JP5246226B2 - OPTICAL SYSTEM, OPTICAL DEVICE, AND OPTICAL SYSTEM MANUFACTURING METHOD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical system and an optical device favorably suppressing aberration fluctuation when correcting blur of an image; and to provide a method for manufacturing the optical system. <P>SOLUTION: This optical system includes, in order from an object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group G3 having the positive refractive power. When focusing from an infinite-distance object to a close-distance object, the second lens group G2 moves, and at least a part of the third lens group G3 moves so as to include a component in the direction orthogonal to the optical axis and satisfies a prescribed conditional expression. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

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

  Conventionally, an 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).

JP 2008-145584 A

However, the conventional optical system as described above has a problem that aberration fluctuations during image blur correction are large.
Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide an optical system, an optical device, and a method for manufacturing the optical system, in which aberration fluctuation during image blur correction is satisfactorily suppressed.

In order to solve the above problems, the present invention
In order from the object side, the first lens group having a positive refractive power, the second lens group having a negative refractive power, and the third lens group having a positive refractive power are substantially three lens groups. Consists of
When focusing from an object at infinity to a near object, the second lens group moves,
Moving so that at least a part of the third lens group includes a component in a direction perpendicular to the optical axis;
An optical system characterized by satisfying the following conditional expression is provided.
0.30 <f1 / f <0.60
0.30 ≦ (−f2) / f <0.60
0.30 <f3 / f <0.60
0.50 <| fVR | /f3≦1.00
However,
f: focal length of the optical system f1: focal length of the first lens group f2: focal length of the second lens group f3: focal length of the third lens group fVR: at least part of the third lens group Focal length

The present invention also provides
An optical device comprising the optical system is provided.
The present invention also provides
In order from the object side, the first lens group having a positive refractive power, the second lens group having a negative refractive power, and the third lens group having a positive refractive power are substantially three lens groups. An optical system manufacturing method comprising:
The first lens group, the second lens group, and the third lens group satisfy the following conditional expressions:
The second lens group moves when focusing from an object at infinity to an object at a short distance,
An optical system manufacturing method is provided, wherein at least a part of the third lens group moves so as to include a component in a direction orthogonal to the optical axis.
0.30 <f1 / f <0.60
0.30 ≦ (−f2) / f <0.60
0.30 <f3 / f <0.60
0.50 <| fVR | /f3≦1.00
However,
f: focal length of the optical system f1: focal length of the first lens group f2: focal length of the second lens group f3: focal length of the third lens group fVR: at least part of the third lens group Focal length

  According to the present invention, it is possible to provide an optical system, an optical device, and a method for manufacturing the optical system, in which aberration fluctuation during image blur correction is satisfactorily suppressed.

It is a figure which shows the lens structure of the optical system which concerns on 1st Example of this application. (A) and (b) are diagrams showing various aberrations of the optical system according to the first example when an object at infinity is in focus, and anti-vibration against rotation blur of 0.3 ° when the object at infinity is in focus. It is a meridional transverse aberration diagram when It is a figure which shows the lens structure of the optical system which concerns on 2nd Example of this application. (A) and (b) are diagrams showing various aberrations of the optical system according to the second example when an object at infinity is in focus, and anti-vibration against 0.3 ° rotation blurring at the time of focusing on an object at infinity. It is a meridional transverse aberration diagram when It is a figure which shows the lens structure of the optical system which concerns on 3rd Example of this application. (A) and (b) are diagrams showing various aberrations of the optical system according to the third example when an object at infinity is in focus, and anti-vibration against 0.3 ° rotation blurring at the time of focusing on an object at infinity. It is a meridional transverse aberration diagram when It is a figure which shows the structure of the camera provided with the optical system of this application. It is a figure which shows the manufacturing method of the optical system of this application.

Hereinafter, an optical system, an optical device, and a method for manufacturing the optical system of the present application will be described.
The 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, and a third lens group having a positive refractive power, When focusing from an object at infinity to an object at a short distance, the second lens group moves, and at least a part of the third lens group moves so as to include a component in a direction perpendicular to the optical axis. Formula (1), (2), (3) is satisfied, It is characterized by the above-mentioned.
(1) 0.30 <f1 / f <0.60
(2) 0.10 <(− f2) / f <0.60
(3) 0.30 <f3 / f <0.60
However,
f: focal length of the optical system f1: focal length of the first lens group f2: focal length of the second lens group f3: focal length of the third lens group

As described above, the optical system of the present application moves the second lens group as the focusing lens group in the optical axis direction and performs focusing from an object at infinity to a short distance object, thereby reducing aberration fluctuations during focusing. Can be small. Further, the focusing lens group can be reduced in weight, thereby enabling high-speed focusing.
In addition, as described above, the optical system of the present application moves image at least part of the third lens group as a vibration-proof lens group so as to include a component in a direction orthogonal to the optical axis, thereby preventing image blur caused by camera shake or the like. Correction (anti-vibration) can be performed. In addition, aberration variation during image blur correction can be reduced.

Conditional expression (1) defines the focal length of the entire optical system of the present application and the focal length of the first lens group. By satisfying conditional expression (1), the optical system of the present application can prevent the total length of the optical system from increasing, and can satisfactorily correct field curvature and coma.
If the corresponding value of the conditional expression (1) of the optical system of the present application exceeds the upper limit value, the refractive power of the first lens group decreases, the total length of the optical system increases, and it becomes difficult to secure the peripheral light amount. This is not preferable. Further, if the refractive power of the third lens unit is increased in order to shorten the total length of the optical system, it is not preferable because it becomes difficult to correct spherical aberration and field curvature. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (1) to 0.59.
On the other hand, if the corresponding value of the conditional expression (1) of the optical system of the present application is less than the lower limit value, the refractive power of the first lens group increases, and it becomes difficult to correct field curvature and coma. It is not preferable. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (1) to 0.40.

Conditional expression (2) defines the focal length of the entire optical system of the present application and the focal length of the second lens group. By satisfying conditional expression (2), the optical system of the present application can satisfactorily correct spherical aberration and curvature of field and prevent the total length of the optical system from increasing.
When the corresponding value of the conditional expression (2) of the optical system of the present application exceeds the upper limit value, the refractive power of the second lens group becomes small, and it becomes impossible to sufficiently correct spherical aberration and curvature of field, which is preferable. Absent. Moreover, the movement amount at the time of focusing of the 2nd lens group which is a focusing lens group becomes large, and since the full length of an optical system will become large, it is unpreferable. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (2) to 0.50.
On the other hand, if the corresponding value of conditional expression (2) of the optical system of the present application is less than the lower limit value, the refractive power of the second lens group becomes large, and it becomes difficult to correct spherical aberration and curvature of field. It is not preferable. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (2) to 0.20.

Conditional expression (3) defines the focal length of the entire optical system of the present application and the focal length of the third lens group. By satisfying conditional expression (3), the optical system of the present application can satisfactorily correct spherical aberration, coma aberration, and distortion aberration, and sufficiently ensure back focus.
If the corresponding value of the conditional expression (3) of the optical system of the present application exceeds the upper limit value, the refractive power of the third lens group becomes small and the entire length of the optical system becomes large, which is not preferable. Increasing the refractive power of the first lens group and the second lens group to alleviate this effect is not preferable because it becomes difficult to correct spherical aberration, coma aberration, and distortion aberration. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (3) to 0.59.
On the other hand, when the corresponding value of conditional expression (3) of the optical system of the present application is less than the lower limit value, the refractive power of the third lens group increases. For this reason, it becomes difficult to correct spherical aberration and coma aberration, and it becomes difficult to secure the back focus, which is not preferable. Increasing the refractive power of the second lens group to ensure back focus is not preferable because it becomes difficult to correct spherical aberration. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (3) to 0.40.
With the above configuration, it is possible to realize an optical system that satisfactorily suppresses aberration fluctuations during image blur correction and aberration fluctuations during focusing.

  In the optical system of the present application, it is preferable that the at least part of the third lens group is a negative lens group having a negative refractive power. With this configuration, it is possible to reduce aberration fluctuations during image blur correction.

The optical system of the present application preferably satisfies the following conditional expression (4).
(4) 0.50 <(− fVR) / f3 <1.00
However,
fVR: focal length of the negative lens group f3: focal length of the third lens group

Conditional expression (4) defines the focal length of the third lens group and the focal length of the negative lens group. By satisfying conditional expression (4), the optical system of the present application can prevent an increase in the size of the optical system and can satisfactorily correct decentration coma during image blur correction.
When the corresponding value of the conditional expression (4) of the optical system of the present application exceeds the upper limit value, the refractive power of the negative lens group in the third lens group, that is, the image stabilizing lens group, becomes small. For this reason, the amount of movement of the image stabilizing lens group at the time of image blur correction becomes large, and the outer diameter of the image stabilizing unit or the lens barrel increases, which is not preferable. Further, if the refractive power of the third lens group is reduced so that the corresponding value of conditional expression (4) of the optical system of the present application does not exceed the upper limit value, the total length of the optical system increases, which is not preferable. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (4) to 0.90.
On the other hand, if the corresponding value of the conditional expression (4) of the optical system of the present application is below the lower limit value, the refractive power of the anti-vibration lens group becomes large, and it becomes difficult to correct decentration coma at the time of image blur correction. Therefore, it is not preferable. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (4) to 0.55.

  In the optical system of the present application, the third lens group is disposed closer to the image side than the negative lens group, and the first positive lens group having a positive refractive power disposed closer to the object side than the negative lens group. And a second positive lens group having positive refractive power. With this configuration, it is possible to reduce aberration fluctuations during image blur correction.

It is desirable that the optical system of the present application satisfies the following conditional expression (5).
(5) 0.60 <(− fVR) / fp2 <1.50
However,
fVR: focal length of the negative lens group fp2: focal length of the second positive lens group

Conditional expression (5) defines the focal length of the second positive lens group and the focal length of the negative lens group in the third lens group. By satisfying conditional expression (5), the optical system of the present application can prevent an increase in the size of the optical system and can satisfactorily correct decentration coma during image blur correction.
When the corresponding value of the conditional expression (5) of the optical system of the present application exceeds the upper limit value, the refractive power of the negative lens group, that is, the image stabilizing lens group, becomes small. For this reason, the amount of movement of the image stabilizing lens group at the time of image blur correction becomes large, and the outer diameter of the image stabilizing unit or the lens barrel increases, which is not preferable. In addition, the effect of this application can be made more reliable by setting the upper limit of conditional expression (5) to 1.30.
On the other hand, if the corresponding value of the conditional expression (5) of the optical system of the present application is below the lower limit value, the refractive power of the image stabilizing lens group becomes large, and it becomes difficult to correct the decentration coma aberration at the time of image blur correction. Therefore, it is not preferable. In addition, the effect of this application can be made more reliable by setting the lower limit of conditional expression (5) to 0.70.

In the optical system of the present application, it is preferable that the first positive lens group includes a single cemented lens formed by cementing a positive lens and a negative lens. With this configuration, the size of the lens barrel can be reduced.
In the optical system of the present application, it is preferable that the second lens group includes two negative lenses and one positive lens. With this configuration, it is possible to reduce aberration fluctuations during focusing.

  The optical device of the present application includes the optical system configured as described above. Thereby, it is possible to realize an optical device that favorably suppresses aberration fluctuation during image blur correction.

The 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. The first lens group, the second lens group, and the third lens group satisfy the following conditional expressions (1), (2), and (3): The second lens group is moved at the time of focusing from an object at infinity to an object at a short distance so that at least a part of the third lens group includes a component in a direction orthogonal to the optical axis. It is characterized by.
(1) 0.30 <f1 / f <0.60
(2) 0.10 <(− f2) / f <0.60
(3) 0.30 <f3 / f <0.60
However,
f: focal length of the optical system f1: focal length of the first lens group f2: focal length of the second lens group f3: focal length of the third lens group It is possible to manufacture an optical system that favorably suppresses fluctuations in aberrations during blur correction.

Hereinafter, optical systems according to numerical examples of the present application will be described with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is a diagram showing a lens configuration of an optical system according to Example 1 of the present application.
The optical system according to this 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 group having a positive refractive power. And G3.
The first lens group G1 includes, in order from the object side, a biconvex positive lens L11, a positive meniscus lens L12 having a convex surface facing the object side, a biconvex positive lens L13, and a biconcave negative lens L14. And a cemented lens of a negative meniscus lens L15 having a convex surface facing the object side and a biconvex positive lens L16.
The second lens group G2 includes, in order from the object side, a biconcave negative lens L21, and a cemented lens of a biconvex positive lens L22 and a biconcave negative lens L23.

The third lens group G3 includes, in order from the object side, an aperture stop S, a first positive lens group Gp1 having a positive refractive power, a negative lens group GVR having a negative refractive power, and a first lens having a positive refractive power. It consists of two positive lens groups Gp2.
The first positive lens group Gp1 includes, in order from the object side, only a cemented lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32.
The negative lens group GVR includes, in order from the object side, only a cemented lens of a positive meniscus lens L33 having a convex surface facing the image side and a biconcave negative lens L34.
The second positive lens group Gp2 is composed of, in order from the object side, only a cemented lens of a biconvex positive lens L35 and a negative meniscus lens L36 having a convex surface directed toward the image side.

In the optical system according to the present embodiment, the entire second lens group G2 moves toward the image side, and thereby focusing from an object at infinity to an object at short distance is performed.
In the optical system according to the present embodiment, the negative lens group GVR in the third lens group G3 moves so as to include a component in a direction orthogonal to the optical axis as an anti-vibration lens group, thereby correcting image blur. be able to.

Table 1 below lists values of specifications of the optical system according to the present example.
In Table 1, f indicates the focal length, and BF indicates the back focus.
In [Surface data], the surface number is the order of the lens surfaces counted from the object side, r is the radius of curvature of the lens surfaces, d is the distance between the lens surfaces, nd is the refractive index with respect to the d-line (wavelength λ = 587.6 nm), νd represents the Abbe number for the d-line (wavelength λ = 587.6 nm). The object plane indicates the object plane, (aperture S) indicates the aperture stop S, and the image plane indicates the image plane I. The radius of curvature r = ∞ indicates a plane, and the description of the refractive index nd of air = 1.000 is omitted.

In [various data], FNO represents the F number, 2ω represents the angle of view, Y represents the image height, and TL represents the total length of the optical system.
Here, “mm” is generally used as a unit of the focal length f, the radius of curvature r, and other lengths listed in Table 1. 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.

  Here, in the lens in which the focal length of the entire lens system is f and the image stabilization coefficient (ratio of the image movement amount on the image plane I to the movement amount of the image stabilization lens group at the time of blur correction) is K, the angle θ In order to correct the rotational blur of the lens, the anti-vibration lens group may be moved in a direction orthogonal to the optical axis by (f · tan θ) / K. Therefore, since the optical system according to the present example has the image stabilization coefficient of 0.80 and the focal length of 132.9 (mm), the movement of the image stabilization lens group for correcting the rotation blur of 0.3 ° is performed. The amount is 0.87 (mm).

(Table 1) First Example
[Surface data]
Surface number r d nd νd
Object ∞
1 218.5583 7.000 1.618000 63.37
2 -540.2614 0.200
3 103.9713 7.000 1.618000 63.37
4 438.0518 0.200
5 70.4602 12.000 1.497820 82.51
6 -296.9672 3.000 1.834807 42.72
7 138.0366 9.005
8 62.1858 2.500 1.800999 34.96
9 38.2633 12.000 1.497820 82.51
10 -456.2726 3.000
11 -496.4748 2.500 1.583130 59.39
12 45.5419 4.281
13 357.5640 4.000 1.846660 23.78
14 -110.4606 2.000 1.658441 50.89
15 46.8715 15.123
16 (Aperture S) ∞ 2.000
17 173.9463 2.000 1.728250 28.46
18 35.3526 7.500 1.834807 42.72
19 -111.2682 2.000
20 -166.6361 4.000 1.846660 23.78
21 -42.0037 1.500 1.667551 41.96
22 44.0612 7.964
23 55.3579 7.500 1.834807 42.72
24 -50.6631 2.000 1.846660 23.78
25 -1557.1808 BF
Image plane ∞

[Various data]
f 132.9
FNO 1.8
2ω 18.3
Y 21.6
TL 162.5
BF 42.2

[Lens group data]
Group start surface f
1 1 72.618
2 11 -39.896
3 16 72.553
p1 17 69.290
VR 20 -62.121
p2 23 65.095

[Conditional expression values]
(1) f1 / f = 0.55
(2) (−f2) /f=0.30
(3) f3 / f = 0.55
(4) (-fVR) /f3=0.86
(5) (-fVR) /fp2=0.95

FIGS. 2A and 2B are diagrams showing various aberrations of the optical system according to the first example when an object at infinity is in focus, and a rotational shake of 0.3 ° when the object at infinity is in focus. FIG. 6 is a meridional lateral aberration diagram in the case where image stabilization is performed.
2A and 2B, FNO indicates an F number and A indicates a half angle of view. The spherical aberration diagram shows the F-number value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum half field angle, and the coma diagram shows the half field value. d represents a d-line (λ = 587.6 nm), and g represents a g-line (λ = 435.8 nm). 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 example are also used in the aberration diagrams of the examples shown below.
From the various aberration diagrams, the optical system according to the present embodiment has excellent imaging performance by properly correcting various aberrations, and also has excellent imaging performance even during image stabilization. Recognize.

(Second embodiment)
FIG. 3 is a diagram showing a lens configuration of an optical system according to the second example of the present application.
The optical system according to this 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 group having a positive refractive power. And G3.
The first lens group G1 includes, in order from the object side, a biconvex positive lens L11, a positive meniscus lens L12 having a convex surface facing the object side, a biconvex positive lens L13, and a biconcave negative lens L14. And a cemented lens of a negative meniscus lens L15 having a convex surface facing the object side and a biconvex positive lens L16.
The second lens group G2 includes, in order from the object side, a biconcave negative lens L21, and a cemented lens of a positive meniscus lens L22 having a convex surface facing the image side and a biconcave negative lens L23.

The third lens group G3 includes, in order from the object side, an aperture stop S, a first positive lens group Gp1 having a positive refractive power, a negative lens group GVR having a negative refractive power, and a first lens having a positive refractive power. It consists of two positive lens groups Gp2.
The first positive lens group Gp1 includes, in order from the object side, only a cemented lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32.
The negative lens group GVR includes, in order from the object side, only a cemented lens of a positive meniscus lens L33 having a convex surface facing the image side and a biconcave negative lens L34.
The second positive lens group Gp2 includes, in order from the object side, only a cemented lens of a biconvex positive lens L35 and a biconcave negative lens L36.

In the optical system according to the present embodiment, the entire second lens group G2 moves toward the image side, and thereby focusing from an object at infinity to an object at short distance is performed.
In the optical system according to the present embodiment, the negative lens group GVR in the third lens group G3 moves so as to include a component in a direction orthogonal to the optical axis as an anti-vibration lens group, thereby correcting image blur. be able to.

Table 2 below lists values of specifications of the optical system according to the present example.
Here, since the optical system according to the present example has an anti-vibration coefficient of 0.80 and a focal length of 132.2 (mm), an anti-vibration lens group for correcting rotational blur of 0.3 ° is used. The amount of movement is 0.87 (mm).

(Table 2) Second Example
[Surface data]
Surface number r d nd νd
Object ∞
1 187.7777 7.000 1.618000 63.37
2 -496.3475 0.200
3 103.0350 7.000 1.618000 63.37
4 361.8571 0.200
5 73.1998 12.000 1.497820 82.51
6 -276.4051 3.000 1.834807 42.72
7 139.3412 8.016
8 82.0080 2.500 1.603420 38.01
9 36.2666 12.000 1.497820 82.51
10 -432.9076 3.000
11 -322.8976 2.500 1.579570 53.71
12 46.9288 5.140
13 -1251.6819 4.000 1.846660 23.78
14 -88.6342 2.000 1.516800 64.11
15 46.3513 15.826
16 (Aperture S) ∞ 2.000
17 100.2261 2.000 1.672700 32.11
18 35.6468 7.500 1.729157 54.66
19 -100.6435 2.000
20 -149.0360 4.000 1.846660 23.78
21 -46.1845 1.500 1.623740 47.05
22 41.7440 8.298
23 51.6961 7.000 1.729157 54.66
24 -53.1754 2.000 1.728250 28.46
25 3202.3299 BF
Image plane ∞

[Various data]
f 132.3
FNO 1.8
2ω 18.4
Y 21.6
TL 162.5
BF 41.8

[Lens group data]
Group start surface f
1 1 74.678
2 11 -42.925
3 16 75.297
p1 17 65.749
VR 20 -62.768
p2 23 71.890

[Conditional expression values]
(1) f1 / f = 0.56
(2) (-f2) /f=0.32
(3) f3 / f = 0.57
(4) (-fVR) /f3=0.83
(5) (-fVR) /fp2=0.87

FIGS. 4A and 4B are diagrams showing various aberrations of the optical system according to the second example when an object at infinity is focused, and a rotational shake of 0.3 ° when the object at infinity is focused. FIG. 6 is a meridional lateral aberration diagram in the case where image stabilization is performed.
From the various aberration diagrams, the optical system according to the present embodiment has excellent imaging performance by properly correcting various aberrations, and also has excellent imaging performance even during image stabilization. Recognize.

(Third embodiment)
FIG. 5 is a diagram showing a lens configuration of an optical system according to the third example of the present application.
The optical system according to this 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 group having a positive refractive power. And G3.
The first lens group G1 includes, in order from the object side, a biconvex positive lens L11, a cemented lens of a biconvex positive lens L12 and a biconcave negative lens L13, and a negative lens with a convex surface facing the object side. It consists of a cemented lens of a meniscus lens L14 and a positive meniscus lens L15 having a convex surface facing the object side.
The second lens group G2 includes, in order from the object side, a biconcave negative lens L21, and a cemented lens of a biconvex positive lens L22 and a biconcave negative lens L23.

The third lens group G3 includes, in order from the object side, an aperture stop S, a first positive lens group Gp1 having a positive refractive power, a negative lens group GVR having a negative refractive power, and a first lens having a positive refractive power. It consists of two positive lens groups Gp2.
The first positive lens group Gp1 includes, in order from the object side, only a cemented lens of a negative meniscus lens L31 having a convex surface facing the object side and a biconvex positive lens L32.
The negative lens group GVR includes, in order from the object side, a cemented lens of a biconvex positive lens L33 and a biconcave negative lens L34, and a negative meniscus lens L35 having a convex surface facing the image side.
The second positive lens group Gp2 includes, in order from the object side, a biconvex positive lens L36, a cemented lens of a biconvex positive lens L37, and a negative meniscus lens L38 having a convex surface facing the image side.

In the optical system according to the present embodiment, the entire second lens group G2 moves toward the image side, and thereby focusing from an object at infinity to an object at short distance is performed.
In the optical system according to the present embodiment, the entire negative lens group GVR in the third lens group G3 moves so as to include a component in a direction orthogonal to the optical axis as an anti-vibration lens group, thereby correcting image blur. It can be carried out.

Table 3 below lists values of specifications of the optical system according to the present example.
Here, since the optical system according to the present example has an anti-vibration coefficient of 0.92 and a focal length of 132.3 (mm), the anti-vibration lens group for correcting the rotation blur of 0.3 ° is used. The amount of movement is 0.75 (mm).

(Table 3) Third Example
[Surface data]
Surface number r d nd νd
Object ∞
1 99.8339 11.000 1.603001 65.46
2 -592.6523 0.200
3 84.1919 13.000 1.497820 82.51
4 -203.6824 3.000 1.672700 32.11
5 331.1476 0.200
6 59.7075 3.000 1.834807 42.72
7 32.0183 14.000 1.618000 63.37
8 129.9551 5.190
9 -417.2325 2.500 1.804000 46.57
10 74.2498 1.659
11 141.2688 5.000 1.846660 23.78
12 -201.1402 2.000 1.603001 65.46
13 42.5251 17.021
14 (Aperture S) ∞ 2.000
15 156.9902 1.800 1.903660 31.27
16 30.0000 8.000 1.816000 46.62
17 -234.0935 2.000
18 403.6661 5.000 2.000690 25.45
19 -56.0817 1.500 1.548141 45.79
20 34.7886 6.892
21 -37.1080 1.500 1.548141 45.79
22 -545.2217 7.499
23 97.2472 6.000 1.603001 65.46
24 -48.6236 0.100
25 74.0949 8.000 1.497820 82.51
26 -40.5063 2.000 1.612930 36.96
27 -788.8992 BF
Image plane ∞

[Various data]
f 132.3
FNO 1.8
2ω 18.4
Y 21.6
TL 172.5
BF 42.4

[Lens group data]
Group start surface f
1 1 74.741
2 9 -49.371
3 14 76.734
p1 15 159.420
VR 18 -52.643
p2 23 43.282

[Conditional expression values]
(1) f1 / f = 0.57
(2) (−f2) /f=0.37
(3) f3 / f = 0.58
(4) (-fVR) /f3=0.69
(5) (-fVR) /fp2=1.22

FIGS. 6A and 6B are diagrams showing various aberrations of the optical system according to the third example when an object at infinity is focused, and a rotational shake of 0.3 ° when the object at infinity is focused. FIG. 6 is a meridional lateral aberration diagram in the case where image stabilization is performed.
From the various aberration diagrams, the optical system according to the present embodiment has excellent imaging performance by properly correcting various aberrations, and also has excellent imaging performance even during image stabilization. Recognize.

According to each of the above embodiments, it is possible to realize an optical system that satisfactorily suppresses the aberration fluctuation at the time of image blur correction and the aberration fluctuation at the time of focusing.
Here, each said Example has shown one specific example of this invention, and this invention is not limited to these.
In addition, the following content can be suitably employ | adopted in the range which does not impair the optical performance of the optical system of this application.
Although a three-group configuration is shown as a numerical example of the optical system of the present application, the present application is not limited to this, and an optical system of another group configuration (for example, a fourth group, a fifth group, etc.) 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 plane side of the optical system of the present application may be used. The lens group indicates a portion having at least one lens separated by an air interval.

Further, the 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 in order to perform focusing from an object at infinity to a near object in the optical axis direction. It is good also as a structure moved to. In particular, it is preferable that at least a part of the second lens group is a 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.
In the optical system of the present application, either the entire lens group or a part thereof is moved so as to include a component perpendicular to the optical axis as an anti-vibration lens group, or rotated in an in-plane direction including the optical axis ( The image blur caused by the camera shake can be corrected by swinging). In particular, in the optical system of the present application, it is preferable that at least a part of the third lens group is a vibration-proof lens group.

  The lens surface of the lens constituting the 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 optical system of the present application, the aperture stop is preferably disposed in or near the third lens group. However, a lens frame may be used as a substitute for the aperture stop without providing a member.
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 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 equipped with the optical system of the present application will be described with reference to FIG.
FIG. 7 is a diagram illustrating a configuration of a camera including the optical system of the present application.
The camera 1 is a digital single-lens reflex camera provided with the optical system according to the first embodiment as a photographing lens 2 as shown in FIG.
In the camera 1, light from an object (subject) (not shown) is collected by the taking lens 2 and imaged on the focusing screen 4 through 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.
With the configuration described above, the present camera 1 equipped with the optical system according to the first embodiment as the photographing lens 2 can satisfactorily suppress aberration fluctuations during image blur correction and achieve good optical performance. It should be noted that the same effect as that of the camera 1 can be obtained even if a camera in which the optical system according to the second and third embodiments is mounted as the photographing lens 2 is configured. Further, even when the 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 effect as the camera 1 can be obtained.

Hereinafter, the outline of the manufacturing method of the optical system of this application is demonstrated based on FIG.
FIG. 8 is a diagram showing a method for manufacturing the optical system of the present application.
The 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. The manufacturing method of the optical system which has, Comprising: Each following step S1-S3 is included.

Step S1: Each lens group is prepared so that the first lens group, the second lens group, and the third lens group satisfy the following conditional expressions (1), (2), and (3). Arrange sequentially from the object side.
(1) 0.30 <f1 / f <0.60
(2) 0.10 <(− f2) / f <0.60
(3) 0.30 <f3 / f <0.60
However,
f: focal length of optical system f1: focal length of first lens group f2: focal length of second lens group f3: focal length of third lens group

Step S2: By providing a known moving mechanism or the like, the second lens group is moved when focusing from an object at infinity to an object at a short distance.
Step S3: By providing a known moving mechanism, at least a part of the third lens group is moved so as to include a component in a direction orthogonal to the optical axis.
According to such an optical system manufacturing method of the present application, it is possible to manufacture an optical system that satisfactorily suppress aberration fluctuations during image blur correction.

G1 1st lens group G2 2nd lens group G3 3rd lens group Gp1 1st positive lens group Gp2 2nd positive lens group GVR Negative lens group I Image surface S Aperture stop

Claims (8)

In order from the object side, the first lens group having a positive refractive power, the second lens group having a negative refractive power, and the third lens group having a positive refractive power are substantially three lens groups. Consists of
When focusing from an object at infinity to a near object, the second lens group moves,
Moving so that at least a part of the third lens group includes a component in a direction perpendicular to the optical axis;
An optical system satisfying the following conditional expression:
0.30 <f1 / f <0.60
0.30 ≦ (−f2) / f <0.60
0.30 <f3 / f <0.60
0.50 <| fVR | /f3≦1.00
However,
f: focal length of the optical system f1: focal length of the first lens group f2: focal length of the second lens group f3: focal length of the third lens group fVR: at least part of the third lens group Focal length   The optical system according to claim 1, wherein the at least part of the third lens group is a negative lens group having negative refractive power.   The third lens group has a first positive lens group having a positive refractive power disposed on the object side relative to the negative lens group, and a positive refractive power disposed on the image side relative to the negative lens group. The optical system according to claim 2, further comprising a second positive lens group. The optical system according to claim 3, wherein the following conditional expression is satisfied.
0.60 <| fVR | / fp2 <1.50
However,
fVR: focal length of the at least part of the third lens group fp2: focal length of the second positive lens group   5. The optical system according to claim 3, wherein the first positive lens group includes one cemented lens formed by cementing a positive lens and a negative lens.   The optical system according to any one of claims 1 to 5, wherein the second lens group includes two negative lenses and one positive lens.   An optical apparatus comprising the optical system according to any one of claims 1 to 6. In order from the object side, the first lens group having a positive refractive power, the second lens group having a negative refractive power, and the third lens group having a positive refractive power are substantially three lens groups. An optical system manufacturing method comprising:
The first lens group, the second lens group, and the third lens group satisfy the following conditional expressions:
The second lens group moves when focusing from an object at infinity to an object at a short distance,
A method of manufacturing an optical system, wherein at least a part of the third lens group moves so as to include a component in a direction orthogonal to the optical axis.
0.30 <f1 / f <0.60
0.30 ≦ (−f2) / f <0.60
0.30 <f3 / f <0.60
0.50 <| fVR | /f3≦1.00
However,
f: focal length of the optical system f1: focal length of the first lens group f2: focal length of the second lens group f3: focal length of the third lens group fVR: at least part of the third lens group Focal length

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