the middle group GM does not include the moving lens group train, the focal length of the leading moving lens group is fMVw. By making the corresponding value of conditional expression (11) not lower than the lower limit, the refractive power of the first lens group G1 does not become too strong, making it easy to suppress spherical aberration and axial chromatic aberration, especially at the telephoto end. In addition, by making the corresponding value of conditional expression (11) not smaller than the lower limit, the refractive power of the moving lens group related to conditional expression (11) does not become too weak, so that the amount of movement of these moving lens groups during zooming can be suppressed. By making the corresponding value of conditional expression (11) not larger than the upper limit, the refractive power of the first lens group G1 does not become too weak, which is advantageous in suppressing the effective diameter of the first lens group G1 from becoming too large and the overall length of the lens system from becoming too long, so that it is easy to achieve a compact and lightweight lens. In addition, by making the corresponding value of conditional expression (11) not larger than the upper limit, the refractive power of the moving lens group related to conditional expression (11) does not become too strong, so that it is easy to suppress aberration fluctuations such as field curvature, distortion, and chromatic aberration of magnification during zooming. From the above, by satisfying conditional expression (11), it is advantageous in suppressing aberration fluctuations during zooming, and it is easy to achieve both high magnification and compact and lightweight lens. In order to obtain better characteristics, it is more preferable that the zoom lens satisfies the following conditional expression (11-1), and it is even more preferable that the zoom lens satisfies the following conditional expression (11-2). -0.4 <fMVw / f1<-0.03 (11) -0.25 <fMVw / f1<-0.03 (11-1) -0.16 <fMVw / f1<-0.03 (11-2)

[0058] For example, in the example of Fig. 1, the second lens group G2, which is the most object-side lens group in the middle group GM, is a moving lens group, the third lens group G3 arranged adjacent to the second lens group G2 is a moving lens group, and the fourth lens group G4 arranged adjacent to the third lens group G3 is a fixed lens group. Therefore, in the example of Fig. 1, the first moving lens group is the second lens group G2, and the moving lens group train is made up of the second lens group G2 and the third lens group G3. In the example of Fig. 1, the composite focal length of the second lens group G2 and the third lens group G3 when focused on an object at infinity at the wide-angle end is fMVw.

[0059] Unlike the example of Fig. 1, in a lens system in which the middle group GM is composed of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5, the second lens group G2, the third lens group G3, and the fourth lens group G4 are moving lens groups, and the fifth lens group G5 is a fixed lens group, the moving lens group train is composed of the second lens group G2, the third lens group G3, and the fourth lens group G4. That is, the "moving lens group train" in this specification is composed of the largest number of moving lens groups arranged in succession, including the leading moving lens group.

[0060] In Example 8 described later, the second lens group G2, which is the most object side in the middle group GM, is a moving lens group, and the third lens group G3 arranged adjacent to the second lens group G2 is a fixed lens group. Therefore, in Example 8, the middle group GM is a lens system that does not include a moving lens group train, and in Example 8, the focal length of the second lens group G2, which is the leading moving lens group, is fMVw. The moving lens group train can be considered in the same way in the next described conditional expression (12).

[0061] When the moving lens group closest to the object among the moving lens groups in the middle group GM is the leading moving lens group, it is preferable that the zoom lens satisfies the following conditional expression (12). Here, βMVt is defined as follows depending on the case. When the middle group GM includes a moving lens group train consisting of a plurality of moving lens groups arranged in succession, including the leading moving lens group, the composite lateral magnification of the moving lens group train in a state in which the moving lens group train is focused on an object at infinity at the telephoto end is βMVt. When the middle group GM does not include the moving lens group train, the lateral magnification of the leading moving lens group in a state in which the moving lens group train is focused on an object at infinity at the telephoto end is βMVt. By making the corresponding value of conditional expression (12) not equal to or less than the lower limit, the zoom magnification carried by the moving lens group related to conditional expression (12) does not become too small, so that it is easy to achieve a high magnification. By making the corresponding value of conditional expression (12) not equal to or more than the upper limit, the zoom magnification carried by the moving lens group related to conditional expression (12) does not become too large, so that the refractive power of the moving lens group related to conditional expression (12) does not become too strong. This makes it easy to correct spherical aberration and axial chromatic aberration, particularly at the telephoto end. As described above, by satisfying conditional expression (12), it becomes easy to suppress aberration fluctuations during zooming while achieving high magnification. In order to obtain better characteristics, it is more preferable for the zoom lens to satisfy the following conditional expression (12-1), and it is even more preferable for the zoom lens to satisfy the following conditional expression (12-2). -20<βMVt<-1.1 (12) -15<βMVt<-2.5 (12-1) -12<βMVt<-4 (12-2)

[0062] It is preferable that the middle group GM includes at least one fixed lens group. In a configuration in which the middle group GM includes at least one fixed lens group, it is preferable that the zoom lens satisfies the following conditional expression (13). Here, the lateral magnification of the final lens group GE at the telephoto end when focused on an object at infinity is designated as βE. By satisfying conditional expression (13), correction of distortion and lateral chromatic aberration is facilitated. In order to obtain better characteristics, it is more preferable that the zoom lens satisfies the following conditional expression (13-1), and it is even more preferable that the zoom lens satisfies the following conditional expression (13-2). 1<βE<2 (13) 1<βE<1.7 (13-1) 1<βE<1.4 (13-2)

[0063] In a configuration in which the middle group GM includes at least one fixed lens group, it is preferable that the zoom lens satisfies the following conditional expression (14). Here, the lateral magnification of the fixed lens group closest to the image among the fixed lens groups in the middle group GM when focused on an object at infinity at the telephoto end is βMS. By making the corresponding value of conditional expression (14) not equal to or less than the lower limit, it is possible to suppress aberrations occurring in the fixed lens group, which is advantageous for reducing spherical aberration and axial chromatic aberration. By making the corresponding value of conditional expression (14) not equal to or more than the upper limit, it is possible to suppress an increase in the diameter of the light beam incident on the lens group closer to the image side than the fixed lens group, which is advantageous for reducing the lens diameter. In order to obtain better characteristics, it is more preferable that the zoom lens satisfies the following conditional expression (14-1), and it is even more preferable that the zoom lens satisfies the following conditional expression (14-2). -1.8<1 / βMS<1.4 (14) -1.2<1 / βMS<1 (14-1) -0.8<1 / βMS<0.6 (14-2)

[0064] It is preferable that the zoom lens simultaneously satisfies conditional expressions (13) and (14). It is more preferable that the zoom lens simultaneously satisfies conditional expressions (13) and (14), and further satisfies at least one of conditional expressions (13-1), (13-2), (14-1), and (14-2).

[0065] Furthermore, at the wide-angle end, it is preferable that the zoom lens satisfy the following conditional expression (15). Here, each symbol is defined as follows. βFw is the lateral magnification of the focusing group when focused on an object at infinity at the wide-angle end. βRw is the combined lateral magnification of all lenses on the image side of the focusing group when focused on an object at infinity at the wide-angle end. γ=(1-βFw 2 ) × βRw 2 γ is the ratio of the amount of movement of the image plane to the unit amount of movement of the focusing group when the lens is focused on an object at infinity at the wide-angle end, that is, the backlash magnification. The focal length of the focusing group is fF. The composite focal length of all lenses on the image side of the focusing group when the lens is focused on an object at infinity at the wide-angle end is fRw. The distance from the exit pupil position to the image plane Sim when the lens is focused on an object at infinity at the wide-angle end is De. The sign of De is positive if the exit pupil position is closer to the object side than the image plane Sim, and negative if the exit pupil position is closer to the image side than the image plane Sim. The maximum image height is Ymax. By making sure that the corresponding value of conditional expression (15) is not equal to or less than the lower limit, it is advantageous to suppress aberration fluctuations during focusing while maintaining compactness. By making sure that the corresponding value of conditional expression (15) is not equal to or more than the upper limit, it is advantageous to suppress fluctuations in the size of the image during focusing. For the above reasons, satisfying conditional expression (15) is advantageous for achieving both compactness and suppression of aberration fluctuations during focusing. In order to obtain better characteristics, it is more preferable for the zoom lens to satisfy the following conditional expression (15-1), and it is even more preferable for the zoom lens to satisfy the following conditional expression (15-2). -0.1<{βFw / (fF×γ)-1 / (βRw×fRw)-(1 / De)}×Ymax<0.1 (15) -0.075<{βFw / (fF×γ)-1 / (βRw×fRw)-(1 / De)}×Ymax<0.075 (15-1) -0.05<{βFw / (fF×γ)-1 / (βRw×fRw)-(1 / De)}×Ymax<0.05 (15-2)

[0066] If the refractive index of the negative lens in the first lens group G1 for the d-line is Nd1n, it is preferable that the first lens group G1 includes at least one negative lens that satisfies the following conditional expression (16). By satisfying conditional expression (16), it is advantageous for the size of the first lens group G1 to be reduced. It is more preferable that at least one negative lens in the first lens group G1 satisfies the following conditional expression (16-1). By ensuring that the corresponding value of conditional expression (16-1) is not equal to or greater than the upper limit, the specific gravity of the material of the negative lens does not become too large, which is advantageous for weight reduction. In order to obtain even better characteristics, it is even more preferable that the zoom lens satisfies the following conditional expression (16-2). 1.9 <Nd1n (16) 1.9 <Nd1n<2.1 (16-1) 1.92 <Nd1n<2.06 (16-2)

[0067] It is preferable that the first lens group G1 includes at least two positive lenses, which makes it easier to correct spherical aberration at the telephoto end.

[0068] It is preferable that the focusing group is disposed closest to the image side within the intermediate group GM, in which case the diameter of the light beam incident on the focusing group can be made small, which is advantageous for making the lens compact.

[0069] Two preferred embodiments that take the above-mentioned configuration and conditional expressions into consideration are described below. The first embodiment is a zoom lens that includes, in order from the object side to the image side, a first lens group G1 having positive refractive power, an intermediate group GM including multiple lens groups whose spacing between adjacent lens groups changes during magnification, and a final lens group GE, in which a focusing group that moves during focusing is located within the intermediate group GM, and that satisfies conditional expression (1).

[0070] The second aspect is a zoom lens that includes, in order from the object side to the image side, a first lens group G1 having positive refractive power, an intermediate group GM including a plurality of lens groups whose spacing between adjacent lens groups changes during zooming, and a final lens group GE, in which a focusing group that moves during focusing is disposed within the intermediate group GM, and that satisfies conditional formula (2).

[0071] Note that the example shown in Fig. 1 is just one example, and various modifications are possible within the scope of the gist of the technology of the present disclosure. For example, the number of lenses included in each lens group may be different from that in the example of Fig. 1. Also, in the example of Fig. 1, the middle group GM is made up of four lens groups, but the number of lens groups included in the middle group GM can be set arbitrarily, and for example, the middle group GM may be configured to be made up of three lens groups.

[0072] Below, three configuration examples of the middle lens group GM and the final lens group GE of the zoom lens of the present disclosure are shown. In the following description, a moving lens group having positive refractive power is called a "positive moving lens group", a moving lens group having negative refractive power is called a "negative moving lens group", a fixed lens group having positive refractive power is called a "positive fixed lens group", and a fixed lens group having negative refractive power is called a "negative fixed lens group".

[0073] In the first configuration example, the middle group GM is composed of, in order from the object side to the image side, a positive moving lens group, a negative moving lens group, a positive fixed lens group, and a positive moving lens group, and the final lens group GE is composed of a negative fixed lens group. In the first configuration example, the negative moving lens group is mainly responsible for the magnification change. And, by disposing the positive moving lens group between this negative moving lens group and the first lens group G1 and moving it during magnification change, it is advantageous to suppress the fluctuation of spherical aberration during magnification change.

[0074] In the second configuration example, the middle group GM is composed of, in order from the object side to the image side, a negative moving lens group, a negative moving lens group, a positive fixed lens group, and a positive moving lens group, and the final lens group GE is composed of a positive fixed lens group. In the second configuration example, the two negative moving lens groups share the main magnification changing action and move during magnification changing, thereby making it possible to suppress fluctuations in field curvature accompanying magnification changing.

[0075] In the third configuration example, the middle group GM is composed of, in order from the object side to the image side, a negative moving lens group, a positive fixed lens group, and a positive moving lens group, and the final lens group GE is composed of a positive fixed lens group. In the third configuration example, the negative moving lens group performs magnification change, and the positive moving lens group can correct the fluctuation of the image plane position during magnification change to achieve focusing.

[0076] The above-mentioned preferred and possible configurations can be arbitrarily combined, and are preferably selectively adopted as appropriate according to the required specifications. Note that the conditional expressions that the zoom lens of the present disclosure preferably satisfies are not limited to the conditional expressions described in the form of an expression, but include all conditional expressions obtained by arbitrarily combining the lower and upper limits of the conditional expressions that are deemed to be preferred, more preferred, and even more preferred.

[0077] Next, an embodiment of the zoom lens of the present disclosure will be described with reference to the drawings. The reference symbols attached to the lenses in the cross-sectional views of each embodiment are used independently for each embodiment to avoid the explanation and the complication of the drawings due to an increase in the number of digits of the reference symbols. Therefore, even if common reference symbols are attached in the drawings of different embodiments, they do not necessarily have the same configuration. Moreover, the following Examples 1 to 3 and Examples 6 to 9 are examples of the present disclosure, and Examples 4 and 5 are reference examples of the present disclosure.

[0078] [Example 1] The configuration and movement locus of the zoom lens of the first embodiment are shown in Fig. 1, and the method of illustration and the configuration are as described above, so some overlapping explanations will be omitted here. The zoom lens of the first embodiment is composed of, in order from the object side to the image side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a negative refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a positive refractive power, and a sixth lens group G6 having a negative refractive power. During magnification change, the first lens group G1, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, and the fifth lens group G5 move along the optical axis Z while changing the interval between the adjacent lens groups. The middle group GM is made up of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE is made up of the sixth lens group G6. The focusing group is made up of the fifth lens group G5.

[0079] For the zoom lens of Example 1, basic lens data is shown in Table 1, specifications and variable surface spacing is shown in Table 2, and aspheric coefficients are shown in Table 3.

[0080] The basic lens data table is written as follows. The Sn column shows the surface numbers, with the surface closest to the object being surface 1 and the numbers increasing by one as you move towards the image side. The R column shows the radius of curvature of each surface. The D column shows the surface spacing on the optical axis between each surface and its adjacent surface on the image side. The Nd column shows the refractive index for each component element with respect to the d-line. The νd column shows the Abbe number for each component element with respect to the d-line. The θgF column shows the partial dispersion ratio between the g-line and F-line of each component element. The partial dispersion ratio θgF between the g-line and F-line of a lens is defined as θgF=(Ng-NF) / (NF-NC), where Ng, NF, and NC are the refractive indices of the lens for the g-line, F-line, and C-line, respectively.

[0081] In the basic lens data table, the sign of the radius of curvature of a surface with a convex surface facing the object side is positive, and the sign of the radius of curvature of a surface with a convex surface facing the image side is negative. In the column for the surface number of the surface corresponding to the aperture stop St, the surface number and the phrase (St) are entered. The basic lens data table also shows the optical member PP. The value in the bottom row of the D column in the table is the distance between the surface in the table closest to the image side and the image plane Sim. The symbol DD[ ] is used to indicate the variable surface distance when varying magnification, and the surface number of this distance on the object side is entered in [ ] in the D column.

[0082] Table 2 shows the maximum zoom magnification Zr, focal length f, maximum open F-number FNo., maximum full angle of view 2ω, maximum image height Ymax, and variable surface spacing based on the d-line. The (°) in the 2ω column means that the unit is degrees. In Table 2, the column marked "WIDE" shows the values ​​when focused on an object at infinity at the wide-angle end, the column marked "TELE" shows the values ​​when focused on an object at infinity at the telephoto end, and the column marked "TELE,β=-0.1" shows the values ​​when the lateral magnification of the zoom lens at the telephoto end is -0.1x.

[0083] In the basic lens data, the aspheric surface numbers are marked with an *, and the paraxial radius of curvature value is given in the aspheric radius of curvature column. In Table 3, the Sn row shows the aspheric surface numbers, and the KA and Am rows show the numerical values ​​of the aspheric coefficients for each aspheric surface. Note that m in Am is an integer between 3 and 20. The numerical values ​​of the aspheric coefficients in Table 3, "E±n" (n: integer), are expressed as "×10 ±n " KA and Am are aspheric coefficients in the aspheric equation expressed below. Zd = C × h 2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+ΣAm×h m however, Zd: Aspheric depth (the length of the perpendicular line drawn from a point on the aspheric surface at height h to a plane perpendicular to the optical axis Z where the apex of the aspheric surface is in contact) h: Height (distance from optical axis Z to lens surface) C: Reciprocal of paraxial curvature radius KA, Am: Aspheric coefficients In the aspheric surface formula, Σ means the summation with respect to m.

[0084] In the data in each table, the angle unit is degrees and the length unit is mm (millimeters), but since the optical system can be used with proportional enlargement or reduction, other appropriate units can be used. Also, in each table shown below, values ​​are rounded to a certain number of decimal places.

[0085] [Table 1]

[0086] [Table 2]

[0087] [Table 3]

[0088] FIG. 3 shows the aberration diagrams of the zoom lens of Example 1. From the left, FIG. 3 shows spherical aberration, astigmatism, distortion, and lateral chromatic aberration. In FIG. 3, the upper row labeled "WIDE" shows the aberration when the lens is focused on an object at infinity at the wide-angle end, the middle row labeled "TELE" shows the aberration when the lens is focused on an object at infinity at the telephoto end, and the lower row labeled "TELE, β=-0.1" shows the aberration when the lateral magnification of the zoom lens at the telephoto end is -0.1 times. The object distance when the lateral magnification of the zoom lens is -0.1 times is 1.6 m (meters). In the spherical aberration diagram, the aberrations at the d-line, C-line, and F-line are shown by solid lines, long dashed lines, and short dashed lines, respectively. In the astigmatism diagram, the aberration at the d-line in the sagittal direction is shown by solid lines, and the aberration at the d-line in the tangential direction is shown by short dashed lines. In the distortion diagram, the aberration at the d-line is shown with a solid line. In the lateral chromatic aberration diagram, the aberration at the C-line and the F-line are shown with long and short dashed lines, respectively. In the spherical aberration diagram, the maximum F-number value is shown after FNo. =. In the other aberration diagrams, the maximum half angle of view value is shown after ω =.

[0089] The symbols, meanings, description methods, and illustration methods of each piece of data related to the above-mentioned Example 1 are the same in the following Examples unless otherwise specified, so duplicated explanations will be omitted below.

[0090] [Example 2] The configuration and movement locus of the zoom lens of the second embodiment are shown in FIG. 4. The zoom lens of the second embodiment is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having positive refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having negative refractive power. During magnification change, the first lens group G1, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, and the fifth lens group G5 move along the optical axis Z while changing the intervals between the adjacent lens groups. The middle group GM is composed of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE is composed of the sixth lens group G6. The focusing group consists of the fifth lens group G5.

[0091] The first lens group G1 is made up of four lenses, L11 to L14, in order from the object side to the image side. The second lens group G2 is made up of one lens, L21. The third lens group G3 is made up of four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 is made up of an aperture stop St and five lenses, L41 to L45, in order from the object side to the image side. The fifth lens group G5 is made up of three lenses, L51 to L53, in order from the object side to the image side. The sixth lens group G6 is made up of two lenses, L61 to L62, in order from the object side to the image side.

[0092] For the zoom lens of Example 2, the basic lens data is shown in Table 4, the specifications and variable surface spacing in Table 5, the aspheric coefficients in Table 6, and the various aberration diagrams in Fig. 5. The object distance when the lateral magnification of the zoom lens is -0.1 times is 1.6 m (meters).

[0093] [Table 4]

[0094] [Table 5]

[0095] [Table 6]

[0096] [Example 3] The configuration and movement locus of the zoom lens of Example 3 are shown in FIG. 6. The zoom lens of Example 3 is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having positive refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having negative refractive power. During magnification change, the first lens group G1, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, and the fifth lens group G5 move along the optical axis Z while changing the intervals between the adjacent lens groups. The middle group GM is composed of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE is composed of the sixth lens group G6. The focusing group consists of the fifth lens group G5.

[0097] The first lens group G1 consists of three lenses, L11 to L13, in order from the object side to the image side. The second lens group G2 consists of one lens, L21. The third lens group G3 consists of four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 consists of an aperture stop St and five lenses, L41 to L45, in order from the object side to the image side. The fifth lens group G5 consists of three lenses, L51 to L53, in order from the object side to the image side. The sixth lens group G6 consists of two lenses, L61 to L62, in order from the object side to the image side.

[0098] For the zoom lens of Example 3, basic lens data is shown in Table 7, specifications and variable surface spacing in Table 8, aspheric coefficients in Table 9, and each aberration diagram is shown in Fig. 7. The object distance when the lateral magnification of the zoom lens is -0.1 times is 1.6 m (meters).

[0099] [Table 7]

[0100] [Table 8]

[0101] [Table 9]

[0102] [Example 4] The configuration and movement locus of the zoom lens of Example 4 are shown in FIG. 8. The configuration and light beam in each state of the zoom lens of Example 4 are shown in FIG. 9. The illustration method of FIG. 9 is the same as that of FIG. 2, so repeated explanation will be omitted. The zoom lens of Example 4 is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having positive refractive power. During magnification change, the first lens group G1, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, and the fifth lens group G5 move along the optical axis Z while changing the interval between the adjacent lens groups. The middle group GM is made up of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE is made up of the sixth lens group G6. The focusing group is made up of the fifth lens group G5.

[0103] The first lens group G1 consists of seven lenses, L11 to L17, in order from the object side to the image side. The second lens group G2 consists of one lens, L21. The third lens group G3 consists of four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 consists of an aperture stop St and four lenses, L41 to L44, in order from the object side to the image side. The fifth lens group G5 consists of three lenses, L51 to L53, in order from the object side to the image side. The sixth lens group G6 consists of two lenses, L61 to L62, in order from the object side to the image side.

[0104] For the zoom lens of Example 4, basic lens data is shown in Tables 10A and 10B, specifications and variable surface spacing in Table 11, aspheric coefficients in Table 12, and each aberration diagram in Fig. 10. The object distance when the lateral magnification of the zoom lens is -0.1x is 0.7m (meters). The basic lens data tables are displayed in two tables to avoid making one table too long.

[0105] [Table 10A]

[0106] [Table 10B]

[0107] [Table 11]

[0108] [Table 12]

[0109] [Example 5] The configuration and movement locus of the zoom lens of the fifth embodiment are shown in FIG. 11. The zoom lens of the fifth embodiment is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having positive refractive power. During magnification change, the first lens group G1, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, and the fifth lens group G5 move along the optical axis Z while changing the intervals between the adjacent lens groups. The middle group GM is composed of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE is composed of the sixth lens group G6. The focusing group consists of the fifth lens group G5.

[0110] The first lens group G1 consists of seven lenses, L11 to L17, in order from the object side to the image side. The second lens group G2 consists of one lens, L21. The third lens group G3 consists of four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 consists of an aperture stop St and four lenses, L41 to L44, in order from the object side to the image side. The fifth lens group G5 consists of three lenses, L51 to L53, in order from the object side to the image side. The sixth lens group G6 consists of two lenses, L61 to L62, in order from the object side to the image side.

[0111] For the zoom lens of Example 5, basic lens data is shown in Tables 13A and 13B, specifications and variable surface spacing in Table 14, aspheric coefficients in Table 15, and each aberration diagram in Fig. 12. The object distance when the lateral magnification of the zoom lens is -0.1x is 0.7m (meters). The basic lens data tables are displayed in two tables to avoid making one table too long.

[0112] [Table 13A]

[0113] [Table 13B]

[0114] [Table 14]

[0115] [Table 15]

[0116] [Example 6] The configuration and movement locus of the zoom lens of Example 6 are shown in FIG. 13. The zoom lens of Example 6 is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having positive refractive power. During magnification change, the first lens group G1, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, and the fifth lens group G5 move along the optical axis Z while changing the intervals between the adjacent lens groups. The middle group GM is composed of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE is composed of the sixth lens group G6. The focusing group consists of the fifth lens group G5.

[0117] The first lens group G1 is made up of four lenses, L11 to L14, in order from the object side to the image side. The second lens group G2 is made up of one lens, L21. The third lens group G3 is made up of four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 is made up of an aperture stop St and four lenses, L41 to L44, in order from the object side to the image side. The fifth lens group G5 is made up of three lenses, L51 to L53, in order from the object side to the image side. The sixth lens group G6 is made up of two lenses, L61 to L62, in order from the object side to the image side.

[0118] For the zoom lens of Example 6, basic lens data is shown in Table 16, the specifications and variable surface spacing in Table 17, the aspheric coefficients in Table 18, and each aberration diagram in Fig. 14. The object distance when the lateral magnification of the zoom lens is -0.1 times is 1.2 m (meters).

[0119] [Table 16]

[0120] [Table 17]

[0121] [Table 18]

[0122] [Example 7] The configuration and movement locus of the zoom lens of Example 7 are shown in FIG. 15. The zoom lens of Example 7 is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having positive refractive power. During magnification change, the first lens group G1, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image surface Sim, and the second lens group G2, the third lens group G3, and the fifth lens group G5 move along the optical axis Z while changing the intervals between the adjacent lens groups. The middle group GM is composed of the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE is composed of the sixth lens group G6. The focusing group consists of the fifth lens group G5.

[0123] The first lens group G1 is made up of four lenses, L11 to L14, in order from the object side to the image side. The second lens group G2 is made up of one lens, L21. The third lens group G3 is made up of four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 is made up of an aperture stop St and four lenses, L41 to L44, in order from the object side to the image side. The fifth lens group G5 is made up of three lenses, L51 to L53, in order from the object side to the image side. The sixth lens group G6 is made up of two lenses, L61 to L62, in order from the object side to the image side.

[0124] For the zoom lens of Example 7, basic lens data is shown in Table 19, specifications and variable surface spacing in Table 20, aspheric coefficients in Table 21, and each aberration diagram is shown in Fig. 16. The object distance when the lateral magnification of the zoom lens is -0.1 times is 1.3 m (meters).

[0125] [Table 19]

[0126] [Table 20]

[0127] [Table 21]

[0128] [Example 8] The configuration and movement locus of the zoom lens of Example 8 are shown in FIG. 17. The configuration and light beam in each state of the zoom lens of Example 8 are shown in FIG. 18. The illustration method of FIG. 18 is the same as that of FIG. 2, so repeated explanations will be omitted. The zoom lens of Example 8 is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having positive refractive power. During magnification change, the first lens group G1, the third lens group G3, and the fifth lens group G5 are fixed with respect to the image surface Sim, and the second lens group G2 and the fourth lens group G4 move along the optical axis Z while changing the interval between the adjacent lens groups. The middle group GM is composed of the second lens group G2, the third lens group G3, and the fourth lens group G4. The final lens group GE is made up of the fifth lens group G5. The focusing group is made up of the fourth lens group G4.

[0129] The first lens group G1 is made up of four lenses, L11 to L14, in order from the object side to the image side. The second lens group G2 is made up of five lenses, L21 to L25, in order from the object side to the image side. The third lens group G3 is made up of an aperture stop St and four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 is made up of three lenses, L41 to L43, in order from the object side to the image side. The fifth lens group G5 is made up of two lenses, L51 to L52, in order from the object side to the image side.

[0130] For the zoom lens of Example 8, basic lens data is shown in Table 22, specifications and variable surface spacing in Table 23, aspheric coefficients in Table 24, and each aberration diagram is shown in Fig. 19. The object distance when the lateral magnification of the zoom lens is -0.1 times is 1.1 m (meters).

[0131] [Table 22]

[0132] [Table 23]

[0133] [Table 24]

[0134] [Example 9] The configuration and movement locus of the zoom lens of Example 9 are shown in FIG. 20. The zoom lens of Example 9 is composed of, in order from the object side to the image side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having positive refractive power. During magnification change, the first lens group G1, the third lens group G3, and the fifth lens group G5 are fixed with respect to the image surface Sim, and the second lens group G2 and the fourth lens group G4 move along the optical axis Z while changing the interval between the adjacent lens groups. The middle group GM is composed of the second lens group G2, the third lens group G3, and the fourth lens group G4. The final lens group GE is composed of the fifth lens group G5. The focusing group is composed of the fourth lens group G4.

[0135] The first lens group G1 is made up of four lenses, L11 to L14, in order from the object side to the image side. The second lens group G2 is made up of five lenses, L21 to L25, in order from the object side to the image side. The third lens group G3 is made up of an aperture stop St and four lenses, L31 to L34, in order from the object side to the image side. The fourth lens group G4 is made up of three lenses, L41 to L43, in order from the object side to the image side. The fifth lens group G5 is made up of two lenses, L51 to L52, in order from the object side to the image side.

[0136] For the zoom lens of Example 9, basic lens data is shown in Table 25, the specifications and variable surface spacing in Table 26, the aspheric coefficients in Table 27, and each aberration diagram in Fig. 21. The object distance when the lateral magnification of the zoom lens is -0.1 times is 1.1 m (meters).

[0137] [Table 25]

[0138] [Table 26]

[0139] [Table 27]

[0140] Tables 28 and 29 show the corresponding values ​​of conditional expressions (1) to (16) for the zoom lenses of Examples 1 to 9.

[0141] [Table 28]

[0142] [Table 29]

[0143] The zoom lenses of Examples 1 to 9 have a maximum zoom magnification of 10x or more, more specifically 13x or more, and thus achieve high magnification. Furthermore, the zoom lenses of Examples 1 to 9 are configured to be compact while achieving high magnification, and various aberrations are well corrected to achieve high optical performance.

[0144] Next, an imaging device according to an embodiment of the present disclosure will be described. Fig. 22 shows a schematic configuration diagram of an imaging device 100 using a zoom lens 1 according to an embodiment of the present disclosure as an example of an imaging device according to an embodiment of the present disclosure. Examples of the imaging device 100 include a broadcast camera, a cinema camera, a digital camera, a video camera, and a surveillance camera.

[0145] The imaging device 100 includes a zoom lens 1, a filter 2 arranged on the image side of the zoom lens 1, and an imaging element 3 arranged on the image side of the filter 2. Note that multiple lenses included in the zoom lens 1 are illustrated in schematic form in FIG.

[0146] The image sensor 3 converts an optical image formed by the zoom lens 1 into an electrical signal. The image sensor 3 may be, for example, a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The image sensor 3 is disposed so that its imaging surface coincides with the image plane of the zoom lens 1.

[0147] The imaging device 100 also includes a signal processing unit 5 that performs arithmetic processing on the output signal from the imaging element 3, a display unit 6 that displays an image formed by the signal processing unit 5, a magnification control unit 7 that controls the magnification of the zoom lens 1, and a focus control unit 8 that controls the focusing of the zoom lens 1. Although only one imaging element 3 is shown in Fig. 22, a so-called three-plate imaging device having three imaging elements may also be used.

[0148] Although the technology of the present disclosure has been described above with reference to the embodiments and examples, the technology of the present disclosure is not limited to the above embodiments and examples, and various modifications are possible. For example, the radius of curvature, surface spacing, refractive index, Abbe number, aspheric coefficient, etc. of each lens are not limited to the values ​​shown in the above numerical examples, and may take other values. [Explanation of symbols]

[0149] 1 Zoom lens 2. Filters 3. Image sensor 5. Signal Processing Section 6 Display section 7 Magnification control section 8 Focus control section 100 Imaging device G1 First lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group G6 6th lens group GE final lens group GM intermediate group L11~L62 Lenses ta, ta1, wa axial luminous flux tb, tb1, wb Light flux at maximum image height PP Optical Components Sim image plane St Aperture Ymax Maximum image height Z optical axis

Claims

1. the first lens group having a positive refractive power, an intermediate lens group having three or four lens groups whose intervals with adjacent lens groups change during magnification change, and a final lens group, During magnification change, the distance between the first lens group and the intermediate lens group changes, and the distance between the intermediate lens group and the final lens group changes, a focusing group that moves during focusing is disposed within the intermediate group; DF is a difference in the optical axis direction between a position of the focusing group when the focusing group is focused on an object at infinity at the telephoto end and a position of the focusing group when the lateral magnification of the entire system at the telephoto end is −0.1 times, The focal length of the entire system when focused on an object at infinity at the telephoto end is ft, a difference in the optical axis direction between a position of each lens group of the intermediate lens group when the lens group is focused on an object at infinity at the wide-angle end and a position of each lens group of the intermediate lens group when the lens group is focused on an object at infinity at the telephoto end is defined as a zoom movement amount; The zoom movement amount of the lens group having the largest zoom movement amount among the intermediate lens groups is defined as DV, The focal length of the entire system when focused on an object at infinity at the wide-angle end is fw, The lateral magnification of the focusing group when focused on an object at infinity at the telephoto end is βFt, The composite lateral magnification of all the lenses on the image side of the focusing group when focused on an object at infinity at the telephoto end is βRt, The focal length of the focusing group is fF, If the focal length of the final lens group is fE, 0.04<DF / ft<0.4 (1) 5.409≦DV / fw<18 (2a) 1.075≦(1−βFt 2 )×βRt 2 <5 (3a) 0.04<|fF / fE|<0.4 (7) A zoom lens that satisfies the conditional expressions (1), (2a), (3a), and (7) represented by the following formula:

2. the first lens group having a positive refractive power, an intermediate lens group having three or four lens groups whose intervals with adjacent lens groups change during magnification change, and a final lens group, During magnification change, the distance between the first lens group and the intermediate lens group changes, and the distance between the intermediate lens group and the final lens group changes, a focusing group that moves during focusing is disposed within the intermediate group; DF is a difference in the optical axis direction between a position of the focusing group when the focusing group is focused on an object at infinity at the telephoto end and a position of the focusing group when the lateral magnification of the entire system at the telephoto end is −0.1 times, The focal length of the entire system when focused on an object at infinity at the telephoto end is ft, a difference in the optical axis direction between a position of each lens group of the intermediate lens group when the lens group is focused on an object at infinity at the wide-angle end and a position of each lens group of the intermediate lens group when the lens group is focused on an object at infinity at the telephoto end is defined as a zoom movement amount; The zoom movement amount of the lens group having the largest zoom movement amount among the intermediate lens groups is defined as DV, The focal length of the entire system when focused on an object at infinity at the wide-angle end is fw, The lateral magnification of the focusing group when focused on an object at infinity at the telephoto end is βFt, When the composite lateral magnification of all the lenses on the image side of the focusing group in a state where an object at infinity is focused at the telephoto end is βRt, 0.04<DF / ft<0.4 (1) 7.374≦DV / fw<18 (2b) 1.075≦(1−βFt 2 )×βRt 2 <5 (3a) A zoom lens that satisfies the conditional expressions (1), (2b), and (3a) expressed by the following formulas:

3. The focal length of the focusing group is fF, If the focal length of the final lens group is fE, 0.04<|fF / fE|<0.4 (7) 3. The zoom lens according to claim 2, which satisfies conditional expression (7) expressed as follows:

4. the intermediate group includes at least one negative moving lens group which has negative refractive power and moves during zooming; In the case where a plurality of the negative moving lens groups are successively arranged in the intermediate group, the composite lateral magnification of the plurality of the negative moving lens groups successively arranged in a state focused on an object at infinity at the wide-angle end is βMnw, and the composite lateral magnification of the plurality of the negative moving lens groups successively arranged in a state focused on an object at infinity at the telephoto end is βMnt, In the case where the plurality of negative moving lens groups are not consecutively arranged within the intermediate group, the lateral magnification of any one of the negative moving lens groups when focused on an object at infinity at the wide-angle end is βMnw, and the lateral magnification of any one of the negative moving lens groups when focused on an object at infinity at the telephoto end is βMnt, -0.5<βMnw<-0.05 (4) -24<βMnt<-2 (5) 4. The zoom lens according to claim 1, which satisfies conditional expressions (4) and (5) represented by the following formula:

5. the intermediate group includes at least one negative moving lens group which has negative refractive power and moves during zooming; The focal length of the negative moving lens group having the strongest refractive power among the negative moving lens groups of the intermediate group is fMn1, If the focal length of the final lens group is fE, 0.02<|fMn1 / fE|<0.2 (6) 5. The zoom lens according to claim 1, which satisfies conditional expression (6) represented by:

6. 6. The zoom lens according to claim 1, wherein the first lens group is fixed with respect to an image plane during zooming.

7. 7. The zoom lens according to claim 1, wherein the first lens group includes at least two positive lenses.

8. 8. The zoom lens according to claim 1, wherein the focusing group is disposed closest to the image side within the intermediate group.

9. When the focal length of the focusing group is fF, 0.1<|DF / fF|<1 (10) 9. The zoom lens according to claim 1, which satisfies conditional expression (10) represented by:

10. When the lens group that moves during zooming is defined as a moving lens group, and the moving lens group closest to the object among the moving lens groups in the intermediate group is defined as the leading moving lens group, In the case where the intermediate group includes a moving lens group train consisting of a plurality of moving lens groups arranged in succession including the leading moving lens group, a composite focal length of the moving lens group train when focused on an object at infinity at the wide-angle end is denoted by fMVw, When the intermediate group does not include the moving lens group row, the focal length of the leading moving lens group is fMVw, If the focal length of the first lens group is f1, -0.4<fMVw / f1<-0.03 (11) 10. The zoom lens according to claim 1, which satisfies conditional expression (11) represented by:

11. When the lens group that moves during zooming is defined as a moving lens group, and the moving lens group closest to the object among the moving lens groups in the intermediate group is defined as the leading moving lens group, In the case where the intermediate group includes a moving lens group train consisting of a plurality of moving lens groups arranged in succession including the leading moving lens group, a composite lateral magnification of the moving lens group train in a state where the lens group train is focused on an object at infinity at the telephoto end is denoted by βMVt, In the case where the intermediate group does not include the moving lens group train, if the lateral magnification of the first moving lens group in a state focused on an object at infinity at the telephoto end is βMVt, then: -20<βMVt<-1.1 (12) 11. The zoom lens according to claim 1, which satisfies conditional expression (12) represented by:

12. the intermediate group includes at least one fixed lens group which is a lens group that is fixed with respect to an image plane during zooming, βE is the lateral magnification of the final lens group at the telephoto end when focused on an object at infinity, When the lateral magnification of the fixed lens group that is closest to the image side among the fixed lens groups in the intermediate group is focused on an object at infinity at the telephoto end, βMS is given, 1<βE<2 (13) -1.8<1 / βMS<1.4 (14) 12. The zoom lens according to claim 1, which satisfies conditional expressions (13) and (14) expressed by:

13. 0.05<DF / ft<0.2 (1-1) 13. The zoom lens according to claim 1, which satisfies conditional expression (1-1) represented by:

14. When the sum of the distance on the optical axis from the lens surface of the first lens group closest to the object side to the lens surface of the final lens group closest to the image side in a state in which the lens is focused on an object at infinity at the telephoto end and the back focus of the entire system in terms of an air equivalent distance is defined as TTL. 0.5<TTL / ft<1.2 (8-2) 14. The zoom lens according to claim 1, which satisfies conditional expression (8-2) represented by:

15. When the maximum image height is Ymax, 6<DV / {Ymax×log(ft / fw)}<10 (9-2) 15. The zoom lens according to claim 1, which satisfies conditional expression (9-2) represented by:

16. The lateral magnification of the focusing group when focused on an object at infinity at the wide-angle end is βFw, The composite lateral magnification of all the lenses on the image side of the focusing group when focused on an object at infinity at the wide-angle end is βRw, γ = (1-βFw ２ ) ×βRw ２ year, The focal length of the focusing group is fF, fRw is the composite focal length of all the lenses on the image side of the focusing group when the lens is focused on an object at infinity at the wide-angle end, The distance from the exit pupil position to the image plane when the focus is on an object at infinity at the wide-angle end is De, The sign of De is positive if the exit pupil position is closer to the object side than the image plane, and is negative if the exit pupil position is closer to the image side than the image plane. If the maximum image height is Ymax, -0.075<{βFw / (fF×γ)-1 / (βRw×fRw)-(1 / De)}×Ymax<0.075 (15-1) 16. The zoom lens according to claim 1, which satisfies conditional expression (15-1) represented by:

17. The intermediate group comprises, in order from the object side to the image side, a lens group having positive refractive power and moving when changing magnification, a lens group having negative refractive power and moving when changing magnification, a lens group having positive refractive power and fixed with respect to the image plane when changing magnification, and a lens group having positive refractive power and moving when changing magnification, 17. The zoom lens according to claim 1, wherein the final lens group is a lens group that has negative refractive power and is fixed with respect to an image plane during zooming.

18. The intermediate group comprises, in order from the object side to the image side, a lens group having negative refractive power and moving when changing magnification, a lens group having negative refractive power and moving when changing magnification, a lens group having positive refractive power and fixed with respect to the image plane when changing magnification, and a lens group having positive refractive power and moving when changing magnification; 17. The zoom lens according to claim 1, wherein the final lens group is a lens group that has positive refractive power and is fixed with respect to an image plane during zooming.

19. The intermediate group comprises, in order from the object side to the image side, a lens group having negative refractive power and moving during zooming, a lens group having positive refractive power and fixed with respect to the image plane during zooming, and a lens group having positive refractive power and moving during zooming, 17. The zoom lens according to claim 1, wherein the final lens group is a lens group that has positive refractive power and is fixed with respect to the image plane during zooming.

20. When the refractive index of the negative lens in the first lens group with respect to the d line is Nd1n, the first lens group has 1.9<Nd1n<2.1 (16-1) 18. The zoom lens according to claim 1, further comprising at least one negative lens which satisfies conditional expression (16-1) represented by:

21. 5.409≦DV / fw<15 (2a-1) 2. The zoom lens according to claim 1, which satisfies conditional expression (2a-1) represented by the following formula:

22. 7.374≦DV / fw<15 (2b-1) 3. The zoom lens according to claim 2, which satisfies conditional expression (2b-1) represented by the following formula (2b-1):

23. An imaging device comprising the zoom lens according to any one of claims 1 to 22.

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