JP2023001878A - Imaging lens and imaging apparatus - Google Patents

Abstract

To provide an imaging lens which is miniaturized regardless of a wide angle and has excellent optical performance and an imaging apparatus including the imaging lens.SOLUTION: The imaging lens comprises a front group, a diaphragm, and a rear group having positive refractive power in order from an object side to an image side. The imaging lens satisfies a predetermined conditional expression.SELECTED DRAWING: Figure 1

Description

The technology of the present disclosure relates to an imaging lens and an imaging device.

2. Description of the Related Art Conventionally, as imaging lenses used in imaging apparatuses such as digital cameras, for example, lens systems disclosed in Patent Documents 1 and 2 below are known.

JP 2020-129022 A JP 2021-047384 A

2. Description of the Related Art In recent years, there has been a demand for an imaging lens that is wide-angle, compact, and has good optical performance.

The present disclosure provides an imaging lens that is wide-angle, compact, and has good optical performance, and an imaging apparatus that includes this imaging lens.

A first aspect of the present disclosure is an imaging lens comprising, in order from an object side to an image side, a front group, a diaphragm, and a rear group having positive refractive power, and focusing on an infinite object. H is the height from the optical axis of the principal ray of the maximum image height on the plane perpendicular to the optical axis passing through the intersection of the lens surface closest to the object side and the optical axis in the state focused on the infinite object. The focal length of the entire system is f, and the sum of the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side when focused on an object at infinity and the back focus in terms of air conversion distance When TL, the maximum half angle of view of the entire system is ωm, and the unit of ωm is degrees,
1<H/(f×tanωm)<1.8 (1)
3.1<TL/(f×tanωm)<5.2 (2)
52<ωm<74 (3)
The conditional expressions (1), (2) and (3) expressed by are satisfied.

In the first aspect described above, at least part of the front group may move during focusing, and the rear group may be fixed with respect to the image plane.

In the first aspect, when the focal length of the front group is ff and the focal length of the rear group is fr when the object is focused at infinity,
0.2<ff/fr<2 (4)
It is preferable to satisfy the conditional expression (4) represented by the following.

In the first aspect described above, at least a portion of the rear group may move during focusing, and the front group may be fixed with respect to the image plane.

In the first aspect, the first lens is arranged closest to the object side and is a negative meniscus lens with a convex surface facing the object side, and the first lens is arranged adjacent to the image side of the first lens and has a convex surface facing the object side. and a second lens that is a negative meniscus lens.

In the first aspect, if the radius of curvature of the object-side surface of the first lens is R1f and the radius of curvature of the image-side surface of the first lens is R1r,
1.3<(R1f+R1r)/(R1f-R1r)<4.2 (5)
It is preferable to satisfy the conditional expression (5) represented by the following.

In the first aspect, the third lens includes a third lens disposed adjacent to the image side of the second lens, and the third lens is a negative meniscus lens with a convex surface facing the object side, or a flat surface on the object side. may be a plano-concave lens.

In the first aspect, if the radius of curvature of the image-side surface of the second lens is R2r and the radius of curvature of the object-side surface of the third lens is R3f,
-1<(R2r-R3f)/(R2r+R3f)<0.3 (6)
It is preferable to satisfy the conditional expression (6) represented by the following.

In the first aspect, the front group may be composed of 5 or more and 7 or less lenses.

In the first aspect, the rear group may be composed of 5 or more and 7 or less lenses.

In the first aspect described above, when fr is the focal length of the rear group when focused on an object at infinity,
1<f/fr<7 (7)
It is preferable to satisfy the conditional expression (7) represented by the following.

In the first aspect, the front group includes an Lfp lens having a positive refractive power, and when the d-line reference Abbe number of the Lfp lens is νfp,
16<νfp<42 (8)
It is preferable to satisfy the conditional expression (8) represented by the following.

In the first aspect, the rear group includes an Lrp1 lens having a positive refractive power, θgFrp1 is the partial dispersion ratio between the g-line and the F-line of the Lrp1 lens, νrp1 is the d-line reference Abbe number of the Lrp1 lens, and
0.01<θgFrp1+0.001618×νrp1−0.6415<0.1 (9)
It is preferable to satisfy the conditional expression (9) represented by the following.

In the first aspect, the rear group includes an Lrp2 lens having a positive refractive power disposed closer to the image side than the Lrp1 lens, and the partial dispersion ratio between the g-line and the F-line of the Lrp2 lens is θgFrp2, and the Lrp2 lens is When the d-line reference Abbe number is νrp2,
0.01<θgFrp2+0.001618×νrp2−0.6415<0.1 (10)
It is preferable to satisfy the conditional expression (10) represented by the following.

In the first aspect, the rear group includes an Lrn1 lens having negative refractive power, and when the refractive index of the Lrn1 lens for the d-line is Nrn1,
1.75<Nrn1<2.2 (11)
It is preferable to satisfy the conditional expression (11) represented by the following.

In the first aspect, the rear group includes an Lrn2 lens having a negative refractive power disposed closer to the image side than the Lrn1 lens.
1.8<Nrn2<2.2 (12)
It is preferable to satisfy the conditional expression (12) represented by the following.

In the first aspect, when the distance on the optical axis from the most object-side lens surface to the stop is Ds,
1.2<Ds/(f×tanωm)<2.8 (13)
It is preferable to satisfy the conditional expression (13) represented by the following.

In the first aspect, when the focal length of the lens group that moves during focusing is fa,
1<f/|fa|<20 (14)
It is preferable to satisfy the conditional expression (14) represented by the following.

In the first aspect, when the distance on the optical axis from the lens surface closest to the object side to the stop is Ds when the lens is focused on an object at infinity,
0.3<Ds/TL<0.6 (15)
It is preferable to satisfy the conditional expression (15) represented by the following.

A second aspect of the present disclosure is an imaging device including the imaging lens according to the above aspect.

In addition, "consisting of" and "consisting of" in this specification refer to lenses other than the listed components, lenses that have substantially no refractive power, and lenses other than lenses such as diaphragms, filters, and cover glasses. It is contemplated that optical elements and mechanical parts such as lens flanges, lens barrels, imaging elements and image stabilization mechanisms may be included.

In the present specification, "a group having positive refractive power" means that the group as a whole has positive refractive power. The "front group" and the "rear group" are not limited to the configuration composed of a plurality of lenses, and may be composed of only one lens. A "lens having positive refractive power" and a "positive lens" are synonymous. A "lens having negative refractive power" and a "negative lens" are synonymous. "Negative meniscus lens" and "meniscus-shaped lens having negative refractive power" are synonymous.

"single lens" means a single lens that is not cemented; However, a compound aspherical lens (that is, a lens in which a spherical lens and an aspherical film formed on the spherical lens are integrally formed to function as a single aspherical lens as a whole) is a cemented It is not regarded as a lens, but treated as a single lens. Unless otherwise specified, the refractive power sign and surface shape of a lens including an aspherical surface are those in the paraxial region.

As used herein, "whole system" means an imaging lens. The "focal length" used in the conditional expression is the paraxial focal length. "Back focus in air conversion distance" is the air conversion distance on the optical axis from the lens surface closest to the image side of the entire system to the image plane. Regarding the sign of the radius of curvature, the sign of the radius of curvature of the surface convex to the object side is positive, and the sign of the radius of curvature of the surface convex to the image side is negative.

In this specification, the values used in the conditional expressions are values when the d-line is used as a reference, except for the partial dispersion ratio. The partial dispersion ratio θgF between the g-line and the F-line of a certain lens is θgF=(Ng−NF) where the refractive indices of the lens for the g-line, F-line and C-line are Ng, NF and NC respectively. /(NF-NC). The "d-line", "C-line", "F-line" and "g-line" described herein are emission lines. The d-line has a wavelength of 587.56 nm (nanometers), the C-line has a wavelength of 656.27 nm (nanometers), the F-line has a wavelength of 486.13 nm (nanometers), and the g-line has a wavelength of 435.84 nm (nanometers). ).

According to the above aspect, the imaging lens and the imaging device of the present disclosure are wide-angle, compact, and have good optical performance.

FIG. 2 is a cross-sectional view showing the configuration and light flux of an imaging lens according to one embodiment; 2 is a cross-sectional view showing the configuration of the imaging lens of Example 1. FIG. FIG. 2 is a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a lateral chromatic aberration diagram of the imaging lens of Example 1. FIG. 4 is a lateral aberration diagram of the imaging lens of Example 1. FIG. FIG. 8 is a cross-sectional view showing the configuration of an imaging lens of Example 2; FIG. 10 is a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a chromatic aberration diagram of magnification of the imaging lens of Example 2; FIG. 10 is a lateral aberration diagram of the imaging lens of Example 2; FIG. 11 is a cross-sectional view showing the configuration of an imaging lens of Example 3; FIG. 10 is a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a chromatic aberration diagram of magnification of the imaging lens of Example 3; FIG. 11 is a lateral aberration diagram of the imaging lens of Example 3; FIG. 11 is a cross-sectional view showing the configuration of an imaging lens of Example 4; FIG. 10 is a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a magnification chromatic aberration diagram of the imaging lens of Example 4; FIG. 11 is a lateral aberration diagram of the imaging lens of Example 4; FIG. 11 is a cross-sectional view showing the configuration of an imaging lens of Example 5; FIG. 10 is a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a magnification chromatic aberration diagram of the imaging lens of Example 5; FIG. 11 is a lateral aberration diagram of the imaging lens of Example 5; FIG. 11 is a cross-sectional view showing the configuration of an imaging lens of Example 6; FIG. 11 is a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a magnification chromatic aberration diagram of the imaging lens of Example 6; FIG. 12 is a lateral aberration diagram of the imaging lens of Example 6; FIG. 11 is a cross-sectional view showing the configuration of an imaging lens of Example 7; FIG. 11 is a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a magnification chromatic aberration diagram of the imaging lens of Example 7; FIG. 11 is a lateral aberration diagram of the imaging lens of Example 7; 1 is a perspective view of the front side of an imaging device according to an embodiment; FIG. 1 is a rear perspective view of an imaging device according to an embodiment; FIG.

Embodiments of the present disclosure will be described below with reference to the drawings.

FIG. 1 shows a cross-sectional view of the configuration and light beams of the imaging lens according to an embodiment of the present disclosure when focused on an infinitely distant object. In this specification, an object whose object distance (distance on the optical axis from the object to the lens surface closest to the object) is infinite is referred to as an infinite object. In FIG. 1, as the luminous flux, an axial luminous flux 2 and a luminous flux 3 with the maximum half angle of view ωm are shown. In FIG. 1, the left side is the object side and the right side is the image side. The example shown in FIG. 1 corresponds to the imaging lens of Example 1 described later.

Assuming that the imaging lens is applied to an imaging apparatus, FIG. 1 shows an example in which a parallel plate-like optical member PP is arranged between the imaging lens and the image plane Sim. The optical member PP is a member assuming various filters and/or cover glass. Various filters include a low-pass filter, an infrared cut filter, and/or a filter that cuts a specific wavelength band. The optical member PP is a member having no refractive power. It is also possible to configure the imaging device without the optical member PP.

The imaging lens of the present embodiment includes, in order from the object side to the image side along the optical axis Z, a front group Gf, an aperture stop St, and a rear group Gr having positive refractive power. Having lenses on the object side and the image side of the aperture stop St facilitates correction of various aberrations. As an example, in the example of FIG. 1, the front group Gf consists of six lenses L11 to L16, and the rear group Gr consists of five lenses L21 to L25. Note that the aperture diaphragm St in FIG. 1 does not indicate the size and shape, but indicates the position in the optical axis direction.

In addition, the imaging lens of the present embodiment has a principal ray of maximum image height on a plane perpendicular to the optical axis Z passing through the intersection of the lens surface closest to the object and the optical axis Z when focused on an object at infinity. If the height from the optical axis Z is H, the focal length of the entire system when focused on an object at infinity is f, and the maximum half angle of view of the entire system is ωm, the following conditional expression (1) is satisfied. preferably. H and ωm are shown in FIG. 1 as an example. By ensuring that the corresponding value of conditional expression (1) does not fall below the lower limit, the light rays at each image height are appropriately separated in the front group Gf, which is advantageous for correcting coma aberration. By keeping the corresponding value of conditional expression (1) from exceeding the upper limit, it is possible to reduce the height from the optical axis Z when rays of peripheral field angles pass through the lens surface closest to the object side. It is advantageous for the diameter reduction of In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (1-1), and it is further preferable to satisfy the following conditional expression (1-2).
1<H/(f×tanωm)<1.8 (1)
1.03<H/(f×tanωm)<1.65 (1-1)
1.05<H/(f×tanωm)<1.35 (1-2)

Further, the imaging lens of this embodiment has a distance on the optical axis Z from the lens surface closest to the object side to the lens surface closest to the image side when focused on an object at infinity, and the back focus at the air conversion distance. is the sum of TL, f is the focal length of the entire system focused on an infinitely distant object, and ωm is the maximum half angle of view of the entire system, it is preferable to satisfy the following conditional expression (2). By ensuring that the value corresponding to conditional expression (2) does not fall below the lower limit, it is advantageous for ensuring good optical performance. By ensuring that the corresponding value of conditional expression (2) does not exceed the upper limit, it is possible to reduce the size and weight of the imaging lens. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (2-1), and it is further preferable to satisfy the following conditional expression (2-2).
3.1<TL/(f×tanωm)<5.2 (2)
3.3<TL/(f×tanωm)<5 (2-1)
3.5<TL/(f×tanωm)<4.8 (2-2)

Further, the imaging lens of this embodiment preferably satisfies the following conditional expression (3), where ωm is the maximum half angle of view of the entire system, and the unit of ωm is degrees. By ensuring that the corresponding value of conditional expression (3) does not fall below the lower limit, it is possible to improve the added value of a super-wide-angle lens that has been demanded in recent years. If the corresponding value of conditional expression (3) does not exceed the upper limit, the angle of view does not become too large, which is advantageous for reducing the diameter of the filter and ensuring good optical performance. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (3-1), and it is further preferable to satisfy the following conditional expression (3-2).
52<ωm<74 (3)
54<ωm<70 (3-1)
56<ωm<67 (3-2)

In the imaging lens of this embodiment, at least a part of the front group Gf may be moved during focusing, and the rear group Gr may be fixed with respect to the image plane. "At least part of the front group Gf" means at least one lens included in the front group Gf. With such a configuration, it is possible to reduce the size and weight of the groups that move during focusing, compared to a configuration in which the entire lens system moves during focusing. Hereinafter, in this specification, the group that moves during focusing is referred to as the "focus group". Focusing is performed by moving the focus group. Examples 1 to 4, which will be described later, correspond to this configuration.

In a configuration in which at least a part of the front group Gf is a focus group, when the focal length of the front group Gf is ff and the focal length of the rear group Gr is fr when focused on an object at infinity, the following conditional expression It is preferable to satisfy (4). By ensuring that the corresponding value of conditional expression (4) does not fall below the lower limit, it becomes easier to secure the back focus. If the corresponding value of conditional expression (4) does not exceed the upper limit, it is advantageous for suppression of barrel-shaped distortion. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (4-1), more preferably to satisfy the following conditional expression (4-2), and the following conditional expression (4-3) is more preferably satisfied.
0.2<ff/fr<2 (4)
0.5<ff/fr<2 (4-1)
0.65<ff/fr<1.85 (4-2)
0.7<ff/fr<1.75 (4-3)

In the imaging lens of this embodiment, at least a part of the rear group Gr may be moved and the front group Gf may be fixed with respect to the image plane during focusing. "At least part of the rear group Gr" means at least one lens included in the rear group Gr. That is, the imaging lens of this embodiment is not limited to the configuration in which at least part of the front group Gf is the focus group, and may be the configuration in which at least part of the rear group Gr is the focus group. With such a configuration as well, it is possible to reduce the size and weight of the focus unit compared to a configuration in which the entire lens system moves during focusing. Embodiments 5 and 6, which will be described later, correspond to this configuration.

The imaging lens of this embodiment is arranged closest to the object side, and the first lens is a negative meniscus lens having a convex surface facing the object side. and a second lens which is a negative meniscus lens directed toward the lens. By making the lens closest to the object side and the second lens from the object side negative lenses, the entrance pupil can be brought closer to the object side, which is advantageous in ensuring the amount of peripheral light. Further, by forming the lens closest to the object side and the second lens from the object side to be negative meniscus lenses having a convex surface facing the object side, it is advantageous in suppressing astigmatism and distortion. In the example of FIG. 1, the lens L11 corresponds to the first lens, and the lens L12 corresponds to the second lens.

Assuming that the radius of curvature of the object-side surface of the first lens is R1f and the radius of curvature of the image-side surface of the first lens is R1r, it is preferable to satisfy the following conditional expression (5). By ensuring that the corresponding value of conditional expression (5) does not fall below the lower limit, it is advantageous for suppressing astigmatism and distortion. By preventing the corresponding value of conditional expression (5) from exceeding the upper limit, the absolute value of the radius of curvature of the object-side surface of the first lens does not become too small, which is advantageous for reducing the filter diameter. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (5-1), and it is further preferable to satisfy the following conditional expression (5-2).
1.3<(R1f+R1r)/(R1f-R1r)<4.2 (5)
1.4<(R1f+R1r)/(R1f-R1r)<4 (5-1)
1.5<(R1f+R1r)/(R1f-R1r)<3.8 (5-2)

The imaging lens of this embodiment preferably includes a third lens arranged adjacent to the image side of the second lens. The third lens is a negative meniscus lens with a convex surface facing the object side, or a plano-concave lens with a flat surface on the object side. By using a negative lens as the third lens from the object side, the entrance pupil can be brought closer to the object side, which is advantageous in ensuring the amount of peripheral light. Also, if the third lens from the object side is a negative meniscus lens with a convex surface facing the object side, or a plano-concave lens with a plane surface on the object side, it is advantageous in suppressing astigmatism and distortion. In the example of FIG. 1, the lens L13 corresponds to the third lens.

Assuming that the radius of curvature of the image-side surface of the second lens is R2r and the radius of curvature of the object-side surface of the third lens is R3f, it is preferable to satisfy the following conditional expression (6). Keeping the corresponding value of conditional expression (6) below the lower limit is advantageous for suppressing astigmatism. By preventing the corresponding value of conditional expression (6) from exceeding the upper limit, it is advantageous to ensure the amount of peripheral light. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (6-1), and it is further preferable to satisfy the following conditional expression (6-2).
-1<(R2r-R3f)/(R2r+R3f)<0.3 (6)
-0.9<(R2r-R3f)/(R2r+R3f)<0.2 (6-1)
-0.8<(R2r-R3f)/(R2r+R3f)<0.1 (6-2)

The front group Gf preferably consists of 5 or more and 7 or less lenses. Such a configuration is advantageous in achieving both weight reduction of the lens system and good optical performance. Moreover, it is preferable that the rear group Gr consists of 5 or more and 7 or less lenses. Such a configuration is advantageous in achieving both weight reduction of the lens system and good optical performance.

If f is the focal length of the entire system when focused on an object at infinity, and fr is the focal length of the rear group Gr when focused on an object at infinity, the following conditional expression (7) must be satisfied. is preferred. If the corresponding value of conditional expression (7) does not fall below the lower limit, the refracting power of the rear group Gr will not become too weak, which is advantageous for correction of curvature of field. If the corresponding value of conditional expression (7) does not exceed the upper limit, the refracting power of the rear group Gr will not become too strong, which is advantageous for correction of distortion. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (7-1), and it is further preferable to satisfy the following conditional expression (7-2).
1<f/fr<7 (7)
1.2<f/fr<5 (7-1)
1.4<f/fr<4 (7-2)

The front group Gf preferably includes an Lfp lens having positive refractive power and satisfies the following conditional expression (8), where νfp is the d-line reference Abbe number of the Lfp lens. Keeping the corresponding value of conditional expression (8) below the lower limit is advantageous for correction of longitudinal chromatic aberration. If the corresponding value of conditional expression (8) does not exceed the upper limit, it is advantageous for correction of chromatic aberration of magnification. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (8-1), more preferably to satisfy the following conditional expression (8-2), and the following conditional expression (8-3) is more preferably satisfied, and more preferably the following conditional expression (8-4) is satisfied. In the example of FIG. 1, the lens L14 corresponds to the Lfp lens.
16<νfp<42 (8)
16<νfp<40 (8-1)
16<νfp<37 (8-2)
17<νfp<35 (8-3)
18<νfp<33 (8-4)

The rear group Gr includes an Lrp1 lens having a positive refractive power, and the following conditions are satisfied when θgFrp1 is the partial dispersion ratio between the g-line and the F-line of the Lrp1 lens, and νrp1 is the Abbe number of the Lrp1 lens based on the d-line. It is preferable to satisfy equation (9). Conditional expression (9) relates to the anomalous dispersion of the lens material. Satisfying conditional expression (9) facilitates correction of the secondary spectrum of chromatic aberration. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (9-1), and it is further preferable to satisfy the following conditional expression (9-2). In the example of FIG. 1, the lens L23 corresponds to the Lrp1 lens.
0.01<θgFrp1+0.001618×νrp1−0.6415<0.1 (9)
0.015<θgFrp1+0.001618×νrp1-0.6415<0.07 (9-1)
0.02<θgFrp1+0.001618×νrp1−0.6415<0.04 (9-2)

The rear group Gr includes an Lrp2 lens having a positive refractive power disposed closer to the image side than the Lrp1 lens, and the partial dispersion ratio between the g-line and the F-line of the Lrp2 lens is θgFrp2, and the d-line reference of the Lrp2 lens is Assuming that the Abbe number is νrp2, it is preferable to satisfy the following conditional expression (10). Conditional expression (10) relates to the anomalous dispersion of the lens material. Satisfying conditional expression (10) facilitates correction of the secondary spectrum of chromatic aberration. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (10-1), and it is further preferable to satisfy the following conditional expression (10-2). In the example of FIG. 1, the lens L25 corresponds to the Lrp2 lens.
0.01<θgFrp2+0.001618×νrp2−0.6415<0.1 (10)
0.015<θgFrp2+0.001618×νrp2−0.6415<0.07 (10−1)
0.02<θgFrp2+0.001618×νrp2−0.6415<0.04 (10−2)

The rear group Gr preferably includes an Lrn1 lens having negative refractive power, and satisfies the following conditional expression (11), where Nrn1 is the refractive index of the Lrn1 lens for the d-line. If the corresponding value of conditional expression (11) does not fall below the lower limit, the refractive power of the Lrn1 lens does not become too weak, which is advantageous for correction of distortion. By keeping the corresponding value of conditional expression (11) from exceeding the upper limit, it is possible to select a material that does not have excessively large dispersion for the Lrn1 lens, which is advantageous for correction of chromatic aberration. In general, a material with a large dispersion has a large specific gravity. By preventing the corresponding value of conditional expression (11) from exceeding the upper limit, it is possible to select a material that does not have an excessively large specific gravity for the Lrn1 lens, which is advantageous for weight reduction. Become. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (11-1), and it is further preferable to satisfy the following conditional expression (11-2). In the example of FIG. 1, the lens L21 corresponds to the Lrn1 lens.
1.75<Nrn1<2.2 (11)
1.8<Nrn1<2.1 (11-1)
1.85<Nrn1<2 (11-2)

The rear group Gr includes an Lrn2 lens having a negative refractive power disposed closer to the image side than the Lrn1 lens, and satisfies the following conditional expression (12) where Nrn2 is the refractive index of the Lrn2 lens for the d-line. is preferred. If the corresponding value of conditional expression (12) does not fall below the lower limit, the refractive power of the Lrn2 lens does not become too weak, which is advantageous for correction of distortion. By keeping the corresponding value of conditional expression (12) from exceeding the upper limit, it is possible to select a material for the Lrn2 lens whose dispersion is not too large, which is advantageous for correction of chromatic aberration. In general, a material with a large dispersion has a large specific gravity. By preventing the corresponding value of conditional expression (12) from exceeding the upper limit, it is possible to select a material that does not have an excessively large specific gravity for the Lrn2 lens, which is advantageous for weight reduction. Become. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (12-1), and it is further preferable to satisfy the following conditional expression (12-2). In the example of FIG. 1, the lens L24 corresponds to the Lrn2 lens.
1.8<Nrn2<2.2 (12)
1.85<Nrn2<2.1 (12-1)
1.9<Nrn2<2 (12-2)

Let Ds be the distance on the optical axis from the lens surface closest to the object to the aperture stop St, f be the focal length of the entire system when focused on an object at infinity, and ωm be the maximum half angle of view of the whole system. In this case, it is preferable to satisfy the following conditional expression (13). Keeping the corresponding value of conditional expression (13) from falling below the lower limit is advantageous for correcting off-axis aberrations, especially coma. By preventing the corresponding value of conditional expression (13) from exceeding the upper limit, it is advantageous for shortening the overall length of the lens system. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (13-1), and it is further preferable to satisfy the following conditional expression (13-2).
1.2<Ds/(f×tanωm)<2.8 (13)
1.35<Ds/(f×tanωm)<2.5 (13-1)
1.5<Ds/(f×tanωm)<2.2 (13-2)

If f is the focal length of the entire system when focused on an object at infinity, and fa is the focal length of the lens group (that is, the focus group) that moves during focusing, then the following conditional expression (14) is satisfied. is preferred. By ensuring that the corresponding value of conditional expression (14) does not fall below the lower limit, it is possible to suppress an increase in the amount of movement of the focus group during focusing, which is advantageous for shortening the overall length of the lens system. If the corresponding value of conditional expression (14) does not exceed the upper limit, the refracting power of the focus group does not become too strong, which is advantageous for suppressing aberration fluctuations due to fluctuations in the object distance. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (14-1), and it is further preferable to satisfy the following conditional expression (14-2).
1<f/|fa|<20 (14)
1.5<f/|fa|<17 (14-1)
1.8<f/|fa|<15 (14-2)

Ds is the distance on the optical axis from the lens surface closest to the object side to the aperture stop St when focused on an object at infinity. If TL is the sum of the distance on the optical axis Z to the lens surface and the back focus in air conversion distance, it is preferable to satisfy the following conditional expression (15). By ensuring that the corresponding value of conditional expression (15) does not fall below the lower limit, shortening of the total length of the front group Gf relative to the total length of the lens system can be suppressed, which is advantageous for correcting off-axis aberrations, especially coma. By preventing the corresponding value of conditional expression (15) from exceeding the upper limit, it is possible to suppress the lengthening of the total length of the front group Gf relative to the total length of the lens system, which is advantageous for reducing the diameter of the lens system. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (15-1), and it is further preferable to satisfy the following conditional expression (15-2).
0.3<Ds/TL<0.6 (15)
0.35<Ds/TL<0.55 (15-1)
0.4<Ds/TL<0.5 (15-2)

In the imaging lens of this embodiment, it is preferable that the lens closest to the object side is a spherical lens, and the second lens from the object side is an aspherical lens. By arranging the aspherical lens at the second position from the object side, it is advantageous in correcting various aberrations, especially coma, and by making the lens closest to the object side with a large outer diameter a spherical lens, it is possible to reduce the cost. Useful for suppression. If the lens closest to the object side is an aspherical lens, the cost will increase due to the large outer diameter of the lens. In the example of FIG. 1, the lens L11 closest to the object side is a spherical lens, and the second lens L12 from the object side is an aspherical lens.

Bf is the back focus at the air conversion distance of the entire system when focused on an infinite object, f is the focal length of the entire system when focused on an infinite object, and ωm is the maximum half angle of view of the entire system. , it is preferable to satisfy the following conditional expression (16). If the corresponding value of conditional expression (16) does not fall below the lower limit, the back focus does not become too short with respect to the image circle, which is advantageous for reducing the diameter of the rear group Gr. If the corresponding value of conditional expression (16) does not exceed the upper limit, the back focus does not become too long with respect to the image circle, which is advantageous for shortening the overall length of the lens system. In order to obtain better characteristics, it is more preferable to satisfy the following conditional expression (16-1), more preferably to satisfy the following conditional expression (16-2), and the following conditional expression (16-3) is more preferably satisfied, and more preferably the following conditional expression (16-4) is satisfied.
0.70<Bf/(f×tanωm)<1.4 (16)
0.72<Bf/(f×tanωm)<1.4 (16-1)
0.74<Bf/(f×tanωm)<1.3 (16-2)
0.77<Bf/(f×tanωm)<1.3 (16-3)
0.82<Bf/(f×tanωm)<1.25 (16-4)

In the configuration in which at least part of the front group Gf is the focus group, the focus group preferably consists of one lens. Such a configuration is advantageous in reducing the size of the focus unit. Examples 1 to 4, which will be described later, correspond to this configuration.

The preferred and possible configurations described above, including the configuration related to the conditional expression, can be arbitrarily combined, and are preferably selectively adopted as appropriate according to the required specifications. In addition, the conditional expression that the imaging lens of the present disclosure preferably satisfies is not limited to the conditional expression described in the form of an equation, It includes all conditional expressions obtained by combining and arbitrarily.

As an example, a preferred aspect of the imaging lens of the present disclosure includes, in order from the object side to the image side, a front group Gf, an aperture stop St, and a rear group Gr having a positive refractive power, and the conditional expression ( An imaging lens that satisfies 1), (2) and (3).

Next, examples of the imaging lens of the present disclosure will be described with reference to the drawings. In order to avoid complicating the description and drawings due to the increase in the number of digits of the reference numerals, the reference numerals attached to the lenses in the cross-sectional views of each example are used independently for each example. Therefore, even if common reference numerals are used in the drawings of different embodiments, they do not necessarily have common configurations.

[Example 1]
A cross-sectional view of the configuration of the imaging lens of Example 1 is shown in FIG. Since the basic drawing method of FIG. 2 is the same as that of FIG. 1, redundant description is partially omitted here. The imaging lens of Example 1 includes, in order from the object side to the image side, a front group Gf, an aperture stop St, and a rear group Gr having positive refractive power. The front group Gf is composed of lenses L11 to L16 in order from the object side to the image side. The rear group Gr is composed of lenses L21 to L25. During focusing from an infinite distance object to a close distance object, the lens L14 moves toward the image side, and the other lenses are fixed with respect to the image plane Sim. The right-pointing arrow below the lens L14 in FIG. 2 indicates that the lens L14 moves toward the image side (that is, the lens L14 is a focus group) when focusing from an infinite object to a close-up object. show.

Table 1 shows basic lens data, Table 2 shows specifications, and Table 3 shows aspheric coefficients of the imaging lens of Example 1. Table 1 is described as follows. The Sn column shows the surface numbers when the surface closest to the object side is the first surface and the number is incremented one by one toward the image side. The R column shows the radius of curvature of each surface. Column D shows the surface distance on the optical axis between each surface and its adjacent surface on the image side. The Nd column shows the refractive index for the d-line of each component. The νd column shows the d-line reference Abbe number of each component. The θgF column shows the partial dispersion ratio between the g-line and the F-line of each component. The ΔθgF column shows the anomalous dispersion of each component. In this specification, for each component, the anomalous dispersion ΔθgF is defined by the following formula, where νd is the d-line reference Abbe number and θgF is the partial dispersion ratio between the g-line and the F-line. .
ΔθgF=θgF+0.001618×νd−0.6415

In Table 1, the sign of the radius of curvature of the surface with the convex surface facing the object side is positive, and the sign of the radius of curvature of the surface with the convex surface facing the image side is negative. Table 1 also shows the aperture diaphragm St and the optical member PP, and the surface number and the phrase (St) are described in the surface number column of the surface corresponding to the aperture diaphragm St. The value in the bottom column of D is the distance between the surface closest to the image side in the table and the image plane Sim.

Table 2 shows the focal length f of the entire system, the back focus Bf at the air conversion distance of the entire system, the F number FNo. , and the maximum total angle of view 2ωm. [°] in the column of 2ωm indicates that the unit is degree. The values shown in Table 2 are values when the d-line is used as a reference when an object at infinity is focused.

In Table 1, the surface numbers of the aspherical surfaces are marked with an asterisk (*), and the column of the radius of curvature of the aspherical surface describes the numerical value of the paraxial radius of curvature. In Table 3, the surface numbers of the aspherical surfaces are shown in the Sn row, and the aspherical coefficient values for each aspherical surface are shown in the rows of KA and Am (m is an integer of 3 or more). "E±n" (n: integer) in the numerical values of the aspheric coefficients in Table 3 means "×10 ^±n ". KA and Am are the aspherical coefficients in the aspherical formula given below.
Zd=C×h ² /{1+(1−KA×C ² ×h ² ) ^1/2 }+ΣAm×h ^m
however,
Zd: Depth of the aspherical surface (the length of the perpendicular drawn from the point on the aspherical surface with height h to the plane perpendicular to the optical axis where the aspherical vertex is in contact)
h: height (distance from optical axis to lens surface)
C: Reciprocal of paraxial radius of curvature KA, Am: Aspherical surface coefficient, Σ in the aspherical expression means the summation with respect to m.

In the data in each table, degrees are used as units of angles and mm (millimeters) are used as units of length. Units can also be used. Also, in each table shown below, numerical values rounded to predetermined digits are described.

3 and 4 show aberration diagrams of the imaging lens of Example 1 in a state in which an object at infinity is focused. FIG. 3 shows spherical aberration, astigmatism, distortion, and chromatic aberration of magnification in order from the left. In spherical aberration diagrams, aberrations at the d-line, C-line, F-line and g-line are indicated by a solid line, a long dashed line, a short dashed line and a two-dot chain line, respectively. In the astigmatism diagrams, the solid line indicates the aberration at the d-line in the sagittal direction, and the short dashed line indicates the aberration at the d-line in the tangential direction. In the distortion diagrams, the solid line indicates the aberration at the d-line. In the diagram of chromatic aberration of magnification, aberrations at the C-line, F-line and g-line are indicated by long dashed lines, short dashed lines and two-dot chain lines, respectively. In the spherical aberration diagram, the value of the F-number is shown after "FNo.=". In other aberration diagrams, the value of the half angle of view corresponding to the upper end of the vertical axis is shown after "ω=".

FIG. 4 shows lateral aberration diagrams for each angle of view. In FIG. 4, the left column shows lateral aberration in the tangential direction, and the right column shows lateral aberration in the sagittal direction. In FIG. 4, aberrations at the d-line, C-line and F-line are indicated by a solid line, a long dashed line and a short dashed line, respectively. In the lateral aberration diagram, the value of the half angle of view is shown after "ω=".

Unless otherwise specified, the symbol, meaning, description method, and illustration method of each data relating to Example 1 above are the same in the following Examples, and therefore duplicate descriptions will be omitted below.

[Example 2]
FIG. 5 shows a cross-sectional view of the configuration of the imaging lens of Example 2. As shown in FIG. The imaging lens of Example 2 includes, in order from the object side to the image side, a front group Gf, an aperture stop St, and a rear group Gr having positive refractive power. The front group Gf is composed of lenses L11 to L16 in order from the object side to the image side. The rear group Gr is composed of lenses L21 to L25. During focusing from an infinite distance object to a close distance object, the lens L14 moves toward the image side, and the other lenses are fixed with respect to the image plane Sim.

Table 4 shows basic lens data, Table 5 shows specifications, and Table 6 shows aspheric coefficients of the imaging lens of Example 2. 6 and 7 show aberration diagrams in a state in which an object at infinity is focused.

[Example 3]
FIG. 8 shows a cross-sectional view of the configuration of the imaging lens of Example 3. As shown in FIG. The imaging lens of Example 3 includes, in order from the object side to the image side, a front group Gf, an aperture stop St, and a rear group Gr having positive refractive power. The front group Gf is composed of lenses L11 to L16 in order from the object side to the image side. The rear group Gr is composed of lenses L21 to L25. During focusing from an infinite distance object to a close distance object, the lens L14 moves toward the image side, and the other lenses are fixed with respect to the image plane Sim.

Table 7 shows basic lens data, Table 8 shows specifications, and Table 9 shows aspheric coefficients of the imaging lens of Example 3. 9 and 10 show aberration diagrams in a state in which an object at infinity is focused.

[Example 4]
FIG. 11 shows a cross-sectional view of the configuration of the imaging lens of Example 4. As shown in FIG. The imaging lens of Example 4 includes, in order from the object side to the image side, a front group Gf, an aperture stop St, and a rear group Gr having positive refractive power. The front group Gf is composed of lenses L11 to L16 in order from the object side to the image side. The rear group Gr is composed of lenses L21 to L25. During focusing from an infinite distance object to a close distance object, the lens L14 moves toward the image side, and the other lenses are fixed with respect to the image plane Sim.

Table 10 shows basic lens data, Table 11 shows specifications, and Table 12 shows aspheric coefficients of the imaging lens of Example 4. 12 and 13 show respective aberration diagrams in a state in which an object at infinity is focused.

[Example 5]
FIG. 14 shows a cross-sectional view of the configuration of the imaging lens of Example 5. As shown in FIG. The imaging lens of Example 5 comprises, in order from the object side to the image side, a front group Gf, an aperture stop St, and a rear group Gr having positive refractive power. The front group Gf is composed of lenses L11 to L16 in order from the object side to the image side. The rear group Gr is composed of lenses L21 to L25. When focusing from an infinity object to a close-up object, the lenses L21 to L25 of the rear group Gr move integrally toward the object side, and the front group Gf is fixed with respect to the image plane Sim. In this specification, the term "integrally moved" means simultaneously moving in the same direction by the same amount.

Table 13 shows basic lens data, Table 14 shows specifications, and Table 15 shows aspheric coefficients of the imaging lens of Example 5. 15 and 16 show respective aberration diagrams in a state in which an object at infinity is focused.

[Example 6]
FIG. 17 shows a cross-sectional view of the configuration of the imaging lens of Example 6. As shown in FIG. The imaging lens of Example 6 comprises, in order from the object side to the image side, a front group Gf, an aperture stop St, and a rear group Gr having positive refractive power. The front group Gf is composed of lenses L11 to L15 in order from the object side to the image side. The rear group Gr is composed of lenses L21 to L25. When focusing from an infinity object to a close-up object, the lenses L21 to L25 of the rear group Gr move integrally toward the object side, and the front group Gf is fixed with respect to the image plane Sim.

Table 16 shows basic lens data, Table 17 shows specifications, and Table 18 shows aspheric coefficients of the imaging lens of Example 6. 18 and 19 show aberration diagrams in a state in which an object at infinity is focused.

[Example 7]
FIG. 20 shows a cross-sectional view of the configuration of the imaging lens of Example 7. As shown in FIG. The imaging lens of Example 7 includes, in order from the object side to the image side, a front group Gf, an aperture stop St, and a rear group Gr having positive refractive power. The front group Gf is composed of lenses L11 to L17 in order from the object side to the image side. The rear group Gr is composed of lenses L21 to L25. During focusing from an infinity object to a close object, the lens L15 moves toward the image side, and the other lenses are fixed with respect to the image plane Sim.

Table 19 shows basic lens data, Table 20 shows specifications, and Table 21 shows aspheric coefficients of the imaging lens of Example 7. 21 and 22 show aberration diagrams in a state in which an object at infinity is focused.

Table 22 shows the corresponding values of the conditional expressions (1) to (16) of the imaging lenses of Examples 1 to 7.

From the above data, it can be seen that the imaging lenses of Examples 1 to 7 are compact and have good optical performance while being configured to have a wide maximum half angle of view exceeding 50 degrees.

Next, an imaging device according to an embodiment of the present disclosure will be described. 23 and 24 show external views of a camera 30, which is an imaging device according to an embodiment of the present disclosure. 23 shows a perspective view of the camera 30 viewed from the front side, and FIG. 24 shows a perspective view of the camera 30 viewed from the rear side. The camera 30 is a so-called mirrorless digital camera, to which the interchangeable lens 20 can be detachably attached. The interchangeable lens 20 includes an imaging lens 1 according to an embodiment of the present disclosure housed in a lens barrel.

The camera 30 has a camera body 31 on which a shutter button 32 and a power button 33 are provided. Further, an operation section 34 , an operation section 35 and a display section 36 are provided on the rear surface of the camera body 31 . The display unit 36 can display the captured image and the image within the angle of view before being captured.

A camera body 31 has a photographic opening through which light from an object to be photographed enters at the center of the front surface thereof. A mount 37 is provided at a position corresponding to the photographic opening. is attached to the

In the camera body 31, there is an imaging device such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) that outputs an imaging signal corresponding to the subject image formed by the interchangeable lens 20, and an imaging device output from the imaging device. A signal processing circuit for processing an imaging signal to generate an image, a recording medium for recording the generated image, and the like are provided. The camera 30 can take a still image or a moving image by pressing the shutter button 32, and the image data obtained by this shooting is recorded in the recording medium.

Also, the camera 30 may have a so-called autofocus function. Specifically, even if the camera body 31 is provided with a processor (for example, a CPU (Central Processing Unit), etc.), a memory, and a lens shift mechanism (for example, an actuator such as a solenoid and a motor) for driving the focus unit. good. The processor determines an appropriate focus position by executing the control program in cooperation with the memory, and controls the lens shift mechanism so that the focus unit moves to the focus position. That is, in the camera 30 according to this embodiment, the position of the focus group may be electrically controlled by the processor in the camera body 31 during focusing. With such a configuration, it becomes easier to focus on the subject, and convenience is improved.

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

Also, the imaging device according to the embodiment of the present disclosure is not limited to the above example, and various modes such as a camera other than a mirrorless type, a film camera, and a video camera are possible.

The following additional items will be disclosed with respect to the above embodiments and examples.
[Appendix 1]
Consists of, in order from the object side to the image side, a front group, a diaphragm, and a rear group having positive refractive power,
H is the height from the optical axis of the principal ray of the maximum image height on the plane perpendicular to the optical axis passing through the intersection of the lens surface closest to the object and the optical axis when the object is focused on at infinity;
The focal length of the entire system when focused on an object at infinity is f,
TL is the sum of the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side when focused on an object at infinity and the back focus in terms of air conversion distance,
The maximum half angle of view of the whole system is ωm,
If the unit of ωm is degrees,
1<H/(f×tanωm)<1.8 (1)
3.1<TL/(f×tanωm)<5.2 (2)
52<ωm<74 (3)
An imaging lens that satisfies conditional expressions (1), (2) and (3) represented by:
[Appendix 2]
2. The imaging lens according to claim 1, wherein at least a portion of the front group moves and the rear group is fixed with respect to the image plane during focusing.
[Appendix 3]
ff the focal length of the front group when focused on an object at infinity,
When the focal length of the rear group is fr,
0.2<ff/fr<2 (4)
3. The imaging lens according to item 2, which satisfies conditional expression (4) represented by:
[Appendix 4]
2. The imaging lens according to claim 1, wherein at least a portion of the rear group moves and the front group is fixed with respect to the image plane during focusing.
[Appendix 5]
a first lens disposed closest to the object side and being a negative meniscus lens with a convex surface facing the object side;
a second lens that is arranged adjacent to the image side of the first lens and that is a negative meniscus lens with a convex surface facing the object side;
The imaging lens according to any one of additional items 1 to 4, comprising:
[Appendix 6]
R1f is the radius of curvature of the object-side surface of the first lens,
When the radius of curvature of the image-side surface of the first lens is R1r,
1.3<(R1f+R1r)/(R1f-R1r)<4.2 (5)
6. The imaging lens according to item 5, which satisfies conditional expression (5) represented by:
[Appendix 7]
a third lens disposed adjacent to the image side of the second lens;
The imaging lens according to item 5 or item 6, wherein the third lens is a negative meniscus lens with a convex surface facing the object side, or a plano-concave lens with a plane surface on the object side.
[Appendix 8]
R2r is the radius of curvature of the image-side surface of the second lens,
When the radius of curvature of the object-side surface of the third lens is R3f,
-1<(R2r-R3f)/(R2r+R3f)<0.3 (6)
8. The imaging lens according to item 7, which satisfies conditional expression (6) represented by:
[Appendix 9]
9. The imaging lens according to any one of additional items 1 to 8, wherein the front group is composed of 5 or more and 7 or less lenses.
[Appendix 10]
10. The imaging lens according to any one of additional items 1 to 9, wherein the rear group is composed of 5 or more and 7 or less lenses.
[Appendix 11]
When fr is the focal length of the rear group when focused on an object at infinity,
1<f/fr<7 (7)
11. The imaging lens according to any one of additional items 1 to 10, which satisfies conditional expression (7) represented by:
[Appendix 12]
The front group includes an Lfp lens having positive refractive power,
When the d-line reference Abbe number of the Lfp lens is νfp,
16<νfp<42 (8)
12. The imaging lens according to any one of additional items 1 to 11, which satisfies conditional expression (8) represented by:
[Appendix 13]
The rear group includes an Lrp1 lens having positive refractive power,
The partial dispersion ratio between the g-line and the F-line of the Lrp1 lens is θgFrp1,
When the d-line reference Abbe number of the Lrp1 lens is νrp1,
0.01<θgFrp1+0.001618×νrp1−0.6415<0.1 (9)
13. The imaging lens according to any one of additional items 1 to 12, which satisfies conditional expression (9) represented by:
[Appendix 14]
The rear group includes an Lrp2 lens having a positive refractive power arranged closer to the image side than the Lrp1 lens,
The partial dispersion ratio between the g-line and the F-line of the Lrp2 lens is θgFrp2,
When the d-line reference Abbe number of the Lrp2 lens is νrp2,
0.01<θgFrp2+0.001618×νrp2−0.6415<0.1 (10)
14. The imaging lens according to item 13, which satisfies conditional expression (10) represented by:
[Appendix 15]
The rear group includes an Lrn1 lens having negative refractive power,
When the refractive index for the d-line of the Lrn1 lens is Nrn1,
1.75<Nrn1<2.2 (11)
15. The imaging lens according to any one of additional items 1 to 14, which satisfies conditional expression (11) represented by:
[Appendix 16]
The rear group includes an Lrn2 lens having a negative refractive power arranged closer to the image side than the Lrn1 lens,
When the refractive index for the d-line of the Lrn2 lens is Nrn2,
1.8<Nrn2<2.2 (12)
16. The imaging lens according to item 15, which satisfies conditional expression (12) represented by:
[Appendix 17]
When the distance on the optical axis from the lens surface closest to the object side to the stop is Ds,
1.2<Ds/(f×tanωm)<2.8 (13)
17. The imaging lens according to any one of additional items 1 to 16, which satisfies conditional expression (13) represented by:
[Appendix 18]
When the focal length of the lens group that moves during focusing is fa,
1<f/|fa|<20 (14)
The imaging lens according to additional item 2 or additional item 4, which satisfies conditional expression (14) represented by:
[Appendix 19]
When Ds is the distance on the optical axis from the lens surface closest to the object to the stop when the object is focused on at infinity,
0.3<Ds/TL<0.6 (15)
19. The imaging lens according to any one of additional items 1 to 18, which satisfies conditional expression (15) represented by:
[Appendix 20]
An imaging apparatus comprising the imaging lens according to any one of claims 1 to 19.

1 Imaging lens 2 On-axis luminous flux 3 Maximum half angle of view luminous flux 20 Interchangeable lens 30 Camera 31 Camera body 32 Shutter button 33 Power button 34 Operation unit 35 Operation unit 36 Display unit 37 Mount Gf Front group Gr Rear group H Height L11 ~ L25 lens PP optical member Sim image plane St aperture stop Z optical axis ωm maximum half angle of view

Claims (20)

Consists of, in order from the object side to the image side, a front group, a diaphragm, and a rear group having positive refractive power,
H is the height from the optical axis of the principal ray of the maximum image height on the plane perpendicular to the optical axis passing through the intersection of the lens surface closest to the object and the optical axis when the object is focused on at infinity;
The focal length of the entire system when focused on an object at infinity is f,
TL is the sum of the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side when focused on an object at infinity and the back focus in terms of air conversion distance,
The maximum half angle of view of the whole system is ωm,
If the unit of ωm is degrees,
1<H/(f×tanωm)<1.8 (1)
3.1<TL/(f×tanωm)<5.2 (2)
52<ωm<74 (3)
An imaging lens that satisfies conditional expressions (1), (2) and (3) represented by: 2. The imaging lens according to claim 1, wherein at least part of said front group moves and said rear group is fixed with respect to an image plane during focusing. ff the focal length of the front group when focused on an object at infinity,
When the focal length of the rear group is fr,
0.2<ff/fr<2 (4)
3. The imaging lens according to claim 2, which satisfies conditional expression (4) represented by: 2. The imaging lens according to claim 1, wherein at least part of said rear group moves and said front group is fixed with respect to an image plane during focusing. a first lens disposed closest to the object side and being a negative meniscus lens with a convex surface facing the object side;
a second lens that is arranged adjacent to the image side of the first lens and that is a negative meniscus lens with a convex surface facing the object side;
The imaging lens according to claim 1, comprising: R1f is the radius of curvature of the object-side surface of the first lens,
When the radius of curvature of the image-side surface of the first lens is R1r,
1.3<(R1f+R1r)/(R1f-R1r)<4.2 (5)
6. The imaging lens according to claim 5, which satisfies conditional expression (5) represented by: a third lens disposed adjacent to the image side of the second lens;
The imaging lens according to claim 5, wherein the third lens is a negative meniscus lens with a convex surface facing the object side, or a plano-concave lens with a plane surface on the object side. R2r is the radius of curvature of the image-side surface of the second lens,
When the radius of curvature of the object-side surface of the third lens is R3f,
-1<(R2r-R3f)/(R2r+R3f)<0.3 (6)
8. The imaging lens according to claim 7, which satisfies conditional expression (6) represented by: The imaging lens according to claim 1, wherein the front group is composed of five or more lenses and seven or less lenses. The imaging lens according to claim 1, wherein the rear group is composed of five or more lenses and seven or less lenses. When fr is the focal length of the rear group when focused on an object at infinity,
1<f/fr<7 (7)
2. The imaging lens according to claim 1, which satisfies conditional expression (7) represented by: The front group includes an Lfp lens having positive refractive power,
When the d-line reference Abbe number of the Lfp lens is νfp,
16<νfp<42 (8)
2. The imaging lens according to claim 1, which satisfies conditional expression (8) represented by: The rear group includes an Lrp1 lens having positive refractive power,
The partial dispersion ratio between the g-line and the F-line of the Lrp1 lens is θgFrp1,
When the d-line reference Abbe number of the Lrp1 lens is νrp1,
0.01<θgFrp1+0.001618×νrp1−0.6415<0.1 (9)
2. The imaging lens according to claim 1, which satisfies conditional expression (9) represented by: The rear group includes an Lrp2 lens having a positive refractive power arranged closer to the image side than the Lrp1 lens,
The partial dispersion ratio between the g-line and the F-line of the Lrp2 lens is θgFrp2,
When the d-line reference Abbe number of the Lrp2 lens is νrp2,
0.01<θgFrp2+0.001618×νrp2−0.6415<0.1 (10)
14. The imaging lens according to claim 13, which satisfies the conditional expression (10) represented by: The rear group includes an Lrn1 lens having negative refractive power,
When the refractive index for the d-line of the Lrn1 lens is Nrn1,
1.75<Nrn1<2.2 (11)
2. The imaging lens according to claim 1, which satisfies conditional expression (11) represented by: The rear group includes an Lrn2 lens having a negative refractive power arranged closer to the image side than the Lrn1 lens,
When the refractive index for the d-line of the Lrn2 lens is Nrn2,
1.8<Nrn2<2.2 (12)
16. The imaging lens according to claim 15, which satisfies conditional expression (12) represented by: When the distance on the optical axis from the lens surface closest to the object side to the stop is Ds,
1.2<Ds/(f×tanωm)<2.8 (13)
2. The imaging lens according to claim 1, which satisfies conditional expression (13) represented by: When the focal length of the lens group that moves during focusing is fa,
1<f/|fa|<20 (14)
3. The imaging lens according to claim 2, which satisfies conditional expression (14) represented by: When Ds is the distance on the optical axis from the lens surface closest to the object to the stop when the object is focused on at infinity,
0.3<Ds/TL<0.6 (15)
2. The imaging lens according to claim 1, which satisfies conditional expression (15) represented by: An imaging apparatus comprising the imaging lens according to any one of claims 1 to 19.

Images