JP2014085488A - Variable magnification optical system, optical device, and manufacturing method for variable magnification optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact variable magnification optical system an optical device which exhibit superior optical performances, and to provide a manufacturing method for the variable magnification optical system.SOLUTION: A variable magnification optical system comprises a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power in this order from the object side, is configured such that a distance between the first lens group G1 and the second lens group G2, a distance between the second lens group G2 and the third lens group G3, and a distance between the third lens group G3 and the fourth lens group G4 are changed when magnification from a wide-angle end state to a telephoto end state, and the optical system includes at least one lens which fulfills prescribed formulae.

Description

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

  Conventionally, as a variable power optical system suitable for an interchangeable lens for a camera, a digital camera, a video camera, and the like, many lenses having a positive refractive power in the most object side lens group have been proposed (for example, Patent Document 1). reference.).

JP 2010-237455 A

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

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

In order to solve the above problems, the present invention
In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power And having a group
At the time of zooming from the wide-angle 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 The distance from the fourth lens group changes,
There is provided a variable magnification optical system having at least one lens satisfying the following conditional expression.
1.928 <ndh
28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to d-line (wavelength 587.6 nm) of the lens

The present invention also provides
Provided is an optical device comprising the variable magnification optical system.

The present invention also provides
In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power A variable magnification optical system having a group,
Having at least one lens satisfying the following conditional expression:
At the time of zooming from the wide-angle 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 A method of manufacturing a variable magnification optical system, characterized in that an interval with the fourth lens group is changed.
1.928 <ndh
28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to d-line (wavelength 587.6 nm) of the lens

  According to the present invention, it is possible to provide a variable magnification optical system, an optical apparatus, and a variable magnification optical system that are small and have high optical performance.

(A), (b), and (c) are sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to the first example of the present application. (A), (b), and (c) are various figures at the time of focusing on an object at 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 example of the present application, respectively. It is an aberration diagram. (A), (b), and (c) are sectional views of the variable magnification optical system according to the second example 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 values at the time of focusing on an object at 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 example of the present application, respectively. It is an aberration diagram. (A), (b), and (c) are sectional views of the variable magnification optical system according to the third example 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 values at the time of focusing on an object at 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 example of the present application, respectively. It is an aberration diagram. (A), (b), and (c) are sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to the fourth example of the present application. (A), (b), and (c) are various values at the time of focusing on an object at 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 example of the present application, respectively. It is an aberration diagram. (A), (b), and (c) are sectional views of the variable magnification optical system according to the fifth example 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 values at the time of focusing on an object at 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 example of the present application, respectively. It is an aberration diagram. It is a figure which shows the structure of the camera provided with 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, a variable magnification optical system, an optical apparatus, and a method for manufacturing the variable magnification optical system of the present application will be described.
The variable magnification optical system of the present application includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, And a fourth lens group having a refractive power of 5 at the time of zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group, and the second lens group and the second lens group. The distance between the third lens group and the distance between the third lens group and the fourth lens group vary. With this configuration, the variable magnification optical system of the present application can realize variable magnification from the wide-angle end state to the telephoto end state, and can suppress fluctuations in distortion due to the variable magnification.

The variable magnification optical system of the present application is characterized by having at least one lens that satisfies the following conditional expressions (1) and (2).
(1) 1.929 <ndh
(2) 28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to d-line (wavelength 587.6 nm) of the lens

Conditional expression (1) defines an optimum refractive index of the lens. By satisfying conditional expression (1), the variable magnification optical system of the present application can suppress the variation in spherical aberration and the variation in astigmatism during zooming while achieving miniaturization.
If the corresponding value of conditional expression (1) of the zoom optical system of the present application is below the lower limit value, it becomes difficult to suppress fluctuations in spherical aberration and astigmatism during zooming, and high optical performance is realized. Will not be able to. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (1) to 1.940.
In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (1) to 2.800. By making the corresponding value of conditional expression (1) of the variable magnification optical system of the present application smaller than 2.800, it is possible to sufficiently ensure the transmittance of visible light to the lens material.

Conditional expression (2) defines the optimal Abbe number of the lens. By satisfying conditional expression (2), the variable magnification optical system of the present application can reduce axial chromatic aberration variation and magnification chromatic aberration variation at the time of zooming while achieving miniaturization.
If the corresponding value of conditional expression (2) of the variable magnification optical system of the present application is below the lower limit value, it will be difficult to suppress fluctuations in axial chromatic aberration and magnification chromatic aberration during zooming, and high optical performance will be realized. Will not be able to. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (2) to 29.00. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (2) to 30.00. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (2) to 32.00.
In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (2) to 50.00. By reducing the corresponding value of conditional expression (2) of the variable magnification optical system of the present application to less than 50.00, it is possible to suppress fluctuations in axial chromatic aberration and magnification chromatic aberration that occur in lenses other than the lens during zooming. And high optical performance can be realized.
With the above configuration, a variable magnification optical system having a small size and high optical performance can be realized.

  In the variable magnification optical system of the present application, it is preferable that the first lens group has at least one lens. With this configuration, it is possible to suppress variations in spherical aberration, astigmatism, axial chromatic aberration, and lateral chromatic aberration that occur in the first lens group during zooming.

Moreover, 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

Conditional expression (3) defines an appropriate range of the focal length ratio between the first lens group and the second lens group. By satisfying conditional expression (3), the zoom optical system of the present application can suppress astigmatism fluctuations during zooming while maintaining a high zoom ratio.
If the corresponding value of 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 order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (3) to 5.60. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (3) to 5.90.
On the other hand, if the corresponding value of conditional expression (3) of the variable magnification optical system of the present application exceeds the upper limit value, it becomes difficult to suppress fluctuations in astigmatism that occurs in the second lens group at the time of zooming. In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (3) to 11.50. In order to further secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (3) to 10.20.

Moreover, 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

Conditional expression (4) defines an appropriate range of the focal length ratio between the second lens group and the third lens group. By satisfying conditional expression (4), the variable magnification optical system of the present application can suppress fluctuations in spherical aberration and astigmatism during magnification while maintaining a high zoom ratio.
If the corresponding value of 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 fluctuations in astigmatism that occurs in the second lens group during zooming. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (4) to 0.270.
On the other hand, if the corresponding value of conditional expression (4) of the variable magnification optical system of the present application exceeds the upper limit value, it becomes difficult to suppress the variation in spherical aberration that occurs in the third lens group at the time of zooming. In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (4) to 0.490. Furthermore, in order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (4) to 0.450.

In the zoom optical system according to the present application, it is preferable that the first lens group includes at least one lens that satisfies the following conditional expression (5).
(5) 0.450 <| fh / f1 | <1.400
However,
fh: focal length of the lens in the first lens group f1: focal length of the first lens group

  Conditional expression (5) defines an optimum focal length range of the lens in the first lens group. When the lens is cemented with another lens, fh represents the focal length of the single lens. By satisfying conditional expression (5), the variable magnification optical system of the present application can suppress variations in spherical aberration, astigmatism, axial chromatic aberration, and lateral chromatic aberration during magnification.

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, if the corresponding value of the conditional expression (5) of the variable power optical system of the present application is below the lower limit value, the variation of axial chromatic aberration and the chromatic aberration of magnification that occur in the lens at the time of zooming It becomes difficult to suppress the fluctuation, and high optical performance cannot be realized. On the other hand, if the corresponding value of conditional expression (5) of the variable magnification optical system of the present application exceeds the upper limit value, it becomes difficult to suppress positive spherical aberration occurring in the second lens group in the telephoto end state, and high optical performance. Can not be realized.

When the lens has a negative refractive power, if 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 zooming can be suppressed. This makes it difficult to achieve high optical performance. On the other hand, if the corresponding value of conditional expression (5) of the variable magnification optical system of the present application exceeds the upper limit value, it is difficult to suppress variations in axial chromatic aberration and magnification chromatic aberration that occur in lenses other than the lens during zooming. As a result, high optical performance cannot be realized.
In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (5) to 0.620. In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (5) to 1.290.

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

  In the variable magnification optical system of the present application, it is preferable that the second lens group has at least one lens. With this configuration, it is possible to suppress each variation in spherical aberration, astigmatism, axial chromatic aberration, and lateral chromatic aberration that occurs in the second lens group during zooming from the wide-angle end state to the telephoto end state.

  In the zoom optical system of the present application, it is desirable that the third lens group has at least one lens. With this configuration, it is possible to suppress each variation in spherical aberration, astigmatism, axial chromatic aberration, and lateral chromatic aberration that occurs in the third lens group during zooming from the wide-angle end state to the telephoto end state.

  In the zoom optical system of the present application, it is preferable that the first lens group has at least one lens having negative refractive power. With this configuration, it is possible to suppress astigmatism fluctuations, spherical aberration fluctuations, lateral chromatic aberration fluctuations, particularly secondary chromatic aberration fluctuations that occur in the first lens group during zooming, and to realize high optical performance. it can.

  In the variable power optical system of the present application, it is preferable that the fourth lens group has at least one lens having negative refractive power. With this configuration, fluctuations in astigmatism, spherical aberration, and axial chromatic aberration that occur in the fourth lens group during zooming can be suppressed, and high optical performance can be realized.

In the zoom optical system according to the present application, it is preferable that the fourth lens group includes at least one lens that satisfies the following conditional expression (6).
(6) 31.60 <νdh4
However,
νdh4: Abbe number of the lens in the fourth lens group with respect to d-line (wavelength: 587.6 nm)

Conditional expression (6) defines an 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 lateral chromatic aberration by satisfying conditional expression (6).
When the corresponding value of conditional expression (6) of the variable magnification optical system of the present application is lower than the lower limit value, in the fourth lens group, it becomes difficult to suppress axial chromatic aberration and lateral chromatic aberration that occur in lenses other than the lens, It becomes impossible to realize high optical performance.

  In the zoom optical system of the present application, it is preferable that the second lens group has at least one lens having negative refractive power. With this configuration, axial chromatic aberration and lateral chromatic aberration, particularly secondary chromatic aberration, generated in the second lens group can be suppressed, and high optical performance can be realized.

  In the zoom optical system of the present application, it is preferable that the third lens group has at least one lens having negative refractive power. With this configuration, axial chromatic aberration, particularly secondary chromatic aberration, generated in the third lens group can be suppressed, and high optical performance can be realized.

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

Conditional expression (7) defines the optimum Abbe number of the positive lens in the first lens group. By satisfying conditional expression (7), the variable magnification optical system of the present application can suppress variations in longitudinal chromatic aberration and magnification chromatic aberration during magnification.
If the corresponding value of conditional expression (7) of the variable magnification optical system of the present application is less than the lower limit value, it will be difficult to suppress fluctuations in axial chromatic aberration and magnification chromatic aberration during zooming, and high optical performance will be realized. Will not be able to.
In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (7) to 99.00. By reducing the corresponding value of conditional expression (7) of the variable magnification optical system of the present application from 99.00, fluctuations in axial chromatic aberration and magnification chromatic aberration that occur in lenses other than the positive lens at the time of zooming are suppressed. And high optical performance can be realized.

In the zoom optical system according to the present application, it is preferable that the fourth lens group includes a positive lens that satisfies the following conditional expression (8).
(8) 75.00 <νdp4
However,
νdp4: Abbe number for the d-line (wavelength 587.6 nm) of the positive lens in the fourth lens group

Conditional expression (8) defines the optimal Abbe number of the positive lens in the fourth lens group. By satisfying conditional expression (8), the variable magnification optical system of the present application can suppress variations in longitudinal chromatic aberration and magnification chromatic aberration during magnification.
If the corresponding value of conditional expression (8) of the variable magnification optical system of the present application is below the lower limit value, it will be difficult to suppress the variation of axial chromatic aberration at the time of zooming, and high optical performance will not be realized. .
In order to secure the effect of the present application, it is more preferable to set the upper limit value of conditional expression (8) to 99.00. When the corresponding value of conditional expression (8) of the variable magnification optical system of the present application is smaller than 99.00, axial chromatic aberration generated in lenses other than the positive lens can be suppressed, and high optical performance can be realized. Can do.

  In the zoom optical system of the present application, it is desirable that the distance between the first lens group and the second lens group is increased when zooming 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, spherical aberration and astigmatism occurring in each lens group can be suppressed, and fluctuations in spherical aberration and astigmatism can be suppressed during zooming.

  In the variable power 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 zooming 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, spherical aberration and astigmatism occurring in each lens group can be suppressed, and fluctuations in spherical aberration and astigmatism can be suppressed during zooming.

  In the zoom optical system of the present application, it is desirable that the distance between the third lens group and the fourth lens group is increased when zooming from the wide-angle end state to the telephoto end state. With this configuration, it is possible to suppress changes in spherical aberration and astigmatism that occur in the third lens group and the fourth lens group during zooming.

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

The variable magnification optical system manufacturing method of the present application includes, in order from the object side, 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. And a fourth lens unit having a positive refractive power, the zoom lens system having at least one lens satisfying the following conditional expressions (1) and (2): During zooming 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 It is characterized in that the distance from the fourth lens group is changed. Thereby, a variable magnification optical system having a small size and high optical performance can be manufactured.
(1) 1.929 <ndh
(2) 28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to d-line (wavelength 587.6 nm) of the lens

Hereinafter, a variable magnification optical system according to numerical examples of the present application will be described with reference to the accompanying drawings.
(First embodiment)
1A, 1B, and 1C are cross-sectional views of the zoom optical system according to the first example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is.
The variable magnification optical system according to the present example includes, 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 having a positive refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power.

The first lens group G1 includes, in order from the object side, a cemented 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. Become.
The second lens group G2 has a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a concave surface directed toward the object side, in order from the object side. And a negative meniscus lens L24. The negative meniscus lens L21 is a glass mold aspheric lens having an aspheric lens surface on the object side.
The third lens group G3 is composed of a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32 in order from the object side. An aperture stop 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 front group G4F having a negative refractive power and a rear group G4R having a positive refractive power.
The front group G4F includes, in order from the object side, a cemented lens of a biconvex positive lens L401 and a biconcave negative lens L402, a biconcave negative lens L403, and a positive meniscus lens L404 having a convex surface facing the object side. And a cemented lens. The negative lens L403 is a glass mold aspherical lens having an aspheric lens surface on the object side.
The rear group G4R includes, in order from the object side, a cemented lens 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, and a convex surface facing the object side. The negative meniscus lens L408 and the biconvex positive lens L409, and a negative meniscus lens L410 having a convex surface facing the image side. The negative meniscus lens L410 is a glass mold aspheric lens having an aspheric lens surface on the image side.
In the zoom optical system according to the present embodiment, a low-pass filter, a sensor cover glass, or the like may be disposed between the fourth lens group G4 and the image plane I.

  With the above-described 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 telephoto end state. The air gap between the second lens group G2 and the third lens group G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 increases, and the air gap between the aperture stop S and the third lens group G3. The first to fourth lens groups G1 to G4 move along the optical axis so that the aperture stop S moves integrally with the front group G4F of the fourth lens group G4. Specifically, the first lens group G1 and the third lens group G3 move to the object side during zooming. The second lens group G2 moves toward the object side 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 during zooming from the wide-angle end state to the telephoto end state. From the intermediate focal length state to the telephoto end state to the image side.

Table 1 below lists values of specifications of the variable magnification optical system according to the present example.
In Table 1, f indicates the focal length, and BF indicates the back focus (the distance on the optical axis between the lens surface closest to the image side and the image plane I).
In [Surface data], the surface number is the order of the optical surfaces counted from the object side, r is the radius of curvature, d is the surface interval (the interval between the nth surface (n is an integer) and the n + 1th surface), and nd is The refractive index for d-line (wavelength 587.6 nm) and νd indicate the Abbe number for d-line (wavelength 587.6 nm), respectively. In addition, the object plane indicates the object plane, the variable indicates the variable plane spacing, the stop S indicates the aperture stop S, and the image plane indicates the image plane I. The radius of curvature r = ∞ indicates a plane. For the aspherical surface, * is added to the surface number, and the value of the paraxial radius of curvature is indicated in the column of the radius of curvature r. The description of the refractive index of air nd = 1.00000 is omitted.

[Aspherical data] shows an aspherical coefficient and a conic 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) from the tangent plane of the apex of the aspheric surface to the aspheric surface at the height h, and κ is the conic constant. , A4, A6, A8, A10 are aspherical coefficients, and r is the radius of curvature of the reference sphere (paraxial radius of curvature). “E−n” (n is an integer) indicates “× 10 ⁻ⁿ ”, for example “1.234E-05” indicates “1.234 × 10 ⁻⁵ ”. The secondary aspherical coefficient A2 is 0 and is not shown.

In [Various data], FNO is the F number, ω is the half angle of view (unit is “°”), Y is the image height, TL is the total length of the variable magnification optical system (image from the first surface when focusing on an object at infinity) (Distance on the optical axis to the surface I), dn represents the variable distance between the nth surface and the (n + 1) th surface, and φ represents the diameter of the aperture stop S. W represents the wide-angle end state, M represents the intermediate focal length state, and T represents the telephoto end state.
[Lens Group Data] indicates 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 the present example.

Here, the focal length f, the radius of curvature r, and other length units listed in Table 1 are generally “mm”. However, the optical system is not limited to this because an equivalent optical performance can be obtained even when proportionally enlarged or proportionally reduced.
In addition, the code | symbol of Table 1 described above shall be similarly used also in the table | surface of each Example mentioned later.

(Table 1) First Example
[Surface data]
Surface number r d nd νd
Object ∞

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]
6th surface κ -8.7294
A4 4.64796E-05
A6 -4.09659E-07
A8 2.44519E-09
A10 -9.90503E-12

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

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

[Various data]
Scaling ratio 9.42

W T
f 10.30 to 97.00
FNO 4.09 to 5.81
ω 40.21 〜 4.76 °
Y 8.19-8.19

W M T
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 start 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 values]
(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) respectively show infinity in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable magnification optical system according to the first example of the present application. It is an aberration diagram at the time of focusing on an object.

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

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the present example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Second embodiment)
FIGS. 3A, 3B, and 3C are cross-sectional views of the zoom optical system according to the second example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is.
The variable magnification optical system according to the present example includes, 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 having a positive refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power.

The first lens group G1 includes, in order from the object side, a cemented 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. Become.
The second lens group G2 includes, in order from the object side, 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. It consists of.
The third lens group G3 is composed of a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32 in order from the object side. An aperture stop 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 front group G4F having a negative refractive power and a rear group G4R having a positive refractive power.
The front group G4F includes, in order from the object side, a cemented lens of a biconvex positive lens L401 and a biconcave negative lens L402, a biconcave negative lens L403, and a positive meniscus lens L404 having a convex surface facing the object side. And a cemented lens. The negative lens L403 is a glass mold aspherical lens having an aspheric lens surface on the object side.
The rear group G4R includes, in order from the object side, a biconvex positive lens L405, a cemented lens of a positive meniscus lens L406 having a concave surface facing the object side, and a negative meniscus lens L407 having a concave surface facing the object side. The positive lens L405 is a glass mold aspheric lens having an aspheric lens surface on the object side.
In the zoom optical system according to the present embodiment, a low-pass filter, a sensor cover glass, or the like may be disposed between the fourth lens group G4 and the image plane I.

With the above-described 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 telephoto end state. The air gap between the second lens group G2 and the third lens group G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 increases, and the air gap between the aperture stop S and the third lens group G3. The first to fourth lens groups G1 to G4 move along the optical axis so that the aperture stop S moves integrally with the front group G4F of the fourth lens group G4. Specifically, the first lens group G1 and the third lens group G3 move to the object side during zooming. The second lens group G2 moves toward the object side 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 toward the object side so that the air gap between the front group G4F and the rear group G4R decreases during zooming from the wide-angle end state to the telephoto end state. To do.
Table 2 below provides values of specifications of the variable magnification optical system according to the present example.

(Table 2) Second Example
[Surface data]
Surface number r d nd νd
Object ∞

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]
21st surface κ -20.0000
A4 1.61374E-05
A6 -2.79859E-08
A8 -1.22068E-09
A10 0.00000E + 00

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

[Various data]
Scaling ratio 9.42

W T
f 10.30 to 97.00
FNO 4.12 to 6.48
ω 43.07 〜 4.70 °
Y 8.19-8.19

W M T
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 start 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 values]
(1) ndh = 1.950 (L11), 1.904 (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) respectively show 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 example of the present application. It is an aberration diagram at the time of focusing on an object.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the present example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Third embodiment)
5A, 5B, and 5C are cross-sectional views of the zoom optical system according to the third example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is.
The variable magnification optical system according to the present example includes, 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 having a positive refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power.

The first lens group G1 includes, in order from the object side, a cemented 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. Become.
The second lens group G2 has a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a concave surface directed toward the object side, in order from the object side. And a negative meniscus lens L24. The negative meniscus lens L21 is a glass mold aspheric lens having an aspheric lens surface on the object side.
The third lens group G3 is composed of a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32 in order from the object side. An aperture stop 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 front group G4F having a negative refractive power and a rear group G4R having a positive refractive power.
The front group G4F has, in order from the object side, a cemented lens of a biconvex positive lens L401 and a negative meniscus lens L402 having a convex surface facing the image side, and a convex surface facing the biconcave negative lens L403 and the object side. It consists of a cemented lens with a positive meniscus lens L404. The negative lens L403 is a glass mold aspherical lens having an aspheric lens surface on the object side.
The rear group G4R includes, in order from the object side, a biconvex positive lens L405, a cemented lens of a biconvex positive lens L406, and a negative meniscus lens L407 having a concave surface facing the object side. The positive lens L405 is a glass mold aspheric lens having an aspheric lens surface on the object side.
In the zoom optical system according to the present embodiment, a low-pass filter, a sensor cover glass, or the like may be disposed between the fourth lens group G4 and the image plane I.

With the above-described 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 telephoto end state. The air gap between the second lens group G2 and the third lens group G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 increases, and the air gap between the aperture stop S and the third lens group G3. The first to fourth lens groups G1 to G4 move along the optical axis so that the aperture stop S moves integrally with the front group G4F of the fourth lens group G4. Specifically, the first lens group G1 and the third lens group G3 move to the object side during zooming. The second lens group G2 moves toward the object side 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 toward the object side so that the air gap between the front group G4F and the rear group G4R decreases during zooming from the wide-angle end state to the telephoto end state. To do.
Table 3 below lists values of specifications of the variable magnification optical system according to the present example.

(Table 3) Third Example
[Surface data]
Surface number r d nd νd
Object ∞

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]
6th surface κ 1.0000
A4 3.45801E-05
A6 -1.38520E-07
A8 -5.59965E-11
A10 1.26030E-11

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

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

[Various data]
Scaling ratio 9.42

W T
f 10.30 to 97.00
FNO 3.50 to 5.62
ω 39.90 〜 4.69 °
Y 8.19-8.19

W M T
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 start 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 values]
(1) ndh = 1.950 (L404), 1.904 (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)

  FIGS. 6A, 6B, and 6C are infinite at 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 example of the present application, respectively. It is an aberration diagram at the time of focusing on an object.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the present example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Fourth embodiment)
FIGS. 7A, 7B, and 7C are cross-sectional views of the zoom optical system according to the fourth example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is.
The variable magnification optical system according to the present example includes, 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 having a positive refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power.

The first lens group G1 includes, in order from the object side, a cemented 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. Become.
The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface directed toward the object side, a negative meniscus lens L22 having a concave surface directed toward the object side, a biconvex positive lens L23, and an object side. And a negative meniscus lens L24 having a concave surface. The negative meniscus lens L21 is a glass mold aspheric lens having an aspheric lens surface on the object side.
The third lens group G3 is composed of a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32 in order from the object side. An aperture stop 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 cemented lens of a biconvex positive lens L401 and a negative meniscus lens L402 with a convex surface facing the image side, a positive meniscus lens L403 with a concave surface facing the object side, and both A cemented lens of a concave negative lens L404, a biconvex positive lens L405, a cemented lens of a positive meniscus lens L406 having a concave surface facing the object side, and a biconcave negative lens L407, and a convex surface facing the object side Is composed of a negative meniscus lens L408 having a convex surface and a biconvex positive lens L409, and a negative meniscus lens L410 having a concave surface facing the object side. The positive meniscus lens L403 is a glass mold aspheric lens having an aspheric lens surface on the object side, and the negative meniscus lens L410 is a glass mold aspheric lens having an aspheric lens surface on the image side.
In the zoom optical system according to the present embodiment, a low-pass filter, a sensor cover glass, or the like may be disposed between the fourth lens group G4 and the image plane I.

With the above-described 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 telephoto end state. The air gap between the second lens group G2 and the third lens group G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 increases, and the air gap between the aperture stop S and the third lens group G3. The first to fourth lens groups G1 to G4 move along the optical axis so that the aperture stop S moves integrally with the fourth lens group G4. Specifically, the first lens group G1, the third lens group G3, and the fourth lens group G4 move to the object side during zooming. The second lens group G2 moves toward the object side 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 values of specifications of the variable magnification optical system according to the present example.

(Table 4) Fourth Example
[Surface data]
Surface number r d nd νd
Object ∞

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]
6th surface κ -20.0000
A4 9.19258E-05
A6 -6.71049E-07
A8 3.76181E-09
A10 -1.11659E-11

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

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

[Various data]
Scaling ratio 9.42

W T
f 10.30 to 97.00
FNO 4.08 to 5.83
ω 40.21 〜 4.78 °
Y 8.19-8.19

W M T
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 start surface f
1 1 63.95755
2 6 -10.21809
3 15 32.27954
4 18 70.96006

[Conditional expression values]
(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) respectively show 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 example of the present application. It is an aberration diagram at the time of focusing on an object.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the present example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(5th Example)
FIGS. 9A, 9B, and 9C are cross-sectional views of the zoom optical system according to the fifth example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is.
The variable magnification optical system according to the present example includes, 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 having a positive refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power.

The first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a plano-convex positive lens having a convex surface facing the object side. L13.
In order from the object side, the second lens group G2 includes a negative meniscus lens L21 having a convex surface directed toward the object side, a negative meniscus lens L22 having a concave surface directed toward the object side, a biconvex positive lens L23, and a concave surface facing the object side. And a cemented 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 into an aspherical shape.
The third lens group G3 is composed of a cemented lens of a negative meniscus lens L31 having a convex surface directed toward 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 cemented lens of a biconvex positive lens L401 and a negative meniscus lens L402 with a convex surface facing the image side, a positive meniscus lens L403 with a concave surface facing the object side, and both A cemented lens with a concave negative lens L404, a biconvex positive lens L405, a cemented lens with a biconvex positive lens L406 and a biconcave negative lens L407, and a biconvex positive lens L408. It consists of a cemented lens with a negative meniscus lens L409 having a convex surface facing the image side, and a negative meniscus lens L410 with a concave surface facing the object side. The negative lens L404 is a glass mold aspheric lens having an aspheric lens surface on the image side, and the negative meniscus lens L410 is a glass mold aspheric lens having an aspheric lens surface on the image side.
In the zoom optical system according to the present embodiment, a low-pass filter, a sensor cover glass, or the like may be disposed between the fourth lens group G4 and the image plane I.

With the above-described 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 telephoto end state. The air gap between the second lens group G2 and the third lens group G3 is reduced, and the air gap between the third lens group G3 and the fourth lens group G4 is reduced from the wide-angle end state to the intermediate focal length state. First to first so that the telephoto end state increases and the air gap between the aperture stop 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 side along the optical axis, and the aperture stop S moves integrally with the fourth lens group G4.
Table 5 below provides values of specifications of the variable magnification optical system according to the present example.

(Table 5) Fifth Example
[Surface data]
Surface number r d nd νd
Object ∞

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]
6th surface κ 20.0000
A4 9.17458E-05
A6 -6.51986E-07
A8 2.69890E-09
A10 -1.23751E-11

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

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

[Various data]
Scaling ratio 9.42

W T
f 10.30-96.99
FNO 4.12 to 5.81
ω 40.44 〜 4.73 °
Y 8.19-8.19

W M T
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 start surface f
1 1 64.09778
2 6 -10.16794
3 15 31.06055
4 18 67.05869

[Conditional expression values]
(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) respectively show 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 example of the present application. It is an aberration diagram at the time of focusing on an object.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the present example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

  According to each of the above embodiments, a variable magnification optical system having a small size and high optical performance can be realized. In addition, each said Example has shown one specific example of this invention, and this invention is not limited to these. The following contents can be adopted as appropriate as long as the optical performance of the variable magnification optical system of the present application is not impaired.

  Although a four-group configuration is shown as a numerical example of the variable magnification optical system of the present application, the present application is not limited to this, and a variable magnification optical system of another group configuration (for example, five groups, six groups, etc.) is configured. You can also. Specifically, a configuration in which a lens or a lens group is added to the most object side or the most image side of the variable magnification optical system of the present application may be used. The lens group refers to a portion having at least one lens separated by an air interval that changes during zooming.

  In addition, the variable magnification optical system of the present application uses a part of a lens group, an entire lens group, or a plurality of lens groups as a focusing lens group for focusing from an object at infinity to a near object. It is good also as a structure moved to an axial direction. In particular, it is preferable that at least part of the second lens group, at least part of the third lens group, or at least part of the fourth lens group be the focusing lens group. Such a focusing lens group can also be applied to autofocus, and is also suitable for driving by an autofocus motor, such as an ultrasonic motor.

  Further, in the variable magnification optical system of the present application, any lens group or a part thereof is moved as a vibration-proof lens group so as to include a component in a direction perpendicular to the optical axis, or a surface including the optical axis A configuration in which image blur caused by camera shake or the like is corrected by rotationally moving (swinging) inward is also possible. 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.

  The lens surface of the lens constituting the variable magnification optical system of the present application may be a spherical surface, a flat surface, or an aspheric surface. When the lens surface is a spherical surface or a flat surface, it is preferable because lens processing and assembly adjustment are easy, and deterioration of optical performance due to errors in lens processing and assembly adjustment can be prevented. Further, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance. When the lens surface is aspherical, any of aspherical surface by grinding, glass mold aspherical surface in which glass is molded into an aspherical shape, or composite aspherical surface in which resin provided on the glass surface is formed in an aspherical shape Good. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

In the variable magnification optical system of the present application, the aperture stop is preferably arranged in the third lens group or in the vicinity of the third lens group, and the role of the aperture stop is replaced by a lens frame without providing a member. Also 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. Thereby, flare and ghost can be reduced, and high optical performance with high contrast can be achieved.

Next, a camera including the variable magnification optical system of the present application will be described with reference to FIG.
FIG. 11 is a diagram illustrating a configuration of a camera including 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 camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and is on the imaging surface of the imaging unit 3 via an OLPF (Optical low pass filter) (not shown). A subject image is formed on the screen. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. Thus, the photographer can observe the subject via the EVF 4.
When the release button (not shown) is pressed by the photographer, the subject image generated by the imaging unit 3 is stored in a 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 as the photographing lens 2 in the camera 1 is a variable magnification optical system that is small in size and has high optical performance. Therefore, the present camera 1 can achieve high optical performance while achieving downsizing. Even if a camera equipped with the variable magnification optical system according to the second to fifth embodiments as the photographing lens 2 is configured, the same effect as the camera 1 can be obtained. Further, even when the variable magnification optical system according to each of the above embodiments is mounted on a single-lens reflex camera that has a quick return mirror and observes a subject with a finder optical system, the same effect as the camera 1 can be obtained. it can.

Finally, the outline of the manufacturing method of the variable magnification optical system of this application is demonstrated based on FIG.
The variable power optical system manufacturing method shown in FIG. 12 has, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive power. 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 expressions (1) and (2), and each lens group is sequentially arranged in the lens barrel from the object side.
(1) 1.929 <ndh
(2) 28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to 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 second lens group and the second lens group at the time of zooming from the wide-angle end state to the telephoto end state. 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, a variable magnification optical system having a small size and high optical performance can be manufactured.

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

Claims (20)

In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power And having a group
At the time of zooming from the wide-angle 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 The distance from the fourth lens group changes,
A variable magnification optical system having at least one lens satisfying the following conditional expression:
1.928 <ndh
28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to d-line (wavelength 587.6 nm) of the lens   The variable magnification optical system according to claim 1, wherein the first lens group includes at least one of the lenses. The zoom lens system according to claim 1 or 2, wherein the following conditional expression is satisfied.
5.50 <f1 / (− f2) <15.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group The zoom lens system according to any one of claims 1 to 3, wherein the following conditional expression is satisfied.
0.220 <(− f2) / f3 <0.530
However,
f2: focal length of the second lens group f3: focal length of the third lens group 5. The zoom optical system according to claim 1, wherein the first lens group includes at least one lens that satisfies the following conditional expression. 6.
0.450 <| fh / f1 | <1.400
However,
fh: focal length of the lens in the first lens group f1: focal length of the first lens group   The variable power optical system according to any one of claims 1 to 5, wherein the fourth lens group includes at least one of the lenses.   The variable power optical system according to any one of claims 1 to 6, wherein the second lens group includes at least one lens.   The variable power optical system according to any one of claims 1 to 7, wherein the third lens group includes at least one of the lenses.   The variable power optical system according to any one of claims 1 to 8, wherein the first lens group includes at least one lens having negative refractive power.   The variable power optical system according to any one of claims 1 to 9, wherein the fourth lens group includes at least one lens having negative refractive power. The variable power optical system according to any one of claims 1 to 10, wherein the fourth lens group includes at least one lens that satisfies the following conditional expression.
31.60 <νdh4
However,
νdh4: Abbe number of the lens in the fourth lens group with respect to d-line (wavelength: 587.6 nm)   The variable power optical system according to any one of claims 1 to 11, wherein the second lens group includes at least one lens having negative refractive power.   The variable magnification optical system according to any one of claims 1 to 12, wherein the third lens group includes at least one lens having negative refractive power. The variable power optical system according to any one of claims 1 to 13, wherein the first lens unit includes a positive lens that satisfies the following conditional expression.
75.00 <νdp1
However,
νdp1: Abbe number of the positive lens in the first lens group with respect to d-line (wavelength: 587.6 nm) The variable magnification optical system according to any one of claims 1 to 14, wherein the fourth lens group includes a positive lens that satisfies the following conditional expression.
75.00 <νdp4
However,
νdp4: Abbe number for the d-line (wavelength 587.6 nm) of the positive lens in the fourth lens group   The distance between the first lens group and the second lens group increases during zooming from the wide-angle end state to the telephoto end state. Variable magnification optical system.   The distance between the second lens group and the third lens group decreases during zooming from the wide-angle end state to the telephoto end state. Variable magnification optical system.   18. The distance between the third lens group and the fourth lens group is increased at the time of zooming from the wide-angle end state to the telephoto end state. Variable magnification optical system.   An optical apparatus comprising the variable magnification optical system according to any one of claims 1 to 18. In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power A variable magnification optical system having a group,
Having at least one lens satisfying the following conditional expression:
At the time of zooming from the wide-angle 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 A method of manufacturing a variable magnification optical system, characterized in that an interval with the fourth lens group is changed.
1.928 <ndh
28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to d-line (wavelength 587.6 nm) of the lens

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