Zoom lens and imaging apparatus

Abstract

To provide a zoom lens that is compact, has a small F-number over the entire variable power area, and has the high optical performance over the entire variable power area, and an imaging apparatus equipped with the zoom lens.SOLUTION: A zoom lens comprises, in order from an object side to an image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, an intermediate group, and a final lens group having a positive refractive power. The intermediate group consists of two or three lens groups. During zooming, all spacings between adjacent lens groups change. An aperture stop is disposed between the lens surface closest to the image side of the second lens group and the lens surface closest to the object side of the final lens group. The zoom lens satisfies a predetermined conditional expression.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, as zoom lenses that can be used in imaging devices such as digital cameras, the zoom lenses described in Patent Document 1, Patent Document 2, and Patent Document 3 below are known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand for a zoom lens that is small in size, has a small F-number throughout the zoom range, and has high optical performance throughout the zoom range. These required levels are increasing year by year.

[0005] The present disclosure provides a zoom lens that is small in size, has a small F-number throughout the zoom range, and has high optical performance throughout the zoom range, and an imaging device including this zoom lens.

Means for Solving the Problems

[0006] The zoom lens according to one aspect of the present disclosure includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, an intermediate group, and a final lens group having a positive refractive power. The intermediate group consists of two or three lens groups. During zooming, the distance between the first lens group and the second lens group changes, the distance between the second lens group and the intermediate group changes, the distance between the intermediate group and the final lens group changes, the distances between all adjacent lens groups within the intermediate group change, and an aperture stop is disposed between the most image-side lens surface of the second lens group and the most object-side lens surface of the final lens group. The first lens group includes, in order from the most object side to the image side, a first lens, which is a negative lens with a convex object-side surface, and a second lens, which is a positive lens. 0 < fw / f1 < 0.3 (1) 0.5 < Fnot / (ft / fw) < 1.3 (2) 0.15 < Bfw / (ft × tanωt) < 2 (3) 7 < TLt / (ft × tanωt) < 11 (4) satisfies the conditional expressions (1), (2), (3), and (4) represented by the following. Here, the symbols are defined as follows. The overall focal length in the state of focusing on an infinite object at the wide-angle end is defined as fw. The focal length of the first lens group is defined as f1. The open F-number in the state of focusing on an infinite object at the telephoto end is defined as Fnot. The overall focal length in the state of focusing on an infinite object at the telephoto end is defined as ft. The overall back focus at the air-equivalent distance at the wide-angle end is defined as Bfw. The maximum half field angle in the state of focusing on an infinite object at the telephoto end is defined as ωt. The sum of the on-axis distance from the object-side surface of the first lens to the most image-side lens surface of the final lens group and the overall back focus at the air-equivalent distance in the state of focusing on an infinite object at the telephoto end is defined as TLt.

[0007] When the on-axis distance between the intermediate group and the final lens group in the state of focusing on an infinite object at the telephoto end is dMEt, and the on-axis distance between the intermediate group and the final lens group in the state of focusing on an infinite object at the wide-angle end is dMEw, the zoom lens of the above aspect 2 < dMEt / dMEw < 10 (5) It is preferable to satisfy the conditional expression (5) represented by

[0008] When the paraxial curvature radius of the lens surface closest to the object side of the second lens group is R2f and the paraxial curvature radius of the lens surface closest to the image side of the second lens group is R2r, the zoom lens of the above aspect is -0.5 < (R2f + R2r) / (R2f - R2r) < 2 (6) It is preferable to satisfy the conditional expression (6) represented by

[0009] When the refractive index with respect to the d line of the lens closest to the image side of the first lens group is Nd1r, the Abbe number based on the d line of the lens closest to the image side of the first lens group is νd1r, the refractive index with respect to the d line of the lens closest to the image side of the second lens group is Nd2r, and the Abbe number based on the d line of the lens closest to the image side of the second lens group is νd2r, the zoom lens of the above aspect is 1.65 < Nd1r < 1.8 (7) 45 < νd1r < 60 (8) 1.4 < Nd2r < 1.65 (9) 60 < νd2r < 100 (10) It is preferable to satisfy the conditional expressions (7), (8), (9), and (10) represented by

[0010] The zoom lens of the above aspect is 1 < fw / (ft × tanωt) < 1.45 (11) It is preferable to satisfy the conditional expression (11) represented by

[0011] When the distance on the optical axis from the object side surface of the first lens to the aperture stop in the state of focusing on an infinite object at the wide-angle end is DDL1STw, and the sum of the distance on the optical axis from the object side surface of the first lens to the lens surface closest to the image side of the final lens group and the overall system back focus in terms of air equivalent distance in the state of focusing on an infinite object at the wide-angle end is TLw, the zoom lens of the above aspect is 0 < DDL1STw / TLw < 0.65 (12) It is preferable to satisfy the conditional expression (12) represented by

[0012] When the center thickness of the first lens is d1 and the outer diameter of the first lens is DA1, the zoom lens of the above aspect is 0.01 < d1 / DA1 < 0.035 (13) It is preferable to satisfy the conditional expression (13) represented by

[0013] Among the negative lenses included in the second lens group, when the center thickness of the most image-side negative lens is d2r and the outer diameter of the most image-side negative lens among the negative lenses included in the second lens group is DA2r, the zoom lens of the above aspect is 0.01 < d2r / DA2r < 0.04 (14) It is preferable to satisfy the conditional expression (14) represented by

[0014] In a configuration including a focusing group that moves along the optical axis during focusing, and the focusing group includes at least one negative lens, among the negative lenses included in the focusing group, when the center thickness of the most image-side negative lens is dffr and the outer diameter of the most image-side negative lens among the negative lenses included in the focusing group is DAffr, the zoom lens of the above aspect is 0.01 < dffr / DAffr < 0.04 (15) It is preferable to satisfy the conditional expression (15) represented by

[0015] When the focal length of the final lens group is fE, the zoom lens of the above aspect is 0 < f1 / fE < 2 (16) It is preferable to satisfy the conditional expression (16) represented by

[0016] When the focal length of the second lens group is f2, the zoom lens of the above aspect is -2 < fw / f2 < -0.7 (17) It is preferable to satisfy the conditional expression (17) represented by

[0017] In a configuration including a focusing group that moves along the optical axis during focusing, when the focal length of the second lens group is f2 and the focal length of the focusing group is ff, the zoom lens of the above aspect is 0.2 < f2 / ff < 0.8 (18) Preferably satisfies the conditional expression (18) represented by

[0018] Among the lens groups included in the intermediate group, when the focal length of the lens group with the strongest positive refractive power is fMp, the zoom lens of the above aspect is 0.4 < fw / fMp < 2 (19) Preferably satisfies the conditional expression (19) represented by

[0019] Among the lens groups included in the intermediate group, when the focal length of the lens group with the strongest positive refractive power is fMp, the zoom lens of the above aspect is 1.5 < ft / fMp < 5 (20) Preferably satisfies the conditional expression (20) represented by

[0020] The zoom lens of the above aspect is 0.1 < fw / f1 < 0.2 (1-1) Preferably satisfies the conditional expression (1-1) represented by

[0021] The first lens group may be configured to consist of three lenses.

[0022] The second lens group may be configured to consist of four lenses.

[0023] During zooming, the first lens group preferably moves.

[0024] The zoom lens of the above aspect preferably includes 14 or more lenses.

[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, the phrases "consisting of ~" and "comprising ~" in this specification are intended to mean that, in addition to the recited components, lenses having substantially no refractive power, optical elements other than lenses such as diaphragms, filters, and cover glasses, and mechanical parts such as lens flanges, lens barrels, imaging elements, and shake correction mechanisms may be included.

[0027] The phrase "~ group having a positive refractive power" in this specification means that the entire group has a positive refractive power. Similarly, the phrase "~ group having a negative refractive power" means that the entire group has a negative refractive power. The "second lens group", "lens group", "final lens group", and "focusing group" in this specification are not limited to configurations consisting of a plurality of lenses, and may also be configurations consisting of only one lens.

[0028] A compound aspherical lens (a lens in which a lens (e.g., a spherical lens) and an aspherical film formed on the lens are integrally formed and function as one aspherical lens as a whole) is not regarded as a cemented lens and is treated as one lens. Unless otherwise specified, the sign of the refractive power and the surface shape of a lens including an aspherical surface are those in the paraxial region. The sign of the radius of curvature is positive for the radius of curvature of a surface convex toward the object side and negative for the radius of curvature of a surface convex toward the image side.

[0029] In this specification, "entire system" means a zoom lens. The "focal length" used in the conditional expressions is the paraxial focal length. The "distance on the optical axis" used in the conditional expressions is the geometric distance unless otherwise specified. Unless otherwise specified, the values used in the conditional expressions are values based on the d-line in the state of focusing on an infinite object.

[0030] The "d-line", "C-line", "F-line", and "g-line" described in this specification are spectral lines. The wavelength of the d-line is treated as 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).

Advantages of the Invention

[0031] According to the present disclosure, it is possible to provide a zoom lens that is compact, has a small F-number over the entire zoom range, and has high optical performance over the entire zoom range, and an imaging device that includes this zoom lens. [Brief explanation of the drawings]

[0032]

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[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 of a zoom lens according to an embodiment of the present disclosure and its movement trajectory. In FIG. 1, the upper row labeled "Wide" shows the wide-angle end state, and the lower row labeled "Tele" shows the telephoto end state. The example shown in FIG. 1 corresponds to the zoom lens of Example 1, which will be described later. FIG. 1 shows a state in which the lens is focused on an object at infinity, with the left side being the object side and the right side being the image side. FIG. 1 also shows the axial light beam wa and the light beam wb at the maximum half angle of view ωw at the wide-angle end, as well as the axial light beam ta and the light beam tb at the maximum half angle of view ωt at the telephoto end.

[0035] The zoom lens of the present disclosure includes, in order from the object side to the image side along the optical axis Z, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an intermediate group GM, and a final lens group GE having a positive refractive power. The intermediate group GM consists of two or three lens groups. By setting the first lens group G1 as a lens group having a positive refractive power, it becomes possible to shorten the overall length, which is advantageous for achieving both miniaturization and a high magnification ratio. Also, by setting the first lens group G1 as a lens group having a positive refractive power, the height of the light beam incident on the second lens group G2 becomes lower, which is advantageous for suppressing aberration variations during zooming. By setting the final lens group GE as a lens group having a positive refractive power, the height of the light beam in the intermediate group GM becomes lower, which is advantageous for reducing the diameter of the lens. By setting the number of lens groups constituting the intermediate group GM to two or three, it is advantageous for achieving both suppression of aberration variations and miniaturization during zooming.

[0036] During zooming, the distance between the first lens group G1 and the second lens group G2 changes, the distance between the second lens group G2 and the intermediate group GM changes, the distance between the intermediate group GM and the final lens group GE changes, and all the distances between adjacent lens groups within the intermediate group GM change. By changing the distances between a plurality of groups during zooming, it is advantageous for suppressing various aberrations over the entire zoom range.

[0037] In this specification, a group whose distance in the optical axis direction from an adjacent group changes during zooming is regarded as one lens group. During zooming, the distance between adjacent lenses does not change within one lens group. That is, a "lens group" is a component of the zoom lens and is a part including at least one lens separated by an air gap that changes during zooming. During zooming, each lens group is moved or fixed as a unit. A "lens group" may include components other than lenses having no refractive power, such as an aperture stop St.

[0038] As an example, the zoom lens shown 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, and a fifth lens group G5. In the example of Fig. 1, the middle lens group GM is composed of the third lens group G3 and the fourth lens group G4, and the final lens group GE is composed of the fifth lens group G5.

[0039] As an example, each lens group in FIG. 1 is configured as follows. 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 four lenses, L21 to L24, in order from the object side to the image side. The third lens group G3 consists of an aperture stop St and six lenses, L31 to L36, in order from the object side to the image side. The fourth lens group G4 consists of two lenses, L41 and L42, in order from the object side to the image side. The fifth lens group G5 consists of a single lens, L51. Note that the aperture stop St in FIG. 1 does not indicate its size or shape, but its position on the optical axis.

[0040] In the example of Fig. 1, when changing magnification, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 move along the optical axis Z while changing the spacing between adjacent lens groups, and the fifth lens group G5 is fixed with respect to the image plane Sim. In Fig. 1, for the moving lens groups, the arrows between the upper and lower rows indicate the approximate movement locus of each lens group when changing magnification from the wide-angle end to the telephoto end.

[0041] When the magnification is changed, the first lens group G1 moves, which is advantageous for suppressing aberration fluctuations when the magnification is changed, and is also advantageous for making the zoom lens compact when it is stored.

[0042] When varying the magnification, the final lens group GE is fixed relative to the image plane Sim, which is advantageous for simplifying the lens drive mechanism. However, in the zoom lens of the present disclosure, the final lens group GE may be configured to move when varying the magnification. Moving the final lens group GE when varying the magnification is advantageous for suppressing aberration fluctuations when varying the magnification.

[0043] In the zoom lens of the present disclosure, the first lens group G1 includes, in order from the object side to the image side, a first lens having a convex surface on the object side and being a negative lens, and a second lens being a positive lens. According to this configuration, aberration correction within the first lens group G1 becomes easy, which is advantageous for suppressing aberration variation during zooming. Also, by arranging a negative lens on the most object side, aberration correction becomes easy when shortening the focal length at the wide-angle end. In the example of FIG. 1, lens L11 corresponds to the first lens, and lens L12 corresponds to the second lens.

[0044] The first lens group G1 may be configured to consist of three lenses. By configuring the first lens group G1 with three lenses, it is advantageous for suppressing aberration variation during zooming and for miniaturization. For example, the first lens group G1 can be configured to consist of, in order from the object side to the image side, a negative lens, a positive lens, and a positive lens.

[0045] The second lens group G2 may be configured to consist of four lenses. By configuring the second lens group G2 with four lenses, it is advantageous for suppressing aberration variation during zooming and for miniaturization. For example, the second lens group G2 can be configured to consist of, in order from the object side to the image side, a negative lens, a negative lens, a positive lens, and a negative lens.

[0046] The aperture stop St is arranged between the most image-side lens surface of the second lens group G2 and the most object-side lens surface of the final lens group GE. According to this configuration, miniaturization of the aperture unit becomes possible, which is advantageous for miniaturization of the entire lens system.

[0047] For example, the aperture stop St may be arranged on the most object side of the intermediate group GM. In this case, since the aperture stop St and the first lens group G1 can be brought closer, the distance from the most object-side lens surface of the first lens group G1 to the entrance pupil position can be shortened. This is advantageous for reducing the diameter of the first lens group G1.

[0048] The zoom lens of the present disclosure may be configured to include a focusing group that moves along the optical axis Z during focusing. Focusing is performed by the movement of the focusing group. In the example of FIG. 1, the focusing group consists of the fourth lens group G4. The parentheses and the rightward arrow below the fourth lens group G4 in FIG. 1 indicate that the fourth lens group G4 is a focusing group that moves toward the image side during focusing from an infinite object to the closest object. Note that the fourth lens group G4 functions as a focusing group throughout the entire zoom range. However, in FIG. 1, for the sake of simplicity of the figure, the parentheses and the arrow indicating the focusing group are attached only to the lower figure.

[0049] The focusing group may be configured to consist of a single cemented lens. In this case, the number of lenses in the focusing group can be reduced. As a result, the mechanism for controlling the focusing group can be simplified, and quick focusing becomes easier.

[0050] When the focusing group consists of a single cemented lens, this cemented lens may be configured to consist of a positive lens and a negative lens in order from the object side to the image side. In this case, it is advantageous for suppressing aberration variation during focusing.

[0051] The zoom lens of the present disclosure may be configured not to include a lens that moves for image blur correction. In this case, the lens mechanism can be simplified.

[0052] The zoom lens may be configured to include 14 or more lenses in total. In this case, it is advantageous for suppressing various aberrations.

[0053] Next, a preferred configuration regarding the conditional expressions of the zoom lens of the present disclosure will be described. In the following description of the conditional expressions, in order to avoid redundant explanations, the same symbols are used for those with the same definitions, and the duplicate explanations of the symbols are partially omitted. Also, hereinafter, for the sake of avoiding redundant explanations, the "zoom lens of the present disclosure" is also simply referred to as the "zoom lens".

[0054] The zoom lens preferably satisfies the following conditional expression (1). Here, the overall focal length in the state of focusing on an infinite object at the wide-angle end is defined as fw. The focal length of the first lens group G1 is defined as f1. Regarding the lower limit value of the conditional expression (1), since the first lens group G1 is a lens group having a positive refractive power, 0 < fw / f1 holds. By ensuring that the corresponding value of the conditional expression (1) does not exceed the upper limit value, the refractive power of the first lens group G1 does not become too strong, which is advantageous for suppressing aberration variation during zooming. 0 < fw / f1 < 0.3 (1)

[0055] The lower limit value of the conditional expression (1) is more preferably 0.05. In this case, since the refractive power of the first lens group G1 does not become too weak, it is advantageous for miniaturizing the first lens group G1. To obtain better characteristics, the lower limit value of the conditional expression (1) is more preferably 0.1, even more preferably 0.12, and even more preferably 0.15. To obtain better characteristics, the upper limit value of the conditional expression (1) is more preferably 0.25, even more preferably 0.2, even more preferably 0.19, and even more preferably 0.18. For example, the zoom lens more preferably satisfies the following conditional expression (1-1). 0.1 < fw / f1 < 0.2 (1-1)

[0056] The zoom lens preferably satisfies the following conditional expression (2). Here, the open F-number in the state of focusing on an infinite object at the telephoto end is defined as Fnot. The overall focal length in the state of focusing on an infinite object at the telephoto end is defined as ft. By ensuring that the corresponding value of the conditional expression (2) does not fall below the lower limit value, it is advantageous for miniaturizing the entire lens system or, in particular, for suppressing various aberrations at the telephoto end. By ensuring that the corresponding value of the conditional expression (2) does not exceed the upper limit value, it becomes easier to maintain a small F-number at the telephoto end, which is advantageous for obtaining sufficient brightness at the telephoto end. 0.5 < Fnot / (ft / fw) < 1.3 (2)

[0057] In order to obtain better characteristics, the lower limit value of conditional expression (2) is more preferably 0.6, even more preferably 0.7, even more preferably 0.8, and even more preferably 0.85. In order to obtain better characteristics, the upper limit value of conditional expression (2) is more preferably 1.2, even more preferably 1.1.

[0058] The zoom lens preferably satisfies the following conditional expression (3). Here, the overall back focus at the air equivalent distance at the wide-angle end is defined as Bfw. The maximum semi-field angle in the state of focusing on an infinite object at the telephoto end is defined as ωt. Tan represents the tangent. Note that the "overall back focus at the air equivalent distance" is the air equivalent distance on the optical axis from the most image-side lens surface of the entire system to the image plane Sim. By ensuring that the corresponding value of conditional expression (3) does not fall below the lower limit value, the back focus does not become too short, making it easier to attach the mount exchange mechanism. By ensuring that the corresponding value of conditional expression (3) does not exceed the upper limit value, the back focus does not become too long, facilitating miniaturization. 0.15 < Bfw / (ft × tan ωt) < 2 (3)

[0059] Fig. 2 shows a cross-sectional view of the zoom lens of Fig. 1, and as an example, shows the above-mentioned back focus Bfw in this zoom lens. In Fig. 2, the upper part marked "Wide" shows the wide-angle end state, and the lower part marked "Tele" shows the telephoto end state.

[0060] In order to obtain better characteristics, the lower limit value of conditional expression (3) is more preferably 0.2, even more preferably 0.25, even more preferably 0.3, and even more preferably 0.35. In order to obtain better characteristics, the upper limit value of conditional expression (3) is more preferably 1.7, even more preferably 1.6, even more preferably 1.5, and even more preferably 1.4.

[0061] It is preferable that the zoom lens satisfy the following conditional expression (4). Here, TLt is the sum of the axial distance from the object-side surface of the first lens to the lens surface closest to the image in the final lens group GE when focused on an object at infinity at the telephoto end, and the back focus of the entire system in air equivalent distance. TLt is the total length when focused on an object at infinity at the telephoto end. As an example, Figure 2 shows the total length TLt. By ensuring that the value corresponding to conditional expression (4) is not less than the lower limit, the axial light beam ta can be gradually converged toward the image plane Sim at the telephoto end, thereby suppressing the axial chromatic aberration that occurs when the axial light beam ta is converged. By ensuring that the value corresponding to conditional expression (4) is not less than the upper limit, the total length TLt at the telephoto end can be easily shortened. 7 <TLt / (ft×tanωt)<11 (4)

[0062] In order to obtain better characteristics, it is more preferable that the lower limit of conditional expression (4) be set to 7.5, even more preferably to 8, even more preferably to 8.5, and even more preferably to 9. In order to obtain better characteristics, it is more preferable that the upper limit of conditional expression (4) be set to 10.5.

[0063] It is preferable that the zoom lens satisfy the following conditional expression (5). Here, the axial distance between the middle group GM and the final lens group GE when focused on an object at infinity at the telephoto end is defined as dMEt. The axial distance between the middle group GM and the final lens group GE when focused on an object at infinity at the wide-angle end is defined as dMEw. As an example, FIG. 2 shows the above-mentioned distances dMEt and dMEw. Ensuring that the corresponding value of conditional expression (5) is not equal to or less than the lower limit is advantageous for suppressing aberration fluctuations during magnification variation. Ensuring that the corresponding value of conditional expression (5) is not equal to or greater than the upper limit is advantageous for reducing the overall length. 2 <dMEt / dMEw<10 (5)

[0064] In order to obtain better characteristics, the lower limit of conditional expression (5) should preferably be set to 2.2, more preferably 2.5, even more preferably 2.8, and even more preferably 3. In order to obtain better characteristics, the upper limit of conditional expression (5) should preferably be set to 9, even more preferably 8, even more preferably 7, and even more preferably 6.

[0065] It is preferable that the zoom lens satisfy the following conditional expression (6). Here, the paraxial radius of curvature of the lens surface in the second lens group G2 closest to the object is defined as R2f. The paraxial radius of curvature of the lens surface in the second lens group G2 closest to the image is defined as R2r. Ensuring that the corresponding value of conditional expression (6) is not equal to or less than the lower limit thereof is advantageous for suppressing spherical aberration at the telephoto end. Ensuring that the corresponding value of conditional expression (6) is not equal to or greater than the upper limit thereof is advantageous for suppressing aberrations for each image height at the wide-angle end. -0.5<(R2f+R2r) / (R2f-R2r)<2 (6)

[0066] In order to obtain better characteristics, the lower limit of conditional expression (6) should preferably be set to -0.2, more preferably to 0.15, even more preferably to 0.2, and even more preferably to 0.3. In order to obtain better characteristics, the upper limit of conditional expression (6) should preferably be set to 1.5, even more preferably to 1, even more preferably to 0.9, and even more preferably to 0.85.

[0067] When the refractive index of the lens closest to the image side in the first lens group G1 with respect to the d-line is Nd1r, it is preferable that the zoom lens satisfy the following conditional expression (7). Ensuring that the corresponding value of conditional expression (7) is not equal to or smaller than the lower limit thereof is advantageous for reducing the size of the first lens group G1. Ensuring that the corresponding value of conditional expression (7) is not equal to or larger than the upper limit thereof is advantageous for suppressing curvature of field at the wide-angle end. 1.65 <Nd1r<1.8 (7)

[0068] In order to obtain better characteristics, the lower limit value of conditional expression (7) is more preferably 1.67, still more preferably 1.68, still more preferably 1.69, and still more preferably 1.7. In order to obtain better characteristics, the upper limit value of conditional expression (7) is more preferably 1.78, still more preferably 1.77, still more preferably 1.76, and still more preferably 1.75.

[0069] When the Abbe number based on the d-line of the most image-side lens of the first lens group G1 is νd1r, the zoom lens preferably satisfies the following conditional expression (8). By preventing the corresponding value of conditional expression (8) from falling below the lower limit value, it is advantageous for suppressing longitudinal chromatic aberration at the wide-angle end. By preventing the corresponding value of conditional expression (8) from exceeding the upper limit value, since the refractive index does not become too low, it is advantageous for miniaturizing the first lens group G1. 45 < νd1r < 60 (8)

[0070] In order to obtain better characteristics, the lower limit value of conditional expression (8) is more preferably 47, still more preferably 49, still more preferably 51, and still more preferably 53. In order to obtain better characteristics, the upper limit value of conditional expression (8) is more preferably 59, still more preferably 58, still more preferably 57, and still more preferably 56.

[0071] When the refractive index with respect to the d-line of the most image-side lens of the second lens group G2 is Nd2r, the zoom lens preferably satisfies the following conditional expression (9). By preventing the corresponding value of conditional expression (9) from falling below the lower limit value, it is advantageous for miniaturizing the second lens group G2. By preventing the corresponding value of conditional expression (9) from exceeding the upper limit value, it is advantageous for suppressing field curvature at the wide-angle end. 1.4 < Nd2r < 1.65 (9)

[0072] In order to obtain better characteristics, the upper limit value of conditional expression (9) is more preferably 1.6, still more preferably 1.58, still more preferably 1.55, and still more preferably 1.5.

[0073] When the Abbe number based on the d-line of the most image-side lens of the second lens group G2 is νd2r, it is preferable that the zoom lens satisfies the following conditional expression (10). By preventing the corresponding value of conditional expression (10) from falling below the lower limit value, it is advantageous for suppressing chromatic coma at the wide-angle end. By preventing the corresponding value of conditional expression (10) from exceeding the upper limit value, the refractive index does not become too low, which is advantageous for miniaturizing the second lens group G2. 60 < νd2r < 100 (10)

[0074] In order to obtain better characteristics, the lower limit value of conditional expression (10) is more preferably 65, still more preferably 70, still more preferably 75, and still more preferably 80.

[0075] It is more preferable that the zoom lens simultaneously satisfies conditional expressions (7), (8), (9), and (10).

[0076] It is preferable that the zoom lens satisfies the following conditional expression (11). By preventing the corresponding value of conditional expression (11) from falling below the lower limit value, it is advantageous for suppressing various aberrations. By preventing the corresponding value of conditional expression (11) from exceeding the upper limit value, it is advantageous for obtaining a wide angle of view at the wide-angle end. 1 < fw / (ft×tanωt) < 1.45 (11)

[0077] In order to obtain better characteristics, the lower limit value of conditional expression (11) is more preferably of 1.05, still more preferably 1.1. In order to obtain better characteristics, the upper limit value of conditional expression (11) is more preferably 1.4, still more preferably 1.35, still more preferably 1.3, and still more preferably 1.25.

[0078] The zoom lens preferably satisfies the following conditional expression (12). Here, the distance on the optical axis from the object-side surface of the first lens to the aperture stop St in a state of being focused on an infinite object at the wide-angle end is defined as DDL1STw. The sum of the distance on the optical axis from the object-side surface of the first lens to the most image-side lens surface of the final lens group GE and the overall system back focus in terms of the air equivalent distance in a state of being focused on an infinite object at the wide-angle end is defined as TLw. TLw is the overall length in a state of being focused on an infinite object at the wide-angle end. As an example, FIG. 2 shows the above distance DDL1STw and the above overall length TLw. By ensuring that the corresponding value of the conditional expression (12) does not fall below the lower limit value, the distance between the aperture stop St and the first lens group G1 does not become too short, so the distance from the object-side surface of the first lens to the entrance pupil position does not become too short either. As a result, it becomes easier to suppress aberration fluctuations during zooming. By ensuring that the corresponding value of the conditional expression (12) does not exceed the upper limit, the distance between the aperture stop St and the first lens group G1 does not become too far apart, so the distance from the object-side surface of the first lens to the entrance pupil position does not become too long. As a result, the increase in the diameter of the first lens group G1 can be suppressed, making miniaturization easier. 0 < DDL1STw / TLw < 0.65 (12)

[0079] To obtain better characteristics, it is more preferable that the lower limit value of the conditional expression (12) is 0.05, even more preferably 0.1, even more preferably 0.15, and even more preferably 0.2. To obtain better characteristics, it is more preferable that the upper limit value of the conditional expression (12) is 0.6, even more preferably 0.55, even more preferably 0.5, and even more preferably 0.46.

[0080] The zoom lens preferably satisfies the following conditional expression (13). Here, the central thickness of the first lens is denoted as d1, and the outer diameter of the first lens is denoted as DA1. As an example, Fig. 2 shows the above central thickness d1 and the above outer diameter DA1. By ensuring that the corresponding value of the conditional expression (13) does not fall below the lower limit value, it is advantageous for the processing accuracy of the lens. By ensuring that the corresponding value of the conditional expression (13) does not exceed the upper limit, it is advantageous for miniaturizing the first lens group G1. 0.01 < d1 / DA1 < 0.035 (13)

[0081] To obtain better characteristics, the lower limit value of the conditional expression (13) is more preferably 0.013, even more preferably 0.015, even more preferably 0.017, and even more preferably 0.019. To obtain better characteristics, the upper limit value of the conditional expression (13) is more preferably 0.03, even more preferably 0.028, even more preferably 0.025, and even more preferably 0.023.

[0082] The zoom lens preferably satisfies the following conditional expression (14). Here, among the negative lenses included in the second lens group G2, the central thickness of the most image-side negative lens is denoted as d2r, and the outer diameter of the most image-side negative lens among the negative lenses included in the second lens group G2 is denoted as DA2r. As an example, Fig. 2 shows the above central thickness d2r and the above outer diameter DA2r. By ensuring that the corresponding value of the conditional expression (14) does not fall below the lower limit value, it is advantageous for the processing accuracy of the lens. By ensuring that the corresponding value of the conditional expression (14) does not exceed the upper limit, it is advantageous for miniaturizing the second lens group G2. 0.01 < d2r / DA2r < 0.04 (14)

[0083] In order to obtain better characteristics, the lower limit of conditional expression (14) should preferably be set to 0.013, more preferably 0.015, even more preferably 0.017, and even more preferably 0.019.In order to obtain better characteristics, the upper limit of conditional expression (14) should preferably be set to 0.038, more preferably 0.035, even more preferably 0.032, and even more preferably 0.03.

[0084] When a zoom lens includes a focusing group that moves along the optical axis Z during focusing, and the focusing group includes at least one negative lens, it is preferable that the zoom lens satisfy the following conditional expression (15). Here, the central thickness of the negative lens closest to the image among the negative lenses included in the focusing group is defined as dffr. The outer diameter of the negative lens closest to the image among the negative lenses included in the focusing group is defined as DAFfr. As an example, FIG. 2 shows the above central thickness dffr and the above outer diameter DAFfr. Ensuring that the corresponding value of conditional expression (15) is not equal to or less than the lower limit is advantageous for lens processing accuracy. Ensuring that the corresponding value of conditional expression (15) is not equal to or greater than the upper limit is advantageous for miniaturizing the focusing group. 0.01 <dffr / DAffr<0.04 (15)

[0085] In order to obtain better characteristics, the lower limit of conditional expression (15) should preferably be set to 0.013, more preferably 0.015, even more preferably 0.017, and even more preferably 0.019.In order to obtain better characteristics, the upper limit of conditional expression (15) should preferably be set to 0.038, more preferably 0.035, even more preferably 0.032, and even more preferably 0.03.

[0086] When the focal length of the final lens group GE is taken as fE, it is preferable that the zoom lens satisfy the following conditional expression (16): Since the first lens group G1 and the final lens group GE are lens groups having positive refractive power, the lower limit of conditional expression (16) is 0 <f1 / fEとなる。条件式(16)の対応値が上限以上とならないようにすることによって、最終レンズ群GEの屈折力が強くなり過ぎないため、小型化に有利となる。また、第1レンズ群G1の屈折力が弱くなり過ぎないため、第1レンズ群G1の小型化に有利となる。 0 <f1 / fE<2 (16)

[0087] It is more preferable to set the lower limit of conditional expression (16) to 0.1. In this case, the refractive power of the final lens group GE will not be too weak, which is advantageous for suppressing aberrations at each image height. Furthermore, the refractive power of the first lens group G1 will not be too strong, which is advantageous for suppressing aberration fluctuations during magnification. In order to obtain better characteristics, it is more preferable to set the lower limit of conditional expression (16) to 0.2, more preferably 0.4, and even more preferably 0.6. In order to obtain better characteristics, it is more preferable to set the upper limit of conditional expression (16) to 1.8, more preferably 1.5, even more preferably 1.2, and even more preferably 1.

[0088] When the focal length of the second lens group G2 is f2, it is preferable that the zoom lens satisfy the following conditional expression (17): By ensuring that the corresponding value of conditional expression (17) is not below the lower limit, the refractive power of the second lens group G2 does not become too strong, which is advantageous for suppressing aberration fluctuations during zooming. By ensuring that the corresponding value of conditional expression (17) is not above the upper limit, the refractive power of the second lens group G2 does not become too weak, which is advantageous for compactness. -2 <fw / f2<-0.7 (17)

[0089] In order to obtain better characteristics, the lower limit value of conditional expression (17) is more preferably -1.8, still more preferably -1.5, still more preferably -1.3, and still more preferably -1. In order to obtain better characteristics, the upper limit value of conditional expression (17) is more preferably -0.75, still more preferably -0.8, still more preferably -0.85, and still more preferably -0.9.

[0090] In a configuration including a focusing group that moves along the optical axis Z when the zoom lens is focused, it is preferable that the zoom lens satisfies the following conditional expression (18). Here, the focal length of the focusing group is denoted as ff. By preventing the corresponding value of conditional expression (18) from falling below the lower limit value, the refractive power of the focusing group does not become too weak, which is advantageous for miniaturization. Also, since the refractive power of the second lens group G2 does not become too strong, it is advantageous for suppressing aberration variation during zooming. By preventing the corresponding value of conditional expression (18) from exceeding the upper limit, the refractive power of the focusing group does not become too strong, so that the strictness of the stop position accuracy can be suppressed. Also, since the refractive power of the second lens group G2 does not become too weak, it is advantageous for miniaturization. 0.2 < f2 / ff < 0.8 (18)

[0091] In order to obtain better characteristics, the lower limit value of conditional expression (18) is more preferably 0.25, still more preferably 0.3, still more preferably 0.35, and still more preferably 0.4. In order to obtain better characteristics, the upper limit value of conditional expression (18) is more preferably 0.75, still more preferably 0.7, still more preferably 0.65, and still more preferably 0.6.

[0092] It is preferable that the zoom lens satisfy the following conditional expression (19). Hereinafter, of the lens groups included in the intermediate group GM, the lens group having the strongest positive refractive power will be referred to as the Mp lens group. Here, the focal length of the Mp lens group will be fMp. By ensuring that the corresponding value of conditional expression (19) is not below the lower limit, the refractive power of the Mp lens group will not become too weak, which is advantageous for size reduction. By ensuring that the corresponding value of conditional expression (19) is not above the upper limit, the refractive power of the Mp lens group will not become too strong, which is advantageous for suppressing aberration fluctuations during magnification variation. 0.4 <fw / fMp<2 (19)

[0093] In order to obtain better characteristics, the lower limit of conditional expression (19) should preferably be set to 0.45, more preferably 0.5, even more preferably 0.55, and even more preferably 0.6.In order to obtain better characteristics, the upper limit of conditional expression (19) should preferably be set to 1.5, more preferably 1.3, even more preferably 1, and even more preferably 0.8.

[0094] It is preferable that the zoom lens satisfy the following conditional expression (20): By ensuring that the corresponding value of conditional expression (20) is not below the lower limit, the refractive power of the Mp lens group does not become too weak, which is advantageous for size reduction. By ensuring that the corresponding value of conditional expression (20) is not above the upper limit, the refractive power of the Mp lens group does not become too strong, which is advantageous for suppressing aberration fluctuations during magnification variation. 1.5 <ft / fMp<5 (20)

[0095] In order to obtain better characteristics, it is more preferable that the lower limit of conditional formula (20) be set to 2, even more preferably to 2.2, even more preferably to 2.3, and even more preferably to 2.4. In order to obtain better characteristics, it is more preferable that the upper limit of conditional formula (20) be set to 4.5, even more preferably to 4, even more preferably to 3.5, and even more preferably to 3.

[0096] In a configuration where the Mp lens group includes one or more cemented lenses, it is preferable that the zoom lens satisfies the following conditional expression (21). Here, among the cemented lenses included in the Mp lens group, the refractive index with respect to the d-line of the positive lens included in the most object-side cemented lens is defined as Ndfp. Among the cemented lenses included in the Mp lens group, the refractive index with respect to the d-line of the negative lens included in the most object-side cemented lens is defined as Ndfn. By satisfying the conditional expression (21), it is advantageous for correcting the first-order spectrum of axial chromatic aberration. -0.7 < Ndfp - Ndfn < -0.2 (21)

[0097] To obtain better characteristics, the lower limit value of the conditional expression (21) is more preferably -0.65, still more preferably -0.6, still more preferably -0.5, and still more preferably -0.45. To obtain better characteristics, the upper limit value of the conditional expression (21) is more preferably -0.25, still more preferably -0.3, still more preferably -0.35, and still more preferably -0.4.

[0098] In a configuration where the Mp lens group includes one or more cemented lenses, it is preferable that the zoom lens satisfies the following conditional expression (22). Here, among the cemented lenses included in the Mp lens group, the Abbe number based on the d-line of the positive lens included in the most object-side cemented lens is defined as νdfp. Among the cemented lenses included in the Mp lens group, the Abbe number based on the d-line of the negative lens included in the most object-side cemented lens is defined as νdfn. By satisfying the conditional expression (22), it is advantageous for correcting the first-order spectrum of axial chromatic aberration. 30 < νdfp - νdfn < 100 (22)

[0099] To obtain better characteristics, the lower limit value of the conditional expression (22) is more preferably 35, still more preferably 40, still more preferably 50, and still more preferably 60. To obtain better characteristics, the upper limit value of the conditional expression (22) is more preferably 90, still more preferably 80, still more preferably 70.

[0100] In a configuration where the Mp lens group includes one or more cemented lenses, it is preferable that the zoom lens satisfies the following conditional expression (23). Here, among the cemented lenses included in the Mp lens group, the partial dispersion ratio between the g-line and the F-line of the positive lens included in the most object-side cemented lens is defined as θgFfp. Among the cemented lenses included in the Mp lens group, the partial dispersion ratio between the g-line and the F-line of the negative lens included in the most object-side cemented lens is defined as θgFfn. By satisfying the conditional expression (23), it is advantageous for correcting the secondary spectrum of axial chromatic aberration. -0.12 < θgFfp - θgFfn < -0.02 (23)

[0101] Note that when the refractive indices of a certain lens with respect to the g-line, F-line, and C-line are Ng, NF, and NC, respectively, and the partial dispersion ratio between the g-line and the F-line of that lens is θgF, θgF is defined by the following formula. θgF = (Ng - NF) / (NF - NC)

[0102] To obtain better characteristics, it is more preferable that the lower limit value of the conditional expression (23) is -0.11, even more preferably -0.1, even more preferably -0.09, and even more preferably -0.08. To obtain better characteristics, it is more preferable that the upper limit value of the conditional expression (23) is -0.03, even more preferably -0.04, even more preferably -0.05, and even more preferably -0.06.

[0103] It is more preferable that the zoom lens simultaneously satisfies the conditional expressions (21), (22), and (23).

[0104] Note that when the most object-side cemented lens includes a plurality of positive lenses, the values of the most object-side positive lens included in this cemented lens are used to calculate the conditional expressions (21), (22), and (23). Similarly, when the most object-side cemented lens includes a plurality of negative lenses, the values of the most object-side negative lens included in this cemented lens are used to calculate the conditional expressions (21), (22), and (23).

[0105] In a configuration where the Mp lens group includes one or more cemented lenses, it is preferable that the zoom lens satisfies the following conditional expression (24). Here, among the cemented lenses included in the Mp lens group, the refractive index with respect to the d-line of the positive lens included in the most image-side cemented lens is defined as Ndrp. Among the cemented lenses included in the Mp lens group, the refractive index with respect to the d-line of the negative lens included in the most image-side cemented lens is defined as Ndrn. By satisfying the conditional expression (24), it is advantageous for correcting the first-order spectrum of axial chromatic aberration. -0.7 < Ndrp - Ndrn < -0.1 (24)

[0106] In order to obtain better characteristics, the lower limit value of the conditional expression (24) is more preferably -0.65, still more preferably -0.6, still more preferably -0.5, and still more preferably -0.4. In order to obtain better characteristics, the upper limit value of the conditional expression (24) is more preferably -0.15, still more preferably -0.2, still more preferably -0.25, and still more preferably -0.3.

[0107] In a configuration where the Mp lens group includes one or more cemented lenses, it is preferable that the zoom lens satisfies the following conditional expression (25). Here, among the cemented lenses included in the Mp lens group, the Abbe number based on the d-line of the positive lens included in the most image-side cemented lens is defined as νdrp. Among the cemented lenses included in the Mp lens group, the Abbe number based on the d-line of the negative lens included in the most image-side cemented lens is defined as νdrn. By satisfying the conditional expression (25), it is advantageous for correcting the first-order spectrum of axial chromatic aberration. 30 < νdrp - νdrn < 100 (25)

[0108] In order to obtain better characteristics, the lower limit value of conditional expression (25) is more preferably 35, still more preferably 40, still more preferably 45, and still more preferably 50. In order to obtain better characteristics, the upper limit value of conditional expression (25) is more preferably 90, still more preferably 80, still more preferably 70, and still more preferably 60.

[0109] In a configuration where the Mp lens group includes one or more cemented lenses, the zoom lens preferably satisfies the following conditional expression (26). Here, among the cemented lenses included in the Mp lens group, the partial dispersion ratio between the g-line and the F-line of the positive lens included in the most image-side cemented lens is defined as θgFrp. Among the cemented lenses included in the Mp lens group, the partial dispersion ratio between the g-line and the F-line of the negative lens included in the most image-side cemented lens is defined as θgFrn. By satisfying conditional expression (26), it is advantageous for correcting the secondary spectrum of axial chromatic aberration. -0.12 < θgFrp - θgFrn < -0.02 (26)

[0110] In order to obtain better characteristics, the lower limit value of conditional expression (26) is more preferably -0.11, still more preferably -0.1, still more preferably -0.09, and still more preferably -0.08. In order to obtain better characteristics, the upper limit value of conditional expression (26) is more preferably -0.03, still more preferably -0.04, still more preferably -0.05, and still more preferably -0.06.

[0111] The zoom lens more preferably satisfies conditional expressions (24), (25), and (26) simultaneously.

[0112] In addition, when the most image-side cemented lens among the above includes a plurality of positive lenses, the conditional expressions (24), (25), and (26) shall be calculated using the value of the most image-side positive lens included in this cemented lens. Similarly, when the most image-side cemented lens among the above includes a plurality of negative lenses, the conditional expressions (24), (25), and (26) shall be calculated using the value of the most image-side negative lens included in this cemented lens.

[0113] Note that the example shown in FIG. 1 is just an example, and various modifications are possible without departing from the gist of the technology of the present disclosure. For example, the number of lens groups included in the intermediate group GM and the number of lenses included in each lens group may be different from those in the example of FIG. 1.

[0114] The zoom lens in the example shown in FIG. 1 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 negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. By adopting such a configuration, it is advantageous for miniaturization and weight reduction.

[0115] However, as shown in the embodiments described later, the zoom lens of the present disclosure may be configured to be 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 negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. By adopting such a configuration, it is advantageous for suppressing aberration variation during zooming.

[0116] The above-described preferred configurations and possible configurations can be arbitrarily combined within a non-contradictory range, and it is preferable to selectively adopt them as appropriate according to the required specifications.

[0117] As an example, a preferred embodiment of a zoom lens according to the present disclosure includes, 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, an intermediate group GM, and a final lens group GE having positive refractive power, wherein the intermediate group GM is composed of two or three lens groups, and during magnification variation, the distance between the first lens group G1 and the second lens group G2 changes, the distance between the second lens group G2 and the intermediate group GM changes, the distance between the intermediate group GM and the final lens group GE changes, and all distances between adjacent lens groups in the intermediate group GM change, an aperture stop St is disposed between the lens surface of the second lens group G2 closest to the image side and the lens surface of the final lens group GE closest to the object side, and the first lens group G1 includes, in succession from the object side to the image side, a first lens which is a negative lens whose object-side surface is convex, and a second lens which is a positive lens, and satisfies the above conditional expressions (1), (2), (3), and (4).

[0118] Next, examples of the zoom lens of the present disclosure will be described with reference to the drawings. Note that the reference symbols assigned to each lens and each group in the cross-sectional views of each example are used independently for each example to avoid cluttering the explanation and drawings due to an increase in the number of digits in the reference symbols. Therefore, even if common reference symbols are assigned in drawings of different examples, this does not necessarily mean that the configuration is the same.

[0119] [Example 1] The configuration and movement locus of the zoom lens of Example 1 are shown in FIG. 1. Since the illustration method and configuration are as described above, redundant explanations are partially omitted here. The zoom lens of Example 1 includes, 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 negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. The intermediate group GM consists of the third lens group G3 and the fourth lens group G4. The final lens group GE consists of the fifth lens group G5. When zooming from the wide-angle end to the telephoto end, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 move along the optical axis Z by changing the interval between adjacent lens groups, and the fifth lens group G5 is fixed with respect to the image plane Sim. The focusing group consists of the fourth lens group G4, and when focusing from an infinite object to the closest object, the focusing group moves toward the image side.

[0120] For the zoom lens of Example 1, the basic lens data is shown in Table 1, the specifications and variable surface intervals are shown in Table 2, and the aspherical coefficients are shown in Table 3.

[0121] The table of basic lens data is described as follows. In the column of "Sn", the surface numbers are shown when the surface closest to the object side is taken as the first surface and the numbers are incremented one by one toward the image side. In the column of "R", the radius of curvature of each surface is shown. In the column of "D", the axial surface interval between each surface and the surface adjacent to it on the image side is shown. In the column of "Nd", the refractive index with respect to the d-line of each lens is shown. In the column of "νd", the Abbe number based on the d-line of each lens is shown. In the column of "θgF", the partial dispersion ratio between the g-line and the F-line of each component is shown. In the column of "DA", the outer diameter is shown. Note that in the column of "DA", values are shown only for the lenses related to the conditional expressions.

[0122] In the table of basic lens data, the sign of the radius of curvature of the surface facing the object side with a convex shape is positive, and the sign of the radius of curvature of the surface facing the image side with a convex shape is negative. In Table 1, in the column of the surface number corresponding to the aperture stop St, the surface number and the phrase (St) are entered. The value in the bottommost column of the D column in the table is the distance between the most image-side surface in the table and the image plane Sim. Regarding the variable surface interval during zooming, the symbol DD[ ] is used, and the surface number on the object side of this interval is attached in [ ] and entered in the column of the surface interval.

[0123] Table 2 shows the zoom ratio Zr, focal length f, back focus Bf, open F-number FNo., maximum full angle of view 2ω, and variable surface interval based on the d line. The zoom ratio is synonymous with the zoom magnification. The [°] in the column of 2ω indicates that the unit is degrees. In Table 2, the values in the columns marked "Wide", "Middle", and "Tele" show the values in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively.

[0124] In the basic lens data, an asterisk is attached to the surface number of the aspherical surface, and the value of the paraxial radius of curvature is described in the column of the radius of curvature of the aspherical surface. In Table 3, the row of Sn shows the surface number of the aspherical surface, and the rows of KA and Am (m = 3, 4, 5, 6, 7, 8, 9, 10) show the numerical values of the aspherical coefficients for each aspherical surface. The "E±n" (n: integer) of the numerical values of the aspherical coefficients in Table 3 means "×10 ±n ". KA and Am are the aspherical coefficients in the aspherical formula represented by the following formula. Zd = C × h 2 / {1 + (1 - KA × C 2 × h 2 ) 1 / 2}+ ΣAm × h m However, Zd: Aspherical depth (the length of the perpendicular dropped from the point on the aspherical surface at height h to the plane perpendicular to the optical axis Z where the aspherical vertex touches) h: Height (the distance from the optical axis Z to the lens surface) C: Reciprocal of the paraxial radius of curvature KA, Am: Aspherical coefficients where Σ in the aspherical formula means the sum with respect to m.

[0125] In the data in each table, degrees are used as the unit of angle and millimeters as the unit of length, but since the optical system can be used with proportional magnification or reduction, other appropriate units can also be used. Also, in each table below, values are listed rounded to a predetermined number of decimal places.

[0126] [Table 1]

[0127] [Table 2]

[0128] [Table 3]

[0129] FIG. 3 shows aberration diagrams of the zoom lens of Example 1 when focused on an object at infinity. From left to right, FIG. 3 shows spherical aberration, astigmatism, distortion, and lateral chromatic aberration. In FIG. 3, the upper row labeled "Wide" shows aberrations at the wide-angle end, the middle row labeled "Middle" shows aberrations at the intermediate focal length, and the lower row labeled "Tele" shows aberrations at the telephoto end. In the spherical aberration diagram, aberrations at the d-line, C-line, F-line, and g-line are shown by solid lines, long-dashed lines, short-dashed lines, and dash-dot lines, respectively. In the astigmatism diagram, aberrations at the d-line in the sagittal direction are shown by solid lines, and aberrations at the d-line in the tangential direction are shown by short-dashed lines. In the distortion diagram, aberrations at the d-line are shown by solid lines. In the lateral chromatic aberration diagram, aberrations for the C-line, F-line, and g-line are shown with long-dashed lines, short-dashed lines, and dash-dot 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=.

[0130] The symbols, meanings, notation methods, and illustration methods of each data item related to the above-mentioned Example 1 are basically the same in the following Examples unless otherwise specified, and therefore, redundant explanations will be omitted below.

[0131] [Example 2] The configuration and movement trajectory of the zoom lens of Example 2 are shown in Figure 4. The zoom lens of Example 2 consists of, 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 negative refractive power, and a fifth lens group G5 having positive refractive power. The middle group GM consists of the third lens group G3 and the fourth lens group G4. The final lens group GE consists of the fifth lens group G5. When varying the magnification from the wide-angle end to the telephoto end, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 move along the optical axis Z while changing the spacing between adjacent lens groups, and the fifth lens group G5 is fixed with respect to the image plane Sim. The focusing group is made up of the fourth lens group G4, and when focusing from an object at infinity to the closest object, the focusing group moves toward the image side.

[0132] 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 four lenses, L21 to L24, in order from the object side to the image side. The third lens group G3 consists of an aperture stop St and six lenses, L31 to L36, in order from the object side to the image side. The fourth lens group G4 consists of two lenses, L41 and L42, in order from the object side to the image side. The fifth lens group G5 consists of a single lens, L51.

[0133] For the zoom lens of Example 2, basic lens data is shown in Table 4, specifications and variable surface spacings are shown in Table 5, aspherical coefficients are shown in Table 6, and aberration diagrams are shown in FIG.

[0134] [Table 4]

[0135] [Table 5]

[0136] [Table 6]

[0137] [Example 3] The configuration and movement trajectory of the zoom lens of Example 3 are shown in Figure 6. The zoom lens of Example 3 consists of, 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 negative refractive power, and a fifth lens group G5 having positive refractive power. The middle group GM consists of the third lens group G3 and the fourth lens group G4. The final lens group GE consists of the fifth lens group G5. During magnification change from the wide-angle end to the telephoto end, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 move along the optical axis Z while changing the spacing between adjacent lens groups, and the fifth lens group G5 is fixed with respect to the image plane Sim. The focusing group is made up of the fourth lens group G4, and when focusing from an object at infinity to the closest object, the focusing group moves toward the image side.

[0138] 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 four lenses, L21 to L24, in order from the object side to the image side. The third lens group G3 consists of an aperture stop St and six lenses, L31 to L36, in order from the object side to the image side. The fourth lens group G4 consists of two lenses, L41 and L42, in order from the object side to the image side. The fifth lens group G5 consists of a single lens, L51.

[0139] For the zoom lens of Example 3, basic lens data is shown in Table 7, specifications and variable surface spacings are shown in Table 8, aspherical coefficients are shown in Table 9, and aberration diagrams are shown in FIG.

[0140] [Table 7]

[0141] [Table 8]

[0142]

Table 9

[0143] [Example 4] The configuration and movement locus of the zoom lens of Example 4 are shown in FIG. 8. The zoom lens of Example 4 includes, 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 negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. The intermediate group GM consists of the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE consists of the sixth lens group G6. When zooming from the wide-angle end to the telephoto end, the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move along the optical axis Z by changing the interval between adjacent lens groups, and the sixth lens group G6 is fixed with respect to the image plane Sim. The focusing group consists of the fifth lens group G5, and when focusing from an infinite object to the closest object, the focusing group moves toward the image side.

[0144] 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 four lenses L21 to L24 in order from the object side to the image side. The third lens group G3 consists of an aperture stop St and three lenses L31 to L33 in order from the object side to the image side. The fourth lens group G4 consists of three lenses L41 to L43 in order from the object side to the image side. The fifth lens group G5 consists of two lenses L51 to L52 in order from the object side to the image side. The sixth lens group G6 consists of one lens L61.

[0145] For the zoom lens of Example 4, the basic lens data is shown in Table 10, the specifications and variable surface intervals are shown in Table 11, the aspherical coefficients are shown in Table 12, and each aberration diagram is shown in FIG. 9.

[0146] [Table 10]

[0147] [Table 11]

[0148] [Table 12]

[0149] [Example 5] The configuration and movement locus of the zoom lens of Example 5 are shown in Figure 10. The zoom lens of Example 5 consists, in order from the object side to the image side, of 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, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. The middle group GM consists of the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE consists of the sixth lens group G6. When varying magnification from the wide-angle end to the telephoto end, the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move along the optical axis Z while changing the spacing between adjacent lens groups, and the sixth lens group G6 is fixed with respect to the image plane Sim. The focusing group is made up of the fifth lens group G5, and when focusing from an object at infinity to the closest object, the focusing group moves toward the image side.

[0150] 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 four lenses, L21 to L24, in order from the object side to the image side. The third lens group G3 consists of an aperture stop St and three lenses, L31 to L33, in order from the object side to the image side. The fourth lens group G4 consists of three lenses, L41 to L43, in order from the object side to the image side. The fifth lens group G5 consists of two lenses, L51 and L52, in order from the object side to the image side. The sixth lens group G6 consists of a single lens, L61.

[0151] For the zoom lens of Example 5, the basic lens data is shown in Table 13, the specifications and variable surface intervals are shown in Table 14, the aspherical coefficients are shown in Table 15, and each aberration diagram is shown in FIG. 11.

[0152]

Table 13

[0153]

Table 14

[0154]

Table 15

[0155] [Example 6] The configuration and movement locus of the zoom lens of Example 6 are shown in FIG. 12. The zoom lens of Example 6 includes, 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 negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. The intermediate group GM consists of the third lens group G3 and the fourth lens group G4. The final lens group GE consists of the fifth lens group G5. When zooming from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z by changing the interval with the adjacent lens group. The focusing group consists of the fourth lens group G4, and when focusing from an infinite object to the closest object, the focusing group moves toward the image side.

[0156] 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 four lenses, L21 to L24, in order from the object side to the image side. The third lens group G3 consists of an aperture stop St and six lenses, L31 to L36, in order from the object side to the image side. The fourth lens group G4 consists of two lenses, L41 and L42, in order from the object side to the image side. The fifth lens group G5 consists of a single lens, L51.

[0157] For the zoom lens of Example 6, basic lens data is shown in Table 16, specifications and variable surface spacing are shown in Table 17, aspherical coefficients are shown in Table 18, and each aberration diagram is shown in FIG.

[0158] [Table 16]

[0159] [Table 17]

[0160] [Table 18]

[0161] [Example 7] The configuration and movement trajectory of the zoom lens of Example 7 are shown in Figure 14. The zoom lens of Example 7 consists of, 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 negative refractive power, and a fifth lens group G5 having positive refractive power. The middle group GM consists of the third lens group G3 and the fourth lens group G4. The final lens group GE consists of the fifth lens group G5. When varying magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing group consists of the fourth lens group G4, and when focusing from an object at infinity to the closest object, the focusing group moves toward the image side.

[0162] 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 four lenses L21 to L24 in order from the object side to the image side. The third lens group G3 consists of an aperture stop St and six lenses L31 to L36 in order from the object side to the image side. The fourth lens group G4 consists of two lenses L41 to L42 in order from the object side to the image side. The fifth lens group G5 consists of one lens L51.

[0163] For the zoom lens of Example 7, the basic lens data is shown in Table 19, the specifications and variable surface intervals are shown in Table 20, the aspherical coefficients are shown in Table 21, and each aberration diagram is shown in FIG. 15.

[0164]

Table 19

[0165]

Table 20

[0166]

Table 21

[0167] [Example 8] The configuration and movement locus of the zoom lens of Example 8 are shown in Figure 16. The zoom lens of Example 8 consists, in order from the object side to the image side, of 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, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power. The middle group GM consists of the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE consists of the sixth lens group G6. When varying magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing group consists of the fifth lens group G5, and when focusing from an object at infinity to the closest object, the focusing group moves toward the image side.

[0168] 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 four lenses, L21 to L24, in order from the object side to the image side. The third lens group G3 consists of an aperture stop St and three lenses, L31 to L33, in order from the object side to the image side. The fourth lens group G4 consists of three lenses, L41 to L43, in order from the object side to the image side. The fifth lens group G5 consists of two lenses, L51 and L52, in order from the object side to the image side. The sixth lens group G6 consists of a single lens, L61.

[0169] For the zoom lens of Example 8, basic lens data is shown in Table 22, specifications and variable surface spacing are shown in Table 23, aspherical coefficients are shown in Table 24, and each aberration diagram is shown in FIG.

[0170] [Table 22]

[0171] [Table 23]

[0172] [Table 24]

[0173] [Example 9] The configuration and movement locus of the zoom lens of Example 9 are shown in FIG. 18. The zoom lens of Example 9 includes, 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 negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. The intermediate group GM includes the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The final lens group GE consists of the sixth lens group G6. When zooming from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z by changing the interval from the adjacent lens group. The focusing group consists of the fifth lens group G5, and when focusing from an infinite object to the closest object, the focusing group moves toward the image side.

[0174] 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 four lenses L21 to L24 in order from the object side to the image side. The third lens group G3 consists of, in order from the object side to the image side, an aperture stop St and three lenses L31 to L33. The fourth lens group G4 consists of three lenses L41 to L43 in order from the object side to the image side. The fifth lens group G5 consists of two lenses L51 to L52 in order from the object side to the image side. The sixth lens group G6 consists of one lens L61.

[0175] Regarding the zoom lens of Example 9, the basic lens data is shown in Table 25, the specifications and variable surface intervals are shown in Table 26, the aspherical coefficients are shown in Table 27, and each aberration diagram is shown in FIG. 19.

[0176]

Table 25

[0177]

Table 26

[0178]

Table 27

[0179] [Example 10] The configuration and movement locus of the zoom lens of Example 10 are shown in FIG. 20. The zoom lens of Example 10 includes, 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 negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power. The intermediate group GM consists of the third lens group G3 and the fourth lens group G4. The final lens group GE consists of the fifth lens group G5. When zooming from the wide-angle end to the telephoto end, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 move along the optical axis Z by changing the interval between adjacent lens groups, and the fifth lens group G5 is fixed with respect to the image plane Sim. The focusing group consists of the fourth lens group G4, and when focusing from an infinite object to the closest object, the focusing group moves toward the image side.

[0180] 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 four lenses L21 to L24 in order from the object side to the image side. The third lens group G3 consists of, in order from the object side to the image side, an aperture stop St and five lenses L31 to L35. The fourth lens group G4 consists of two lenses L41 to L42 in order from the object side to the image side. The fifth lens group G5 consists of one lens L51.

[0181] Regarding the zoom lens of Example 10, the basic lens data is shown in Table 28, the specifications and variable surface intervals are shown in Table 29, the aspherical coefficients are shown in Table 30, and each aberration diagram is shown in FIG. 21.

[0182]

Table 28

[0183] [Table 29]

[0184] [Table 30]

[0185] Tables 31 and 32 show the corresponding values of conditional expressions (1) to (26) for the zoom lenses of Examples 1 to 10. The corresponding values of the Examples shown in Tables 31 and 32 may be used as the upper or lower limits of the conditional expressions to set preferred ranges for the conditional expressions.

[0186] [Table 31]

[0187] [Table 32]

[0188] The zoom lenses of Examples 1 to 10 have an F-number at the telephoto end of less than 3, and realize a small F-number over the entire zoom range. Furthermore, while the zoom lenses of Examples 1 to 10 are constructed to be compact, they maintain high optical performance with various aberrations well corrected over the entire zoom range.

[0189] Next, an imaging device according to an embodiment of the present disclosure will be described. Fig. 22 and Fig. 23 show external views of a camera 30, which is an imaging device according to an embodiment of the present disclosure. Fig. 22 shows a perspective view of the camera 30 as seen from the front side, and Fig. 23 shows a perspective view of the camera 30 as seen from the rear side. The camera 30 is a so-called mirrorless digital camera, to which an interchangeable lens 20 can be removably attached. The interchangeable lens 20 is configured to include a zoom lens 1 according to an embodiment of the present disclosure housed in a lens barrel.

[0190] The camera 30 includes a camera body 31. On the upper surface of the camera body 31, a shutter button 32 and a power button 33 are provided. Also, on the back surface of the camera body 31, an operation unit 34, an operation unit 35, and a display unit 36 are provided. The display unit 36 can display the captured image and the image within the angle of view before being captured.

[0191] In the central part of the front surface of the camera body 31, a shooting aperture through which light from the shooting object enters is provided. A mount 37 is provided at a position corresponding to the shooting aperture, and an interchangeable lens 20 is attached to the camera body 31 via the mount 37.

[0192] An image sensor 38 is provided inside the camera body 31. The image sensor 38 outputs an imaging signal corresponding to the subject image formed by the interchangeable lens 20. As the image sensor 38, for example, a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like is used. Inside the camera body 31, a signal processing circuit (not shown), a recording medium (not shown), and the like are provided. The signal processing circuit processes the imaging signal output from the image sensor 38 to generate an image. The recording medium is for recording the generated image. In the camera 30, by pressing the shutter button 32, still images or moving images can be taken, and the image data obtained by this shooting is recorded on the above recording medium.

[0193] As described above, the technology of the present disclosure has been described with reference to embodiments and examples, but 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, the distance between surfaces, the refractive index, the Abbe number, and the aspherical coefficient of each lens are not limited to the values shown in the above examples, and can take other values.

[0194] Also, the imaging device according to the embodiment of the present disclosure is not limited to the above example, and can be in various forms, such as a camera other than the mirrorless type, a film camera, a video camera, and a security camera.

[0195] Regarding the above embodiments and examples, the following appendices are further disclosed. [Appendix 1] It consists of a first lens group having a positive refractive power, a second lens group having a negative refractive power, an intermediate group, and a final lens group having a positive refractive power, in order from the object side to the image side. The intermediate group consists of two or three lens groups. During zooming, the distance between the first lens group and the second lens group changes, the distance between the second lens group and the intermediate group changes, the distance between the intermediate group and the final lens group changes, and all the distances between adjacent lens groups within the intermediate group change. An aperture stop is disposed between the most image-side lens surface of the second lens group and the most object-side lens surface of the final lens group. The first lens group includes, in order from the most object side to the image side, a first lens that is a negative lens with a convex object-side surface and a second lens that is a positive lens. Let fw be the focal length of the entire system in the state of focusing on an infinite object at the wide-angle end. Let f1 be the focal length of the first lens group. Let Fnot be the open F-number in the state of focusing on an infinite object at the telephoto end. Let ft be the focal length of the entire system in the state of focusing on an infinite object at the telephoto end. Let Bfw be the back focus of the entire system at the air-equivalent distance at the wide-angle end. Let ωt be the maximum half field angle in the state of focusing on an infinite object at the telephoto end. When the sum of the distance on the optical axis from the object-side surface of the first lens to the most image-side lens surface of the final lens group and the back focus of the entire system at the air-equivalent distance in the state of focusing on an infinite object at the telephoto end is defined as TLt. 0 < fw / f1 < 0.3 (1) 0.5 < Fnot / (ft / fw) < 1.3 (2) 0.15 < Bfw / (ft × tanωt) < 2 (3) 7 < TLt / (ft × tanωt) < 11 (4) A zoom lens that satisfies the conditional expressions (1), (2), (3), and (4) represented by [Appendix 2] With the intermediate group and the final lens group in a state of being focused on an infinite object at the telephoto end, the on-axis distance between them is dMEt, When the on-axis distance between the intermediate group and the final lens group in a state of being focused on an infinite object at the wide-angle end is dMEw, 2 < dMEt / dMEw < 10 (5) The zoom lens according to Appendix 1 that satisfies the conditional expression (5) represented by [Appendix 3] Let the paraxial curvature radius of the object-side lens surface of the second lens group be R2f, When the paraxial curvature radius of the image-side lens surface of the second lens group is R2r, -0.5 < (R2f + R2r) / (R2f - R2r) < 2 (6) The zoom lens according to Appendix 1 or Appendix 2 that satisfies the conditional expression (6) represented by [Appendix 4] Let the refractive index with respect to the d line of the image-side lens of the first lens group be Nd1r, Let the Abbe number with respect to the d line of the image-side lens of the first lens group be νd1r, Let the refractive index with respect to the d line of the image-side lens of the second lens group be Nd2r, When the Abbe number with respect to the d line of the image-side lens of the second lens group is νd2r, 1.65 < Nd1r < 1.8 (7) 45 < νd1r < 60 (8) 1.4 < Nd2r < 1.65 (9) 60 < νd2r < 100 (10) The zoom lens according to any one of Appendices 1 to 3 that satisfies the conditional expressions (7), (8), (9), and (10) represented by [Appendix 5] 1 < fw / (ft × tanωt) < 1.45 (11) The zoom lens according to any one of Appendices 1 to 4 that satisfies the conditional expression (11) represented by [Appendix 6] The distance on the optical axis from the object side surface of the first lens to the aperture stop in the state of being focused on an infinite object at the wide-angle end is DDL1STw, When the sum of the distance on the optical axis from the object side surface of the first lens to the most image side lens surface of the final lens group and the overall system back focus in terms of air equivalent distance is defined as TLw in the state of being focused on an infinite object at the wide-angle end, 0 < DDL1STw / TLw < 0.65 (12) The zoom lens according to any one of Appendices 1 to 5 that satisfies the conditional expression (12) represented by the above. [Appendix 7] When the center thickness of the first lens is d1, and the outer diameter of the first lens is DA1, 0.01 < d1 / DA1 < 0.035 (13) The zoom lens according to any one of Appendices 1 to 6 that satisfies the conditional expression (13) represented by the above. [Appendix 8] Among the negative lenses included in the second lens group, when the center thickness of the most image side negative lens is d2r, and the outer diameter of the most image side negative lens among the negative lenses included in the second lens group is DA2r, 0.01 < d2r / DA2r < 0.04 (14) The zoom lens according to any one of Appendices 1 to 7 that satisfies the conditional expression (14) represented by the above. [Appendix 9] Including a focusing group that moves along the optical axis during focusing, the focusing group includes at least one negative lens, Among the negative lenses included in the focusing group, when the center thickness of the most image side negative lens is dffr, and the outer diameter of the most image side negative lens among the negative lenses included in the focusing group is DAffr, 0.01 < dffr / DAffr < 0.04 (15) The zoom lens according to any one of Appendices 1 to 8 that satisfies the conditional expression (15) represented by the above. [Appendix 10] When the focal length of the final lens group is fE, 0 <f1 / fE<2 (16) 10. The zoom lens according to claim 1, which satisfies conditional expression (16) below. [Appendix 11] If the focal length of the second lens group is f2, then -2 <fw / f2<-0.7 (17) 11. The zoom lens according to claim 1, which satisfies conditional expression (17) below. [Appendix 12] a focusing group that moves along the optical axis during focusing; The focal length of the second lens group is f2, If the focal length of the focusing group is ff, 0.2 <f2 / ff<0.8 (18) 12. The zoom lens according to claim 1, which satisfies conditional expression (18) below. [Appendix 13] If the focal length of the lens group with the strongest positive refractive power among the lens groups included in the intermediate group is fMp, then 0.4 <fw / fMp<2 (19) 13. The zoom lens according to claim 1, which satisfies conditional expression (19) below. [Appendix 14] If the focal length of the lens group with the strongest positive refractive power among the lens groups included in the intermediate group is fMp, then 1.5 <ft / fMp<5 (20) 14. The zoom lens according to claim 1, which satisfies conditional expression (20) below. [Appendix 15] 0.1 <fw / f1<0.2 (1-1) 15. The zoom lens according to claim 1, which satisfies conditional expression (1-1) shown below. [Appendix 16] 16. The zoom lens according to claim 1, wherein the first lens group is composed of three lenses. [Appendix 17] The second lens group consists of four lenses, and is the zoom lens according to any one of Appendices 1 to 16. [Appendix 18] During zooming, the first lens group moves, and is the zoom lens according to any one of Appendices 1 to 17. [Appendix 19] The zoom lens includes 14 or more lenses, and is the zoom lens according to any one of Appendices 1 to 18. [Appendix 20] An imaging device equipped with the zoom lens according to any one of Claims 1 to 19.

Explanation of Signs

[0196] 1 Zoom lens 20 Interchangeable lens 30 Camera 31 Camera body 32 Shutter button 33 Power button 34 Operation part 35 Operation part 36 Display part 37 Mount 38 Imaging element Bfw Back focus DA1 Outer diameter DA2r Outer diameter DAffr Outer diameter DDL1STw Distance d1 Central thickness d2r Central thickness dffr Central thickness dMEt Interval dMEw Interval G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group G6 Sixth lens group GE Final lens group GM Intermediate group L11~L61 Lenses Sim Image plane St Aperture stop Beam on the ta axis tb beam Total length TLt Total length TLw Beam on the wa axis wb beam Z optical axis Maximum semi-aperture angle ωt Maximum semi-aperture angle ωw

Claims

1. It consists of a first lens group having a positive refractive power, a second lens group having a negative refractive power, an intermediate group, and a final lens group having a positive refractive power, in order from the object side to the image side. The intermediate group consists of two or three lens groups. During zooming, the distance between the first lens group and the second lens group changes, the distance between the second lens group and the intermediate group changes, the distance between the intermediate group and the final lens group changes, and all the distances between adjacent lens groups within the intermediate group change. An aperture stop is disposed between the most image-side lens surface of the second lens group and the most object-side lens surface of the final lens group. The first lens group includes, in order from the most object side to the image side, a first lens that is a negative lens with a convex object-side surface and a second lens that is a positive lens. Let the focal length of the entire system in the state of focusing on an infinite object at the wide-angle end be fw. Let the focal length of the first lens group be f1. Let the open F-number in the state of focusing on an infinite object at the telephoto end be Fnot. Let the focal length of the entire system in the state of focusing on an infinite object at the telephoto end be ft. Let the back focus of the entire system at the air-equivalent distance at the wide-angle end be Bfw. Let the maximum half field angle in the state of focusing on an infinite object at the telephoto end be ωt. When the sum of the distance on the optical axis from the object-side surface of the first lens to the most image-side lens surface of the final lens group and the back focus of the entire system at the air-equivalent distance in the state of focusing on an infinite object at the telephoto end is defined as TLt. 0 < fw / f1 < 0.3 (1) 0.5 < Fnot / (ft / fw) < 1.3 (2) 0.15 < Bfw / (ft × tanωt) < 2 (3) 7 < TLt / (ft × tanωt) < 11 (4) A zoom lens that satisfies the conditional expressions (1), (2), (3), and (4) represented by the above.

2. Let the distance on the optical axis between the intermediate group and the final lens group in the state of focusing on an infinite object at the telephoto end be dMEt. When the distance on the optical axis between the intermediate group and the final lens group in the state of focusing on an infinite object at the wide-angle end is defined as dMEw. 2 < dMEt / dMEw < 10 (5) The zoom lens according to Claim 1, which satisfies the conditional expression (5) represented by the above.

3. Let the paraxial curvature radius of the most object-side lens surface of the second lens group be R2f. When the paraxial curvature radius of the most image-side lens surface of the second lens group is defined as R2r. -0.5 < (R2f + R2r) / (R2f - R2r) < 2 (6) The zoom lens according to claim 1, which satisfies the conditional expression (6) represented by

4. Let the refractive index with respect to the d-line of the lens closest to the image side of the first lens group be Nd1r, Let the Abbe number based on the d-line of the lens closest to the image side of the first lens group be νd1r, Let the refractive index with respect to the d-line of the lens closest to the image side of the second lens group be Nd2r, When the Abbe number based on the d-line of the lens closest to the image side of the second lens group is νd2r, 1.65 < Nd1r < 1.8 (7) 45 < νd1r < 60 (8) 1.4 < Nd2r < 1.65 (9) 60 < νd2r < 100 (10) The zoom lens according to claim 1, which satisfies the conditional expressions (7), (8), (9), and (10) represented by

5. 1 < fw / (ft × tan ωt) < 1.45 (11) The zoom lens according to claim 1, which satisfies the conditional expression (11) represented by

6. Let the distance on the optical axis from the object-side surface of the first lens to the aperture stop in the state of focusing on an infinite object at the wide-angle end be DDL1STw, When the sum of the distance on the optical axis from the object-side surface of the first lens to the image-side lens surface of the final lens group and the overall back focus in terms of air-equivalent distance in the state of focusing on an infinite object at the wide-angle end is TLw, 0 < DDL1STw / TLw < 0.65 (12) The zoom lens according to claim 1, which satisfies the conditional expression (12) represented by

7. Let the center thickness of the first lens be d1, When the outer diameter of the first lens is DA1, 0.01 < d1 / DA1 < 0.035 (13) The zoom lens according to claim 1, which satisfies the conditional expression (13) represented by

8. Let the center thickness of the negative lens closest to the image side among the negative lenses included in the second lens group be d2r, When the outer diameter of the negative lens closest to the image side among the negative lenses included in the second lens group is DA2r, 0.01 < d2r / DA2r < 0.04 (14) The zoom lens according to claim 1, which satisfies the conditional expression (14) represented by

9. Including a focusing group that moves along the optical axis during focusing, The focusing group includes at least one negative lens, Let the center thickness of the negative lens closest to the image side among the negative lenses included in the focusing group be dffr, When the outer diameter of the negative lens closest to the image side among the negative lenses included in the focusing group is DAffr, 0.01 < dffr / DAffr < 0.04 (15) The zoom lens according to claim 1, which satisfies the conditional expression (15) represented by

10. When the focal length of the final lens group is fE, 0 < f1 / fE < 2 (16) The zoom lens according to claim 1, which satisfies the conditional expression (16) represented by

11. When the focal length of the second lens group is f2, -2 < fw / f2 < -0.7 (17) The zoom lens according to claim 1, which satisfies the conditional expression (17) represented by

12. Including a focusing group that moves along the optical axis during focusing, When the focal length of the second lens group is f2, When the focal length of the focusing group is ff, 0.2 < f2 / ff < 0.8 (18) The zoom lens according to claim 1, which satisfies the conditional expression (18) represented by

13. Among the lens groups included in the intermediate group, when the focal length of the lens group with the strongest positive refractive power is fMp, 0.4 < fw / fMp < 2 (19) The zoom lens according to claim 1, which satisfies the conditional expression (19) represented by

14. Among the lens groups included in the intermediate group, when the focal length of the lens group with the strongest positive refractive power is fMp, 1.5 < ft / fMp < 5 (20) The zoom lens according to claim 1, which satisfies the conditional expression (20) represented by

15. 0.1 < fw / f1 < 0.2 (1-1) The zoom lens according to claim 1, which satisfies the conditional expression (1-1) represented by

16. The zoom lens according to claim 1, wherein the first lens group consists of three lenses.

17. The zoom lens according to claim 1, wherein the second lens group consists of four lenses.

18. The zoom lens according to claim 1, wherein the first lens group moves during zooming.

19. The zoom lens according to claim 1, including 14 or more lenses.

20. An imaging device provided with the zoom lens according to any one of claims 1 to 19.

Images