JP2016224234A - Variable magnification optical system, optical device, and variable magnification optical system manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable magnification optical system that includes excellent optical performance, an optical device and a variable magnification optical system manufacturing method.SOLUTION: A variable magnification optical system includes, in order from an object side,: a first lens group G1 that has negative refractive power; a second lens group G2 that has positive refractive power; a third lens group G3 that has the negative refractive power; a fourth lens group G4 that has the positive refractive power; a fifth lens group G5 that has the negative refractive power; and a sixth lens group G6 that has the positive refractive power. Upon varying a magnification between a wide-angle end state and a telephoto end state, an air space among the lens groups G1 to G6 varies, the third lens group G3 moves upon focusing, and the variable magnification optical system satisfies a prescribed conditional expression.SELECTED DRAWING: Figure 1

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, a variable magnification optical system suitable for a photographic camera, an electronic still camera, a video camera, and the like has been proposed (see, for example, Patent Document 1). However, the variable power optical system as in Patent Document 1 has a problem that the optical performance is insufficient.

JP 2014-32358 A

The present invention
In order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens having a positive refractive power A group, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power,
During zooming between the wide-angle end state and the telephoto end state, the distance between the lens groups changes,
During focusing, the third lens group moves,
A variable magnification optical system that satisfies the following conditional expression is provided.
1.00 <fG1 / f1 <3.00
However,
fG1: Focal length of the lens element closest to the object side in the first lens group f1: Focal length of the first lens group

The present invention also provides
In order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens having a positive refractive power A variable magnification optical system having a group, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power,
When changing the magnification between the wide-angle end state and the telephoto end state, the interval between the lens groups changes,
The third lens group is moved during focusing,
A variable magnification optical system manufacturing method is provided that allows the variable magnification optical system to satisfy the following conditional expression.
1.00 <fG1 / f1 <3.00
However,
fG1: Focal length of the lens element closest to the object side in the first lens group f1: Focal length of the first lens group

It is sectional drawing of the wide-angle end state of the variable magnification optical system which concerns on 1st Example. (A), (b), and (c) are various aberration diagrams 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. . It is sectional drawing of the wide-angle end state of the variable magnification optical system which concerns on 2nd Example. (A), (b), and (c) are various aberration diagrams 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. . It is sectional drawing of the wide angle end state of the variable magnification optical system which concerns on 3rd Example. (A), (b), and (c) are various aberration diagrams 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. . It is sectional drawing of the wide angle end state of the variable magnification optical system which concerns on 4th Example. (A), (b), and (c) are various aberration diagrams 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. . It is sectional drawing of the wide-angle end state of the variable magnification optical system which concerns on 5th Example. (A), (b), and (c) are various aberration diagrams 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. . It is sectional drawing of the wide-angle end state of the variable magnification optical system which concerns on 6th Example. (A), (b), and (c) are various aberration diagrams 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 sixth example. . It is a figure which shows the structure of the camera provided with the variable magnification optical system. It is a figure which shows the outline of the manufacturing method of a variable magnification optical system.

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 negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, A fourth lens group having a refractive power of 5, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power, and between the wide-angle end state and the telephoto end state The distance between the lens groups changes during zooming, and the third lens group moves during focusing, which satisfies the following conditional expression (1).
(1) 1.00 <fG1 / f1 <3.00
However,
fG1: Focal length of the lens element closest to the object side in the first lens group f1: Focal length of the first lens group

  As described above, in the variable magnification optical system of the present application, the third lens group moves as a focusing lens group when focusing from an object at infinity to an object at a short distance. With this configuration, the diameter of the focusing lens group can be made relatively small. Therefore, it is possible to reduce the size and weight of the variable magnification optical system of the present application and to reduce the noise of the focusing operation. Further, by performing focusing with a focusing lens group having negative refractive power, it is possible to satisfactorily correct variations in various aberrations such as spherical aberration and field curvature during focusing.

Conditional expression (1) defines the refractive power of the most object side lens component in the first lens group. In this specification, the lens component means a single lens or a cemented lens. By satisfying conditional expression (1), the variable magnification optical system of the present application can satisfactorily correct the curvature of field and the spherical aberration in the telephoto end state while reducing the size. When the corresponding value of conditional expression (1) of the variable magnification optical system of the present application is below the lower limit value, the focal length of the lens component closest to the object side in the first lens group becomes small and the focal length of the first lens group becomes large. Become. This makes it difficult to correct spherical aberration in the telephoto end state. In order to secure the effect of the present application, it is preferable to set the lower limit of conditional expression (1) to 1.20. On the other hand, when the corresponding value of conditional expression (1) of the variable magnification optical system of the present application exceeds the upper limit value, the focal length of the lens component closest to the object side in the first lens group increases and the focal length of the first lens group increases. Becomes smaller. This increases the overall length of the variable magnification optical system of the present application, making it difficult to correct field curvature. In order to secure the effect of the present application, it is preferable to set the upper limit of conditional expression (1) to 2.00.
With the configuration described above, a variable magnification optical system having good optical performance can be realized.

Moreover, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (2).
(2) 0.30 <(− f1) / f6 <0.60
However,
f1: Focal length of the first lens group f6: Focal length of the sixth lens group

  Conditional expression (2) defines the focal length of the sixth lens group relative to the focal length of the first lens group. By satisfying conditional expression (2), the variable magnification optical system of the present application can favorably correct curvature of field and spherical aberration in the telephoto end state while achieving downsizing. When the corresponding value of conditional expression (2) of the variable magnification optical system of the present application is less than the lower limit value, the focal length of the first lens group decreases and the focal length of the sixth lens group increases. This makes it difficult to correct spherical aberration in the telephoto end state. In order to secure the effect of the present application, it is preferable to set the lower limit of conditional expression (2) to 0.40. On the other hand, when the corresponding value of conditional expression (2) of the variable magnification optical system of the present application exceeds the upper limit value, the focal length of the first lens group increases and the focal length of the sixth lens group decreases. This increases the overall length of the variable magnification optical system of the present application, making it difficult to correct field curvature. In order to secure the effect of the present application, it is preferable to set the upper limit of conditional expression (2) to 0.52.

Moreover, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (3).
(3) 0.68 <(− fn) / fp <1.00
However,
fn: focal length of the most image-side negative lens in the first lens group fp: focal length of the most image-side positive lens in the first lens group

  Conditional expression (3) defines the focal length of the most image-side positive lens in the first lens group relative to the focal length of the most image-side negative lens in the first lens group. By satisfying conditional expression (3), the variable magnification optical system of the present application can satisfactorily correct lateral chromatic aberration, field curvature, and spherical aberration in the telephoto end state while reducing the size. When the corresponding value of the conditional expression (3) of the variable magnification optical system of the present application is below the lower limit value, the focal length of the negative lens closest to the image side in the first lens group becomes small and the most image side in the first lens group. The focal length of the positive lens increases. This makes it difficult to correct lateral chromatic aberration and spherical aberration in the telephoto end state. In order to secure the effect of the present application, it is preferable to set the lower limit of conditional expression (3) to 0.70. On the other hand, when the corresponding value of conditional expression (3) of the variable magnification optical system of the present application exceeds the upper limit value, the focal length of the negative lens closest to the image side in the first lens group increases and the longest in the first lens group. The focal length of the positive lens on the image side is reduced. This increases the overall length of the variable magnification optical system of the present application, making it difficult to correct field curvature. In order to secure the effect of the present application, it is preferable to set the upper limit of conditional expression (3) to 0.90.

  In the variable magnification optical system of the present application, it is desirable that the third lens group is composed of two or less lens components (preferably one lens component). If the third lens group, that is, the focusing lens group is composed of many lenses, it is easy to correct variations in various aberrations such as spherical aberration and field curvature during focusing. However, as the number of lenses in the third lens group increases, the overall length of the variable magnification optical system of the present application increases, making it difficult to reduce the size and weight. Therefore, in the variable magnification optical system of the present application, the number of lenses can be reduced by configuring the third lens group with only two or less lens components as described above to form a focusing lens group. In particular, it is preferable to configure the third lens group with a single lens because the number of lenses can be reduced. Also, if the focusing lens group is moved to the object side when focusing from an object at infinity to an object at close distance, fluctuations in various aberrations such as spherical aberration and field curvature during focusing will be improved. It can be corrected.

  In the variable power optical system of the present application, it is preferable that at least one lens component in the second lens group moves so as to include a component in a direction perpendicular to the optical axis. With this configuration, it is possible to correct image blur due to camera shake, vibration, or the like, that is, to prevent vibration. In addition, it is possible to effectively and efficiently correct the variation in field curvature during zooming.

In the variable magnification optical system of the present application, it is desirable that the first lens group is composed of two or three lens components. With this configuration, it is possible to achieve both correction of various aberrations, particularly spherical aberration, curvature of field and distortion, and miniaturization of the variable magnification optical system of the present application.
In the variable magnification optical system of the present application, it is preferable that the first lens group has at least one positive lens. With this configuration, it is possible to satisfactorily correct various aberrations, particularly spherical aberration, field curvature, and distortion.

  In the variable magnification optical system of the present application, it is preferable that at least one of the first lens group and the most image side lens group has an aspherical surface. With this configuration, coma aberration can be corrected.

  In the variable magnification optical system of the present application, it is desirable that the lens component in the first lens group has an aspherical surface. With this configuration, it is possible to more efficiently correct curvature of field in the wide-angle end state and spherical aberration in the telephoto end state. In particular, in the variable magnification optical system of the present application, it is desirable that the image side lens surface of the most object side lens in the first lens group be an aspherical surface. With this configuration, it is possible to correct distortion and reduce costs and size. The most object side lens in the first lens group is preferably a negative meniscus lens. With this configuration, the front lens diameter (the diameter of the lens surface closest to the object) can be reduced.

  In the variable magnification optical system of the present application, it is desirable that the first lens group has a cemented lens. With this configuration, it is possible to effectively correct coma for each wavelength in the wide-angle end state. Moreover, it is desirable that the cemented lens as a whole has a meniscus shape or a biconcave shape with a convex surface facing the object side. The cemented lens is preferably composed of a negative lens and a positive lens in order from the object side. It is desirable that the negative lens in the cemented lens has a meniscus shape. It is desirable that the positive lens in the cemented lens has a meniscus shape. The more the cemented lens satisfies these conditions, the less aberration occurs in the cemented lens, and there is no waste in manufacturing because high mounting accuracy is not required.

  In the variable magnification optical system of the present application, it is desirable that the fourth lens group includes a single lens and a cemented lens. With this configuration, spherical aberration and axial chromatic aberration can be corrected.

  The variable magnification optical system of the present application preferably includes a plastic lens in the lens group closest to the image side. Thereby, cost reduction can be achieved. Further, an aspherical surface can be provided on the plastic lens without increasing the cost, and thereby coma can be corrected well. When the variable power optical system of the present application is an interchangeable lens, the lens on the most image side can be easily touched by the user, so that it is desirable to use a glass lens having higher durability than a plastic lens.

  The optical apparatus of the present application has the variable magnification optical system having the above-described configuration. Thereby, an optical device having good optical performance can be realized.

The variable magnification optical system manufacturing method of the present application includes, in order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power. A fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power, At the time of zooming between the wide-angle end state and the telephoto end state, the distance between the lens groups is changed, and at the time of focusing, the third lens group is moved. The conditional expression (1) is satisfied. Thereby, a variable magnification optical system having good optical performance can be manufactured.
(1) 1.00 <fG1 / f1 <3.00
However,
fG1: Focal length of the lens element closest to the object side in the first lens group f1: Focal length of the first lens group

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)
FIG. 1 is a sectional view of the zoom optical system according to the first example of the present application in the wide-angle end state. 1 and FIG. 3, FIG. 5, FIG. 7, FIG. 9 and FIG. 11, which will be described later, indicate the movement of each lens group during zooming from the wide-angle end state (W) to the telephoto end state (T). The trajectory is shown.

  The variable magnification optical system according to this example includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a negative refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. An aperture stop S is disposed between the fourth lens group G4 and the fifth lens group G5.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side. It consists of a cemented lens. Note that the image side lens surface of the negative meniscus lens L11 is aspheric.
The second lens group G2 is composed of a biconvex positive lens L21.
The third lens group G3 includes a negative meniscus lens L31 having a concave surface directed toward the object side.
The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L41, a biconvex positive lens L42, and a negative meniscus lens L43 having a concave surface facing the object, an aperture stop S, Consists of.
The fifth lens group G5 is composed of a cemented lens of a positive meniscus lens L51 having a concave surface directed toward the object side and a biconcave negative lens L52 in order from the object side.
The sixth lens group G6 includes, in order from the object side, a positive meniscus lens L61 having a convex surface directed toward the object side, and a positive meniscus lens L62 having a concave surface directed toward the object side. The positive meniscus lens L61 is a plastic lens, and the image-side lens surface is aspheric.

  In the zoom optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 and the second lens group G2 and the third lens group during zooming from the wide-angle end state to the telephoto end state. The air gap between G3, the third lens group G3 and the fourth lens group G4, the air gap between the fourth lens group G4 and the fifth lens group G5, and the fifth lens group G5 and the sixth lens group G6. The first to sixth lens groups G1 to G6 move along the optical axis so that the air gap between them changes. Specifically, the second, fourth, and sixth lens groups G2, G4, and G6 move integrally when zooming. Note that the aperture stop S moves integrally with the fourth lens group G4 during zooming.

In the variable magnification optical system according to the present example, the third lens group G3 is moved to the object side along the optical axis, thereby focusing from an object at infinity to a near object.
In the variable magnification optical system according to the present example, image stabilization is performed by moving the second lens group G2 so as to include a component in a direction perpendicular to the optical axis.

Table 1 below lists values of specifications of the variable magnification optical system according to the present example.
In Table 1, f represents the focal length, and Bf represents the back focus, that is, the distance on the optical axis between the lens surface closest to the image side and the image surface.
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. The object plane indicates the object plane, the variable indicates the variable surface interval, and the stop S indicates the aperture stop S. The radius of curvature r = ∞ indicates a plane. For an aspherical surface, “*” is attached to the surface number, and the value of the paraxial radius of curvature is shown in the column of the radius of curvature r.

[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
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 are aspheric 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 “1.23456E-07” indicates “1.23456 × 10 ⁻⁷ ”. The secondary aspherical coefficient A2 is 0 and is not shown.

In [various data], FNO is the F number, 2ω is the angle of view (unit is “°”), Y is the image height, TL is the total length of the variable magnification optical system according to the present embodiment, that is, the first surface to the image surface. A distance on the optical axis, dn, indicates a variable distance between the nth surface and the (n + 1) th surface. 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 80.72 2.00 1.58913 61.22
2 18.88 0.17 1.56093 36.64
* 3 17.05 9.35 1.00000
4 240.48 1.40 1.62299 58.12
5 17.63 5.00 1.84666 23.80
6 32.74 Variable 1.00000
7 164.19 1.65 1.48749 70.31
8 -48.23 Variable 1.00000
9 -30.49 0.80 1.77250 49.62
10 -87.64 Variable 1.00000
11 46.43 3.05 1.48749 70.31
12 -31.99 0.10 1.00000
13 25.50 4.20 1.48749 70.31
14 -25.50 0.80 1.84666 23.80
15 -60.79 0.75 1.00000
16 (Aperture S) ∞ Variable 1.00000
17 -43.88 2.27 1.75520 27.57
18 -13.90 0.80 1.70154 41.02
19 38.98 Variable 1.00000
20 81.93 1.30 1.52444 56.21
* 21 91.62 1.60 1.00000
22 -179.92 2.30 1.51680 63.88
23 -21.95 Bf 1.00000
Image plane ∞
[Aspherical data]
Surface number κ A4 A6 A8 A10
3 0.0000 1.43618E-05 3.23919E-08 -6.25295E-11 2.95784E-13
21 0.0000 2.43150E-05 -6.35221E-09 2.24760E-10 -3.95108E-12
[Various data]
Scaling ratio 2.89
W M T
f 18.50 35.00 53.40
FNO 3.64 4.62 5.88
2ω 80.60 45.84 30.70
TL 134.86 128.74 136.72
Y 14.25 14.25 14.25
d6 33.51 11.32 3.41
d8 6.23 7.18 7.40
d10 2.96 2.00 1.78
d16 1.70 5.67 9.57
d19 9.07 5.10 1.20
Bf 43.85 59.92 75.82
[Lens group data]
Group start surface f
1 1 -24.58
2 7 76.67
3 9 -60.89
4 11 22.86
5 17 -31.47
6 20 46.90
[Conditional expression values]
(1) fG1 / f1 = 1.5
(2) (−f1) /f6=0.52
(3) (-fn) / fp = 0.7813

  2 (a), 2 (b) and 2 (c) respectively show the infinite object combination 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. FIG. 5 is a diagram showing various aberrations during focusing.

  In each aberration diagram, FNO represents an F number, and Y represents an image height. Specifically, the spherical aberration diagram shows the value of the F number FNO corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum value of the image height Y, and the coma diagram shows the value of each image height. . In each aberration diagram, d indicates the aberration at the d-line (wavelength 587.6 nm), and g indicates the aberration at the g-line (wavelength 435.8 nm). In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. The coma aberration diagram shows coma aberration at each image height Y. Note that the same reference numerals as in this embodiment are used in the aberration diagrams of each embodiment described later.

  From each aberration diagram, it is understood that the variable magnification optical system according to the present example has excellent imaging performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Second embodiment)
FIG. 3 is a sectional view of the zoom optical system according to the second example of the present application in the wide-angle end state.
The variable magnification optical system according to this example includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a negative refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. An aperture stop S is disposed between the fourth lens group G4 and the fifth lens group G5.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a cemented lens of a biconcave negative lens L12, and a positive meniscus lens L13 having a convex surface facing the object side. Become. Note that the image side lens surface of the negative meniscus lens L11 is aspheric.
The second lens group G2 is composed of a biconvex positive lens L21.
The third lens group G3 includes a negative meniscus lens L31 having a concave surface directed toward the object side.
The fourth lens group G4 includes, in order from the object side, a biconvex positive lens L41, a cemented lens of a biconvex positive lens L42, and a negative meniscus lens L43 having a concave surface facing the object side.
The fifth lens group G5 includes, in order from the object side, an aperture stop S, and a cemented lens of a positive meniscus lens L51 having a concave surface facing the object side and a biconcave negative lens L52.
The sixth lens group G6 includes, in order from the object side, a negative meniscus lens L61 having a convex surface directed toward the object side, and a positive meniscus lens L62 having a concave surface directed toward the object side. The negative meniscus lens L61 is a plastic lens, and the image-side lens surface is aspheric.

  In the zoom optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 and the second lens group G2 and the third lens group during zooming from the wide-angle end state to the telephoto end state. The air gap between G3, the third lens group G3 and the fourth lens group G4, the air gap between the fourth lens group G4 and the fifth lens group G5, and the fifth lens group G5 and the sixth lens group G6. The first to sixth lens groups G1 to G6 move along the optical axis so that the air gap between them changes. Specifically, the second, fourth, and sixth lens groups G2, G4, and G6 move integrally when zooming. Note that the aperture stop S moves integrally with the fifth lens group G5 during zooming.

In the variable magnification optical system according to the present example, the third lens group G3 is moved to the object side along the optical axis, thereby focusing from an object at infinity to a near object.
In the variable magnification optical system according to the present example, image stabilization is performed by moving the second lens group G2 so as to include a component in a direction perpendicular to the optical axis.
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 58.61 1.30 1.51680 63.88
2 18.70 0.15 1.56093 36.64
* 3 16.70 12.36 1.00000
4 -539.76 1.20 1.63854 55.34
5 21.43 5.00 1.84666 23.78
6 43.93 Variable 1.00000
7 76.20 1.70 1.48749 70.31
8 -74.28 Variable 1.00000
9 -33.55 0.79 1.77250 49.62
10 -126.41 Variable 1.00000
11 49.80 3.33 1.48749 70.31
12 -30.52 0.10 1.00000
13 23.62 3.51 1.48749 70.31
14 -29.49 0.80 1.84666 23.80
15 -75.25 Variable 1.00000
16 (Aperture S) ∞ 1.50 1.00000
17 -51.95 2.42 1.75520 27.57
18 -15.57 0.90 1.70154 41.02
19 45.98 Variable 1.00000
20 96.48 1.37 1.52444 56.21
* 21 88.50 1.50 1.00000
22 -58.97 2.38 1.51680 63.88
23 -21.70 Bf 1.00000
Image plane ∞
[Aspherical data]
Surface number κ A4 A6 A8 A10
3 0.0000 1.72915E-05 4.86464E-08 -1.24525E-10 4.71298E-13
21 0.0000 3.10082E-05 1.62502E-09 -1.14900E-10 1.87133E-13
[Various data]
Scaling ratio 2.89
W M T
f 18.50 35.00 53.40
FNO 3.64 4.70 5.84
2ω 80.61 45.83 30.72
TL 135.29 129.95 136.93
Y 14.25 14.25 14.25
d6 35.50 13.00 3.00
d8 6.10 9.67 10.06
d10 5.11 1.55 1.15
d15 0.95 3.60 6.50
d19 6.85 4.20 1.30
Bf 40.47 57.64 74.61
[Lens group data]
Group start surface f
1 1 -27.41
2 7 77.45
3 9 -59.34
4 11 22.44
5 17 -37.49
6 20 67.25
[Conditional expression values]
(1) fG1 / f1 = 1.6
(2) (-f1) / f6 = 0.41
(3) (−fn) /fp=0.7192

  4 (a), 4 (b) and 4 (c) respectively show the infinite object combination in the wide-angle end state, intermediate focal length state and telephoto end state of the variable magnification optical system according to the second example of the present application. FIG. 5 is a diagram showing various aberrations during focusing.

  From each aberration diagram, it is understood that the variable magnification optical system according to the present example has excellent imaging performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Third embodiment)
FIG. 5 is a sectional view of the zoom optical system according to the third example of the present application in the wide-angle end state.
The variable magnification optical system according to this example includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a negative refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. An aperture stop S is disposed between the fourth lens group G4 and the fifth lens group G5.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side. It consists of a cemented lens. Note that the image side lens surface of the negative meniscus lens L11 is aspheric.
The second lens group G2 includes a positive meniscus lens L21 having a concave surface directed toward the object side.
The third lens group G3 includes a negative meniscus lens L31 having a concave surface directed toward the object side.
The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L41, a biconvex positive lens L42, and a negative meniscus lens L43 having a concave surface facing the object, an aperture stop S, Consists of.
The fifth lens group G5 is composed of a cemented lens of a positive meniscus lens L51 having a concave surface directed toward the object side and a biconcave negative lens L52 in order from the object side.
The sixth lens group G6 includes, in order from the object side, a negative meniscus lens L61 having a convex surface directed toward the object side, and a positive meniscus lens L62 having a concave surface directed toward the object side. The negative meniscus lens L61 is a plastic lens, and the image-side lens surface is aspheric.

  In the zoom optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 and the second lens group G2 and the third lens group during zooming from the wide-angle end state to the telephoto end state. The air gap between G3, the third lens group G3 and the fourth lens group G4, the air gap between the fourth lens group G4 and the fifth lens group G5, and the fifth lens group G5 and the sixth lens group G6. The first to sixth lens groups G1 to G6 move along the optical axis so that the air gap between them changes. Note that the aperture stop S moves integrally with the fourth lens group G4 during zooming.

In the variable magnification optical system according to the present example, the third lens group G3 is moved to the object side along the optical axis, thereby focusing from an object at infinity to a near object.
In the variable magnification optical system according to the present example, image stabilization is performed by moving the second lens group G2 so as to include a component in a direction perpendicular to the optical axis.
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 79.69 2.00 1.58913 61.22
2 20.75 0.17 1.56093 36.64
* 3 19.00 9.65 1.00000
4 416.05 1.40 1.60311 60.69
5 17.31 5.19 1.84666 23.80
6 28.95 Variable 1.00000
7 -396.42 1.63 1.48749 70.31
8 -34.31 Variable 1.00000
9 -24.55 0.80 1.77250 49.62
10 -67.66 Variable 1.00000
11 53.51 2.86 1.60311 60.69
12 -36.03 0.10 1.00000
13 26.08 4.26 1.48749 70.31
14 -23.14 0.80 1.84666 23.80
15 -52.27 0.75 1.00000
16 (Aperture S) ∞ Variable 1.00000
17 -45.51 2.28 1.84666 23.80
18 -14.24 0.80 1.74950 35.25
19 41.61 Variable 1.00000
20 100.00 1.30 1.52444 56.21
* 21 97.03 1.55 1.00000
22 -306.68 2.44 1.48749 70.31
23 -21.59 Bf 1.00000
Image plane ∞
[Aspherical data]
Surface number κ A4 A6 A8 A10
3 0.0000 9.56997E-06 2.46213E-08 -3.67381E-11 1.68777E-13
21 0.0000 2.66274E-05 2.95181E-08 -8.46694E-11 -4.35134E-12
[Various data]
Scaling ratio 2.89
W M T
f 18.50 35.00 53.40
FNO 3.64 4.60 5.88
2ω 80.59 45.80 30.69
TL 134.92 128.32 136.32
Y 14.25 14.25 14.25
d6 33.91 11.51 3.67
d8 5.54 6.25 6.51
d10 2.36 1.94 1.78
d16 1.70 5.75 9.71
d19 9.61 5.26 1.20
Bf 43.82 59.63 75.47
[Lens group data]
Group start surface f
1 1 -24.72
2 7 76.93
3 9 -50.29
4 11 21.61
5 17 -33.17
6 20 48.02
[Conditional expression values]
(1) fG1 / f1 = 1.7
(2) (−f1) /f6=0.51
(3) (-fn) / fp = 0.7099

  FIGS. 6 (a), 6 (b) and 6 (c) respectively show the infinite object combination 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. FIG. 5 is a diagram showing various aberrations during focusing.

  From each aberration diagram, it is understood that the variable magnification optical system according to the present example has excellent imaging performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Fourth embodiment)
FIG. 7 is a sectional view of the zoom optical system according to the fourth example of the present application in the wide-angle end state.
The variable magnification optical system according to this example includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a negative refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. An aperture stop S is disposed between the fourth lens group G4 and the fifth lens group G5.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface facing the object side, a cemented lens of a biconcave negative lens L12, and a positive meniscus lens L13 having a convex surface facing the object side. Become. Note that the image side lens surface of the negative meniscus lens L11 is aspheric.
The second lens group G2 includes a positive meniscus lens L21 having a concave surface directed toward the object side.
The third lens group G3 includes a negative meniscus lens L31 having a concave surface directed toward the object side.
The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L41, a biconvex positive lens L42, and a negative meniscus lens L43 having a concave surface facing the object, an aperture stop S, Consists of.
The fifth lens group G5 is composed of a cemented lens of a positive meniscus lens L51 having a concave surface directed toward the object side and a biconcave negative lens L52 in order from the object side.
The sixth lens group G6 includes, in order from the object side, a negative meniscus lens L61 having a convex surface directed toward the object side, and a positive meniscus lens L62 having a concave surface directed toward the object side. The negative meniscus lens L61 is a plastic lens, and the image-side lens surface is aspheric.

  In the zoom optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 and the second lens group G2 and the third lens group during zooming from the wide-angle end state to the telephoto end state. The air gap between G3, the third lens group G3 and the fourth lens group G4, the air gap between the fourth lens group G4 and the fifth lens group G5, and the fifth lens group G5 and the sixth lens group G6. The first to sixth lens groups G1 to G6 move along the optical axis so that the air gap between them changes. Note that the aperture stop S moves integrally with the fourth lens group G4 during zooming.

In the variable magnification optical system according to the present example, the third lens group G3 is moved to the object side along the optical axis, thereby focusing from an object at infinity to a near object.
In the variable magnification optical system according to the present example, image stabilization is performed by moving the second lens group G2 so as to include a component in a direction perpendicular to the optical axis.
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 56.24 2.00 1.69680 55.52
2 20.35 0.17 1.56093 36.64
* 3 18.69 9.97 1.00000
4 -2982.47 1.40 1.60300 65.44
5 18.31 5.00 1.84666 23.80
6 32.46 Variable 1.00000
7 -620.57 1.63 1.48749 70.31
8 -35.68 Variable 1.00000
9 -25.12 0.80 1.77250 49.62
10 -71.26 Variable 1.00000
11 54.96 2.89 1.60311 60.69
12 -35.02 0.10 1.00000
13 25.68 4.30 1.48749 70.31
14 -23.22 0.80 1.84666 23.80
15 -52.65 0.75 1.00000
16 (Aperture S) ∞ Variable 1.00000
17 -45.18 2.27 1.84666 23.80
18 -14.36 0.80 1.74950 35.25
19 41.64 Variable 1.00000
20 100.05 1.30 1.52444 56.21
* 21 80.01 1.54 1.00000
22 -416.31 2.37 1.48749 70.31
23 -21.63 Bf 1.00000
Image plane ∞
[Aspherical data]
Surface number κ A4 A6 A8 A10
3 0.0000 1.09721E-05 2.63109E-08 -3.94901E-11 1.79030E-13
21 0.0000 2.64794E-05 1.52619E-08 5.85840E-11 -4.79996E-12
[Various data]
Scaling ratio 2.89
W M T
f 18.50 35.00 53.40
FNO 3.63 4.60 5.88
2ω 80.59 45.83 30.72
TL 134.92 128.32 136.32
Y 14.25 14.25 14.25
d6 34.40 11.79 3.56
d8 5.58 6.27 6.52
d10 2.36 1.87 1.82
d15 1.70 5.48 9.09
d19 8.98 5.00 1.20
Bf 43.82 59.84 76.07
[Lens group data]
Group start surface f
1 1 -24.76
2 7 77.60
3 9 -50.59
4 11 21.42
5 17 -32.97
6 20 49.70
[Conditional expression values]
(1) fG1 / f1 = 1.7
(2) (−f1) /f6=0.50
(3) (−fn) /fp=0.7067

  8 (a), 8 (b) and 8 (c) respectively show the 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. FIG. 5 is a diagram showing various aberrations during focusing.

  From each aberration diagram, it is understood that the variable magnification optical system according to the present example has excellent imaging performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(5th Example)
FIG. 9 is a sectional view of the variable magnification optical system according to the fifth example of the present application in the wide-angle end state.
The variable magnification optical system according to this example includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a negative refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. An aperture stop S is disposed between the fourth lens group G4 and the fifth lens group G5.

The first lens group G1, in order from the object side, includes a negative meniscus lens L11 having a convex surface directed toward the object side, a negative meniscus lens L12 having a convex surface directed toward the object side, and a positive meniscus lens L13 having a convex surface directed toward the object side. Consists of. Note that the image side lens surface of the negative meniscus lens L11 is aspheric.
The second lens group G2 includes a positive meniscus lens L21 having a concave surface directed toward the object side.
The third lens group G3 includes a negative meniscus lens L31 having a concave surface directed toward the object side.
The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L41, a biconvex positive lens L42, and a negative meniscus lens L43 having a concave surface facing the object, an aperture stop S, Consists of.
The fifth lens group G5 is composed of a cemented lens of a positive meniscus lens L51 having a concave surface directed toward the object side and a biconcave negative lens L52 in order from the object side.
The sixth lens group G6 includes, in order from the object side, a positive lens L61 and a positive meniscus lens L62 with a concave surface facing the object side. The positive lens L61 is a plastic lens, and the lens surface on the image side is aspheric.

  In the zoom optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 and the second lens group G2 and the third lens group during zooming from the wide-angle end state to the telephoto end state. The air gap between G3, the third lens group G3 and the fourth lens group G4, the air gap between the fourth lens group G4 and the fifth lens group G5, and the fifth lens group G5 and the sixth lens group G6. The first to sixth lens groups G1 to G6 move along the optical axis so that the air gap between them changes. Note that the aperture stop S moves integrally with the fourth lens group G4 during zooming.

In the variable magnification optical system according to the present example, the third lens group G3 is moved to the object side along the optical axis, thereby focusing from an object at infinity to a near object.
In the variable magnification optical system according to the present example, image stabilization is performed by moving the second lens group G2 so as to include a component in a direction perpendicular to the optical axis.
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 ∞
1 159.78 2.00 1.58913 61.22
2 21.25 0.17 1.56093 36.64
* 3 18.31 8.37 1.00000
4 80.67 1.40 1.62299 58.12
5 17.61 0.45 1.00000
6 18.34 5.10 1.84666 23.80
7 31.58 Variable 1.00000
8 -1394.74 1.62 1.48749 70.31
9 -36.39 Variable 1.00000
10 -23.60 0.80 1.77250 49.62
11 -66.38 Variable 1.00000
12 52.65 2.85 1.60311 60.69
13 -38.60 0.10 1.00000
14 32.14 4.27 1.48749 70.31
15 -22.40 0.80 1.84666 23.80
16 -43.56 0.75 1.00000
17 (Aperture S) ∞ Variable 1.00000
18 -58.32 2.38 1.80518 25.45
19 -14.79 0.80 1.74950 35.25
20 51.07 Variable 1.00000
21 100.00 1.30 1.52444 56.21
* 22 100.00 1.60 1.00000
23 -157.66 2.20 1.48749 70.31
24 -23.26 Bf 1.00000
Image plane ∞
[Aspherical data]
Surface number κ A4 A6 A8 A10
3 0.0000 7.24382E-06 8.06638E-13 5.77349E-11 -2.00588E-13
22 0.0000 2.45605E-05 6.34787E-08 -1.05676E-09 5.28455E-12
[Various data]
Scaling ratio 2.89
W M T
f 18.50 35.00 53.40
FNO 3.63 4.60 5.88
2ω 80.59 45.92 30.76
TL 134.92 128.32 136.32
Y 14.25 14.25 14.25
d7 34.09 11.78 3.56
d9 5.92 6.31 6.55
d11 3.79 2.29 1.78
d17 1.70 6.12 10.47
d20 8.58 5.27 1.20
Bf 43.85 59.57 75.79
[Lens group data]
Group start surface f
1 1 -26.08
2 8 76.62
3 10 -47.81
4 12 22.59
5 18 -40.02
6 21 55.85
[Conditional expression values]
(1) fG1 / f1 = 1.4
(2) (−f1) /f6=0.4670
(3) (-fn) / fp = 0.8096

  FIGS. 10 (a), 10 (b) and 10 (c) respectively show the infinite object combination 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. FIG. 5 is a diagram showing various aberrations during focusing.

  From each aberration diagram, it is understood that the variable magnification optical system according to the present example has excellent imaging performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Sixth embodiment)
FIG. 11 is a sectional view of the zoom optical system according to the sixth example of the present application in the wide-angle end state.
The variable magnification optical system according to this example includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens having a negative refractive power. The lens group G3 includes a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. An aperture stop S is disposed between the fourth lens group G4 and the fifth lens group G5.

The first lens group G1, in order from the object side, includes a negative meniscus lens L11 having a convex surface directed toward the object side, a negative meniscus lens L12 having a convex surface directed toward the object side, and a positive meniscus lens L13 having a convex surface directed toward the object side. Consists of. Note that the image side lens surface of the negative meniscus lens L11 is aspheric.
The second lens group G2 includes a positive meniscus lens L21 having a concave surface directed toward the object side.
The third lens group G3 includes a negative meniscus lens L31 having a concave surface directed toward the object side.
The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L41, a biconvex positive lens L42, and a negative meniscus lens L43 having a concave surface facing the object, an aperture stop S, Consists of.
The fifth lens group G5 includes, in order from the object side, a cemented lens of a biconcave negative lens L51 and a positive meniscus lens L52 having a convex surface directed toward the object side.
The sixth lens group G6 includes, in order from the object side, a positive meniscus lens L61 having a convex surface directed toward the object side, and a positive meniscus lens L62 having a concave surface directed toward the object side. The positive meniscus lens L61 is a plastic lens, and the image-side lens surface is aspheric.

  In the zoom optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 and the second lens group G2 and the third lens group during zooming from the wide-angle end state to the telephoto end state. The air gap between G3, the third lens group G3 and the fourth lens group G4, the air gap between the fourth lens group G4 and the fifth lens group G5, and the fifth lens group G5 and the sixth lens group G6. The first to sixth lens groups G1 to G6 move along the optical axis so that the air gap between them changes. Note that the aperture stop S moves integrally with the fourth lens group G4 during zooming.

In the variable magnification optical system according to the present example, the third lens group G3 is moved to the object side along the optical axis, thereby focusing from an object at infinity to a near object.
In the variable magnification optical system according to the present example, image stabilization is performed by moving the second lens group G2 so as to include a component in a direction perpendicular to the optical axis.
Table 6 below lists values of specifications of the variable magnification optical system according to the present example.

(Table 6) Sixth Example
[Surface data]
Surface number r d nd νd
Object ∞
1 157.01 2.00 1.58913 61.22
2 21.49 0.17 1.56093 36.64
* 3 18.52 8.66 1.00000
4 106.51 1.40 1.62299 58.12
5 18.80 0.53 1.00000
6 19.87 4.91 1.84666 23.80
7 36.41 Variable 1.00000
8 -11963.03 1.64 1.48749 70.31
9 -37.51 Variable 1.00000
10 -26.10 0.80 1.77250 49.62
11 -85.54 Variable 1.00000
12 52.74 2.90 1.60311 60.69
13 -36.25 0.10 1.00000
14 27.94 4.00 1.48749 70.31
15 -28.59 0.80 1.84666 23.80
16 -77.61 0.81 1.00000
17 (Aperture S) ∞ Variable 1.00000
18 -78.97 0.80 1.74950 35.25
19 13.08 2.35 1.80518 25.45
20 37.73 Variable 1.00000
21 80.00 1.30 1.52444 56.21
* 22 96.77 1.61 1.00000
23 -143.56 2.26 1.48749 70.31
24 -21.47 Bf 1.00000
Image plane ∞
[Aspherical data]
Surface number κ A4 A6 A8 A10
3 0.0000 6.82101E-06 5.13428E-09 1.12442E-11 -1.05343E-13
22 0.0000 2.46633E-05 1.73045E-07 -3.90358E-09 3.12442E-11
[Various data]
Scaling ratio 2.89
W M T
f 18.50 35.00 53.40
FNO 3.61 4.60 5.88
2ω 80.60 45.96 30.78
TL 134.92 128.32 136.72
Y 14.25 14.25 14.25
d7 34.87 11.92 3.45
d9 5.77 6.47 6.64
d11 3.33 2.07 1.82
d17 1.70 5.70 9.50
d20 8.37 4.94 1.21
Bf 43.85 60.19 77.07
[Lens group data]
Group start surface f
1 1 -26.64
2 8 77.18
3 10 -48.90
4 12 23.15
5 18 -37.32
6 21 48.99
[Conditional expression values]
(1) fG1 / f1 = 1.3
(2) (−f1) /f6=0.5499
(3) (-fn) / fp = 0.7942

  12 (a), 12 (b), and 12 (c) respectively show the infinite object combination 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 sixth example of the present application. FIG. 5 is a diagram showing various aberrations during focusing.

  From each aberration diagram, it is understood that the variable magnification optical system according to the present example has excellent imaging performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

  According to each of the above-described embodiments, it is possible to realize a variable power optical system that is small and light, suppresses aberration fluctuations during zooming, and has excellent optical performance.

  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 six-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 having other group configurations (for example, seven groups) can also be configured. . 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 each of the above embodiments may be used. Further, the lens group on the most image side of the variable magnification optical system of each of the above embodiments may be divided into two, and the distance between these may change at the time of zooming.

In each of the variable power optical systems of the above embodiments, each lens group moves along the optical axis when zooming from the wide-angle end state to the telephoto end state. However, the variable magnification optical system of each of the above embodiments may fix the position of at least one lens group, for example, the most image side lens group. Further, it is preferable that the movement locus of the first lens group upon zooming from the wide-angle end state to the telephoto end state is a U-turn shape that once moves to the image side and then moves to the object side. In addition, by making the movement trajectories of the lens groups that are not adjacent to each other the same when zooming, the plurality of lens groups can be linked and moved together. By linking a plurality of lens groups and moving them together, the lens group holding structure in the lens barrel can be simplified, contributing to downsizing.
In addition, the variable magnification optical system of each of the above embodiments may be in a reduced tube state in which the distance between the lenses is further reduced. The variable magnification optical system of each of the above embodiments can improve portability by taking a contracted state. In the variable power optical systems of the above-described embodiments, it is preferable that the distance between the first lens group and the second lens group having the largest distance between the lens groups is reduced to be changed into a contracted state.

  Further, the variable magnification optical system of each of the above embodiments includes a focusing lens that includes a part of a lens group, an entire lens group, or a plurality of lens groups in order to perform focusing from an object at infinity to an object at a short distance. It is good also as a structure which moves to an optical axis direction as a group. In particular, in the variable power optical system of each of the above embodiments, it is desirable that the third lens group is a focusing lens group. Such a focusing lens group can be applied to autofocus, and is also suitable for driving by an autofocus motor such as an ultrasonic motor.

  In the variable magnification optical system of each of the above embodiments, either the entire 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 the optical axis It can also be set as the structure which carries out anti-vibration by carrying out rotational movement (oscillation) to the in-plane direction containing. In particular, in the variable power optical system of each of the above embodiments, it is preferable that the second lens group is an anti-vibration lens group. In the variable power optical system of each of the above embodiments, the fifth lens group may be an anti-vibration lens group.

  Further, the lens surface of the lens constituting the variable magnification optical system of each of the above embodiments may be a spherical surface, a flat surface, or an aspherical 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 each of the above embodiments, the aperture stop is preferably disposed between the fourth lens group and the fifth lens group, and the role is replaced by a lens frame without providing a member as the aperture stop. It is good also as a structure.

  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 each of the above embodiments. Thereby, flare and ghost can be reduced, and high optical performance with high contrast can be achieved. In particular, in the variable magnification optical systems of the above embodiments, it is preferable to provide an antireflection film on the object side lens surface of the lens included in the most image side lens group.

Next, a camera equipped with the variable magnification optical system of the present application will be described with reference to FIG.
FIG. 13 is a diagram illustrating a configuration of a camera including the variable magnification optical system of the present application.
This camera 1 is an interchangeable lens type digital single-lens reflex camera 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 (not shown) that is a subject is collected by the photographing lens 2 and imaged on the focusing screen 4 via the quick return mirror 3. The light imaged on the focusing screen 4 is reflected in the pentaprism 5 a plurality of times and guided to the eyepiece lens 6. Thus, the photographer can observe the subject image as an erect image through the eyepiece 6.
When the release button (not shown) is pressed by the photographer, the quick return mirror 3 is retracted out of the optical path, and light from the subject (not shown) reaches the image sensor 7. Thereby, the light from the subject is picked up by the image pickup device 7 and recorded as a subject image 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 on the camera 1 is small and has good optical performance as described above. That is, the camera 1 can achieve downsizing and good optical performance. Even if a camera equipped with the variable magnification optical system according to the second to sixth examples as the photographing lens 2 is configured, the same effect as the camera 1 can be obtained. In addition, even when the zoom optical system according to each of the above embodiments is mounted on a camera having a configuration that does not include the quick return mirror 3, the same effects as those of the camera 1 can be obtained.

Finally, the outline of the manufacturing method of the variable magnification optical system of this application is demonstrated based on FIG.
FIG. 14 is a diagram showing an outline of the manufacturing method of the variable magnification optical system of the present application.
The variable magnification optical system manufacturing method shown in FIG. 14 has, in order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a negative refractive power. Manufacturing method of variable power optical system having third lens group, fourth lens group having positive refractive power, fifth lens group having negative refractive power, and sixth lens group having positive refractive power However, the following steps S1 to S3 are included.
Step S1: First to sixth lens groups are prepared, and each lens group is sequentially arranged in the lens barrel from the object side. Then, by providing a known moving mechanism in the lens barrel, the distance between the lens groups changes at the time of zooming from the wide-angle end state to the telephoto end state.
Step S2: A known moving mechanism is provided in the lens barrel so that the third lens group moves when focusing from an object at infinity to an object at a short distance.
Step S3: The variable magnification optical system is made to satisfy the following conditional expression (1).
(1) 1.00 <fG1 / f1 <3.00
However,
fG1: Focal length of the lens component closest to the object side in the first lens group f1: Focal length of the first lens group

  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 good optical performance can be manufactured.

G1: first lens group, G2: second lens group, G3: third lens group, G4: fourth lens group, G5: fifth lens group, G6: sixth lens group, G7: seventh lens group, S : Aperture stop, W: wide-angle end state, T: telephoto end state

Claims (7)

In order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens having a positive refractive power A group, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power,
During zooming between the wide-angle end state and the telephoto end state, the distance between the lens groups changes,
During focusing, the third lens group moves,
A variable magnification optical system that satisfies the following conditional expression.
1.00 <fG1 / f1 <3.00
However,
fG1: Focal length of the lens element closest to the object side in the first lens group f1: Focal length of the first lens group The zoom optical system according to claim 1, wherein the following conditional expression is satisfied.
0.30 <(− f1) / f6 <0.60
However,
f1: Focal length of the first lens group f6: Focal length of the sixth lens group The zoom optical system according to claim 1 or 2, wherein the following conditional expression is satisfied.
0.68 <(-fn) / fp <1.00
However,
fn: focal length of the most image-side negative lens in the first lens group fp: focal length of the most image-side positive lens in the first lens group   The zoom optical system according to any one of claims 1 to 3, wherein the third lens group includes one lens component.   5. The variable magnification optical system according to claim 1, wherein at least one lens component in the second lens group moves so as to include a component in a direction perpendicular to the optical axis.   An optical apparatus having the variable magnification optical system according to any one of claims 1 to 5. In order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens having a positive refractive power A variable magnification optical system having a group, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power,
When changing the magnification between the wide-angle end state and the telephoto end state, the interval between the lens groups changes,
The third lens group is moved during focusing,
A method of manufacturing a variable power optical system in which the variable power optical system satisfies the following conditional expression.
1.00 <fG1 / f1 <3.00
However,
fG1: Focal length of the lens element closest to the object side in the first lens group f1: Focal length of the first lens group

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