WO2023127527A1

WO2023127527A1 - Optical system, optical apparatus, and method for manufacturing optical system

Info

Publication number: WO2023127527A1
Application number: PCT/JP2022/046226
Authority: WO
Inventors: 孝道倉茂
Original assignee: 株式会社ニコン
Priority date: 2021-12-28
Filing date: 2022-12-15
Publication date: 2023-07-06

Abstract

This optical system, comprising a front group, an aperture diaphragm, and a rear group in the stated order from the object side, the front group having at least three negative lenses and at least one positive lens in the stated order from the object side, and the rear group having at least four lenses, is configured so as to satisfy all of the following conditional expressions: 1.40 < f14/(-f112) < 5.20, 0.70 < T14/f < 4.50, and 160.00° < 2ω, where f14 is the focal length of the lens arranged fourth from the object side in the front group, f112 is the composite focal length of the lens arranged furthest toward the object side and the lens arranged second from the object side in the front group, T14 is the thickness on the optical axis of the lens arranged fourth from the object side in the front group, f is the focal length of the optical system, and 2ω is the total angle of view of the optical system.

Description

Optical system, optical instrument, and method for manufacturing optical system

The present disclosure relates to an optical system, an optical device, and a method of manufacturing an optical system.

Conventionally, optical systems used in optical equipment such as photographic cameras, electronic still cameras, and video cameras have been proposed (see Patent Document 1, for example).

JP 2018-081240 A

The optical system of the present disclosure consists of a front group, an aperture stop, and a rear group in order from the object side, and the front group has at least three negative lenses and at least one positive lens in order from the object side. The rear group has at least four lenses and satisfies both of the following conditional expressions.
1.40<f14/(-f112)<5.20
0.70<T14/f<4.50
160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group T14: Front Thickness on the optical axis of the fourth lens from the object side in the group f: focal length of the optical system 2ω: total angle of view of the optical system

The optical system of the present disclosure consists of a front group, an aperture stop, and a rear group in order from the object side, and the front group has at least three negative lenses and at least one positive lens in order from the object side. The rear group has at least four lenses and satisfies both of the following conditional expressions.
1.40<f14/(-f112)<5.20
1.50<ΣT1/T14<7.90
160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group ΣT1: Front Thickness on the optical axis of the group T14: Thickness on the optical axis of the fourth lens from the object side in the front group 2ω: Total angle of view of the optical system

The optical system of the present disclosure consists of a front group, an aperture stop, and a rear group in order from the object side, and the front group has at least three negative lenses and at least one positive lens in order from the object side. The rear group has at least four lenses and satisfies both of the following conditional expressions.
1.50 < f14/(-f112) < 4.90
0.65 < f/DS < 8.00
160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group f: Optical System focal length DS : Air distance on the optical axis between the lens closest to the image side in the front group and the lens closest to the object side in the rear group 2ω : Total angle of view of the optical system

The optical system of the present disclosure consists of a front group, an aperture stop, and a rear group in order from the object side, and the front group has at least three negative lenses and at least one positive lens in order from the object side. The rear group has at least four lenses and satisfies both of the following conditional expressions.
1.80 < f14/T14 < 5.00
0.60<(-f1)/f2<1.85
160.00° < 2ω
f14: Focal length of the fourth lens in the front group from the object side T14: Thickness on the optical axis of the fourth lens in the front group from the object side f1: Focal length of the front group f2: Rear group focal length 2ω : total angle of view of the optical system

The optical system of the present disclosure consists of a front group, an aperture stop, and a rear group in order from the object side, and the front group has at least three negative lenses and at least one positive lens in order from the object side. The rear group has at least four lenses and satisfies both of the following conditional expressions.
2.00<ΣT1/T14<7.90
3.50 < ΣT1/f < 6.60
160.00° < 2ω
however,
ΣT1: Optical axis thickness of the front group T14: Optical axis thickness of the fourth lens from the object side in the front group f: Focal length of the optical system 2ω: Total angle of view of the optical system

The manufacturing method of the optical system of the present disclosure comprises, in order from the object side, a front group, an aperture stop, and a rear group, and the front group includes, in order from the object side, at least three negative lenses and at least one positive lens. A method for manufacturing an optical system having a lens and a rear group having at least four lenses, wherein the lenses are arranged so as to satisfy both of the following conditional expressions.
1.40<f14/(-f112)<5.20
0.70<T14/f<4.50
160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group T14: Front Thickness on the optical axis of the fourth lens from the object side in the group f: focal length of the optical system 2ω: total angle of view of the optical system

1 is a cross-sectional view of an optical system of a first embodiment; FIG. FIG. 2 is a diagram of various aberrations of the optical system of the first example; It is a cross-sectional view of the optical system of the second embodiment. FIG. 10 is a diagram of various aberrations of the optical system of the second embodiment; It is a cross-sectional view of the optical system of the third embodiment. FIG. 10 is a diagram of various aberrations of the optical system of the third embodiment; It is a cross-sectional view of the optical system of the fourth embodiment. FIG. 11 is a diagram of various aberrations of the optical system of the fourth embodiment; FIG. 11 is a cross-sectional view of the optical system of the fifth embodiment; FIG. 10 is a diagram of various aberrations of the optical system of the fifth embodiment; FIG. 12 is a cross-sectional view of the optical system of the sixth embodiment; FIG. 11 is a diagram of various aberrations of the optical system of the sixth embodiment; FIG. 12 is a cross-sectional view of the optical system of the seventh embodiment; FIG. 11 is a diagram of various aberrations of the optical system of the seventh embodiment; FIG. 11 is a cross-sectional view of an optical system of an eighth embodiment; FIG. 11 is a diagram of various aberrations of the optical system of the eighth embodiment; 1 is a schematic diagram of a camera provided with the optical system of this embodiment; FIG. 4 is a flow chart showing an outline of a method for manufacturing an optical system according to the present embodiment;

The optical system, the optical device, and the method of manufacturing the optical system according to the embodiments of the present application will be described below.

The optical system of this embodiment comprises, in order from the object side, a front group, an aperture stop, and a rear group. The front group comprises, in order from the object side, at least three negative lenses and at least one positive lens. The rear group has at least four lenses and satisfies both of the following conditional expressions.
(1) 1.40 < f14/(-f112) < 5.20
(2) 0.70<T14/f<4.50
(3) 160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group T14: Front Thickness on the optical axis of the fourth lens from the object side in the group f: focal length of the optical system 2ω: total angle of view of the optical system

The optical system of this embodiment has a front group having at least three negative lenses and at least one positive lens in order from the object side, and a rear group having at least four lenses. It is possible to realize an optical system with excellent correction of aberration, distortion, coma, and spherical aberration.

Conditional expression (1) is the combination of the focal length of the fourth lens from the object side in the front group, the lens closest to the object side in the front group, and the second lens from the object side. Defines the ratio to the focal length. By satisfying conditional expression (1), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma, chromatic aberration, curvature of field, astigmatism, and distortion.

When the value of conditional expression (1) in the optical system of this embodiment exceeds the upper limit, the power of the fourth lens from the object side in the front group becomes weak, and spherical aberration, coma, and chromatic aberration are corrected appropriately. Correction becomes difficult.

In the optical system of this embodiment, by setting the upper limit of conditional expression (1) to 5.20, the effects of this embodiment can be made more reliable. Further, in order to ensure the effect of this embodiment, the upper limit of conditional expression (1) is set to 5.15, 5.10, 5.00, 4.95, 4.90, 4.50, 4.50 Preferably set to 25, 4.00, 3.75 and even 3.50.

Further, when the value of conditional expression (1) in the optical system of this embodiment is below the lower limit, the power of the lens arranged closest to the object side and the lens arranged second from the object side in the front group becomes weak. , it becomes difficult to appropriately correct curvature of field, astigmatism, and distortion.

By setting the lower limit of conditional expression (1) to 1.40 in the optical system of this embodiment, the effects of this embodiment can be made more reliable. Further, in order to ensure the effect of this embodiment, the lower limit of conditional expression (1) is set to 1.50, 1.60, 1.68, 1.76, 1.84, 1.92, and further to 2 It is preferably set to .00.

Conditional expression (2) defines the ratio between the thickness on the optical axis of the fourth lens from the object side in the front group and the focal length of the entire optical system. By satisfying conditional expression (2), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration while suppressing an increase in the total length of the optical system.

If the value of conditional expression (2) exceeds the upper limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the upper limit of conditional expression (2) to 4.50, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 4.35, 4.20, 4.00, 3.85, and further to 3.70. .

Also, if the value of conditional expression (2) is below the lower limit in the optical system of this embodiment, the total length of the optical system increases, making it difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the lower limit of conditional expression (2) to 0.70, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 1.05, 1.40, 1.70, 2.00, and further to 2.40. .

Conditional expression (3) defines the total angle of view of the optical system. The optical system of this embodiment can be a super-wide-angle lens by satisfying conditional expression (3).

An optical system that satisfies conditional expressions (1), (2), and (3) is an ultra-wide-angle lens that appropriately corrects various aberrations while suppressing an increase in the total length of the optical system. be able to.

The optical system of this embodiment comprises, in order from the object side, a front group, an aperture stop, and a rear group. The front group comprises, in order from the object side, at least three negative lenses and at least one positive lens. The rear group has at least four lenses and satisfies both of the following conditional expressions.
(1) 1.40 < f14/(-f112) < 5.20
(4) 1.50 < ΣT1/T14 < 7.90
(3) 160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group T14: Front Thickness on the optical axis of the fourth lens from the object side in the group f: focal length of the optical system 2ω: total angle of view of the optical system

Conditional expression (4) defines the ratio between the optical axis thickness of the front group and the optical axis thickness of the fourth lens from the object side in the front group. By satisfying conditional expression (4), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration while suppressing an increase in the total length of the optical system.

If the value of conditional expression (4) in the optical system of this embodiment exceeds the upper limit, the overall length of the optical system increases, making it difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the upper limit of conditional expression (4) to 7.90, the effect of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (4) to 7.00, 6.15, 5.25, 4.40, and further to 3.50. .

Also, if the value of conditional expression (4) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the lower limit of conditional expression (4) to 1.50, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (4) to 1.70, 1.90, 2.10, 2.30, and more preferably 2.50. .

An optical system that satisfies conditional expressions (1), (4), and (3) is an ultra-wide-angle lens that appropriately corrects various aberrations while suppressing an increase in the total length of the optical system. be able to.

The optical system of this embodiment comprises, in order from the object side, a front group, an aperture stop, and a rear group. The front group comprises, in order from the object side, at least three negative lenses and at least one positive lens. The rear group has at least four lenses and satisfies both of the following conditional expressions.
(5) 1.50 < f14/(-f112) < 4.90
(6) 0.65 < f/DS < 8.00
(3) 160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group f: Optical System focal length DS : Air distance on the optical axis between the lens closest to the image side in the front group and the lens closest to the object side in the rear group 2ω : Total angle of view of the optical system

Conditional expression (5) is the combination of the focal length of the fourth lens from the object side in the front group, the lens closest to the object side in the front group, and the second lens from the object side. Defines the ratio to the focal length. By satisfying conditional expression (5), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma, chromatic aberration, field curvature, astigmatism, and distortion.

When the value of conditional expression (5) in the optical system of this embodiment exceeds the upper limit, the power of the fourth lens from the object side in the front group becomes weak, and spherical aberration, coma aberration, and chromatic aberration are corrected appropriately. Correction becomes difficult.

In the optical system of this embodiment, by setting the upper limit of conditional expression (5) to 4.90, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, the upper limit of conditional expression (5) is set to 4.80, 4.50, 4.25, 4.00, 3.75, and further to 3.50. preferably.

Further, when the value of conditional expression (5) in the optical system of this embodiment is below the lower limit, the power of the lens arranged closest to the object side and the lens arranged second from the object side in the front group becomes weak. , it becomes difficult to appropriately correct curvature of field, astigmatism, and distortion.

In the optical system of this embodiment, by setting the lower limit of conditional expression (5) to 1.50, the effects of this embodiment can be made more reliable. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (5) to 1.60, 1.70, 1.80, 1.90, and more preferably 2.00. .

Conditional expression (6) is the ratio of the focal length of the entire optical system to the air gap on the optical axis between the lens closest to the image side in the front group and the lens closest to the object side in the rear group. stipulate. By satisfying conditional expression (6), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration and coma while suppressing an increase in the total length of the optical system.

If the value of conditional expression (6) exceeds the upper limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration and coma.

In the optical system of this embodiment, by setting the upper limit of conditional expression (6) to 8.00, the effects of this embodiment can be made more reliable. Moreover, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (6) to 7.60, 7.20, 6.80, 6.40, and further to 6.00. .

Also, if the value of conditional expression (6) is below the lower limit in the optical system of this embodiment, the total length of the optical system increases, making it difficult to appropriately correct various aberrations such as spherical aberration and coma.

In the optical system of this embodiment, by setting the lower limit of conditional expression (6) to 0.65, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (6) to 0.66, 0.67, 0.68, 0.69, and more preferably 0.70. .

An optical system that satisfies conditional expressions (5), (6), and (3) is an ultra-wide-angle lens that appropriately corrects various aberrations while suppressing an increase in the total length of the optical system. be able to.

The optical system of this embodiment comprises, in order from the object side, a front group, an aperture stop, and a rear group. The front group comprises, in order from the object side, at least three negative lenses and at least one positive lens. The rear group has at least four lenses and satisfies both of the following conditional expressions.
(7) 1.80 < f14/T14 < 5.00
(8) 0.60 < (-f1)/f2 < 1.85
(3) 160.00° < 2ω
f14: Focal length of the fourth lens in the front group from the object side T14: Thickness on the optical axis of the fourth lens in the front group from the object side f1: Focal length of the front group f2: Rear group focal length 2ω : total angle of view of the optical system

Conditional expression (7) defines the ratio between the focal length of the fourth lens in the front group from the object side and the thickness on the optical axis of the fourth lens in the front group from the object side. By satisfying conditional expression (7), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma aberration, and chromatic aberration.

If the value of conditional expression (7) exceeds the upper limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the upper limit of conditional expression (7) to 5.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (7) to 4.60, 4.25, 3.85, 3.50, and more preferably 3.10. .

Also, if the value of conditional expression (7) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the lower limit of conditional expression (7) to 1.80, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (7) to 1.84, 1.88, 1.92, 1.96, and more preferably 2.00. .

Conditional expression (8) defines the ratio between the focal length of the front group and the focal length of the rear group. By satisfying the conditional expression (8), the optical system of the present embodiment suppresses an increase in the diameter of the lens disposed closest to the object side in the front group, while suppressing various aberrations such as spherical aberration and coma. can be corrected.

In the optical system of this embodiment, when the value of conditional expression (8) exceeds the upper limit, the power of the front group weakens, the diameter of the lens located closest to the object side in the front group increases, and the power of the rear group increases. becomes stronger and the spherical aberration worsens.

In the optical system of this embodiment, by setting the upper limit of conditional expression (8) to 1.85, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (8) to 1.80, 1.75, 1.70, 1.65, and more preferably 1.60. .

Also, if the value of conditional expression (8) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration and coma.

In the optical system of this embodiment, by setting the lower limit of conditional expression (8) to 0.60, the effects of this embodiment can be made more reliable. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (8) to 0.65, more preferably 0.70.

An optical system that satisfies conditional expression (7), conditional expression (8), and conditional expression (3) is a super-wide-angle lens that appropriately corrects various aberrations while suppressing an increase in the total length of the optical system. be able to.

The optical system of this embodiment comprises, in order from the object side, a front group, an aperture stop, and a rear group. The front group comprises, in order from the object side, at least three negative lenses and at least one positive lens. The rear group has at least four lenses and satisfies both of the following conditional expressions.
(9) 2.00 < ΣT1/T14 < 7.90
(10) 3.50 < ΣT1/f < 6.60
(3) 160.00° < 2ω
however,
ΣT1: Optical axis thickness of the front group T14: Optical axis thickness of the fourth lens from the object side in the front group f: Focal length of the optical system 2ω: Total angle of view of the optical system

Conditional expression (9) defines the ratio between the optical axis thickness of the front group and the optical axis thickness of the fourth lens from the object side in the front group. By satisfying conditional expression (9), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration while suppressing an increase in the total length of the optical system.

If the value of conditional expression (9) in the optical system of this embodiment exceeds the upper limit, the total length of the optical system increases, making it difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the upper limit of conditional expression (9) to 7.90, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (9) to 7.00, 6.15, 5.25, 4.40, and further to 3.50. .

Also, if the value of conditional expression (9) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the lower limit of conditional expression (9) to 2.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (9) to 2.10, 2.20, 2.30, 2.40, and more preferably 2.50. .

Conditional expression (10) defines the ratio between the thickness of the front group on the optical axis and the focal length of the entire optical system. By satisfying conditional expression (10), the optical system of the present embodiment appropriately corrects various aberrations such as distortion, curvature of field, spherical aberration, and coma while suppressing an increase in the total length of the optical system. be able to.

If the value of conditional expression (10) exceeds the upper limit in the optical system of this embodiment, the total length of the optical system increases, making it difficult to appropriately correct various aberrations such as distortion and curvature of field.

In the optical system of this embodiment, by setting the upper limit of conditional expression (10) to 6.60, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (10) to 6.55.

Also, if the value of conditional expression (10) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and curvature of field.

In the optical system of this embodiment, by setting the lower limit of conditional expression (10) to 3.50, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (10) to 3.58, 3.66, 3.74, 3.82, and further to 3.90. .

An optical system that satisfies conditional expressions (9), (10), and (3) is a super-wide-angle lens that appropriately corrects various aberrations while suppressing an increase in the total length of the optical system. be able to.

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(11) 1.00 < f14/T14 < 5.00

Conditional expression (11) defines the ratio between the focal length of the fourth lens in the front group from the object side and the thickness on the optical axis of the fourth lens in the front group from the object side. By satisfying conditional expression (11), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma aberration, and chromatic aberration.

If the value of conditional expression (11) exceeds the upper limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the upper limit of conditional expression (11) to 5.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (11) to 4.60, 4.25, 3.85, 3.50, and further to 3.10. .

Also, if the value of conditional expression (11) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the lower limit of conditional expression (11) to 1.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (11) to 1.05, 1.10, 1.20, 1.25, and more preferably 1.30. .

Also, the optical system of this embodiment preferably satisfies the following equations.
(12) 3.50 < ΣT1/f < 18.00
however,
ΣT1: thickness of the front group on the optical axis

Conditional expression (12) defines the ratio between the thickness of the front group on the optical axis and the focal length of the entire optical system. By satisfying conditional expression (12), the optical system of the present embodiment appropriately corrects various aberrations such as distortion, curvature of field, spherical aberration, and coma while suppressing an increase in the total length of the optical system. be able to.

If the value of conditional expression (12) in the optical system of this embodiment exceeds the upper limit, the total length of the optical system increases, making it difficult to appropriately correct various aberrations such as distortion and curvature of field.

In the optical system of this embodiment, by setting the upper limit of conditional expression (12) to 18.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (12) to 16.50, 15.20, 13.80, 12.40, and further to 11.00. .

Also, if the value of conditional expression (12) is below the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and curvature of field.

In the optical system of this embodiment, by setting the lower limit of conditional expression (12) to 3.50, the effects of this embodiment can be made more reliable. Moreover, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (12) to 4.40, 5.30, 6.20, 7.10, and further to 8.00. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(13) 0.30 < (-f1)/f2 < 3.30
however,
f1: focal length of the front group f2: focal length of the rear group

Conditional expression (13) defines the ratio between the focal length of the front group and the focal length of the rear group. By satisfying the conditional expression (13), the optical system of the present embodiment suppresses an increase in the diameter of the lens disposed closest to the object side in the front group, and appropriately reduces various aberrations such as spherical aberration and coma. can be corrected.

In the optical system of this embodiment, when the value of conditional expression (13) exceeds the upper limit, the power of the front group weakens, the diameter of the lens located closest to the object side in the front group increases, and the power of the rear group increases. becomes stronger and the spherical aberration worsens.

In the optical system of this embodiment, by setting the upper limit of conditional expression (13) to 3.30, the effects of this embodiment can be made more reliable. Moreover, in order to ensure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (13) to 3.00, 2.60, 2.30, 2.00, and further to 1.60. .

Also, if the value of conditional expression (13) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration and coma.

In the optical system of this embodiment, by setting the lower limit of conditional expression (13) to 0.30, the effects of this embodiment can be made more reliable. Further, in order to ensure the effect of this embodiment, the lower limit of conditional expression (13) is set to 0.35, 0.40, 0.50, 0.55, 0.60, 0.65, and further to 0 It is preferably set to .70.

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(14) 0.20 < f/DS < 9.00
however,
DS: Air space on the optical axis between the lens closest to the image side in the front group and the lens closest to the object side in the rear group

Conditional expression (14) defines the ratio between the focal length of the entire optical system and the air gap between the lens located closest to the image side in the front group and the lens located closest to the object side in the rear group. By satisfying conditional expression (14), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration and coma while suppressing an increase in the total length of the optical system.

When the value of conditional expression (14) exceeds the upper limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration and coma.

In the optical system of this embodiment, by setting the upper limit of conditional expression (14) to 9.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (14) to 8.40, 7.80, 7.20, 6.60, and further to 6.00. .

Also, if the value of conditional expression (14) is less than the lower limit in the optical system of this embodiment, the overall length of the optical system increases, making it difficult to appropriately correct various aberrations such as spherical aberration and coma.

By setting the lower limit of conditional expression (14) to 0.20 in the optical system of this embodiment, the effects of this embodiment can be made more reliable. Moreover, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (14) to 0.30, 0.40, 0.50, 0.60, and more preferably 0.70. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(15) 3.00 < f14/f < 13.00

Conditional expression (15) defines the ratio between the focal length of the fourth lens in the front group from the object side and the focal length of the entire optical system. By satisfying conditional expression (15), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma aberration, and chromatic aberration.

If the value of conditional expression (15) exceeds the upper limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the upper limit of conditional expression (15) to 13.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (15) to 12.50, 12.00, 11.50, 11.00, and further to 10.50. .

Also, if the value of conditional expression (15) is below the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and chromatic aberration.

In the optical system of this embodiment, by setting the lower limit of conditional expression (15) to 3.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (15) to 3.30, 3.55, 3.85, 4.10, and further to 4.40. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(16) 3.00 < ΣT2/f < 7.00
however,
ΣT2: Thickness of the rear group on the optical axis

Conditional expression (16) defines the ratio between the thickness of the rear group on the optical axis and the focal length of the entire optical system. By satisfying conditional expression (16), the optical system of the present embodiment appropriately corrects various aberrations such as spherical aberration, coma, curvature of field, and chromatic aberration of magnification while suppressing an increase in the total length of the optical system. be able to.

In the optical system of this embodiment, if the value of conditional expression (16) exceeds the upper limit, the total length of the optical system increases, making it difficult to appropriately correct various aberrations such as spherical aberration and coma.

In the optical system of this embodiment, by setting the upper limit of conditional expression (16) to 7.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (16) to 6.80, 6.60, 6.40, 6.20, and further to 6.00. .

Also, if the value of conditional expression (16) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as curvature of field, coma, and chromatic aberration of magnification.

In the optical system of this embodiment, by setting the lower limit of conditional expression (16) to 3.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (16) to 3.20, 3.40, 3.60, 3.80, and further to 4.00. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(17) 0.80 < D112/f < 4.50
however,
D112: Air gap on the optical axis between the lens closest to the object side and the lens second from the object side in the front group

Conditional expression (17) defines the ratio of the focal length of the optical system to the air space on the optical axis between the lens located closest to the object side and the lens located second from the object side in the front group. By satisfying conditional expression (17), the optical system of the present embodiment appropriately corrects various aberrations such as curvature of field, astigmatism, coma, and distortion while suppressing an increase in the total length of the optical system. can do.

If the value of conditional expression (17) in the optical system of this embodiment exceeds the upper limit, the overall length of the optical system increases, making it difficult to appropriately correct various aberrations such as curvature of field, astigmatism, and coma. .

In the optical system of this embodiment, by setting the upper limit of conditional expression (17) to 4.50, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (17) to 4.25, 4.00, 3.70, 3.45, and further to 3.20. .

Also, if the value of conditional expression (17) is below the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as distortion, curvature of field, and astigmatism.

In the optical system of this embodiment, by setting the lower limit of conditional expression (17) to 0.80, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (17) to 1.10, 1.35, 1.65, 1.90, and further to 2.20. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(18) 10.00<TL/f<19.00
however,
TL: Total length of the optical system in air conversion length

Conditional expression (18) defines the ratio between the total length of the optical system in terms of air conversion length and the focal length of the entire optical system. By satisfying conditional expression (18), the optical system of the present embodiment appropriately corrects various aberrations such as curvature of field, astigmatism, coma, and distortion while suppressing an increase in the total length of the optical system. can do.

If the value of conditional expression (18) in the optical system of this embodiment exceeds the upper limit, the overall length of the optical system increases, making it difficult to appropriately correct various aberrations such as curvature of field, astigmatism, and coma. .

In the optical system of this embodiment, by setting the upper limit of conditional expression (18) to 19.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (18) to 18.70, 18.45, 18.15, 17.90, and further to 17.60. .

Also, if the value of conditional expression (18) is below the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as distortion, curvature of field, and astigmatism.

In the optical system of this embodiment, by setting the lower limit of conditional expression (18) to 10.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (18) to 10.80, 11.60, 12.40, 13.20, and further to 14.00. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(19) 2.00 < f2l/f < 28.00
however,
f2l: focal length of the lens located closest to the image side in the rear group

Conditional expression (19) defines the ratio between the focal length of the lens arranged closest to the image side in the rear group and the focal length of the optical system. By satisfying the conditional expression (19), the optical system of this embodiment can appropriately correct various aberrations such as curvature of field and astigmatism while suppressing an increase in the total length of the optical system.

In the optical system of this embodiment, if the value of conditional expression (19) exceeds the upper limit, the total length of the optical system increases, making it difficult to appropriately correct various aberrations such as curvature of field and astigmatism.

In the optical system of this embodiment, by setting the upper limit of conditional expression (19) to 28.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (19) to 27.40, 26.80, 26.20, 25.60, and further to 25.00. .

Also, if the value of conditional expression (19) is below the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as curvature of field and astigmatism.

In the optical system of this embodiment, by setting the lower limit of conditional expression (19) to 2.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (19) to 2.20, 2.40, 2.60, 2.80, and further to 3.00. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(20) 0.30 < (-f11)/f2l < 4.00
however,
f11: Focal length of the lens closest to the object side in the front group f2l: Focal length of the lens closest to the image side in the rear group

Conditional expression (20) defines the ratio between the focal length of the lens located closest to the object side in the front group and the focal length of the lens located closest to the image side in the rear group. By satisfying the conditional expression (20), the optical system of the present embodiment suppresses an increase in the diameter of the lens located closest to the object side in the front group, while suppressing various aberrations such as spherical aberration and coma. can be corrected.

In the optical system of this embodiment, when the value of conditional expression (20) exceeds the upper limit, the power of the front group weakens, the diameter of the lens located closest to the object side in the front group increases, and the power of the rear group increases. becomes stronger and the spherical aberration worsens.

In the optical system of this embodiment, by setting the upper limit of conditional expression (20) to 4.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (20) to 3.80, 3.65, 3.45, 3.30, and further to 3.10. .

Also, if the value of conditional expression (20) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as spherical aberration and coma.

In the optical system of this embodiment, by setting the lower limit of conditional expression (20) to 0.30, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (20) to 0.32, 0.34, 0.36, 0.38, and further to 0.40. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(21) 2.00 < (-f12)/f < 6.00
however,
f12: focal length of the second lens from the object side in the front group

Conditional expression (21) defines the ratio between the focal length of the lens arranged second from the object side in the front group and the focal length of the entire optical system. By satisfying the conditional expression (21), the optical system of this embodiment can appropriately correct various aberrations such as distortion, curvature of field, and astigmatism.

If the value of conditional expression (21) exceeds the upper limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as distortion, curvature of field, and astigmatism.

In the optical system of this embodiment, by setting the upper limit of conditional expression (21) to 6.00, the effects of this embodiment can be made more reliable. Moreover, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (21) to 5.80, 5.55, 5.35, 5.10, and further to 4.90. .

Also, if the value of conditional expression (21) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as distortion, curvature of field, and astigmatism.

In the optical system of this embodiment, by setting the lower limit of conditional expression (21) to 2.00, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (21) to 2.25, 2.50, 2.70, 3.00, and more preferably 3.20. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(22) 1.40 < f11/f12 < 3.50
however,
f11: focal length of the lens closest to the object side in the front group f12: focal length of the lens second from the object side in the front group

Conditional expression (22) defines the ratio between the focal length of the lens located closest to the object side in the front group and the focal length of the lens located second from the object side in the front group. By satisfying the conditional expression (22), the optical system of the present embodiment suppresses an increase in the diameter of the lens located closest to the object side in the front group, while suppressing various aberrations such as curvature of field and astigmatism. can be corrected appropriately.

When the value of conditional expression (22) in the optical system of this embodiment exceeds the upper limit, the diameter of the lens located closest to the object side in the front group increases, and various aberrations such as curvature of field and astigmatism are corrected appropriately. correction becomes difficult.

In the optical system of this embodiment, by setting the upper limit of conditional expression (22) to 3.50, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (22) to 3.40, 3.35, 3.25, 3.20, and further to 3.10. .

Also, if the value of conditional expression (22) is less than the lower limit in the optical system of this embodiment, it becomes difficult to appropriately correct various aberrations such as curvature of field and astigmatism.

In the optical system of this embodiment, by setting the lower limit of conditional expression (22) to 1.40, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (22) to 1.50, 1.60, 1.70, 1.83, and more preferably 1.95. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(23) 1.85 < nd1 < 2.20
however,
nd1: Refractive index of the lens closest to the object in the front group with respect to the d-line

Conditional expression (23) defines the refractive index of the lens located closest to the object side in the front group with respect to the d-line. The optical system of this embodiment satisfies the conditional expression (23), so that the curvature of field can be appropriately corrected.

When the value of conditional expression (23) exceeds the upper limit value in the optical system of this embodiment, the power of the lens located closest to the object side in the front group becomes strong, making it difficult to appropriately correct curvature of field.

In the optical system of this embodiment, by setting the upper limit of conditional expression (23) to 2.20, the effects of this embodiment can be made more reliable. Moreover, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (23) to 2.15, 2.10, 2.05, and further to 1.95.

In addition, if the value of conditional expression (23) in the optical system of this embodiment falls below the lower limit, the power of the lens located closest to the object side in the front group becomes weak, making it difficult to appropriately correct curvature of field. Become.

In the optical system of this embodiment, by setting the lower limit of conditional expression (23) to 1.85, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (23) to 1.87, 1.89, 1.91, 1.93, and more preferably 1.95. .

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(24) 1.50 < nd2 < 1.95
however,
nd2: Refractive index with respect to the d-line of the second lens from the object side in the front group

Conditional expression (24) defines the refractive index of the second lens from the object side in the front group with respect to the d-line. The optical system of this embodiment satisfies the conditional expression (24), so that the curvature of field can be appropriately corrected.

In the optical system of this embodiment, when the value of conditional expression (24) exceeds the upper limit, the power of the second lens from the object side in the front group becomes strong, making it difficult to appropriately correct curvature of field. Become.

In the optical system of this embodiment, by setting the upper limit of conditional expression (24) to 1.95, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (24) to 1.90, 1.85, 1.80, 1.75, and more preferably 1.70. .

Further, when the value of conditional expression (24) in the optical system of the present embodiment is below the lower limit, the power of the second lens from the object side in the front group becomes weak, and appropriate correction of field curvature is not possible. becomes difficult.

In the optical system of this embodiment, by setting the lower limit of conditional expression (24) to 1.50, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (24) to 1.51, 1.52, and more preferably 1.53.

Moreover, the optical system of this embodiment preferably satisfies the following conditional expression.
(25) 1.45 < nd3 < 1.90
however,
nd3: Refractive index of the lens closest to the image side in the rear group with respect to the d-line

Conditional expression (25) defines the refractive index of the lens located closest to the image side in the rear group with respect to the d-line. By satisfying the conditional expression (25), the optical system of this embodiment can appropriately correct various aberrations such as curvature of field and astigmatism.

When the value of conditional expression (25) in the optical system of this embodiment exceeds the upper limit, the power of the lens located closest to the image side in the rear group becomes strong, and various aberrations such as curvature of field and astigmatism are corrected appropriately. correction becomes difficult.

In the optical system of this embodiment, by setting the upper limit of conditional expression (25) to 1.90, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (25) to 1.85, 1.80, 1.75, and more preferably 1.70.

Further, when the value of conditional expression (25) in the optical system of this embodiment is below the lower limit, the power of the lens located closest to the image side in the rear group becomes weak, and various aberrations such as curvature of field and astigmatism It becomes difficult to appropriately correct the

In the optical system of this embodiment, by setting the lower limit of conditional expression (25) to 1.45, the effects of this embodiment can be made more reliable. Also, in order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (25) to 1.46, 1.47, 1.48, and more preferably 1.49.

With the above configuration, it is possible to realize an optical system that is compact and has good imaging performance.

The optical apparatus of this embodiment has the optical system having the above configuration. As a result, it is possible to realize an optical device that is compact and has good optical performance.

The manufacturing method of the optical system of this embodiment comprises, in order from the object side, a front group, an aperture stop, and a rear group. The front group comprises, in order from the object side, at least three negative lenses and at least one A manufacturing method for an optical system having a positive lens and at least four lenses in a rear group, wherein the lenses are arranged so as to satisfy both of the following conditional expressions.
(1) 1.60 < f14/(-f112) < 5.20
(2) 0.70<T14/f<4.50
(3) 160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group T14: Front Thickness on the optical axis of the fourth lens from the object side in the group f: focal length of the optical system 2ω: total angle of view of the optical system

With such an optical system manufacturing method, it is possible to manufacture a compact optical system with good optical performance.

(Numerical example)
Embodiments of the present application will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a sectional view of the optical system of the first embodiment.

The optical system of this embodiment has, in order from the object side, a front group G1 having negative refractive power, an aperture diaphragm S, and a rear group G2 having positive refractive power.

The front group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, a negative meniscus lens L2 having a convex surface facing the object side, and a negative meniscus lens L3 having a convex surface facing the object side. and a convex positive lens L4.

The rear group G2 comprises, in order from the object side, a biconvex positive lens L5, a cemented negative lens constructed by cementing a biconvex positive lens L6 and a biconcave negative lens L7, and a biconvex positive lens L8. Become.

On the image plane I, an imaging device (not shown) composed of a CCD, CMOS, or the like is arranged.

A filter FL is arranged between the optical system and the image plane I of this embodiment.

Table 1 below lists the values of the specifications of the optical system of this embodiment.

In [Overall specifications] in Table 1, TL indicates the total length of the optical system in air conversion length, and f indicates the focal length of the optical system.

In [Lens specifications] in Table 1, m is the order of the optical surfaces counted from the object side, r is the radius of curvature, d is the surface spacing, nd is the refractive index for the d-line (wavelength 587.6 nm), and νd is for the d-line. Indicates the Abbe number. A radius of curvature r=∞ indicates a plane. Also, the optical surfaces marked with "*" are aspheric surfaces.

In [Aspheric data] in Table 1, m is the optical surface corresponding to the aspheric data, K is the conic constant, and A4 to A12 are the aspheric coefficients.

The height of the aspherical surface in the direction perpendicular to the optical axis is y, and the distance (sag) along the optical axis from the tangent plane of the vertex of each aspherical surface to each aspherical surface at height y is S(y) where r is the radius of curvature (paraxial radius of curvature) of the reference spherical surface, K is the conic constant, and An is the n-th order aspheric coefficient. In each example, the second-order aspheric coefficient A2 is zero. Also, "En" indicates "×10 ^-n ".

(a) S(y) = ( ^y2 /r)/{1+(1-K× ^y2 / ^r2 ) ^1/2 }
+ A4× ^y4 + A6× ^y6 + A8× ^y8 + A10× ^y10 + A12× ^y12

The unit of focal length f, radius of curvature r and other lengths listed in Table 1 is "mm". However, the optical system is not limited to this because equivalent optical performance can be obtained even if the optical system is proportionally enlarged or proportionally reduced.

The symbols in Table 1 described above are also used in the tables of other examples described later.

(Table 1)
[Overall specifications]
TL 25.11
f1.58

[Lens specifications]
m r d nd νd
1) 16.242 1.550 2.001000 29.12
2) 7.470 4.000
* 3) 7.800 1.000 1.693500 53.20
* 4) 2.526 2.640
5) 150.000 0.350 1.603000 65.44
6) 3.308 0.720
7) 11.331 5.160 1.846660 23.80
8) -11.331 0.200
9> ∞ 0.100 (aperture diaphragm)
10) 6.695 1.750 1.693500 53.20
11) -6.695 0.100
12) 9.627 1.580 1.618000 63.34
13) -3.017 0.350 1.846660 23.80
14) 8.500 1.860
*15) 4.300 1.620 1.553319 71.68
*16) -21.831 1.000
17) ∞ 1.000 1.516800 63.88
18) ∞ 0.466

[Aspheric data]
mK A4 A6 A8 A10
3) 1.0000 -2.37E-03 4.92E-05 -9.48E-07 9.14E-09
4) 1.0000 1.88E-02 -2.00E-03 2.46E-04 -1.20E-05
15) 1.0000 -4.42E-03 -1.33E-04 -9.98E-05 5.00E-06
16) 1.0000 2.93E-04 3.04E-04 -2.09E-04 1.63E-05

[Each group focal length data]
Group Starting surface Focal length
G1 1 -5.61
G2 10 5.27

FIG. 2 is a diagram of various aberrations of the optical system of the first embodiment. From each aberration chart, it can be seen that the optical system of this example appropriately corrects various aberrations and has high optical performance.

(Second embodiment)
FIG. 3 is a sectional view of the optical system of the second embodiment.

The rear group G2 includes, in order from the object side, a positive lens cemented by a negative meniscus lens L5 having a convex surface facing the object side cemented with a biconvex positive lens L6, a biconvex positive lens L7 and a biconcave negative lens. It consists of a cemented negative lens L8 and a biconvex positive lens L9.

Table 2 below lists the values of the specifications of the optical system of this example.

(Table 2)
[Overall specifications]
TL 24.92
f1.46

[Lens specifications]
m r d nd νd
1) 17.000 1.350 2.001000 29.12
2) 7.470 4.000
* 3) 7.148 1.000 1.693500 53.20
* 4) 2.404 2.726
5) 150.000 0.350 1.603000 65.44
6) 2.948 0.839
7) 8.259 5.242 1.846660 23.80
8) -8.681 0.200
9> ∞ 0.100 (aperture diaphragm)
10) 8.000 0.350 1.846660 23.80
11) 3.836 1.180 1.772500 49.62
12) -7.944 0.729
13) 22.427 1.332 1.618000 63.34
14) -3.378 0.350 1.846660 23.80
15) 8.000 1.010
*16) 4.300 2.000 1.553319 71.68
*17) -7.734 0.644
18) ∞ 0.900 1.516800 63.88
19) ∞ 0.930

[Aspheric data]
mK A4 A6 A8 A10
3) 1.0000 -1.17E-04 -9.10E-05 2.28E-06 -2.20E-08
4) 1.0000 2.39E-02 -2.26E-03 2.77E-04 -1.71E-05
16) 1.0000 -3.29E-03 -2.05E-04 1.18E-05 -3.25E-06
17) 1.0000 -1.26E-03 -1.59E-04 -2.61E-05 1.21E-06

[Each group focal length data]
Group Starting surface Focal length
G1 1 -17.47
G2 10 11.66

FIG. 4 is a diagram of various aberrations of the optical system of the second embodiment. From each aberration diagram, it can be seen that the optical system of this example properly corrects various aberration fluctuations and has high optical performance.

(Third embodiment)
FIG. 5 is a cross-sectional view of the optical system of the third embodiment.

The front group G1 includes, in order from the object, a negative meniscus lens L1 with a convex surface facing the object, a negative meniscus lens L2 with a convex surface facing the object, a biconcave negative lens L3, and a biconvex positive lens. and a lens L4.

The rear group G2 includes, in order from the object side, a positive lens cemented with a biconvex positive lens L5 cemented with a negative meniscus lens L6 having a concave surface facing the object side, a biconvex positive lens L7 and a biconcave negative lens. It consists of a cemented negative lens L8 and a biconvex positive lens L9.

Table 3 below lists the values of the specifications of the optical system of this embodiment.

(Table 3)
[Overall specifications]
TL 25.10
f1.55

[Lens specifications]
m r d nd νd
1) 14.911 1.100 2.001000 29.12
2) 8.018 3.870
* 3) 7.715 0.900 1.693500 53.20
* 4) 2.951 3.137
5) -34.050 0.350 1.618000 63.34
6) 2.899 0.800
7) 9.146 5.604 1.846660 23.80
8) -10.196 0.100
9> ∞ 0.100 (aperture diaphragm)
10) 6.378 1.319 1.703891 48.40
11) -3.167 0.350 1.694100 30.84
12) -8.017 0.266
13) 11.309 1.335 1.618000 63.34
14) -3.703 0.353 1.846660 23.80
15) 6.257 0.997
*16) 4.477 2.392 1.637394 54.33
*17) -15.887 0.600
18) ∞ 0.900 1.516800 63.88
19) ∞ 0.934

[Aspheric data]
mK A4 A6 A8 A10
3) 1.0000 -6.00E-04 -4.00E-05 1.16E-06 -1.14E-08
4) 1.0000 1.23E-02 -7.84E-04 5.93E-05 -2.47E-06
16) 1.0000 -3.28E-03 -1.15E-04 8.12E-06 -4.39E-06
17) 1.0000 5.89E-04 3.02E-04 -9.50E-05 5.82E-06

[Each group focal length data]
Group Starting surface Focal length
G1 1 -8.27
G2 10 11.84

FIG. 6 is a diagram of various aberrations of the optical system of the third embodiment. From each aberration diagram, it can be seen that the optical system of this example appropriately corrects various aberration fluctuations and has high optical performance.

(Fourth embodiment)
FIG. 7 is a sectional view of the optical system of the fourth embodiment.

The rear group G2 includes, in order from the object side, a biconvex positive lens L5, a biconcave negative lens L6, a cemented negative lens composed of a biconvex positive lens L7 and a biconcave negative lens L8, and a biconvex positive lens L9.

Table 4 below lists the values of the specifications of the optical system of this example.

(Table 4)
[Overall specifications]
TL23.85
f1.37

[Lens specifications]
m r d nd νd
1) 16.071 1.000 2.001000 29.12
2) 7.253 4.000
* 3) 8.826 0.900 1.693500 53.20
* 4) 2.255 2.199
* 5) 8.819 0.800 1.583130 59.46
*6) 3.162 1.026
7) 14.975 4.610 1.846660 23.80
*8) -11.571 0.200
9> ∞ 0.100 (aperture diaphragm)
*10) 6.802 1.595 1.693500 53.20
*11) -6.090 0.119
*12) -14.806 0.800 1.688930 31.16
*13) 18.559 0.100
14) 4.391 1.800 1.618000 63.34
15) -3.503 0.350 1.846660 23.80
16) 4.912 0.481
*17) 3.602 1.641 1.553319 71.68
*18) -7.222 0.600
19) ∞ 0.900 1.516800 63.88
20) ∞ 0.934

[Aspheric data]
mK A4 A6 A8 A10 A12
3) 0.0000 4.80E-06 -1.03E-09 1.15E-12 5.58E-15
3) 1.0000 -9.52E-04 5.89E-06 5.51E-07 -1.26E-08
4) 1.0000 1.17E-02 -1.15E-03 1.21E-04 -4.47E-06
5) 1.0000 -5.07E-03 -2.73E-04 -2.59E-05 7.72E-06
6) 1.0000 3.70E-03 -6.14E-04 -1.97E-04 6.46E-05
8) 1.0000 -4.96E-03 2.59E-03
10) 1.0000 -7.47E-04 4.27E-03 2.06E-03 -6.13E-04
11) 1.0000 -2.06E-02 1.73E-02 5.97E-03 -3.17E-04
12) 1.0000 -4.77E-02 1.90E-02 8.47E-03 -2.11E-03 8.46224E-25
13) 1.0000 -2.36E-02 4.42E-03 2.93E-04 -1.48E-04 8.46224E-25
17) 1.0000 -1.85E-03 -2.10E-03 3.39E-04 -4.25E-05
18) 1.0000 1.58E-02 -4.32E-03 3.55E-04 -2.33E-05

[Each group focal length data]
Group Starting surface Focal length
G1 1 -5.81
G2 10 6.56

FIG. 8 is a diagram of various aberrations of the optical system of the fourth embodiment. From each aberration diagram, it can be seen that the optical system of this example properly corrects various aberrations and has high optical performance.

(Fifth embodiment)
FIG. 9 is a sectional view of the optical system of the fifth embodiment.

The rear group G2 includes, in order from the object side, a biconvex positive lens L5, a cemented negative lens constructed by cementing a biconvex positive lens L6 and a biconcave negative lens L7, and a positive meniscus with a convex surface facing the object side. and a lens L8.

Table 5 below lists the values of the specifications of the optical system of this example.

(Table 5)
[Overall specifications]
TL 25.11
f1.67

[Lens specifications]
m r d nd νd
1) 15.025 1.200 2.001000 29.12
2) 7.434 4.100
* 3) 7.122 0.900 1.693500 53.20
* 4) 2.909 2.309
5) 150.000 0.350 1.603000 65.44
6) 3.355 0.831
7) 16.124 4.804 1.846660 23.80
8) -17.479 0.200
9> ∞ 0.100 (aperture diaphragm)
10) 6.246 2.485 1.755000 52.34
11) -7.595 0.153
12) 5.970 1.564 1.603110 60.69
13) -3.361 0.350 1.846660 23.80
14) 7.747 1.403
*15) 3.949 1.150 1.622625 58.16
*16) 21.622 0.600
17) ∞ 0.900 1.516800 63.88
18) ∞ 0.934

[Aspheric data]
mK A4 A6 A8 A10
3) 1.0000 -2.51E-03 3.20E-05 -8.07E-08 -5.30E-09
4) 1.0000 1.58E-02 -1.84E-03 2.20E-04 -1.00E-05
15) 1.0000 -2.51E-03 4.30E-04 -2.56E-04 2.59E-06
16) 1.0000 -5.18E-04 1.50E-03 -6.32E-04 4.30E-05

[Each group focal length data]
Group Starting surface Focal length
G1 1 -3.83
G2 10 4.45

FIG. 10 is a diagram of various aberrations of the optical system of the fifth embodiment. From each aberration diagram, it can be seen that the optical system of this example properly corrects various aberration fluctuations and has high optical performance.

(Sixth embodiment)
FIG. 11 is a sectional view of the optical system of the sixth embodiment.

The front group G1 comprises, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a biconcave negative lens L2, a negative meniscus lens L3 with a convex surface facing the object side, and a biconvex positive lens element L3. and a lens L4.

Table 6 below lists the values of the specifications of the optical system of this example.

(Table 6)
[Overall specifications]
TL 15.63
f1.40

[Lens specifications]
m r d nd νd
1) 10.756 0.700 1.751854 31.11
2) 3.274 2.152
3) -26.768 0.500 1.533408 65.98
4) 2.304 0.948
5) 16.058 0.500 1.487490 70.41
6) 2.884 0.369
7) 5.360 1.045 1.846660 23.80
8) -16.318 1.047
9> ∞ 0.485 (aperture diaphragm)
10) 12.074 1.031 1.620410 60.32
11) -4.062 0.100
12) 5.908 2.034 1.717510 54.36
13) -2.566 0.600 1.846660 23.80
14) 3.942 0.215
*15) 3.666 2.113 1.772502 49.50
*16) -6.641 0.197
17) ∞ 0.700 1.516800 63.88
18) ∞ 1.132

[Aspheric data]
mK A4 A6 A8 A10
15) 1.0000 -5.53E-03 5.95E-04 -4.97E-05 -2.76E-06
16) 1.0000 5.53E-03 -4.60E-04 1.92E-04 -2.47E-05

[Each group focal length data]
Group Starting surface Focal length
G1 1 -3.50
G2 10 3.47

12A and 12B are various aberration diagrams of the optical system of the sixth embodiment. From each aberration chart, it can be seen that the optical system of this example appropriately corrects various aberrations and has high optical performance.

(Seventh embodiment)
FIG. 13 is a sectional view of the optical system of the seventh embodiment.

The front group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, a biconcave negative lens L2, a negative meniscus lens L3 having a convex surface facing the object side, and a convex surface facing the object side. and a positive meniscus lens L4 directed toward

Table 7 below lists the values of the specifications of the optical system of this example.

(Table 7)
[Overall specifications]
TL 20.40
f1.68

[Lens specifications]
m r d nd νd
1) 31.650 0.600 1.603110 60.69
2) 5.000 3.899
3) -29.751 0.850 1.487490 70.32
4) 2.551 0.925
5) 5.443 0.600 1.740770 27.74
6) 3.030 0.427
7) 6.327 3.650 1.846660 23.80
8) 45.258 0.348
9> ∞ 0.200 (aperture diaphragm)
10) 21.008 1.148 1.700000 48.10
11) -4.239 0.374
12) 4.193 2.068 1.593190 67.90
13) -5.179 0.600 1.846660 23.80
14) 4.698 0.651
*15) 5.118 1.375 1.772502 49.50
*16) -11.838 0.197
17) ∞ 0.500 1.516800 63.88
18) ∞ 1.984

[Aspheric data]
mK A4 A6 A8 A10
15) 1.0000 -4.72E-03 9.24E-05 -2.12E-04 1.10E-06
16) 1.0000 -8.79E-04 -1.93E-05 -2.22E-04 1.23E-05

[Each group focal length data]
Group Starting surface Focal length
G1 1 -2.64
G2 10 3.74

14A and 14B are various aberration diagrams of the optical system of the seventh embodiment. From each aberration chart, it can be seen that the optical system of this example appropriately corrects various aberrations and has high optical performance.

(Eighth embodiment)
FIG. 15 is a sectional view of the optical system of the eighth embodiment.

The front group G1 comprises, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a biconcave negative lens L2, a biconcave negative lens L3, and a biconvex positive lens L4. Become.

Table 8 below lists the values of the specifications of the optical system of this example.

(Table 8)
[Overall specifications]
TL 18.18
f1.97

[Lens specifications]
m r d nd νd
1) 15.647 0.600 1.567320 42.58
2) 5,000 3,214
* 3) -25.000 0.600 1.548140 45.51
* 4) 3.187 1.319
5) -24.365 0.684 1.487490 70.32
6) 3.605 0.451
7) 13.884 1.025 1.749500 35.25
8) -5.510 1.101
9> ∞ 0.200 (aperture diaphragm)
10) 8.161 1.871 1.622990 58.12
11) -4.084 0.104
12) 8.146 1.925 1.607380 56.74
13) -2.437 1.073 1.805180 25.45
14) 4.005 0.169
*15) 3.615 1.965 1.693430 53.30
*16) -13.172 0.641
17) ∞ 0.500 1.516800 63.88
18) ∞ 0.906

[Aspheric data]
mK A4 A6 A8 A10
3) 28.0453 -2.39E-03 1.32E-04 1.03E-05 -8.17E-07
4) 0.6581 8.82E-03 8.60E-04 2.70E-05 4.56E-05
15) 1.0000 -4.72E-03 9.24E-05 -2.12E-04 1.10E-06
16) 1.0000 -8.79E-04 -1.93E-05 -2.22E-04 1.23E-05

[Each group focal length data]
Group Starting surface Focal length
G1 1 -6.17
G2 10 4.26

FIG. 16 is a diagram of various aberrations of the optical system of the eighth embodiment. From each aberration chart, it can be seen that the optical system of this example appropriately corrects various aberrations and has high optical performance.

According to each of the above embodiments, it is possible to realize an optical system that is compact and has good optical performance.

The values corresponding to the conditional expressions for each example are shown below.

　TL is the total length of the optical system in air conversion length, f is the focal length of the optical system, and 2ω is the total angle of view of the optical system. ΣT1 is the thickness of the front group on the optical axis, and f1 is the focal length of the front group. f11 is the focal length of the lens located closest to the object side in the front group. f12 is the focal length of the second lens from the object side in the front group. D112 is the air space on the optical axis between the lens closest to the object side in the front group and the second lens from the object side, and f112 is the distance between the lens closest to the object side in the front group and the object side. This is the combined focal length with the second lens from the side. T14 is the thickness on the optical axis of the fourth lens in the front group from the object side, and f14 is the focal length of the fourth lens in the front group from the object side. DS is the air space between the lens located closest to the image side in the front group and the lens located closest to the object side in the rear group. ΣT2 is the thickness of the rear group on the optical axis, and f2 is the focal length of the rear group. f2l is the focal length of the lens located closest to the image side in the rear group. nd1 is the refractive index of the lens closest to the object in the front group with reference to the d-line, and nd2 is the refractive index of the lens second from the object in the front group with respect to the d-line. and ndl is the refractive index of the lens located closest to the image side in the rear group with respect to the d-line.

[Value corresponding to conditional expression]
Conditional expression: 1st 2nd 3rd 4th
(1)(5) f14/-f112: 2.129 1.739 - 2.968
(2) T14/f: 3.265 3.582 3.624 3.371
(3) 2ω: 210.0 212.0 212.0 195.0
(4)(9) ΣT1/T14: 2.988 2.958 2.812 3.153
(6)(14) f/DS: 5.268 4.878 7.732 4.559
(7)(11) f14/T14: 1.448 1.111 1.172 1.817
(8)(13) (-f1)/f2 : 1.066 3.133 1.601 1.215
(10)(12) ΣT1/f: 9.757 10.596 10.192 10.628
(15) f14/f: 4.727 3.981 4.247 6.125
(16) ΣT2/f: 4.594 4.749 4.535 5.035
(17) D112/f: 2.531 2.733 2.503 2.925
(18) TL/f: 15.885 17.031 16.232 17.438
(19) f2l/f: 4.201 3.628 3.714 3.357
(20) (-f11)/f2l : 2.283 2.699 3.279 3.049
(21) (-f12)/f : 3.695 3.906 4.829 3.382
(22) f11/f12: 2.596 2.507 2.522 3.027
(23) nd1: 2.001 2.001 2.001 2.001
(24) nd2: 1.694 1.694 1.694 1.694
(25) nd3: 1.553 1.553 1.637 1.553

Conditional expression: 5th 6th 7th 8th
(1)(5) f14/-f112: 2.409 2.408 3.346 1.728
(2) T14/f: 2.868 0.745 2.167 -
(3) 2ω: 212.0 200.0 200.0 190.0
(4)(9) ΣT1/T14: 3.017 5.948 3.000 7.700
(6)(14) f/DS: 5.583 0.915 3.074 1.516
(7)(11) f14/T14: 2.207 4.665 2.282 －
(8)(13) (-f1)/f2 : 0.862 1.009 0.707 1.448
(10)(12) ΣT1/f : 8.654 4.433 6.500 4.000
(15) f14/f: 6.329 3.476 4.944 －
(16) ΣT2/f : 4.242 4.347 3.690 3.601
(17) D112/f: 2.448 1.535 2.314 1.629
(18) TL/f: 14.989 11.150 12.106 －
(19) f2l/f: 4.520 2.395 2.846 2.177
(20) (-f11)/f2l : 2.108 1.942 2.071 3.077
(21) (-f12)/f : 4.639 2.821 2.836 2.593
(22) f11/f12: 2.054 1.649 2.078 2.583
(23) nd1: 2.001 - - -
(24) nd2: 1.694 1.533 - 1.548
(25) nd3: 1.623 1.773 1.773 1.693

Each of the above examples shows one specific example of the present invention, and the present invention is not limited to these. The following content can be appropriately adopted within a range that does not impair the optical performance of the optical system of the embodiment of the present application.

In the optical system of each of the above embodiments, the aperture stop may be configured so that a lens frame substitutes for its role without providing a member.

The lens surfaces of the lenses that constitute the optical system of each of the above embodiments may be spherical, planar, or aspherical. A spherical or flat lens surface is preferable because it facilitates lens processing and assembly adjustment, and can prevent deterioration of optical performance due to errors in lens processing and assembly adjustment. In addition, even when the image plane is shifted, deterioration in rendering performance is small, which is preferable. If the lens surface is aspherical, it can be aspherical by grinding, glass-molded aspherical by molding glass into an aspherical shape, or composite aspherical by forming resin on the glass surface into an aspherical shape. good. Further, the lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

An anti-reflection film having high transmittance in a wide wavelength range may be applied to the lens surfaces of the lenses constituting the optical system of each of the above examples. As a result, flare and ghost can be reduced, and optical performance with high contrast can be achieved.

Next, a camera provided with the optical system of this embodiment will be described with reference to FIG.
FIG. 17 is a schematic diagram of a camera provided with the optical system of this embodiment.

The camera 1 is a so-called omnidirectional camera having the optical system according to the first embodiment as taking lenses 2-1 and 2-2 on one surface and the opposite surface.

In the camera 1, light from an unillustrated object (subject) is condensed by the taking lens 2-1 or 2-2 and reaches the imaging element 3-1 or 3-2. The imaging devices 3-1 and 3-2 convert the light from the subject into image data.

Also, when a release button (not shown) is pressed by the photographer, the image data is stored in a memory (not shown). In this way, the photographer can photograph the subject with the camera 1 .

Here, the optical system of the first embodiment mounted as the photographing lenses 2-1 and 2-2 in the camera 1 is a compact optical system having good optical performance. Therefore, the camera 1 is small and can achieve good optical performance. It should be noted that the same effect as the camera 1 can be obtained even if a camera is constructed in which the optical systems of the above-described second to eighth embodiments are mounted as the photographing lenses 2-1 and 2-2. Also, the number of optical systems mounted on the camera 1 is not limited to two, and may be one or three or more.

Finally, the outline of the method for manufacturing the optical system of this embodiment will be described with reference to FIG. FIG. 18 is a flow chart showing an outline of the method for manufacturing the optical system of this embodiment.

The manufacturing method of the optical system of this embodiment shown in FIG. 18 includes the following steps S1 and S2.

Step S1: A front group having at least three negative lenses and at least one positive lens, an aperture stop, and a rear group having at least four lenses are prepared in order from the object side.

Step S2: Make the optical system satisfy both of the following conditional expressions.
(1) 1.40 < f14/(-f112) < 5.20
(2) 0.70<T14/f<4.50
(3) 160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group T14: Front Thickness on the optical axis of the fourth lens from the object side in the group f: focal length of the optical system 2ω: total angle of view of the optical system

According to the manufacturing method of the optical system of the present embodiment, it is possible to manufacture a compact optical system having good imaging performance.

It should be understood that those skilled in the art can make various changes, substitutions and modifications to this without departing from the spirit and scope of the present invention.

S aperture diaphragm I image plane 1 camera 2-1, 2-2 taking lens 3-1, 3-2 image sensor

Claims

In order from the object side, it consists of a front group, an aperture stop, and a rear group,
The front group has, in order from the object side, at least three negative lenses and at least one positive lens,
The rear group has at least four lenses,
An optical system that satisfies both of the following conditional expressions.
1.40<f14/(-f112)<5.20
0.70<T14/f<4.50
160.00° < 2ω
however,
f14: focal length of the fourth lens from the object side in the front group f112: combined focal length of the lens closest to the object side and the second lens from the object side in the front group T14 : Thickness on the optical axis of the fourth lens from the object side in the front group f : Focal length of the optical system 2ω : Total angle of view of the optical system
In order from the object side, it consists of a front group, an aperture stop, and a rear group,
The front group has, in order from the object side, at least three negative lenses and at least one positive lens,
The rear group has at least four lenses,
An optical system that satisfies both of the following conditional expressions.
1.40<f14/(-f112)<5.20
1.50<ΣT1/T14<7.90
160.00° < 2ω
however,
f14: Focal length of the fourth lens from the object side in the front group f112: Combined focal length of the lens closest to the object side and the second lens from the object side in the front group ΣT1 : Thickness on the optical axis of the front group T14 : Thickness on the optical axis of the fourth lens from the object side in the front group 2ω : Total angle of view of the optical system
In order from the object side, it consists of a front group, an aperture stop, and a rear group,
The front group has, in order from the object side, at least three negative lenses and at least one positive lens,
The rear group has at least four lenses,
An optical system that satisfies both of the following conditional expressions.
1.50 < f14/(-f112) < 4.90
0.65 < f/DS < 8.00
160.00° < 2ω
however,
f14: focal length of the fourth lens from the object side in the front group f112: combined focal length of the lens closest to the object side and the second lens from the object side in the front group f : Focal length of the optical system DS : Air gap on the optical axis between the lens in the front group that is closest to the image side and the lens in the rear group that is closest to the object side 2ω: Full image of the optical system corner
In order from the object side, it consists of a front group, an aperture stop, and a rear group,
The front group has, in order from the object side, at least three negative lenses and at least one positive lens,
The rear group has at least four lenses,
An optical system that satisfies both of the following conditional expressions.
1.80 < f14/T14 < 5.00
0.60<(-f1)/f2<1.85
160.00° < 2ω
f14: focal length of the fourth lens from the object side in the front group T14: thickness on the optical axis of the fourth lens from the object side in the front group f1: focal length of the front group f2 : focal length of the rear group 2ω: total angle of view of the optical system
In order from the object side, it consists of a front group, an aperture stop, and a rear group,
The front group has, in order from the object side, at least three negative lenses and at least one positive lens,
The rear group has at least four lenses,
An optical system that satisfies both of the following conditional expressions.
2.00<ΣT1/T14<7.90
3.50 < ΣT1/f < 6.60
160.00° < 2ω
however,
ΣT1: thickness on the optical axis of the front group T14: thickness on the optical axis of the fourth lens from the object side in the front group f: focal length of the optical system 2ω: total angle of view of the optical system
6. The optical system according to any one of claims 1 to 3 or 5, which satisfies the following formula.
1.00 < f14/T14 < 5.00
however,
f14: focal length of the fourth lens from the object side in the front group
5. The optical system according to any one of claims 1 to 4, which satisfies the following conditional expressions.
3.50 < ΣT1/f < 18.00
however,
ΣT1: thickness of the front group on the optical axis f: focal length of the optical system
6. The optical system according to any one of claims 1 to 3 or 5, which satisfies the following formula.
0.30<(-f1)/f2<3.30
however,
f1: focal length of the front group f2: focal length of the rear group
6. The optical system according to any one of claims 1, 2, 4, and 5, which satisfies the following conditional expression.
0.20 < f/DS < 9.00
however,
f: focal length of the optical system DS: air distance on the optical axis between the lens closest to the image side in the front group and the lens closest to the object side in the rear group
5. The optical system of any one of claims 1, 3, or 4, satisfying the following equation:
1.50<ΣT1/T14<7.90
however,
ΣT1: Optical axis thickness of the front group T14: Optical axis thickness of the fourth lens from the object side in the front group
11. The optical system according to any one of claims 1-10, which satisfies the following formula:
3.00 < f14/f < 13.00
however,
f14: focal length of the fourth lens from the object side in the front group f: focal length of the optical system
12. The optical system according to any one of claims 1-11, satisfying the following formula:
3.00 < ΣT2/f < 7.00
however,
ΣT2: thickness of the rear group on the optical axis f: focal length of the optical system
13. The optical system according to any one of claims 1 to 12, satisfying the following equations.
0.80<D112/f<4.50
however,
D112: Air gap between the lens closest to the object side and the lens second from the object side in the front group f: Focal length of the optical system
14. The optical system according to any one of claims 1 to 13, satisfying the following equations.
10.00 < TL/f < 19.00
however,
TL: total length of the optical system in air equivalent length f: focal length of the optical system
15. The optical system according to any one of claims 1 to 14, satisfying the following equations.
2.00 < f2l/f < 28.00
however,
f2l: focal length of the lens arranged closest to the image side in the rear group f: focal length of the optical system
16. The optical system according to any one of claims 1 to 15, satisfying the following formula:
0.30 < (-f11)/f2l < 4.00
however,
f11: focal length of the lens closest to the object side in the front group f2l: focal length of the lens closest to the image side in the rear group
17. An optical system according to any one of claims 1 to 16, satisfying the following formula:
2.00<(-f12)/f<6.00
however,
f12: focal length of the second lens from the object side in the front group f: focal length of the optical system
18. An optical system according to any one of claims 1 to 17, satisfying the following formula:
1.40 < f11/f12 < 3.50
however,
f11: focal length of the lens in the front group that is closest to the object side f12: focal length of the lens that is second from the object side in the front group
19. The optical system according to any one of claims 1-18, satisfying the following formula:
1.85 < nd1 < 2.20
however,
nd1: Refractive index with respect to the d-line of the lens located closest to the object side in the front group
20. The optical system according to any one of claims 1-19, satisfying the following formula:
1.50 < nd2 < 1.95
however,
nd2: Refractive index of the second lens from the object side in the front group with respect to the d-line
21. An optical system according to any one of claims 1-20, satisfying the following formula:
1.45 < nd3 < 1.90
however,
nd3: Refractive index with respect to the d-line of the lens located closest to the image side in the rear group
An optical instrument comprising the optical system according to any one of claims 1-21.
In order from the object side, it consists of a front group, an aperture stop, and a rear group,
The front group has, in order from the object side, at least three negative lenses and at least one positive lens,
A method for manufacturing an optical system in which the rear group has at least four lenses,
A method of manufacturing an optical system in which lenses are arranged so as to satisfy both of the following conditional expressions.
1.40<f14/(-f112)<5.20
0.70<T14/f<4.50
160.00° < 2ω
however,
f14: focal length of the fourth lens from the object side in the front group f112: combined focal length of the lens closest to the object side and the second lens from the object side in the front group T14 : Thickness on the optical axis of the fourth lens from the object side in the front group f : Focal length of the optical system 2ω : Total angle of view of the optical system