JP6984643B2 - Variable magnification optical system, optical device - Google Patents

Description

The present invention relates to a variable magnification optical system, an optical device, and a method for manufacturing a variable magnification optical system.

Conventionally, many variable magnification optical systems suitable for interchangeable lenses for cameras, digital cameras, video cameras, etc. have been proposed in which the lens group on the most object side has a positive refractive power (for example, Patent Document 1). reference.).

Japanese Unexamined Patent Publication No. 2010-237455

However, the conventional variable magnification optical system as described above has a problem that it is difficult to obtain sufficiently high optical performance in order to reduce the size.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a variable magnification optical system, an optical device, and a method for manufacturing a variable magnification optical system which are small in size and have high optical performance.

The present invention for solving the above-
From the object side, the first lens group having a positive refractive force, the second lens group having a negative refractive force, the third lens group having a positive refractive force, and the fourth lens having a positive refractive force. The group consists of substantially four lens groups, or has a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a third lens group having a positive refractive force. The fourth lens group having a negative refractive force and the fifth lens group having a positive refractive force are substantially composed of five lens groups.
When scaling from the wide-angle end state to the telephoto end state, the distance between adjacent lens groups changes,
Having at least one lens that satisfies the following conditional expression,
1.928 <ndh
29.37 ≤ νdh
However,
ndh: Refractive index with respect to the d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to the d-line (wavelength 587.6 nm) of the lens The fourth lens group has at least one of the lenses having a negative refractive power. Provided is a variable magnification optical system characterized by having .

Further, the present invention
Provided is an optical device characterized by having the variable magnification optical system.

According to the present invention, it is possible to provide a variable magnification optical system, an optical device, and a method for manufacturing a variable magnification optical system which are small in size and have high optical performance.

(A), (b), and (c) are cross-sectional views of the variable magnification optical system according to the first embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. (A), (b), and (c) are various aspects of the variable magnification optical system according to the first embodiment of the present application at the time of focusing on an infinite object in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. (A), (b), and (c) are cross-sectional views of the variable magnification optical system according to the second embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. (A), (b), and (c) are various aspects of the variable magnification optical system according to the second embodiment of the present application at the time of focusing on an infinite object in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. (A), (b), and (c) are cross-sectional views of the variable magnification optical system according to the third embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. (A), (b), and (c) are various aspects of the variable magnification optical system according to the third embodiment of the present application at the time of focusing on an infinite object in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. (A), (b), and (c) are cross-sectional views of the variable magnification optical system according to the fourth embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. (A), (b), and (c) are various aspects of the variable magnification optical system according to the fourth embodiment of the present application at the time of focusing on an infinite object in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. (A), (b), and (c) are cross-sectional views of the variable magnification optical system according to the fifth embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. (A), (b), and (c) are various aspects of the variable magnification optical system according to the fifth embodiment of the present application at the time of focusing on an infinite object in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is an aberration diagram. It is a figure which shows the structure of the camera which provided the variable magnification optical system of this application. It is a figure which shows the outline of the manufacturing method of the variable magnification optical system of this application.

Hereinafter, the variable magnification optical system, the optical device, and the method for manufacturing the variable magnification optical system of the present application will be described.
In the variable magnification optical system of the present application, in order from the object side, a first lens group having a positive refractive force, a second lens group having a negative refractive force, a third lens group having a positive refractive force, and a positive lens group. It has a fourth lens group having a refractive force of the above, and when the magnification is changed from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group, the second lens group and the first lens group. It is characterized in that the distance between the three lens groups and the distance between the third lens group and the fourth lens group changes. With this configuration, the variable magnification optical system of the present application can realize the scaling from the wide-angle end state to the telephoto end state, and can suppress the fluctuation of the distortion aberration due to the scaling.

Further, the variable magnification optical system of the present application is characterized by having at least one lens satisfying the following conditional expressions (1) and (2).
(1) 1.928 <ndh
(2) 28.60 <νdh
However,
ndh: Refractive index with respect to the d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to the d-line (wavelength 587.6 nm) of the lens

The conditional expression (1) defines the optimum refractive index of the lens. By satisfying the conditional expression (1), the variable magnification optical system of the present application can suppress fluctuations in spherical aberration and astigmatism during scaling while achieving miniaturization.
When the corresponding value of the conditional expression (1) of the variable magnification optical system of the present application falls below the lower limit, it becomes difficult to suppress the fluctuation of spherical aberration and the fluctuation of astigmatism at the time of scaling, and high optical performance is realized. Can no longer be done. In addition, in order to further ensure the effect of the present application, it is more preferable to set the lower limit value of the conditional expression (1) to 1.940.
In addition, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (1) to 2.800. When the corresponding value of the conditional expression (1) of the variable magnification optical system of the present application is smaller than 2.800, the transmittance of visible light to the material of the lens can be sufficiently secured.

The conditional expression (2) defines the optimum Abbe number of the lens. By satisfying the conditional expression (2), the variable magnification optical system of the present application can suppress fluctuations in axial chromatic aberration and fluctuations in chromatic aberration of magnification at the time of scaling while achieving miniaturization.
If the corresponding value of the conditional expression (2) of the variable magnification optical system of the present application falls below the lower limit, it becomes difficult to suppress the fluctuation of the axial chromatic aberration and the fluctuation of the chromatic aberration of magnification at the time of scaling, and high optical performance is realized. Can no longer be done. In addition, in order to further ensure the effect of the present application, it is more preferable to set the lower limit value of the conditional expression (2) to 29.00. Further, in order to further ensure the effect of the present application, it is more preferable to set the lower limit value of the conditional expression (2) to 30.00. Further, in order to further ensure the effect of the present application, it is more preferable to set the lower limit value of the conditional expression (2) to 32.00.
In addition, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (2) to 50.00. By making the corresponding value of the conditional equation (2) of the variable magnification optical system of the present application smaller than 50.00, it is possible to suppress fluctuations in axial chromatic aberration and fluctuations in chromatic aberration of magnification that occur in lenses other than the lens at the time of scaling. It is possible to realize high optical performance.
With the above configuration, it is possible to realize a variable magnification optical system that is compact and has high optical performance.

Further, in the variable magnification optical system of the present application, it is desirable that the first lens group has at least one lens. With this configuration, it is possible to suppress fluctuations in spherical aberration, astigmatism, axial chromatic aberration, and chromatic aberration of magnification that occur in the first lens group during scaling.

Further, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (3).
(3) 5.50 <f1 / (-f2) <15.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group

The conditional expression (3) defines an appropriate range of the focal length ratio between the first lens group and the second lens group. By satisfying the conditional equation (3), the variable magnification optical system of the present application can suppress fluctuations in astigmatism during scaling while maintaining a high magnification ratio.
If the corresponding value of the conditional expression (3) of the variable magnification optical system of the present application is less than the lower limit value, astigmatism is greatly generated in the wide-angle end state, and high optical performance cannot be realized. In addition, in order to further ensure the effect of the present application, it is more preferable to set the lower limit value of the conditional expression (3) to 5.60. Further, in order to further ensure the effect of the present application, it is more preferable to set the lower limit value of the conditional expression (3) to 5.90.
On the other hand, if the corresponding value of the conditional expression (3) of the variable magnification optical system of the present application exceeds the upper limit value, it becomes difficult to suppress the fluctuation of astigmatism generated in the second lens group at the time of magnification change. In addition, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (3) to 11.50. Further, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (3) to 10.20.

Further, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (4).
(4) 0.220 <(-f2) / f3 <0.530
However,
f2: Focal length of the second lens group f3: Focal length of the third lens group

The conditional expression (4) defines an appropriate range of the focal length ratio of the second lens group and the third lens group. By satisfying the conditional equation (4), the variable magnification optical system of the present application can suppress fluctuations in spherical aberration and astigmatism during scaling while maintaining a high magnification ratio.
If the corresponding value of the conditional expression (4) of the variable magnification optical system of the present application is less than the lower limit value, it becomes difficult to suppress the fluctuation of astigmatism generated in the second lens group at the time of magnification change. In addition, in order to further ensure the effect of the present application, it is more preferable to set the lower limit value of the conditional expression (4) to 0.270.
On the other hand, if the corresponding value of the conditional expression (4) of the variable magnification optical system of the present application exceeds the upper limit value, it becomes difficult to suppress the fluctuation of the spherical aberration generated in the third lens group at the time of scaling. In addition, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (4) to 0.490. Further, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (4) to 0.450.

Further, it is desirable that the variable magnification optical system of the present application has at least one lens in which the first lens group satisfies the following conditional expression (5).
(5) 0.450 << | fh / f1 | <1.40
However,
fh: Focal length of the lens in the first lens group f1: Focal length of the first lens group

The conditional expression (5) defines the optimum focal length range of the lens in the first lens group. When the lens is joined to another lens, fh represents the focal length of the lens alone. By satisfying the conditional equation (5), the variable magnification optical system of the present application can suppress fluctuations of spherical aberration, astigmatism, axial chromatic aberration, and chromatic aberration of magnification at the time of scaling.

Here, the conditional expression (5) will be described separately for the case where the lens has a positive refractive power and the case where the lens has a negative refractive power.
When the lens has a positive refractive power and the corresponding value of the conditional expression (5) of the variable magnification optical system of the present application falls below the lower limit value, the fluctuation of the axial chromatic aberration and the chromatic aberration of magnification generated in the lens at the time of magnification change It becomes difficult to suppress fluctuations, and it becomes impossible to achieve high optical performance. On the other hand, if the corresponding value of the conditional expression (5) of the variable magnification optical system of the present application exceeds the upper limit value, it becomes difficult to suppress the positive spherical aberration generated in the second lens group in the telephoto end state, and high optical performance is achieved. Will not be possible.

When the lens has a negative refractive power and the corresponding value of the conditional expression (5) of the variable magnification optical system of the present application is less than the lower limit value, the fluctuation of astigmatism generated in the lens at the time of magnification change can be suppressed. It becomes difficult and it becomes impossible to realize high optical performance. On the other hand, if the corresponding value of the conditional expression (5) of the variable magnification optical system of the present application exceeds the upper limit value, it is difficult to suppress fluctuations in axial chromatic aberration and fluctuations in chromatic aberration of magnification that occur in lenses other than the lens at the time of scaling. Therefore, it becomes impossible to realize high optical performance.
In addition, in order to further ensure the effect of the present application, it is more preferable to set the lower limit value of the conditional expression (5) to 0.620. Further, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (5) to 1.290.

Further, in the variable magnification optical system of the present application, it is desirable that the fourth lens group has at least one lens. With this configuration, spherical aberration, astigmatism, axial chromatic aberration, and magnifying chromatic aberration generated in the fourth lens group can be suppressed from the wide-angle end state to the telephoto end state.

Further, in the variable magnification optical system of the present application, it is desirable that the second lens group has at least one lens. With this configuration, fluctuations of spherical aberration, astigmatism, axial chromatic aberration, and chromatic aberration of magnification generated in the second lens group at the time of scaling can be suppressed from the wide-angle end state to the telephoto end state.

Further, in the variable magnification optical system of the present application, it is desirable that the third lens group has at least one lens. With this configuration, fluctuations of spherical aberration, astigmatism, axial chromatic aberration, and chromatic aberration of magnification generated in the third lens group at the time of scaling can be suppressed from the wide-angle end state to the telephoto end state.

Further, it is desirable that the variable magnification optical system of the present application has at least one lens having a negative refractive power in the first lens group. With this configuration, it is possible to suppress fluctuations in astigmatism, spherical aberration, and chromatic aberration of magnification, especially secondary chromatic aberration, which occur in the first lens group during scaling, and high optical performance can be realized. can.

Further, it is desirable that the variable magnification optical system of the present application has at least one of the lenses having a negative refractive power in the fourth lens group. With this configuration, it is possible to suppress fluctuations in astigmatism, spherical aberration, and axial chromatic aberration that occur in the fourth lens group during scaling, and high optical performance can be realized.

Further, it is desirable that the variable magnification optical system of the present application has at least one lens in which the fourth lens group satisfies the following conditional expression (6).
(6) 31.60 <νdh4
However,
νdh4: Abbe number with respect to the d-line (wavelength 587.6 nm) of the lens in the fourth lens group.

The conditional expression (6) defines the optimum Abbe number of the lens in the fourth lens group. The variable magnification optical system of the present application can suppress axial chromatic aberration and chromatic aberration of magnification by satisfying the conditional expression (6).
When the corresponding value of the conditional expression (6) of the variable magnification optical system of the present application is less than the lower limit value, it becomes difficult to suppress the axial chromatic aberration and the chromatic aberration of magnification generated in the lens other than the lens in the fourth lens group. It will not be possible to achieve high optical performance.

Further, it is desirable that the variable magnification optical system of the present application has at least one lens having a negative refractive power in the second lens group. With this configuration, axial chromatic aberration and chromatic aberration of magnification, particularly secondary chromatic aberration, which occur in the second lens group can be suppressed, and high optical performance can be realized.

Further, it is desirable that the variable magnification optical system of the present application has at least one lens in which the third lens group has a negative refractive power. With this configuration, axial chromatic aberration, particularly secondary chromatic aberration, which occurs in the third lens group can be suppressed, and high optical performance can be realized.

Further, it is desirable that the variable magnification optical system of the present application has a positive lens in which the first lens group satisfies the following conditional expression (7).
(7) 75.00 <νdp1
However,
νdp1: Abbe number with respect to the d-line (wavelength 587.6 nm) of the positive lens in the first lens group.

The conditional expression (7) defines the optimum Abbe number of the positive lens in the first lens group. By satisfying the conditional expression (7), the variable magnification optical system of the present application can suppress fluctuations in axial chromatic aberration and fluctuations in chromatic aberration of magnification at the time of scaling.
When the corresponding value of the conditional expression (7) of the variable magnification optical system of the present application falls below the lower limit, it becomes difficult to suppress the fluctuation of the axial chromatic aberration and the fluctuation of the chromatic aberration of magnification at the time of scaling, and high optical performance is realized. Can no longer be done.
In addition, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (7) to 99.00. By making the corresponding value of the conditional equation (7) of the variable magnification optical system of the present application smaller than 99.00, it is possible to suppress fluctuations in axial chromatic aberration and fluctuations in chromatic aberration of magnification that occur in lenses other than the positive lens at the time of scaling. And high optical performance can be realized.

Further, it is desirable that the variable magnification optical system of the present application has a positive lens in which the fourth lens group satisfies the following conditional expression (8).
(8) 75.00 <νdp4
However,
νdp4: Abbe number with respect to the d-line (wavelength 587.6 nm) of the positive lens in the fourth lens group.

The conditional expression (8) defines the optimum Abbe number of the positive lens in the fourth lens group. By satisfying the conditional expression (8), the variable magnification optical system of the present application can suppress fluctuations in axial chromatic aberration and fluctuations in chromatic aberration of magnification at the time of scaling.
If the corresponding value of the conditional expression (8) of the variable magnification optical system of the present application is less than the lower limit, it becomes difficult to suppress the fluctuation of the axial chromatic aberration at the time of scaling, and it becomes impossible to realize high optical performance. ..
In addition, in order to further ensure the effect of the present application, it is more preferable to set the upper limit value of the conditional expression (8) to 99.00. By making the corresponding value of the conditional expression (8) of the variable magnification optical system of the present application smaller than 99.00, it is possible to suppress the axial chromatic aberration that occurs in lenses other than the positive lens, and to realize high optical performance. Can be done.

Further, in the variable magnification optical system of the present application, it is desirable that the distance between the first lens group and the second lens group increases when the magnification is changed from the wide-angle end state to the telephoto end state. With this configuration, the focal length of the first lens group and the focal length of the second lens group can be made appropriate. Then, it is possible to suppress the fluctuation of spherical aberration and astigmatism generated in each lens group, and to suppress the fluctuation of spherical aberration and the fluctuation of astigmatism at the time of scaling.

Further, in the variable magnification optical system of the present application, it is desirable that the distance between the second lens group and the third lens group is reduced when the magnification is changed from the wide-angle end state to the telephoto end state. With this configuration, the focal length of the second lens group and the focal length of the third lens group can be made appropriate. Then, it is possible to suppress the fluctuation of spherical aberration and astigmatism generated in each lens group, and to suppress the fluctuation of spherical aberration and the fluctuation of astigmatism at the time of scaling.

Further, in the variable magnification optical system of the present application, it is desirable that the distance between the third lens group and the fourth lens group increases when the magnification is changed from the wide-angle end state to the telephoto end state. With this configuration, it is possible to suppress fluctuations in spherical aberration and astigmatism that occur in the third lens group and the fourth lens group during scaling.

The optical device of the present application is characterized by having a variable magnification optical system having the above-described configuration. This makes it possible to realize an optical device that is small in size and has high optical performance.

The method for manufacturing the variable magnification optical system of the present application is a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power in order from the object side. It is a method for manufacturing a variable magnification optical system having a fourth lens group having a positive refractive force, and has at least one lens satisfying the following conditional equations (1) and (2), and has a wide angle. When scaling from the end state to the telephoto end state, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, and the third lens group and the above. It is characterized in that the distance from the fourth lens group is changed. This makes it possible to manufacture a variable magnification optical system that is small in size and has high optical performance.
(1) 1.928 <ndh
(2) 28.60 <νdh
However,
ndh: Refractive index with respect to the d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to the d-line (wavelength 587.6 nm) of the lens

Hereinafter, the variable magnification optical system according to the numerical embodiment of the present application will be described with reference to the attached drawings. The second, third, and fifth embodiments described later are reference examples of the present application.
(First Example)
1 (a), 1 (b), and 1 (c) are cross-sectional views of the variable magnification optical system according to the first embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. Is.
In the variable magnification optical system according to the present embodiment, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a positive refractive power. It is composed of a lens group G3 and a fourth lens group G4 having a positive refractive power.

The first lens group G1 is composed of a junction lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side, in order from the object side. Become.
The second lens group G2 has a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a concave surface facing the object side in order from the object side. It consists of a negative meniscus lens L24. The negative meniscus lens L21 is a glass-molded aspherical lens having an aspherical lens surface on the object side.
The third lens group G3 is composed of a junction lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 in order from the object side. An aperture diaphragm S is provided on the object side of the third lens group G3.

The fourth lens group G4 is composed of a front group G4F having a negative refractive power and a rear group G4R having a positive refractive power in order from the object side.
The front group G4F includes a junction lens of a biconvex positive lens L401 and a biconcave negative lens L402, a biconcave negative lens L403, and a positive meniscus lens L404 with a convex surface facing the object side, in order from the object side. It consists of a junction lens with. The negative lens L403 is a glass-molded aspherical lens having an aspherical shape on the lens surface on the object side.
In the rear group G4R, the biconvex positive lens L405, the biconvex positive lens L406, and the negative meniscus lens L407 with the concave surface facing the object side are joined in order from the object side, and the convex surface is directed toward the object side. It is composed of a junction lens of a negative meniscus lens L408 and a biconvex positive lens L409, and a negative meniscus lens L410 with a convex surface facing the image side. The negative meniscus lens L410 is a glass-molded aspherical lens having an aspherical shape on the lens surface on the image side.
In the variable magnification optical system according to the present embodiment, a low-pass filter, a cover glass for a sensor, or the like may be arranged between the fourth lens group G4 and the image plane I.

Under the above configuration, in the variable magnification optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 increases when the magnification is changed from the wide-angle end state to the telescopic end state. The air gap between the 2 lens group G2 and the 3rd lens group G3 decreases, the air gap between the 3rd lens group G3 and the 4th lens group G4 increases, and the air gap between the aperture aperture S and the 3rd lens group G3. The first to fourth lens groups G1 to G4 move along the optical axis, and the aperture aperture S moves integrally with the front group G4F of the fourth lens group G4 so as to decrease. Specifically, the first lens group G1 and the third lens group G3 move to the object side at the time of scaling. The second lens group G2 moves toward the object from the wide-angle end state to the intermediate focal length state, and moves toward the image side from the intermediate focal length state to the telephoto end state. In the fourth lens group G4, the front group G4F and the rear group G4R are in the wide-angle end state so that the air gap between the front group G4F and the rear group G4R decreases when the magnification is changed from the wide-angle end state to the telephoto end state. It moves to the object side from the intermediate focal length state to the image side from the intermediate focal length state to the telephoto end state.

Table 1 below lists the values of the specifications of the variable magnification optical system according to this embodiment.
In Table 1, f indicates the focal length, and BF indicates the back focus (the distance on the optical axis between the lens surface on the image side and the image surface I).
In [plane data], the plane number is the order of the optical planes counted from the object side, r is the radius of curvature, d is the plane spacing (distance between the nth plane (n is an integer) and the n + 1th plane), and nd is. The refractive index for the d-line (wavelength 587.6 nm) and νd indicate the Abbe number for the d-line (wavelength 587.6 nm). Further, the object surface is an object surface, the variable is a variable surface spacing, the aperture S is an aperture stop S, and the image surface is an image surface I. The radius of curvature r = ∞ indicates a plane. For aspherical surfaces, * is added to the surface number and the value of the paraxial radius of curvature is shown in the column of radius of curvature r. The description of the refractive index nd of air = 1.000000 is omitted.

[Aspherical surface data] shows the aspherical surface coefficient and the conical constant when the shape of the aspherical surface shown in [Surface data] is expressed by the following equation.
x = (h ² / r) / [1 + {1-κ (h / r) ² } ^1/2 ]
＋ A4h ⁴ ＋ A6h ⁶ ＋ A8h ⁸ ＋ A10h ¹⁰
Here, h is the height in the direction perpendicular to the optical axis, x is the distance (sag amount) along the optical axis direction from the tangent plane of the apex of the aspherical surface to the aspherical surface at height h, and κ is the conical constant. , A4, A6, A8, A10 are the aspherical surface coefficients, and r is the radius of curvature of the reference sphere (near-axis radius of curvature). In addition, "E −n" (n is an integer) indicates “× 10 ⁻ⁿ ”, and for example, “1.234E-05” indicates “1.234 × 10 ⁻⁵ ”. The second-order aspherical coefficient A2 is 0, and the description is omitted.

In [Various data], FNO is F number, ω is half angle of view (unit is "°"), Y is image height, and TL is the total length of the variable magnification optical system (image from the first plane when focusing on an infinity object). The distance on the optical axis to the plane I), dn is the variable distance between the nth plane and the n + 1th plane, and φ is the diaphragm diameter of the aperture stop S. W indicates a wide-angle end state, M indicates an intermediate focal length state, and T indicates a telephoto end state.
[Lens group data] shows the start surface and focal length of each lens group.
[Conditional expression corresponding value] shows the corresponding value of each conditional expression of the variable magnification optical system according to this embodiment.

Here, "mm" is generally used as the unit of the focal length f, the radius of curvature r and other lengths shown in Table 1. However, the optical system is not limited to this because the same optical performance can be obtained even if the optical system is proportionally expanded or contracted.
The reference numerals in Table 1 described above shall be used in the same manner in the tables of the respective examples described later.

(Table 1) First Example
[Surface data]
Surface number r d nd ν d
Paraboloid ∞

1 104.5118 1.6000 2.003300 28.27
2 39.3751 7.4000 1.497820 82.57
3 -463.5701 0.1000
4 40.3116 5.4000 1.834810 42.73
5 241.9089 Variable

* 6 79.9711 1.0000 1.851350 40.10
7 8.1252 4.8500
8 -14.2116 1.0000 1.883000 40.66
9 124.9279 0.1000
10 30.8124 3.3500 1.808090 22.74
11 -15.1873 0.3000
12 -13.2222 1.0000 1.883000 40.66
13 -23.0302 Variable

14 (Aperture S) ∞ Variable

15 26.1923 1.0000 1.954000 33.46
16 12.2483 2.8500 1.719990 50.27
17 -43.5073 Variable

18 14.5527 2.8500 1.497820 82.57
19 -40.3302 1.0000 1.950000 29.37
20 173.4596 2.1500
* 21 -105.0156 1.0000 1.806100 40.71
22 10.9037 2.2000 1.808090 22.74
23 28.6084 Variable

24 30.6882 2.8500 1.579570 53.74
25 -18.3905 0.1000
26 18.8919 3.6000 1.518230 58.82
27 -13.1344 1.0000 2.000690 25.46
28 -2198.5412 0.7500
29 412.2295 1.0000 1.954000 33.46
30 12.8823 3.5000 1.755200 27.57
31 -23.7185 1.1500
32 -16.1296 1.0000 1.806100 40.71
* 33 -97.3104 BF

Image plane ∞

[Aspherical data]
Side 6 κ -8.7294
A4 4.64796E-05
A6 -4.09659E-07
A8 2.44519E-09
A10 -9.90503E-12

Side 21 κ -1.5760
A4 1.72590E-05
A6 9.45415E-08
A8 -1.00397 E-09
A10 0.00000E + 00

Side 33 κ -19.8082
A4 -1.67719E-05
A6 -2.11776E-07
A8 -4.15932E-10
A10 -1.15008E-11

[Various data]
Scale ratio 9.42

WT
f 10.30 ~ 97.00
FNO 4.09 ~ 5.81
ω 40.21 ~ 4.76 °
Y 8.19 ~ 8.19

WMT
f 10.30000 50.00013 97.00039
ω 40.21337 9.15519 4.75685
FNO 4.09 5.78 5.81
φ 7.68 8.50 9.20
TL 100.29944 130.25093 139.59967
d5 2.10000 28.50000 39.66696
d13 17.38897 3.31447 2.00000
d14 4.87082 3.98262 1.60000
d17 2.59389 3.48209 5.86471
d23 5.29632 3.42829 3.30000
BF 13.94944 33.44346 33.06800

[Lens group data]
Group starting surface f
1 1 64.38705
2 6 -9.57903
3 15 29.91408
4 18 58.41425 (W), 61.26584 (M), 61.47193 (T)
4F 18 -81.48313
4R 24 28.77173

[Conditional expression correspondence value]
(1) ndh = 1.954 (L31), 1.950 (L402), 1.954 (L408)
(2) νdh = 33.46 (L31), 29.37 (L402), 33.46 (L408)
(3) f1 / (-f2) = 6.72
(4) (-f2) / f3 = 0.320
(6) νdh4 = 33.46 (L408)
(7) νdp1 = 82.57 (L12)
(8) νdp4 = 82.57 (L401)

2 (a), 2 (b), and 2 (c) are infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the first embodiment of the present application, respectively. It is a diagram of various aberrations at the time of focusing on an object.

In each aberration diagram, FNO indicates an F number, and A indicates a ray incident angle, that is, a half angle of view (unit: “°”). d indicates an aberration at the d line (wavelength 587.6 nm), g indicates an aberration at the g line (wavelength 435.8 nm), and those without d and g indicate an aberration at the d line. In the astigmatism diagram, the solid line shows the sagittal image plane and the broken line shows the meridional image plane. In the aberration diagram of each embodiment described later, the same reference numerals as those of this embodiment are used.

From each aberration diagram, it can be seen that the variable magnification optical system according to this embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(Second Example)
3 (a), 3 (b), and 3 (c) are cross-sectional views of the variable magnification optical system according to the second embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. Is.
In the variable magnification optical system according to the present embodiment, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a positive refractive power. It is composed of a lens group G3 and a fourth lens group G4 having a positive refractive power.

The first lens group G1 is composed of a junction lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side, in order from the object side. Become.
The second lens group G2 includes a biconcave negative lens L21, a biconcave negative lens L22, a biconvex positive lens L23, and a negative meniscus lens L24 with a concave surface facing the object side, in order from the object side. It consists of.
The third lens group G3 is composed of a junction lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 in order from the object side. An aperture diaphragm S is provided on the object side of the third lens group G3.

The fourth lens group G4 is composed of a front group G4F having a negative refractive power and a rear group G4R having a positive refractive power in order from the object side.
The front group G4F includes a junction lens of a biconvex positive lens L401 and a biconcave negative lens L402, a biconcave negative lens L403, and a positive meniscus lens L404 with a convex surface facing the object side, in order from the object side. It consists of a junction lens with. The negative lens L403 is a glass-molded aspherical lens having an aspherical shape on the lens surface on the object side.
The rear group G4R is composed of a biconvex positive lens L405, a positive meniscus lens L406 with a concave surface facing the object side, and a negative meniscus lens L407 with a concave surface facing the object side, in this order from the object side. The positive lens L405 is a glass-molded aspherical lens having an aspherical shape on the lens surface on the object side.
In the variable magnification optical system according to the present embodiment, a low-pass filter, a cover glass for a sensor, or the like may be arranged between the fourth lens group G4 and the image plane I.

Under the above configuration, in the variable magnification optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 increases when the magnification is changed from the wide-angle end state to the telescopic end state. The air gap between the 2 lens group G2 and the 3rd lens group G3 decreases, the air gap between the 3rd lens group G3 and the 4th lens group G4 increases, and the air gap between the aperture aperture S and the 3rd lens group G3. The first to fourth lens groups G1 to G4 move along the optical axis, and the aperture aperture S moves integrally with the front group G4F of the fourth lens group G4 so as to decrease. Specifically, the first lens group G1 and the third lens group G3 move to the object side at the time of scaling. The second lens group G2 moves toward the object from the wide-angle end state to the intermediate focal length state, and moves toward the image side from the intermediate focal length state to the telephoto end state. In the fourth lens group G4, the front group G4F and the rear group G4R move to the object side so that the air gap between the front group G4F and the rear group G4R decreases when the magnification is changed from the wide-angle end state to the telephoto end state. do.
Table 2 below lists the values of the specifications of the variable magnification optical system according to this embodiment.

(Table 2) Second Example
[Surface data]
Surface number r d nd ν d
Paraboloid ∞

1 251.8446 1.6000 1.950000 29.37
2 36.8495 7.9000 1.497820 82.57
3 -162.8867 0.1000
4 41.6898 5.7500 1.883000 40.66
5 7827.2710 Variable

6 -808.8261 1.0000 1.883000 40.66
7 9.5148 3.6000
8 -15.5435 1.0000 1.883000 40.66
9 143.0303 0.1000
10 28.6318 3.0500 1.808090 22.74
11 -13.3111 0.2500
12 -12.1771 1.0000 1.834810 42.73
13 -36.4394 Variable

14 (Aperture S) ∞ Variable

15 27.0772 1.0000 2.000690 25.46
16 15.7705 2.5000 1.744000 44.80
17 -35.2142 Variable

18 12.6941 2.9500 1.497820 82.57
19 -24.8876 1.0000 1.846660 23.80
20 775.1758 2.1500
* 21 -227.6550 1.0000 1.806100 40.97
22 8.8217 2.2000 1.846660 23.80
23 19.5840 Variable

* 24 15.0000 3.1500 1.583130 59.42
25 -23.9888 0.1000
26 -509.6518 4.2000 1.581440 40.98
27 -7.8594 1.0000 1.954000 33.46
28 -200.0000 BF

Image plane ∞

[Aspherical data]
Side 21 κ -20.0000
A4 1.61374E-05
A6 -2.79859E-08
A8 -1.22068E-09
A10 0.00000E + 00

Side 24 κ 3.6281
A4 -1.21377E-04
A6 -7.10924E-07
A8 1.36403E-08
A10 -4.10781E-10

[Various data]
Scale ratio 9.42

WT
f 10.30 ~ 97.00
FNO 4.12 ~ 6.48
ω 43.07 ~ 4.70 °
Y 8.19 ~ 8.19

WMT
f 10.30000 50.00001 96.99995
ω 43.07103 9.11914 4.70123
FNO 4.12 5.81 6.48
φ 6.80 7.90 7.90
TL 90.80323 122.13334 131.09941
d5 2.28937 28.97477 38.62002
d13 13.12572 3.71901 2.00000
d14 6.29895 3.32684 1.40000
d17 2.43367 5.40578 7.33262
d23 6.60623 3.30000 3.30000
BF 13.44928 30.80693 31.84677

[Lens group data]
Group starting surface f
1 1 59.94630
2 6 -8.99248
3 15 24.34092
4 18 71.07089 (W), 75.48860 (M), 75.48860 (T)
4F 18 -112.21259
4R 24 35.78226

[Conditional expression correspondence value]
(1) ndh = 1.950 (L11), 1.954 (L407)
(2) νdh = 29.37 (L11), 33.46 (L407)
(3) f1 / (-f2) = 6.67
(4) (-f2) / f3 = 0.369
(5) | fh / f1 | = 0.761 (L11)
(6) νdh4 = 33.46 (L407)
(7) νdp1 = 82.57 (L12)
(8) νdp4 = 82.57 (L401)

4 (a), 4 (b), and 4 (c) are infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the second embodiment of the present application, respectively. It is a diagram of various aberrations at the time of focusing on an object.

From each aberration diagram, it can be seen that the variable magnification optical system according to this embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(Third Example)
5 (a), 5 (b), and 5 (c) are cross-sectional views of the variable magnification optical system according to the third embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. Is.
In the variable magnification optical system according to the present embodiment, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a positive refractive power. It is composed of a lens group G3 and a fourth lens group G4 having a positive refractive power.

The first lens group G1 is composed of a junction lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side, in order from the object side. Become.
The second lens group G2 has a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a concave surface facing the object side in order from the object side. It consists of a negative meniscus lens L24. The negative meniscus lens L21 is a glass-molded aspherical lens having an aspherical lens surface on the object side.
The third lens group G3 is composed of a junction lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 in order from the object side. An aperture diaphragm S is provided on the object side of the third lens group G3.

The fourth lens group G4 is composed of a front group G4F having a negative refractive power and a rear group G4R having a positive refractive power in order from the object side.
In the front group G4F, in order from the object side, the junction lens of the biconvex positive lens L401 and the negative meniscus lens L402 with the convex surface facing the image side, and the biconcave negative lens L403 and the convex surface facing the object side. It consists of a junction lens with a positive meniscus lens L404. The negative lens L403 is a glass-molded aspherical lens having an aspherical shape on the lens surface on the object side.
The rear group G4R is composed of a biconvex positive lens L405, a biconvex positive lens L406, and a negative meniscus lens L407 with a concave surface facing the object side, in this order from the object side. The positive lens L405 is a glass-molded aspherical lens having an aspherical shape on the lens surface on the object side.
In the variable magnification optical system according to the present embodiment, a low-pass filter, a cover glass for a sensor, or the like may be arranged between the fourth lens group G4 and the image plane I.

Under the above configuration, in the variable magnification optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 increases when the magnification is changed from the wide-angle end state to the telescopic end state. The air gap between the 2 lens group G2 and the 3rd lens group G3 decreases, the air gap between the 3rd lens group G3 and the 4th lens group G4 increases, and the air gap between the aperture aperture S and the 3rd lens group G3. The first to fourth lens groups G1 to G4 move along the optical axis, and the aperture aperture S moves integrally with the front group G4F of the fourth lens group G4 so as to decrease. Specifically, the first lens group G1 and the third lens group G3 move to the object side at the time of scaling. The second lens group G2 moves toward the object from the wide-angle end state to the intermediate focal length state, and moves toward the image side from the intermediate focal length state to the telephoto end state. In the fourth lens group G4, the front group G4F and the rear group G4R move to the object side so that the air gap between the front group G4F and the rear group G4R decreases when the magnification is changed from the wide-angle end state to the telephoto end state. do.
Table 3 below lists the values of the specifications of the variable magnification optical system according to this embodiment.

(Table 3) Third Example
[Surface data]
Surface number r d nd ν d
Paraboloid ∞

1 149.8692 1.6000 1.949665 27.56
2 44.3736 6.8398 1.497820 82.51
3-243.5058 0.1000
4 45.3756 5.3508 1.867900 41.78
5 311.4136 Variable

* 6 89.0243 1.2000 1.834810 42.73
7 8.4900 3.7581
8 -15.7255 1.0000 1.834810 42.73
9 250.0000 0.1000
10 25.2749 3.2925 1.808090 22.74
11 -17.4750 0.5480
12 -12.6196 1.0000 1.816000 46.59
13 -33.4252 Variable

14 (Aperture S) ∞ Variable

15 29.1681 1.0000 1.889044 39.77
16 18.2404 3.2071 1.593125 66.16
17 -26.5261 Variable

18 14.2857 3.5654 1.497820 82.51
19 -21.9776 1.0000 1.902000 25.23
20 -82.8398 2.2052
* 21 -52.3071 1.0000 1.848976 43.01
22 9.1414 2.6915 1.950000 29.37
23 25.8642 Variable

* 24 35.4414 3.3350 1.589130 61.22
25 -21.3191 0.3000
26 42.3100 4.4029 1.581440 40.98
27 -10.1979 1.2000 1.954000 33.46
28 -300.4717 BF

Image plane ∞

[Aspherical data]
Side 6 κ 1.0000
A4 3.45801E-05
A6 -1.38520E-07
A8 -5.59965E-11
A10 1.26030E-11

Side 21 κ 1.0000
A4 1.74477E-06
A6 1.28096E-07
A8 -2.63692E-09
A10 0.00000E + 00

Side 24 κ 1.0000
A4 -1.22983E-05
A6 1.47314E-07
A8 -5.48742E-10
A10 0.00000E + 00

[Various data]
Scale ratio 9.42

WT
f 10.30 ~ 97.00
FNO 3.50 ~ 5.62
ω 39.90 ~ 4.69 °
Y 8.19 ~ 8.19

WMT
f 10.30001 49.99971 96.99932
ω 39.90076 9.01930 4.68610
FNO 3.50 5.20 5.62
φ 8.99 8.81 9.00
TL 99.25773 129.21001 139.67596
d5 1.99991 30.68218 41.26022
d13 18.53440 4.14191 2.00000
d14 3.76478 2.96318 1.40000
d17 3.54181 4.34341 5.90655
d23 8.01786 3.30678 3.30001
BF 14.70262 35.07621 37.11281

[Lens group data]
Group starting surface f
1 1 66.85483
2 6 -9.36043
3 15 27.88295
4 18 53.04244 (W), 55.61603 (M), 55.61991 (T)
4F 18 -160.91663
4R 24 33.55859

[Conditional expression correspondence value]
(1) ndh = 1.950 (L404), 1.954 (L407)
(2) νdh = 29.37 (L404), 33.46 (L407)
(3) f1 / (-f2) = 7.14
(4) (-f2) / f3 = 0.336
(6) νdh4 = 33.46 (L407)
(7) νdp1 = 82.51 (L12)
(8) νdp4 = 82.51 (L401)

6 (a), 6 (b), and 6 (c) are infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the third embodiment of the present application, respectively. It is a diagram of various aberrations at the time of focusing on an object.

From each aberration diagram, it can be seen that the variable magnification optical system according to this embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(Fourth Example)
7 (a), 7 (b), and 7 (c) are cross-sectional views of the variable magnification optical system according to the fourth embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. Is.
In the variable magnification optical system according to the present embodiment, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a positive refractive power. It is composed of a lens group G3 and a fourth lens group G4 having a positive refractive power.

The first lens group G1 is composed of a junction lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side, in order from the object side. Become.
The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a negative meniscus lens L22 having a concave surface facing the object side, a biconvex positive lens L23, and an object side in order from the object side. It consists of a negative meniscus lens L24 with a concave surface facing. The negative meniscus lens L21 is a glass-molded aspherical lens having an aspherical lens surface on the object side.
The third lens group G3 is composed of a junction lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 in order from the object side. An aperture diaphragm S is provided on the object side of the third lens group G3.

The fourth lens group G4 includes, in order from the object side, a junction lens of a biconvex positive lens L401 and a negative meniscus lens L402 with a convex surface facing the image side, and a positive meniscus lens L403 with a concave surface facing the object side. A junction lens with a concave negative lens L404, a biconvex positive lens L405, a positive meniscus lens L406 with a concave surface facing the object side, and a junction lens with a biconcave negative lens L407, and a convex surface toward the object side. It is composed of a junction lens of a negative meniscus lens L408 facing the lens and a biconvex positive lens L409, and a negative meniscus lens L410 with a concave surface facing the object side. The positive meniscus lens L403 is a glass-molded aspherical lens having an aspherical shape on the lens surface on the object side, and the negative meniscus lens L410 is a glass-molded aspherical lens having an aspherical shape on the lens surface on the image side.
In the variable magnification optical system according to the present embodiment, a low-pass filter, a cover glass for a sensor, or the like may be arranged between the fourth lens group G4 and the image plane I.

Under the above configuration, in the variable magnification optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 increases when the magnification is changed from the wide-angle end state to the telescopic end state. The air gap between the 2 lens group G2 and the 3rd lens group G3 decreases, the air gap between the 3rd lens group G3 and the 4th lens group G4 increases, and the air gap between the aperture aperture S and the 3rd lens group G3. The first to fourth lens groups G1 to G4 move along the optical axis, and the aperture aperture S moves integrally with the fourth lens group G4 so that Specifically, the first lens group G1, the third lens group G3, and the fourth lens group G4 move to the object side at the time of scaling. The second lens group G2 moves toward the object from the wide-angle end state to the intermediate focal length state, and moves toward the image side from the intermediate focal length state to the telephoto end state.
Table 4 below lists the values of the specifications of the variable magnification optical system according to this embodiment.

(Table 4) Fourth Example
[Surface data]
Surface number r d nd ν d
Paraboloid ∞

1 134.9416 1.6000 2.001000 29.14
2 37.4620 7.6500 1.497820 82.57
3 -339.5674 0.1000
4 41.6639 5.5500 1.883000 40.66
5 520.6025 Variable

* 6 2429.7649 1.0000 1.851350 40.10
7 8.6673 5.7500
8 -10.8429 1.0000 1.487490 70.31
9 -45.5363 0.8500
10 52.5147 3.1000 1.808090 22.74
11 -17.4657 0.3000
12 -16.1357 1.0000 1.954000 33.46
13 -39.2793 Variable

14 (Aperture S) ∞ Variable

15 29.3843 1.0000 1.902650 35.73
16 14.8567 2.8000 1.719990 50.27
17 -55.5590 Variable

18 13.5564 3.3500 1.497820 82.57
19 -24.9755 1.0000 1.950000 29.37
20 -183.0794 2.1500
* 21 -145.2052 2.2500 1.802440 25.55
22 -14.7800 1.0000 1.766840 46.78
23 23.7425 2.8000
24 25.8106 3.0000 1.516800 63.88
25 -15.0644 0.1000
26 -568.8377 3.0000 1.568830 56.00
27 -9.3137 1.0000 1.954000 33.46
28 98.3635 0.1000
29 15.0059 1.0000 1.950000 29.37
30 7.0809 4.2500 1.647690 33.73
31 -21.2496 1.4500
32 -11.4669 1.0000 1.743300 49.32
* 33 -29.8012 BF

Image plane ∞

[Aspherical data]
Side 6 κ -20.0000
A4 9.19258E-05
A6 -6.71049E-07
A8 3.76181E-09
A10 -1.11659E-11

Side 21 κ -13.2727
A4 1.25451E-05
A6 1.56196E-07
A8 -2.20815E-09
A10 0.00000E + 00

Side 33 κ -0.9208
A4 -8.91367E-05
A6 -1.72158E-06
A8 2.40673E-08
A10 -6.77013E-10

[Various data]
Scale ratio 9.42

WT
f 10.30 ~ 97.00
FNO 4.08 ~ 5.83
ω 40.21 ~ 4.78 °
Y 8.19 ~ 8.19

WMT
f 10.30000 50.00021 97.00042
ω 40.21108 9.16962 4.78008
FNO 4.08 5.79 5.83
φ 8.40 9.20 10.10
TL 102.69006 133.09448 142.59913
d5 2.10000 29.30442 39.87067
d13 19.87565 4.17251 2.00000
d14 4.49060 3.80672 1.60000
d17 3.02442 3.70831 5.91502
BF 14.04941 32.95254 34.06346

[Lens group data]
Group starting surface f
1 1 63.95755
2 6 -10.21809
3 15 32.27954
4 18 70.96006

[Conditional expression correspondence value]
(1) ndh = 2.001 (L11), 1.954 (L24), 1.950 (L402), 1.954 (L407), 1.950 (L408)
(2) νdh = 29.14 (L11), 33.46 (L24), 29.37 (L402), 33.46 (L407), 29.37 (L408)
(3) f1 / (-f2) = 6.26
(4) (-f2) / f3 = 0.317
(5) | fh / f1 | = 0.817 (L11)
(6) νdh4 = 33.46 (L407)
(7) νdp1 = 82.57 (L12)
(8) νdp4 = 82.57 (L401)

8 (a), 8 (b), and 8 (c) are infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the fourth embodiment of the present application, respectively. It is a diagram of various aberrations at the time of focusing on an object.

From each aberration diagram, it can be seen that the variable magnification optical system according to this embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(Fifth Example)
9 (a), 9 (b), and 9 (c) are cross-sectional views of the variable magnification optical system according to the fifth embodiment of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. Is.
In the variable magnification optical system according to the present embodiment, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a positive refractive power. It is composed of a lens group G3 and a fourth lens group G4 having a positive refractive power.

The first lens group G1 is a junction lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12 in order from the object side, and a plano-convex positive lens having a convex surface facing the object side. It consists of L13.
The second lens group G2 includes a negative meniscus lens L21 having a convex surface facing the object side, a negative meniscus lens L22 having a concave surface facing the object side, a biconvex positive lens L23, and a concave surface toward the object side in order from the object side. It consists of a junction lens with a negative meniscus lens L24. The negative meniscus lens L21 is a composite aspherical lens formed by forming a resin layer provided on the glass surface on the object side in an aspherical shape.
The third lens group G3 is composed of a junction lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32 in order from the object side.

The fourth lens group G4 includes, in order from the object side, a junction lens of a biconvex positive lens L401 and a negative meniscus lens L402 with a convex surface facing the image side, and a positive meniscus lens L403 with a concave surface facing the object side. A junction lens with a concave negative lens L404, a biconvex positive lens L405, a junction lens between a biconvex positive lens L406 and a biconcave negative lens L407, and a biconvex positive lens L408. It is composed of a junction lens with a negative meniscus lens L409 having a convex surface facing the image side and a negative meniscus lens L410 having a concave surface facing the object side. The negative lens L404 is a glass-molded aspherical lens having an aspherical shape on the image side lens surface, and the negative meniscus lens L410 is a glass-molded aspherical lens having an aspherical shape on the image side lens surface.
In the variable magnification optical system according to the present embodiment, a low-pass filter, a cover glass for a sensor, or the like may be arranged between the fourth lens group G4 and the image plane I.

Under the above configuration, in the variable magnification optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 increases when the magnification is changed from the wide-angle end state to the telescopic end state. The air gap between the 2 lens group G2 and the 3rd lens group G3 decreases, and the air gap between the 3rd lens group G3 and the 4th lens group G4 decreases from the wide-angle end state to the intermediate focal length state, and from the intermediate focal length state. The first to first lenses increase to the telephoto end state, and the air gap between the aperture aperture S and the third lens group G3 increases from the wide-angle end state to the intermediate focal length state and decreases from the intermediate focal length state to the telephoto end state. The four lens groups G1 to G4 move toward the object along the optical axis, and the aperture aperture S moves integrally with the fourth lens group G4.
Table 5 below lists the values of the specifications of the variable magnification optical system according to this embodiment.

(Table 5) Fifth Example
[Surface data]
Surface number r d nd ν d
Paraboloid ∞

1 145.1831 1.7000 2.001000 29.14
2 36.6390 8.1000 1.497820 82.57
3 -399.3519 0.1000
4 43.2076 6.0000 1.883000 40.66
5 ∞ variable

* 6 436.5967 0.1000 1.553890 38.09
7 87.0031 1.1000 1.834810 42.73
8 8.3001 5.3500
9 -12.6073 1.0000 1.755000 52.34
10 -32.7993 0.8000
11 41.1197 2.9500 1.808090 22.74
12 -19.6043 0.9000 1.883000 40.66
13 -73.1316 Variable

14 (Aperture S) ∞ Variable

15 22.3725 0.9000 1.902650 35.73
16 12.2299 3.4500 1.670030 47.14
17 -59.6992 Variable

18 13.7390 3.6000 1.497820 82.57
19 -24.8201 0.9000 2.000690 25.46
20 -270.0138 2.2000
21 -117.0547 2.0500 1.846660 23.80
22 -15.9850 1.0000 1.773770 47.25
* 23 24.1750 2.0836
24 66.3654 2.8000 1.568830 56.00
25 -15.4473 0.1000
26 44.9939 2.7500 1.517420 52.20
27 -15.2012 0.9000 1.903660 31.27
28 29.9926 0.3000
29 14.6093 5.0500 1.672700 32.19
30 -9.1997 0.9000 2.000690 25.46
31 -24.3892 1.4000
32 -12.8617 1.0000 1.851350 40.10
* 33 -27.4946 BF

Image plane ∞

[Aspherical data]
Side 6 κ 20.0000
A4 9.17458E-05
A6 -6.51986E-07
A8 2.69890E-09
A10 -1.23751E-11

Side 23 κ 0.4823
A4 -7.24815E-06
A6 -3.60139E-07
A8 4.05630E-09
A10 0.00000E + 00

Side 33 κ -20.0000
A4 -1.22780E-04
A6 8.28360E-07
A8 -6.05245E-09
A10 -9.88805E-11

[Various data]
Scale ratio 9.42

WT
f 10.30 ~ 96.99
FNO 4.12 ~ 5.81
ω 40.44 ~ 4.73 °
Y 8.19 ~ 8.19

WMT
f 10.30260 30.00000 96.99284
ω 40.44283 14.85841 4.72723
FNO 4.12 5.48 5.81
φ 8.12 8.12 9.70
TL 103.02710 121.37977 143.32397
d5 2.10606 20.13084 40.20889
d13 19.66416 6.24359 1.80000
d14 4.27874 4.97381 1.80000
d17 3.43763 2.74256 5.91637
BF 14.05688 27.80535 34.11509

[Lens group data]
Group starting surface f
1 1 64.09778
2 6 -10.16794
3 15 31.06055
4 18 67.05869

[Conditional expression correspondence value]
(1) ndh = 2.001 (L11)
(2) νdh = 29.14 (L11)
(3) f1 / (-f2) = 6.31
(4) (-f2) / f3 = 0.327
(5) | fh / f1 | = 0.770 (L11)
(7) νdp1 = 82.57 (L12)
(8) νdp4 = 82.57 (L401)

10 (a), 10 (b), and 10 (c) are infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the fifth embodiment of the present application, respectively. It is a diagram of various aberrations at the time of focusing on an object.

From each aberration diagram, it can be seen that the variable magnification optical system according to this embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

According to each of the above embodiments, it is possible to realize a variable magnification optical system that is compact and has high optical performance. It should be noted that each of the above examples shows a specific example of the invention of the present application, and the invention of the present application is not limited thereto. The following contents can be appropriately adopted as long as the optical performance of the variable magnification optical system of the present application is not impaired.

As a numerical example of the variable magnification optical system of the present application, a four-group configuration is shown, but the present application is not limited to this, and other group configurations (for example, 5 groups, 6 groups, etc.) are configured. You can also do it. Specifically, a lens or a lens group may be added to the most object side or the most image side of the variable magnification optical system of the present application. The lens group refers to a portion having at least one lens separated by an air interval that changes at the time of scaling.

Further, in the variable magnification optical system of the present application, in order to focus from an infinity object to a short-range object, a part of a lens group, one lens group as a whole, or a plurality of lens groups are used as an in-focus lens group. It may be configured to move in the axial direction. In particular, it is preferable that at least a part of the second lens group, at least a part of the third lens group, or at least a part of the fourth lens group be the focusing lens group. Further, such a focusing lens group can be applied to autofocus, and is also suitable for driving by a motor for autofocus, for example, an ultrasonic motor.

Further, in the variable magnification optical system of the present application, the entire lens group or a part thereof is moved as an anti-vibration lens group so as to include a component in the direction perpendicular to the optical axis, or a surface including the optical axis. By rotating (swinging) inward, it is possible to correct the image blur caused by camera shake or the like. In particular, in the variable magnification optical system of the present application, it is preferable that at least a part of the third lens group or at least a part of the fourth lens group is an anti-vibration lens group.

Further, the lens surface of the lens constituting the variable magnification optical system of the present application may be a spherical surface or a flat surface, or may be an aspherical surface. When the lens surface is spherical or flat, lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in lens processing and assembly adjustment can be prevented, which is preferable. Further, even if the image plane is displaced, the deterioration of the depiction performance is small, which is preferable. When the lens surface is an aspherical surface, it can be either an aspherical surface formed by grinding, a glass mold aspherical surface formed by molding glass into an aspherical shape, or a composite aspherical surface formed by forming a resin provided on the glass surface into an aspherical shape. good. Further, the lens surface may be a diffraction surface, and the lens may be a refractive index distribution type lens (GRIN lens) or a plastic lens.

Further, in the variable magnification optical system of the present application, the aperture diaphragm is preferably arranged in the third lens group or in the vicinity of the third lens group, and the lens frame substitutes the role of the aperture diaphragm without providing a member. May be good.
Further, an antireflection film having a high transmittance in a wide wavelength range may be applied to the lens surface of the lens constituting the variable magnification optical system of the present application. As a result, flare and ghost can be reduced, and high-contrast and high optical performance can be achieved.

Next, a camera provided with the variable magnification optical system of the present application will be described with reference to FIG.
FIG. 11 is a diagram showing a configuration of a camera provided with the variable magnification optical system of the present application.
As shown in FIG. 11, the camera 1 is a so-called mirrorless camera with an interchangeable lens provided with the variable magnification optical system according to the first embodiment as the photographing lens 2.
In the present camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and passed through an OLPF (Optical low pass filter) (not shown) on the image pickup surface of the image pickup unit 3. Form a subject image. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the image pickup unit 3, and the image of the subject is generated. This image is displayed on an EVF (Electronic viewfinder) 4 provided in the camera 1. This allows the photographer to observe the subject via the EVF4.
Further, when the photographer presses the release button (not shown), the image of the subject generated by the image pickup unit 3 is stored in the memory (not shown). In this way, the photographer can shoot the subject with the camera 1.

Here, the variable magnification optical system according to the first embodiment mounted on the camera 1 as a photographing lens 2 is a small size variable magnification optical system having high optical performance. Therefore, the present camera 1 can realize high optical performance while reducing the size. Even if a camera equipped with the variable magnification optical system according to the second to fifth embodiments is configured as the photographing lens 2, the same effect as that of the camera 1 can be obtained. Further, even when the single-lens reflex type camera having a quick return mirror and observing the subject by the finder optical system is equipped with the variable magnification optical system according to each of the above embodiments, the same effect as that of the camera 1 can be obtained. can.

Finally, the outline of the manufacturing method of the variable magnification optical system of the present application will be described with reference to FIG.
The method for manufacturing the variable magnification optical system of the present application shown in FIG. 12 has a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive power in order from the object side. It is a method for manufacturing a variable magnification optical system having a third lens group and a fourth lens group having a positive refractive power, and includes the following steps S1 and S2.

Step S1: The variable magnification optical system has at least one lens satisfying the following conditional equations (1) and (2), and each lens group is arranged in the lens barrel in order from the object side.
(1) 1.928 <ndh
(2) 28.60 <νdh
However,
ndh: Refractive index with respect to the d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to the d-line (wavelength 587.6 nm) of the lens

Step S2: By providing a known moving mechanism in the lens barrel, the distance between the first lens group and the second lens group, the distance between the second lens group and the second lens group at the time of scaling from the wide-angle end state to the telephoto end state, etc. The distance between the three lens groups and the distance between the third lens group and the fourth lens group are changed.

According to the method for manufacturing a variable magnification optical system of the present application, it is possible to manufacture a small size variable magnification optical system having high optical performance.

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G4F Front group G4R Rear group S Aperture aperture I Image plane

Claims (14)

From the object side, the first lens group having a positive refractive force, the second lens group having a negative refractive force, the third lens group having a positive refractive force, and the fourth lens having a positive refractive force. The group consists of substantially four lens groups, or has a first lens group having a positive refractive force, a second lens group having a negative refractive force, and a third lens group having a positive refractive force. The fourth lens group having a negative refractive force and the fifth lens group having a positive refractive force are substantially composed of five lens groups.
When scaling from the wide-angle end state to the telephoto end state, the distance between adjacent lens groups changes,
Having at least one lens that satisfies the following conditional expression,
1.928 <ndh
29.37 ≤ νdh
However,
ndh: Refractive index with respect to the d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to the d-line (wavelength 587.6 nm) of the lens The fourth lens group has at least one of the lenses having a negative refractive power. A variable magnification optical system characterized by having. The variable magnification optical system according to claim 1, wherein the fourth lens group has at least one lens. The variable magnification optical system according to claim 1 or 2, wherein the variable magnification optical system satisfies the following conditional expression.
5.50 <f1 / (-f2) <15.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group The variable magnification optical system according to any one of claims 1 to 3 , wherein the variable magnification optical system satisfies the following conditional expression.
0.220 <(-f2) / f3 <0.530
However,
f2: Focal length of the second lens group f3: Focal length of the third lens group The variable magnification optical system according to any one of claims 1 to 4 , wherein the second lens group has at least one lens. The variable magnification optical system according to any one of claims 1 to 5 , wherein the third lens group has at least one lens. The variable magnification optical system according to any one of claims 1 to 6 , wherein the second lens group has at least one lens having a negative refractive power. The variable magnification optical system according to any one of claims 1 to 7 , wherein the third lens group has at least one lens having a negative refractive power. The variable magnification optical system according to any one of claims 1 to 8 , wherein the first lens group has a positive lens satisfying the following conditional expression.
75.00 <νdp1
However,
νdp1: Abbe number with respect to the d-line (wavelength 587.6 nm) of the positive lens in the first lens group. The variable magnification optical system according to any one of claims 1 to 9 , wherein the fourth lens group has a positive lens satisfying the following conditional expression.
75.00 <νdp4
However,
νdp4: Abbe number with respect to the d-line (wavelength 587.6 nm) of the positive lens in the fourth lens group. The aspect according to any one of claims 1 to 10 , wherein the distance between the first lens group and the second lens group increases when the magnification is changed from the wide-angle end state to the telephoto end state. Variable magnification optical system. The aspect according to any one of claims 1 to 11 , wherein the distance between the second lens group and the third lens group is reduced when the magnification is changed from the wide-angle end state to the telephoto end state. Variable magnification optical system. The invention according to any one of claims 1 to 12 , wherein the distance between the third lens group and the fourth lens group increases when the magnification is changed from the wide-angle end state to the telephoto end state. Variable magnification optical system. An optical device comprising the variable magnification optical system according to any one of claims 1 to 13.

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