JP2009086537A - Zoom lens and optical apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens having higher optical performance. <P>SOLUTION: The zoom lens 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; a third lens group G3 having a positive refractive power; and a fourth lens group G4 having a positive refractive power. The first lens group includes two pairs of cemented lenses having a positive refractive power. Upon zooming from a wide angle end state W to a telephoto end state T, a distance between the first lens group and the second lens group varies, a distance between the second lens group and the third lens group varies, and at least a portion of the fourth lens group moves in a direction perpendicular to the optical axis. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a zoom lens for a single-lens reflex camera using a film or a solid-state imaging device, and an optical apparatus having the same.

Conventionally, a large-diameter zoom lens having an anti-vibration function has been proposed (see, for example, Patent Document 1).
JP 2003-344766 A

  In recent years, a zoom lens having higher optical performance has been demanded as the performance of cameras has been improved.

  An object of the present invention is to provide a zoom lens having higher optical performance and an optical apparatus having the same.

  In order to solve the above-described problems, the present invention is arranged in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive refractive power. A fourth lens group, and the first lens group includes two sets of cemented lenses having a positive refractive power, and the first lens group and the second lens at the time of zooming from the wide-angle end state to the telephoto end state The distance between the groups changes, the distance between the second lens group and the third lens group changes, and the fourth lens group moves at least a part of the lenses in a direction orthogonal to the optical axis. Provide zoom lens.

  The present invention also provides an optical device having the zoom lens.

  Further, according to the present invention, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power are provided. The first lens group includes two sets of cemented lenses having positive refractive power, and the fourth lens group is a zoom lens that moves at least a part of the lenses in a direction perpendicular to the optical axis, Varying from the wide-angle end state to the telephoto end state is performed by changing the distance between the first lens group and the second lens group and the distance between the second lens group and the third lens group. A zoom lens zooming method is provided.

  According to the present invention, it is possible to provide a zoom lens having higher optical performance and an optical apparatus having the same.

  The zoom lens having the image stabilization function according to the embodiment of the present invention will be described in detail below.

  The zoom lens having the image stabilization mechanism according to the embodiment includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, The fourth lens group has a refractive power, the first lens group has two sets of cemented lenses having a positive refractive power, and the second lens group and the third lens group upon zooming from the wide-angle end state to the telephoto end state. It is the structure which moves. Such a configuration is advantageous for simplifying the zoom mechanism.

  Further, since the first lens group includes two sets of cemented lenses having positive refractive power, the refractive power of each cemented lens can be reduced, and various aberrations such as axial chromatic aberration and spherical aberration can be corrected well. Can do.

  The fourth lens group is configured to perform image blur correction on the image plane when camera shake occurs by moving at least a part of the lenses in the direction orthogonal to the optical axis as an anti-vibration lens. With such a configuration, the effective diameter of the anti-vibration lens can be reduced compared to the effective diameter of the first lens group to the third lens group, and the anti-vibration mechanism can be reduced in size. This is advantageous for downsizing the entire lens.

  In addition, with such a configuration, it is possible to reduce deterioration in imaging performance when the vibration-proof lens is moved in a direction orthogonal to the optical axis.

  In addition, the fourth lens group includes, in order from the object side, a front group having a positive refractive power, a middle group having a negative refractive power, and a rear group. By moving only the middle group in a direction orthogonal to the optical axis, It is desirable to perform an image blur correction on the image plane when camera shake occurs. By making the front group positive refracting power and the middle group negative refracting power, the effective diameter of the middle group is made smaller than the effective diameters of the front group and the rear group of the first to fourth lens groups. This makes it possible to reduce the size of the anti-vibration mechanism, which is advantageous for reducing the size of the entire zoom lens.

  In addition, with such a configuration, it is possible to reduce deterioration in imaging performance when the middle group is moved in a direction orthogonal to the optical axis.

  In the zoom lens having the image stabilization mechanism according to the embodiment, the gap between the first lens group and the second lens group increases during zooming from the wide-angle end state to the telephoto end state. It is desirable to move so that the gap between the three lens groups decreases. Such a configuration is advantageous for simplifying the zoom mechanism.

  In the zoom lens having the image stabilization mechanism according to the embodiment, it is desirable that the first lens group is fixed when zooming from the wide-angle end state to the telephoto end state. Such a configuration is advantageous for simplifying the zoom mechanism.

  In the zoom lens having the image stabilization mechanism according to the embodiment, it is desirable that the fourth lens group is fixed when zooming from the wide-angle end state to the telephoto end state. Such a configuration is advantageous for simplifying the zoom mechanism.

In addition, it is desirable that the zoom lens having the image stabilization mechanism according to the embodiment satisfies the following conditional expression (1).
(1) 1.26 <f3 / fw <1.50
Here, f3 is the focal length of the third lens group, and fw is the focal length of the zoom lens in the wide-angle end state.

  Conditional expression (1) defines an appropriate range of the focal length of the third lens group. In the following description, a strong or weak refractive power means that the absolute value of the refractive power is large or small.

  When the upper limit value of conditional expression (1) is exceeded, the negative refractive power of the third lens group becomes weak, and the overall length of the zoom lens increases. In addition, it is difficult to correct various aberrations such as spherical aberration.

  When the lower limit value of conditional expression (1) is exceeded, the positive refractive power of the third lens group becomes strong, and it becomes difficult to correct various aberrations such as spherical aberration.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (1) to 1.31. In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (1) to 1.46.

In addition, it is desirable that the zoom lens having the image stabilization mechanism according to the embodiment satisfies the following conditional expression (2).
(2) 1.39 <f1 / fw <2.00
Here, f1 is the focal length of the first lens group.

  Conditional expression (2) defines an appropriate range of the focal length of the first lens group.

  If the upper limit of conditional expression (2) is exceeded, the refractive power of the first lens group will be weakened and the overall length of the zoom lens will be increased. In addition, it becomes difficult to correct spherical aberration.

  When the lower limit value of conditional expression (1) is exceeded, the refractive power of the first lens group becomes strong, and it becomes difficult to correct spherical aberration and axial chromatic aberration.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (1) to 1.90.

In addition, the zoom lens having the image stabilization mechanism according to the embodiment preferably has a configuration that satisfies the following conditional expression (3).
(3) 1.25 <f4 / fw <1.50
Here, f4 is the focal length of the fourth lens group.

  Conditional expression (3) defines an appropriate range of the focal length of the fourth lens group.

  If the upper limit of conditional expression (3) is exceeded, the refractive power of the fourth lens group will be weakened and the overall length of the zoom lens will be increased. In addition, it becomes difficult to correct spherical aberration and curvature of field.

  When the lower limit of conditional expression (3) is exceeded, the refractive power of the fourth lens group becomes strong, and it becomes difficult to correct various aberrations such as spherical aberration.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (3) to 1.40.

In addition, it is desirable that the zoom lens having the image stabilization mechanism according to the embodiment satisfies the following conditional expression (4).
(4) −0.80 <f42 / f4 <−0.43
Here, f42 is the focal length of the middle group of the fourth lens group.

  Conditional expression (4) defines an appropriate range of the focal length of the middle group of the fourth lens group.

  If the upper limit of conditional expression (4) is exceeded, the negative refractive power of the middle group becomes stronger, and the ratio of the amount of image movement on the imaging surface to the amount of movement of the middle group at the time of shake correction becomes larger. In this case, the tolerance of the middle group drive error becomes small, and the middle group drive control becomes difficult. In addition, it becomes difficult to correct spherical aberration and coma.

  If the lower limit of conditional expression (4) is exceeded, the negative refractive power of the middle group becomes weak, and the ratio of the amount of image movement on the imaging surface to the amount of movement of the middle group at the time of shake correction becomes smaller. This increases the amount of movement of the middle group required to increase the shake correction drive mechanism. In addition, it becomes difficult to correct spherical aberration and coma.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (4) to −0.70. In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (4) to −0.44.

In addition, it is desirable that the zoom lens having the image stabilization mechanism according to the embodiment satisfies the following conditional expression (5).
(5) 0.50 <f43 / f4 <1.0
Here, f43 is the focal length of the rear group of the fourth lens group.

  Conditional expression (5) defines an appropriate range of the focal length of the rear group of the fourth lens group.

  When the upper limit of conditional expression (5) is exceeded, the positive refractive power of the rear group becomes weak and the overall length of the zoom lens becomes large. In addition, it becomes difficult to correct spherical aberration.

  When the lower limit of conditional expression (5) is exceeded, the positive refractive power of the rear group becomes strong, and it becomes difficult to correct coma and distortion. In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (5) to 0.51. In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (5) to 0.80.

  In the zoom lens having the image stabilization mechanism according to the embodiment, it is desirable that the rear group of the fourth lens group is composed of only a single lens. With such a configuration, it is possible to satisfactorily correct lateral chromatic aberration and color coma.

  In the zoom lens having the image stabilization mechanism according to the embodiment, it is desirable that the focusing from the long distance object to the short distance object is performed by moving the third lens group along the optical axis. By performing focusing with the small and light third lens group, rapid focusing can be performed.

  In addition, it is desirable that the zoom lens having the image stabilization mechanism according to the embodiment has an aperture stop, and the aperture stop is disposed closer to the image plane side than the third lens group. With this configuration, spherical aberration can be corrected satisfactorily.

  Embodiments of the zoom lens having the image stabilization function according to the embodiment of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a lens configuration diagram of a zoom lens having an image stabilization function according to a first example of the embodiment.

  In FIG. 1, a zoom lens having an anti-vibration function includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens having a positive refractive power. An air gap between the first lens group G1 and the second lens group G2 includes a group G3 and a fourth lens group having positive refracting power, and changes magnification from the wide-angle end state (W) to the telephoto end state (T). Increases, and the second lens group G2 moves in the image plane I direction so that the air gap between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 temporarily moves in the image plane I direction. It is the structure which moves to an object direction after moving.

  The first lens group G1 has, in order from the object side, a first cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. It comprises a second meniscus lens consisting of a positive meniscus lens L13, a negative meniscus lens L14 having a convex surface facing the object side, and a positive meniscus lens L15 having a convex surface facing the object side.

  The second lens group G2, in order from the object side, is a cemented lens of a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, and a positive meniscus lens L23 having a convex surface directed toward the object side. It comprises a negative meniscus lens L24 having a convex surface facing the image surface I side.

  The third lens group G3 is composed of, in order from the object side, a cemented lens including a positive meniscus lens L31 having a concave surface directed toward the object side, a biconvex positive lens L32, and a negative meniscus lens L33 having a concave surface directed toward the object side. .

  The fourth lens group G4 includes, in order from the object side, a front group G41 having a positive refractive power, a middle group G42 having a negative refractive power, and a rear group G43 having a positive refractive power.

  The front group G41 includes, in order from the object side, a cemented lens of a biconvex positive lens L41 and a biconcave negative lens L42, and a biconvex positive lens L43.

  The middle group G42 includes, in order from the object side, a cemented lens of a biconvex positive lens L44 and a biconcave negative lens L45, and a biconcave negative lens L46.

  The rear group G43 includes, in order from the object side, a biconvex positive lens L47, a biconvex positive lens L48, and a negative meniscus lens L49 with a concave surface facing the object side.

  The aperture stop S is disposed on the image plane I side of the third lens group G3, and is fixed together with the fourth lens group G4 upon zooming from the wide-angle end state (W) to the telephoto end state (T).

  When camera shake occurs, image blur correction on the image plane I is performed by moving only the middle group G42 in a direction orthogonal to the optical axis.

  Focusing from the long distance state to the short distance state is performed by moving the third lens group G3 in the image plane I direction.

  It should be noted that the focal length of the entire system is f, and the image blur correction coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) corrects rotational shake at an angle θ with a K lens. For this, the moving lens group for blur correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K. This relationship is the same for the other embodiments described below, and a description thereof will be omitted.

  In the wide-angle end state (W) of the first embodiment, since the image stabilization coefficient is 1.56 and the focal length is 71.40 (mm), it is a medium for correcting rotational shake of 0.30 °. The movement amount of the group G42 is 0.240 (mm). In the telephoto end state (T), since the image stabilization coefficient is 1.56 and the focal length is 196.00 (mm), the movement of the middle group G42 for correcting the rotation blur of 0.15 ° is performed. The amount is 0.330 (mm).

  Table 1 below lists values of specifications of the zoom lens having the image stabilization function according to the first example.

  In (surface data) in the table, the object surface is the object surface, the surface number is the surface number from the object side, r is the radius of curvature, d is the surface spacing, and nd is the refraction at the d-line (wavelength λ = 587.6 nm). The ratio, νd represents the Abbe number in the d-line (wavelength λ = 587.6 nm), (variable) represents the variable surface interval, (diaphragm) represents the aperture stop S, and the image plane represents the image plane I. Note that the description of the refractive index nd of air = 1.000 is omitted. Further, “∞” in the curvature radius r and the surface interval d column indicates a plane. In (various data) and (short-distance in-focus data), the zoom ratio is the zoom ratio of the zoom lens, W is the wide-angle end state, M is the intermediate focal length state, T is the telephoto end state, f is the focal length, FNo. Is the F number, 2ω is the angle of view (unit: degree), Y is the image height, TL is the total length of the zoom lens, Bf is the back focus, di is the variable surface interval value at surface number i, β is the magnification, and d0 is the most object This represents the distance from the lens surface on the side to the object surface. In (focusing movement amount data), δ3 indicates the value of the focusing movement amount in the image plane I direction of the third lens group G3 when the shooting distance is 1500 (mm). (Zoom lens group data) indicates the focal length of each lens group. (Conditional expression corresponding value) indicates the corresponding value of each conditional expression.

  In all the following specification values, “mm” is generally used as the focal length f, radius of curvature r, surface interval d and other lengths, etc. unless otherwise specified, but the optical system is proportional. Even if it is enlarged or proportionally reduced, the same optical performance can be obtained. Further, the unit is not limited to “mm”, and other appropriate units may be used. Further, the explanation of these symbols is the same in the other embodiments, and the explanation is omitted.

(Table 1)
(Surface data)
Surface number rd nd νd
Object ∞ ∞
1 137.3586 2.20 1.81600 46.62
2 78.0351 8.50 1.49780 82.52
3 315.9697 0.20
4 90.8884 7.00 1.49782 82.52
5 1076.7754 1.481
6 79.5195 2.00 1.85026 32.35
7 52.3014 10.00 1.60300 65.46
8 512.417 (variable)

9 323.6534 1.90 1.772499 49.61
10 33.7204 7.37
11 -135.1209 1.80 1.49782 82.52
12 37.2034 5.10 1.84666 23.78
13 145.1812 4.82
14 -46.6119 1.90 1.72916 54.66
15 -142.5263 (variable)

16 -1403.7596 3.99 1.51680 64.10
17 -85.3454 0.20
18 157.2705 6.61 1.49782 82.52
19 -54.7982 2.00 1.83481 42.72
20 -114.4624 (variable)

21 (Aperture) ∞ 1.00
22 54.3790 8.584 1.61800 63.37
23 -81.1663 2.00 1.85026 32.35
24 222.7831 11.48
25 121.0519 3.67 1.60300 65.46
26 -351.3110 10.16
27 527.7577 4.10 1.80810 22.76
28 -66.0038 1.50 1.51742 52.31
29 52.1902 3.49
30 -270.3345 1.50 1.83400 37.16
31 63.0653 4.99
32 414.1926 4.36 1.49782 82.52
33 -62.1134 1.01
34 46.4837 5.84 1.60300 65.46
35 -783.3010 4.81
36 -48.4788 2.00 1.78472 25.68
37 -78.4091 (Bf)
Image plane ∞

(Various data)
Zoom ratio 2.7451
W M T
f = 71.40 135.00 196.00
FNO = 2.88 2.88 2.88
2ω = 34.26 17.82 12.24
Y = 21.60 21.60 21.60
d8 3.45 25.72 33.62
d15 33.20 17.46 2.00
d20 18.40 11.88 19.44
TL 259.60 259.60 259.60
Bf 67.00 67.00 67.00

(Data at close range)
W M T
β -0.053 -0.088 -0.115
d0 1240.42 1240.48 1240.45
d8 3.45 25.72 33.62
d15 33.20 26.15 18.53
d20 15.62 3.18 2.91
Bf 67.00 67.00 67.00

(Focusing distance data)
W M T
f 71.40 135.00 196.00
δ3 2.7706 15.2367 15.4582

(Zoom lens group data)
Focal length of each group First lens group 100.02
Second lens group -29.11
Third lens group 100.67
Fourth lens group 106.02
Front group 91.53
Middle group -49.12
Rear group 56.65

(Values for conditional expressions)
(1) 1.410
(2) 1.401
(3) 1.485
(4) -0.463
(5) 0.534

  2A and 2B are graphs showing various aberrations in the wide-angle end state of the zoom lens having the image stabilization function according to the first example. FIG. 2A is an aberration diagram at the time of focusing on infinity, and FIG. The meridional lateral aberration diagram when the shake correction for the 0.3 ° rotational shake is performed in the focus is shown. FIG. 3 is a diagram illustrating various aberrations when the zoom lens having the image stabilization function according to the first example is focused at ∞ distance in the intermediate focal length state. 4A and 4B show various aberration diagrams in the telephoto end state of the zoom lens having the image stabilization function according to the first example. FIG. 4A is an aberration diagram at the time of focusing on infinity, and FIG. The meridional lateral aberration diagram when blur correction is performed with respect to a rotational blur of 0.15 ° during focusing is shown. FIGS. 5A and 5B are graphs showing various aberrations of the zoom lens having the image stabilization function according to the first example when focusing at a short distance, where FIG. 5A is a wide angle end state, FIG. 5B is an intermediate focal length state, and FIG. Indicates the telephoto end state.

  In each aberration diagram, FNO is the F number, NA is the numerical aperture, Y is the image height, d is the d-line (wavelength λ = 587.6 nm), and g is the g-line (wavelength λ = 435.8 nm). Further, in the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. Note that these symbols are the same in the other embodiments, and the description thereof is omitted.

  From each aberration diagram, it is apparent that the zoom lens having the image stabilization function according to the first example has excellent aberrations and excellent imaging performance.

(Second embodiment)
FIG. 6 is a lens configuration diagram of a zoom lens having an image stabilization function according to the second example of the embodiment.

  In FIG. 6, the zoom lens having the image stabilization function includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens having a positive refractive power. An air gap between the first lens group G1 and the second lens group G2 includes a group G3 and a fourth lens group having positive refracting power, and changes magnification from the wide-angle end state (W) to the telephoto end state (T). Increases, and the second lens group G2 moves in the image plane I direction so that the air gap between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 temporarily moves in the image plane I direction. It is the structure which moves to an object direction after moving.

  The first lens group G1 has, in order from the object side, a first cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, and a convex surface facing the object side. It comprises a second meniscus lens consisting of a positive meniscus lens L13, a negative meniscus lens L14 having a convex surface facing the object side, and a positive meniscus lens L15 having a convex surface facing the object side.

  The second lens group G2, in order from the object side, is a cemented lens of a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, and a positive meniscus lens L23 having a convex surface directed toward the object side. It comprises a negative meniscus lens L24 having a convex surface facing the image surface I side.

  The third lens group G3 is composed of, in order from the object side, a cemented lens including a positive meniscus lens L31 having a concave surface directed toward the object side, a biconvex positive lens L32, and a negative meniscus lens L33 having a concave surface directed toward the object side. .

  The fourth lens group G4 includes, in order from the object side, a front group G41 having a positive refractive power, a middle group G42 having a negative refractive power, and a rear group G43 having a positive refractive power.

  The front group G41 includes, in order from the object side, a cemented lens of a biconvex positive lens L41 and a biconcave negative lens L42, and a biconvex positive lens L43.

  The middle group G42 includes, in order from the object side, a cemented lens of a biconvex positive lens L44 and a biconcave negative lens L45, and a biconcave negative lens L46.

  The rear group G43 includes, in order from the object side, a biconvex positive lens L47, a biconvex positive lens L48, and a negative meniscus lens L49 with a concave surface facing the object side.

  The aperture stop S is disposed on the image plane I side of the third lens group G3, and is fixed together with the fourth lens group G4 upon zooming from the wide-angle end state (W) to the telephoto end state (T).

  When camera shake occurs, image blur correction on the image plane I is performed by moving only the middle group G42 in a direction orthogonal to the optical axis.

  Focusing from a long distance object to a short distance object is performed by moving the third lens group G3 in the image plane I direction.

  In the wide-angle end state (W) of the second embodiment, since the image stabilization coefficient is 1.45 and the focal length is 71.40 (mm), it is a medium for correcting rotational shake of 0.30 °. The movement amount of the group G42 is 0.257 (mm). In the telephoto end state (T), since the image stabilization coefficient is 1.45 and the focal length is 196.00 (mm), the movement of the middle group G42 for correcting the rotation blur of 0.15 °. The amount is 0.353 (mm).

  Table 2 below provides values of specifications of the zoom lens having the image stabilization function according to the second example.

(Table 2)
(Surface data)
Surface number rd nd νd
Object ∞ ∞
1 252.5638 2.20 1.83400 37.16
2 100.6417 8.50 1.49782 82.52
3 816.5458 0.20
4 108.6228 7.00 1.49782 82.52
5 1931.4674 5.80
6 82.0121 2.00 1.83400 37.16
7 57.8634 9.50 1.60311 60.67
8 790.3493 (variable)

9 -4501.3771 1.90 1.77250 49.61
10 38.0814 7.16
11 -105.3486 1.80 1.48749 70.41
12 42.9840 5.23 1.84666 23.78
13 321.8747 3.86
14 -58.7721 1.90 1.72916 54.66
15 -374.7053 (variable)

16 -1272.6118 4.15 1.49782 82.52
17 -82.4347 0.20
18 139.2707 7.00 1.49782 82.52
19 -53.3323 2.00 1.83481 42.72
20 -111.5754 (variable)

21 (Aperture) ∞ 1.00
22 55.0147 8.04 1.61800 63.37
23 -93.5758 2.00 1.85026 32.35
24 166.6852 0.20
25 80.5139 4.40 1.60300 65.46
26 -9820.6280 13.90
27 195.5776 4.09 1.80810 22.76
28 -84.7153 1.50 1.51742 52.31
29 35.6546 4.72
30 -94.4116 1.50 1.83400 37.16
31 319.6584 4.00
32 -348.3450 4.12 1.49782 82.52
33 -47.0124 0.10
34 50.3328 4.80 1.60300 65.46
35 -825.3848 5.26
36 -43.6938 2.00 1.78472 25.68
37 -75.369 (Bf)
Image plane ∞

(Various data)
Zoom ratio 2.7451
W M T
f = 71.40 135.00 196.00
FNO = 2.88 2.88 2.88
2ω = 34.48 17.91 12.27
Y = 21.60 21.60 21.60
d8 3.00 30.69 40.60
d15 29.23 15.52 2.00
d20 26.61 12.63 16.23
TL = 259.50 259.50 259.50
Bf 68.70 68.70 68.70

(Data at close range)
W M T
β -0.053 -0.089 -0.116
d0 1240.42 1240.49 1240.46
d5 3.00 30.69 40.60
d10 31.69 23.12 16.43
d15 24.15 5.02 1.81
Bf 68.70 68.70 68.70

(Focusing distance data)
W M T
f 71.40 135.00 196.00
δ3 2.4467 21.6196 24.7737
(Zoom lens group data)
Focal length of each group First lens group 111.41
Second lens group -30.64
Third lens group 96.94
Fourth lens group 106.28
Front group 89.52
Middle group -54.39
Rear group 64.10

(Values for conditional expressions)
(1) 1.358
(2) 1.560
(3) 1.488
(4) -0.512
(5) 0.603

  FIGS. 7A and 7B are graphs showing various aberrations in the wide-angle end state of the zoom lens having the image stabilization function according to the second example. FIG. 7A is an aberration diagram at the time of focusing on infinity, and FIG. The meridional lateral aberration diagram when the shake correction for the 0.3 ° rotational shake is performed in the focus is shown. FIG. 8 is a diagram illustrating various aberrations when the zoom lens having the image stabilization function according to the second example is in focus at ∞ in the intermediate focal length state. FIGS. 9A and 9B are graphs showing various aberrations in the telephoto end state of the zoom lens having the image stabilization function according to the second example. FIG. 9A is an aberration diagram at the time of focusing on infinity, and FIG. The meridional lateral aberration diagram when blur correction is performed with respect to a rotational blur of 0.15 ° during focusing is shown. FIG. 10 is a diagram illustrating various aberrations of the zoom lens having the image stabilization function according to the second example at the time of focusing at a short distance, where (a) is a wide-angle end state, (b) is an intermediate focal length state, and (c). Indicates the telephoto end state.

  From each aberration diagram, it is clear that the zoom lens having the image stabilization function according to the second example has various aberrations corrected satisfactorily and has excellent imaging performance.

  Next, an optical device (single-lens reflex camera) equipped with a zoom lens having an image stabilization function according to an embodiment will be described.

  FIG. 11 is a schematic configuration diagram of an optical apparatus (single-lens reflex camera) equipped with a zoom lens having an image stabilization function according to the embodiment.

  In FIG. 11, light from a subject (not shown) is collected by the zoom lens 11 having the image stabilization function according to the embodiment, reflected by the quick return mirror 12, and imaged on the focusing screen 13. The subject image formed on the focusing screen 13 is reflected by the pentaprism 14 a plurality of times, and can be viewed as an erect image by the photographer via the eyepiece lens 15.

  The photographer presses the release button fully after observing the subject image through the eyepiece lens 15 and determining the shooting composition while pressing the release button (not shown) halfway. When the release button is fully pressed, the quick return mirror 12 is flipped upward, the light from the subject is received by the image sensor 16 and a photographed image is acquired and recorded in a memory (not shown).

  When the release button is fully pressed, the sensor 17 (for example, an angle sensor) built in the zoom lens 11 detects the tilt of the zoom lens 11 and transmits it to the CPU 18, and the CPU 18 detects the amount of rotational shake and corrects camera shake. The lens driving means 19 for driving the lens group in the direction orthogonal to the optical axis is driven to correct image blur on the image sensor 16 when camera shake occurs. Thus, the optical device 10 including the zoom lens 11 having the image stabilization function according to the embodiment is configured.

  As described above, according to the zoom lens having the image stabilization function according to the embodiment, the zoom lens having the zoom ratio of about 3 times with the large aperture, the field angle of 34 degrees or more at the wide angle end state, and the image stabilization function. Can be achieved. In addition, a camera having this zoom lens can be provided.

  The contents described below can be appropriately adopted as long as the optical performance is not impaired.

  Although the four-group configuration is shown in the embodiment, the present invention can be applied to other group configurations such as a five-group configuration.

  Alternatively, a single lens group, a plurality of lens groups, or a partial lens group may be moved in the optical axis direction to be a focusing lens group that performs focusing from an object at infinity to a near object.

  The focusing lens group can also be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor). In particular, the third lens group is preferably a focusing lens group.

  Alternatively, the lens group or the partial lens group may be vibrated in a direction perpendicular to the optical axis so as to correct an image blur caused by camera shake. In particular, the middle group of the fourth lens group is preferably an anti-vibration lens group.

  The lens surface may be an aspherical surface. The aspherical surface may be any of an aspherical surface by grinding, a glass mold aspherical surface in which a glass is formed into an aspherical shape, or a composite aspherical surface in which a resin is formed in an aspherical shape on the glass surface.

  The aperture stop is preferably disposed in the vicinity of the fourth lens group, but the role may be substituted by a lens frame without providing a member as an aperture stop.

  If each lens surface is provided with an antireflection film having a high transmittance in a wide wavelength range, flare and ghost can be reduced and high contrast and high optical performance can be achieved.

  In addition, in order to explain the present invention in an easy-to-understand manner, the configuration requirements of the embodiment have been described, but it goes without saying that the present invention is not limited to this.

FIG. 3 is a lens configuration diagram of a zoom lens having an image stabilization function according to the first example. FIG. 4A illustrates various aberration diagrams in the wide-angle end state of the zoom lens having an image stabilization function according to the first example. FIG. 5A illustrates an aberration diagram at the time of focusing on infinity, and FIG. Each shows a meridional transverse aberration diagram when shake correction is performed for 30 ° rotational shake. FIG. 6 is a diagram illustrating various aberrations when the zoom lens having the image stabilization function according to the first example is focused at infinity in the intermediate focal length state. FIG. 6A shows various aberration diagrams of the zoom lens having the image stabilization function according to the first example in the telephoto end state. FIG. 10A is an aberration diagram at the time of focusing on infinity, and FIG. Each of the meridional transverse aberration charts when shake correction is performed for rotational shake of 15 ° is shown. FIG. 5A shows various aberration diagrams of the zoom lens having the image stabilization function according to the first example when focusing at a short distance, where (a) is a wide-angle end state, (b) is an intermediate focal length state, and (c) is a telephoto end state. Respectively. It is a lens block diagram of the zoom lens which has a vibration isolating function concerning 2nd Example. FIG. 4A illustrates various aberration diagrams of the zoom lens having the image stabilization function according to the second example in the wide-angle end state. FIG. 5A illustrates an aberration diagram at the time of focusing on infinity, and FIG. Each shows a meridional transverse aberration diagram when shake correction is performed for 30 ° rotational shake. FIG. 6 shows various aberration diagrams when the zoom lens having the image stabilization function according to the second example is focused at infinity in the intermediate focal length state. FIG. 9A shows aberration diagrams of the zoom lens having the image stabilization function according to the second example in the telephoto end state, FIG. 10A shows aberration diagrams at the time of focusing on infinity, and FIG. Each of the meridional transverse aberration charts when shake correction is performed for rotational shake of 15 ° is shown. FIG. 4A shows various aberration diagrams of the zoom lens having the image stabilization function according to the second embodiment when focusing at a short distance, (a) is a wide-angle end state, (b) is an intermediate focal length state, and (c) is a telephoto end state. Respectively. It is a schematic block diagram of the optical apparatus (single-lens reflex camera) which mounts the zoom lens which has the image stabilization function which concerns on embodiment.

Explanation of symbols

G1 first lens group
G2 second lens group
G3 Third lens group
G4 4th lens group
G41 front group
G42 Medium group
G43 back group
S Aperture stop
I Image plane

Claims (15)

In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power,
The first lens group has two pairs of positive refractive power cemented lenses,
During zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group changes, and the distance between the second lens group and the third lens group changes,
The zoom lens according to claim 4, wherein the fourth lens group moves at least a part of the lenses in a direction orthogonal to the optical axis.   The fourth lens group includes, in order from the object side, a front group having positive refractive power, a middle group having negative refractive power, and a rear group, and moves only the middle group in a direction orthogonal to the optical axis. The zoom lens according to claim 1.   In zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases. The zoom lens according to claim 1 or 2.   4. The zoom lens according to claim 1, wherein the first lens group is fixed during zooming from the wide-angle end state to the telephoto end state. 5.     5. The zoom lens according to claim 1, wherein the fourth lens group is fixed during zooming from the wide-angle end state to the telephoto end state. 6. The zoom lens according to claim 1, wherein the following condition is satisfied.
1.26 <f3 / fw <1.50
However,
f3: focal length of the third lens group,
fw: focal length of the zoom lens in the wide-angle end state The zoom lens according to claim 1, wherein the following condition is satisfied.
1.39 <f1 / fw <2.00
However,
f1: Focal length of the first lens group The zoom lens according to any one of claims 1 to 7, wherein the following condition is satisfied.
1.25 <f4 / fw <1.50
However,
f4: focal length of the fourth lens group The zoom lens according to claim 1, wherein the following condition is satisfied.
−0.80 <f42 / f4 <−0.43
However,
f42: the focal length of the middle group of the fourth lens group, The zoom lens according to claim 1, wherein the following condition is satisfied.
0.50 <f43 / f4 <1.00
However,
f43: focal length of the rear group of the fourth lens group   The zoom lens according to any one of claims 1 to 10, wherein the rear group of the fourth lens group includes only a single lens.   12. The zoom lens according to claim 1, wherein focusing from a long-distance object to a short-distance object is performed by moving the third lens group along an optical axis. Having an aperture stop,
The zoom lens according to any one of claims 1 to 12, wherein the aperture stop is disposed closer to the image plane than the third lens group.   An optical apparatus comprising the zoom lens according to claim 1. In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power,
The first lens group has two pairs of positive refractive power cemented lenses,
The fourth lens group is a zoom lens zooming method for moving at least a part of the lenses in a direction orthogonal to the optical axis,
By changing the distance between the first lens group and the second lens group and the distance between the second lens group and the third lens group, zooming from the wide-angle end state to the telephoto end state is performed. Zoom lens zooming method.

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