JP2023093687A - Variable magnification optical system, optical device, and method for manufacturing variable magnification optical system - Google Patents

Abstract

To solve the problem that there is conventionally proposed a variable magnification optical system which is compact, yet suitable for large-sized imaging device, and which can perform fast focusing suitable for photographing of a moving picture, however in the conventional variable magnification optical systems, various aberrations has not been sufficiently corrected.SOLUTION: A variable magnification optical system is provided, comprising in order from the object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a subsequent lens group having positive refractive power. When zooming from a wide-angle end state to a telephoto end state, the interval between the first and the second lens groups changes, the interval between the second and the third lens groups changes, and the interval between the third and the subsequent lens groups changes. The subsequent lens group includes a focusing lens group which moves upon focusing from an infinite-distance object to a short-distance object, and satisfies a prescribed conditional expression. Thus, various aberrations can be suitably corrected.SELECTED DRAWING: Figure 1

Description

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

2. Description of the Related Art Conventionally, there has been proposed a variable power optical system that is small but compatible with a large image pickup device and capable of high-speed focusing suitable for moving image shooting. For example, see JP-A-2015-064492. However, conventional variable power optical systems do not sufficiently correct various aberrations.

JP 2015-064492 A

The present invention
In order from the object side, a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a subsequent lens group with positive refractive power. and
During zooming, the distance between the first lens group and the second lens group changes, the distance between the second lens group and the third lens group changes, and the third lens group and the subsequent lens group change. The interval between and changes,
the trailing lens group has a focusing lens group that moves during focusing;
This is a variable magnification optical system that satisfies the following conditional expression.
2.00 < f1/fw < 8.000
0.100<BFw/fw<1.00
however,
f1: focal length of the first lens group fw: focal length of the variable power optical system in the wide-angle end state BFw: back focus of the variable power optical system in the wide-angle end state fw: focal length of the variable power optical system in the wide-angle end state Focal length

In addition, the present invention
In order from the object side, a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a subsequent lens group with positive refractive power. A method for manufacturing a variable magnification optical system comprising
During zooming, the distance between the first lens group and the second lens group changes, the distance between the second lens group and the third lens group changes, and the third lens group and the subsequent lens group change. Configured so that the interval between and
wherein the trailing lens group has a focusing lens group that moves when focused;
This is a method of manufacturing a variable magnification optical system that satisfies the following conditional expressions.
2.00 < f1/fw < 8.000
0.100<BFw/fw<1.00
however,
f1: focal length of the first lens group fw: focal length of the variable power optical system in the wide-angle end state BFw: back focus of the variable power optical system in the wide-angle end state fw: focal length of the variable power optical system in the wide-angle end state Focal length

1A, 1B, and 1C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable power optical system according to the first embodiment. 2A, 2B, and 2C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the first embodiment, respectively, when focusing on an object at infinity. 3A, 3B, and 3C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the first embodiment, respectively, when focusing on a short-distance object. 4A, 4B, and 4C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable power optical system according to the second embodiment. 5A, 5B, and 5C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the second embodiment, respectively, when focusing on an object at infinity. 6A, 6B, and 6C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the second embodiment, respectively, when focusing on a short-distance object. 7A, 7B, and 7C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to the third example. 8A, 8B, and 8C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the third embodiment, respectively, when focusing on an object at infinity. 9A, 9B, and 9C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the third embodiment, respectively, when focusing on a short-distance object. 10A, 10B, and 10C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable power optical system according to the fourth example. FIGS. 11A, 11B, and 11C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the fourth example when focusing on an object at infinity. FIGS. 12A, 12B, and 12C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the fourth embodiment, respectively, when focusing on a short-distance object. 13A, 13B, and 13C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable power optical system according to the fifth example. 14A, 14B, and 14C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the fifth embodiment, respectively, when focusing on an object at infinity. 15A, 15B, and 15C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the fifth embodiment, respectively, when focusing on a short-distance object. 16A, 16B, and 16C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable power optical system according to the sixth example. 17A, 17B, and 17C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the sixth embodiment, respectively, when focusing on an object at infinity. 18A, 18B, and 18C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the sixth embodiment, respectively, when focusing on a short-distance object. 19A, 19B, and 19C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable power optical system according to the seventh embodiment. 20A, 20B, and 20C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the seventh embodiment, respectively, when focusing on an object at infinity. 21A, 21B, and 21C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the seventh embodiment, respectively, when focusing on a short-distance object. 22A, 22B, and 22C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to the eighth embodiment. 23A, 23B, and 23C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the eighth embodiment, respectively, when focusing on an object at infinity. 24A, 24B, and 24C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the eighth embodiment, respectively, when focusing on a short-distance object. FIG. 25 is a diagram showing the configuration of a camera equipped with a variable magnification optical system. FIG. 26 is a flowchart showing an outline of a method for manufacturing a variable power optical system.

A variable power optical system, an optical device, and a method for manufacturing the variable power optical system according to the present embodiment will be described below. First, a variable magnification optical system according to this embodiment will be described.

The variable power optical system according to this embodiment includes, in order from the object side, a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power. and a succeeding lens group having a positive refractive power, wherein 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 second lens group The distance between the lens group and the third lens group is varied, the distance between the third lens group and the subsequent lens group is varied, and the subsequent lens group is changed during focusing from an infinity object to a close object. It has a moving focusing lens group and is constructed to satisfy the following conditional expressions (1) and (2).
(1) 2.00 < f1/fw < 8.000
(2) 0.100<BFw/fw<1.00
however,
f1: focal length of the first lens group fw: focal length of the variable power optical system in the wide-angle end state BFw: back focus of the variable power optical system in the wide-angle end state fw: focal length of the variable power optical system in the wide-angle end state Focal length

The subsequent lens group of the variable magnification optical system of this embodiment has at least two lens groups. Note that the lens group in this embodiment means a portion having at least one lens separated by an air gap. Further, in this embodiment, the lens component refers to a single lens or a cemented lens formed by cementing two or more lenses.
The variable power optical system of this embodiment can achieve good aberration correction during zooming by changing the distance between the lens groups during zooming from the wide-angle end state to the telephoto end state. By arranging the focusing lens group in the subsequent lens group, the size and weight of the focusing lens group can be reduced. can be planned.

Conditional expression (1) defines the ratio between the focal length of the first lens group and the focal length of the variable power optical system in the wide-angle end state. By satisfying conditional expression (1), the variable power optical system of the present embodiment can satisfactorily correct various aberrations including coma in the wide-angle end state.

If the corresponding value of conditional expression (1) of the variable magnification optical system of this embodiment exceeds the upper limit, the refractive power of the first lens group becomes small, making it difficult to satisfactorily correct various aberrations in the wide-angle end state. Become. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (1) to 7.000. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (1) to 6.500, more preferably 6.000.

On the other hand, if the corresponding value of conditional expression (1) of the variable-magnification optical system of the present embodiment is below the lower limit, the refractive power of the first lens group increases, and various aberrations, especially coma, in the wide-angle end state are favorably reduced. It becomes difficult to correct. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (1) to 3.00. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (1) to 4.00, more preferably 4.50.

Conditional expression (2) defines the ratio between the back focus of the variable power optical system in the wide-angle end state and the focal length of the variable power optical system in the wide-angle end state. By satisfying conditional expression (2), the variable magnification optical system of the present embodiment can satisfactorily correct various aberrations including coma in the wide-angle end state. The back focus is the distance on the optical axis from the lens surface closest to the image side to the image plane.

When the corresponding value of conditional expression (2) of the variable-magnification optical system of the present embodiment exceeds the upper limit value, the back focus of the variable-magnification optical system in the wide-angle end state is becomes large, making it difficult to satisfactorily correct various aberrations in the wide-angle end state. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (2) to 0.91. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (2) to 0.85, more preferably 0.80.

On the other hand, if the corresponding value of conditional expression (2) of the variable-power optical system of the present embodiment is below the lower limit, the focal length of the variable-power optical system in the wide-angle end state is The back focus becomes small, and it becomes difficult to satisfactorily correct various aberrations, especially coma, in the wide-angle end state. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (2) to 0.300. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (2) to 0.400, more preferably 0.500.

In the conditional expression (2), "the back focus of the variable-magnification optical system in the wide-angle end state" indicated by BFw is assumed to be "the back focus of the variable-magnification optical system in the shortest state", and fw indicates the "wide-angle The focal length of the variable-magnification optical system in the extreme state may be replaced with the "focal length of the variable-magnification optical system in the shortest state." That is, conditional expression (2) may be expressed as follows.
(2) 0.100 < BFs/fs < 1.00
however,
BFs: back focus of the variable-magnification optical system with the shortest total length fs: focal length of the variable-magnification optical system with the shortest total length

With the above configuration, the variable magnification optical system of the present embodiment is compact, yet compatible with a large image pickup device, and is a variable magnification optical system capable of satisfactorily correcting various aberrations during zooming and focusing. system can be realized.

Moreover, it is desirable that the variable power optical system of this embodiment satisfy the following conditional expression (3).
(3) 0.040 < βFw < 0.800
however,
βFw: Lateral magnification of the focusing lens group in the wide-angle end state

Conditional expression (3) defines the lateral magnification of the focusing lens group in the wide-angle end state. By satisfying the conditional expression (3), the variable magnification optical system of this embodiment can reduce the amount of movement of the focusing lens group at the time of focusing, and can reduce the size of the variable magnification optical system. can.

If the corresponding value of conditional expression (3) of the variable magnification optical system of this embodiment exceeds the upper limit, the amount of movement of the focusing lens group during focusing becomes large, making it difficult to reduce the size of the variable magnification optical system. becomes. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (3) to 0.770. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (3) to 0.750, more preferably 0.730.

On the other hand, when the corresponding value of conditional expression (3) of the variable power optical system of the present embodiment is below the lower limit, the sensitivity becomes high and the amount of movement of the focusing lens group during focusing becomes small. becomes difficult. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (3) to 0.200. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (3) to 0.300, more preferably 0.400.

Further, in the variable power optical system of the present embodiment, the succeeding lens group has a fourth lens group having positive refractive power and a fifth lens group having negative refractive power, and the following conditional expression (4) should be satisfied.
(4) -3.000 < f5/f3 < -0.500
however,
f3: focal length of the third lens group f5: focal length of the fifth lens group

Conditional expression (4) defines the ratio between the focal length of the third lens group and the focal length of the fifth lens group. By satisfying the conditional expression (4), the variable power optical system of this embodiment can keep the power ratio between the third lens group and the fifth lens group within an appropriate range, and reduce astigmatism and coma. Good correction is possible.

When the corresponding value of conditional expression (4) of the variable-magnification optical system of this embodiment exceeds the upper limit, the refractive power of the third lens group becomes greater than the refractive power of the fifth lens group. It becomes difficult to satisfactorily correct aberrations, especially astigmatism. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (4) to −0.800. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (4) to -1.000, more preferably -1.100.

On the other hand, if the corresponding value of conditional expression (4) of the variable-magnification optical system of this embodiment falls below the lower limit, the refractive power of the fifth lens group becomes greater than the refractive power of the third lens group, resulting in a telephoto end state. It becomes difficult to satisfactorily correct various aberrations, especially coma aberration. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (4) to -2.500. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (4) to -2.000, more preferably -1.400.

Also, in the variable power optical system of this embodiment, it is desirable that the fourth lens group has a focusing lens group. With this configuration, the variable power optical system according to the present embodiment can reduce the size and weight of the focusing lens group, and as a result, the size of the variable power optical system and the lens barrel can be reduced.

Further, it is desirable that the variable magnification optical system of this embodiment satisfy the following conditional expression (5).
(5) 4.000 < f1/f1Rw < 9.000
however,
f1: focal length of the first lens group f1Rw: combined focal length in the wide-angle end state of the lens groups arranged closer to the image plane than the first lens group

Conditional expression (5) defines the ratio between the focal length of the first lens group and the composite focal length of the lens groups arranged closer to the image plane than the first lens group in the wide-angle end state. By satisfying conditional expression (5), the variable magnification optical system of the present embodiment can satisfactorily correct various aberrations including coma in the wide-angle end state. Further, by satisfying conditional expression (5), it is possible to suppress fluctuations in various aberrations including spherical aberration during zooming from the wide-angle end state to the telephoto end state.

When the corresponding value of conditional expression (5) of the variable-magnification optical system of this embodiment exceeds the upper limit, the refractive power of the lens group arranged closer to the image plane than the first lens group in the wide-angle end state becomes large. It becomes difficult to satisfactorily correct various aberrations, especially coma, in the end state. In addition, it becomes difficult to suppress variations in various aberrations including spherical aberration when zooming from the wide-angle end state to the telephoto end state. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (5) to 8.500. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (5) to 8.000, more preferably 6.500.

On the other hand, if the corresponding value of conditional expression (5) of the variable-magnification optical system of the present embodiment is below the lower limit, the refractive power of the first lens group increases, and various aberrations, especially coma, in the wide-angle end state are favorably reduced. It becomes difficult to correct. In addition, it becomes difficult to suppress variations in various aberrations including spherical aberration when zooming from the wide-angle end state to the telephoto end state. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (5) to 5.000. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (5) to 5.100, more preferably 5.200.

Moreover, it is desirable that the variable magnification optical system of this embodiment satisfy the following conditional expression (6).
(6) nd3fp < 1.800
however,
nd3fp: refractive index of the lens with the highest refractive index in the third lens group

Conditional expression (6) defines the refractive index of the lens having the highest refractive power in the third lens group. The variable magnification optical system of this embodiment can satisfactorily correct axial chromatic aberration and spherical aberration by using a glass material with high refractive power that satisfies conditional expression (6).

If the corresponding value of conditional expression (6) of the variable magnification optical system of this embodiment exceeds the upper limit, the refractive power of the third lens group increases, making it difficult to satisfactorily correct longitudinal chromatic aberration and spherical aberration. Become. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (6) to 1.750. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (6) to 1.700, more preferably 1.650.

Moreover, it is desirable that the variable power optical system of this embodiment satisfy the following conditional expression (7).
(7) 50.000 < vd3p
however,
νd3p: Abbe number of the lens with the smallest Abbe number in the third lens group

Conditional expression (7) defines the Abbe number of the lens having the smallest Abbe number in the third lens group. In the variable power optical system of this embodiment, by using a low-dispersion glass material that satisfies conditional expression (7), anomalous dispersion can be imparted to the third lens group, and longitudinal chromatic aberration and spherical aberration are reduced. can be corrected to

If the corresponding value of conditional expression (7) of the variable magnification optical system of this embodiment is below the lower limit, the third lens group cannot have sufficient anomalous dispersion, and longitudinal chromatic aberration and spherical aberration are reduced. It becomes difficult to correct to In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (7) to 55.000. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (7) to 58.000, more preferably 60.000.

Moreover, it is desirable that the variable power optical system of this embodiment satisfy the following conditional expression (8).
(8) 0.500 < 1/βRw < 1.000
however,
βRw: Lateral magnification of the lens group closest to the image plane in the wide-angle end state

Conditional expression (8) defines the lateral magnification of the lens group closest to the image plane in the wide-angle end state. By satisfying the conditional expression (8), the variable power optical system of the present embodiment can satisfactorily correct various aberrations including astigmatism in the wide-angle end state.

When the corresponding value of conditional expression (8) of the variable-magnification optical system of the present embodiment exceeds the upper limit, the lateral magnification of the lens group arranged closest to the image plane in the wide-angle end state becomes small, resulting in various problems in the wide-angle end state. It becomes difficult to satisfactorily correct aberrations, especially astigmatism. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (8) to 0.950. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (8) to 0.900, more preferably 0.850.

On the other hand, when the corresponding value of conditional expression (8) of the variable-magnification optical system of the present embodiment falls below the lower limit, the lateral magnification of the lens group arranged closest to the image plane in the wide-angle end state increases, and the wide-angle end state increases. At this time, field curvature tends to occur, and it becomes difficult to satisfactorily correct various aberrations. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (8) to 0.550. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (8) to 0.600, more preferably 0.650.

Moreover, it is desirable that the variable magnification optical system of this embodiment satisfy the following conditional expression (9).
(9) 0.500 < f2fn/f2 < 1.100
however,
f2fn: focal length of the most object side lens component in the second lens group f2: focal length of the second lens group

Conditional expression (9) defines the ratio between the focal length of the lens component closest to the object in the second lens group and the focal length of the second lens group. By satisfying the conditional expression (9), the variable power optical system of the present embodiment can appropriately arrange the power of the lens component closest to the object side in the second lens group. Various aberrations can be satisfactorily corrected.

When the corresponding value of conditional expression (9) of the variable-magnification optical system of this embodiment exceeds the upper limit, the refractive power of the lens component closest to the object side in the second lens group becomes small, causing various problems such as spherical aberration. It becomes difficult to correct aberration satisfactorily. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (9) to 1.000. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (9) to 0.900, more preferably 0.850.

On the other hand, if the corresponding value of conditional expression (9) of the variable power optical system of this embodiment is below the lower limit, the refractive power of the lens component closest to the object side in the second lens group increases, causing spherical aberration and other problems. It becomes difficult to satisfactorily correct various aberrations that occur. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (9) to 0.600. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (9) to 0.650, more preferably 0.700.

Moreover, it is desirable that the variable magnification optical system of this embodiment satisfy the following conditional expression (10).
(10) 0.300 < fF/ft < 1.400
however,
fF: focal length of the focusing lens group ft: focal length of the variable magnification optical system in the telephoto end state

Conditional expression (10) defines the ratio between the focal length of the focusing lens group and the focal length of the variable magnification optical system in the telephoto end state. By satisfying conditional expression (10), the variable power optical system of the present embodiment suppresses fluctuations in various aberrations including spherical aberration when focusing from an object at infinity to a close object. It is possible to reduce the size of the magnification optical system and the lens barrel.

When the corresponding value of conditional expression (10) of the variable magnification optical system of this embodiment exceeds the upper limit, the refractive power of the focusing lens group becomes small, and various problems occur when focusing from an infinite distance object to a short distance object. It becomes difficult to satisfactorily correct aberration variations, particularly spherical aberration variations. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (10) to 1.000. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (10) to 0.900, more preferably 0.850.

On the other hand, if the corresponding value of conditional expression (10) of the variable-magnification optical system of this embodiment is below the lower limit, the refractive power of the focusing lens group increases, and when focusing from an infinity object to a close object, It becomes difficult to satisfactorily correct fluctuations in various aberrations, particularly fluctuations in spherical aberration. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (10) to 0.500. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (10) to 0.600, more preferably 0.700.

Moreover, it is desirable that the variable power optical system of this embodiment satisfy the following conditional expression (11).
(11) 40.00° < ωw < 85.00°
however,
ωw: Half angle of view of the variable magnification optical system in the wide-angle end state

Conditional expression (11) defines the half angle of view of the variable magnification optical system in the wide-angle end state. By satisfying conditional expression (11), the variable power optical system of the present embodiment can satisfactorily correct various aberrations such as coma, distortion, and curvature of field while maintaining a wide angle of view. .

If the corresponding value of conditional expression (11) of the variable-magnification optical system of the present embodiment exceeds the upper limit, the angle of view becomes too wide, and various aberrations such as coma, distortion, and curvature of field can be satisfactorily corrected. becomes difficult. In order to ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (11) to 84.00°. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (11) to 83.00°, more preferably 82.00°.

On the other hand, if the corresponding value of conditional expression (11) of the variable-magnification optical system of this embodiment falls below the lower limit, the angle of view becomes narrow, making it difficult to satisfactorily correct various aberrations. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (11) to 41.00°. Moreover, in order to further ensure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (11) to 42.00°, more preferably 43.00°.

The optical device of the present embodiment has the variable power optical system having the configuration described above. As a result, it is possible to realize an optical device that is small but can be adapted to a large imaging device, and that can satisfactorily correct various aberrations during zooming and focusing.

The method of manufacturing the variable magnification optical system of the present embodiment includes, in order from the object side, a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power. A method for manufacturing a variable power optical system having a lens group and a subsequent lens group having positive refractive power, wherein the first lens group and the second lens are adjusted during zooming from a wide-angle end state to a telephoto end state. a distance between the second lens group and the third lens group; a distance between the third lens group and the subsequent lens group; and a distance between the third lens group and the subsequent lens group. A variable-power optical system configured to have a focusing lens group that moves when focusing from an infinity object to a short-distance object, and configured to satisfy the following conditional expressions (1) and (2): is a manufacturing method. As a result, it is possible to manufacture a variable-power optical system that is compact but can be adapted to a large-sized imaging device, and that can satisfactorily correct various aberrations during zooming and focusing.
(1) 2.00 < f1/fw < 8.000
(2) 0.100<BFw/fw<1.00
however,
f1: focal length of the first lens group fw: focal length of the variable power optical system in the wide-angle end state BFw: back focus of the variable power optical system in the wide-angle end state fw: focal length of the variable power optical system in the wide-angle end state Focal length

A variable magnification optical system according to numerical examples of the present embodiment will be described below with reference to the accompanying drawings.
(First embodiment)
1A, 1B, and 1C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable power optical system according to Example 1 of the present embodiment. The arrows under each lens group in FIG. 1A indicate the moving direction of each lens group during zooming from the wide-angle end state to the intermediate focal length state. The arrows under each lens group in FIG. 1B indicate the locus of movement of each lens group during zooming from the intermediate focal length state to the telephoto end state.

The variable power optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S , a third lens group G3 having positive refractive power, and a subsequent lens group GR having positive refractive power.

The first lens group G1 is composed of, in order from the object side along the optical axis, a cemented lens constructed by cementing 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.
The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Consists of The negative meniscus lens L21 is a glass mold aspherical lens having an aspherical lens surface on the image plane I side.
The third lens group G3 comprises, in order from the object side along the optical axis, a biconvex positive lens L31, a cemented lens constructed by a negative meniscus lens L32 having a convex surface facing the object side, and a biconvex positive lens L33. , a cemented lens of a biconcave negative lens L34 and a biconvex positive lens L35. The biconvex positive lens L31 is a glass-molded aspherical lens having an aspherical surface on the object side.

The subsequent lens group GR is composed of, in order from the object side along the optical axis, a fourth lens group G4 having positive refractive power and a fifth lens group G5 having negative refractive power.
The fourth lens group G4 is composed of, in order from the object side along the optical axis, a negative meniscus lens L41 having a concave surface facing the object side, and a biconvex positive lens L42. The biconvex positive lens L42 is a glass-molded aspherical lens having an aspherical lens surface on the image plane I side.
The fifth lens group G5 consists of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface facing the object side, and a biconcave negative lens L52. The positive meniscus lens L51 is a glass molded aspherical lens having an aspherical lens surface on the image plane I side.

Between the fifth lens group G5 and the image plane I, a filter FL such as a low-pass filter is arranged.
An imaging device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I. FIG.

The variable-magnification optical system according to the present embodiment has a distance between the first lens group G1 and the second lens group G2, and a distance between the second lens group G2 and the third lens group G3 during zooming from the wide-angle end state to the telephoto end state. , the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5. move along the optical axis. Also, the aperture stop S moves integrally with the third lens group G3 during zooming from the wide-angle end state to the telephoto end state.
In the variable-magnification optical system according to the present embodiment, the fourth lens group G4 as a focusing lens group is moved along the optical axis toward the object, thereby focusing from an infinity object to a short distance object.

Table 1 below lists the values of the specifications of the variable magnification optical system according to this example.
In [surface data], m is the order of the optical surfaces counted from the object side, r is the radius of curvature, d is the surface distance (the distance between the nth surface (n is an integer) and the n+1th surface), and nd is the d line ( νd indicates the Abbe number for the d-line (wavelength 587.6 nm), respectively. Also, OP indicates an object plane, Dn (n is an integer) a variable surface interval, S an aperture stop, and I an image plane. Note that the radius of curvature r=∞ indicates a plane. The description of the refractive index of air nd=1.00000 is omitted. When the lens surface is an aspherical surface, the surface number is marked with an asterisk (*), and the paraxial radius of curvature is shown in the column of radius of curvature r.

In [various data], f is the focal length, FNo is the F number, ω is the half angle of view (unit is “°”), Y is the maximum image height, and TL is the total length of the variable magnification optical system according to the present embodiment, that is, the first The distances on the optical axis from surface 1 to image plane I are shown. BF is the back focus, that is, the distance on the optical axis from the lens surface closest to the image side to the image plane I, and BF (air conversion length) is the distance on the optical axis from the lens surface closest to the image side to the image plane I. , are values measured with optical blocks such as filters removed from the optical path. W indicates the wide-angle end state, M indicates the intermediate focal length state, and T indicates the telephoto end state.
[Lens Group Data] shows the starting surface number ST and focal length f of each lens group.

[Aspheric surface data] shows the aspheric surface coefficient and conic constant when the shape of the aspheric surface shown in [Surface data] is expressed by the following equation.
x=(h ² /r)/[1+{1−κ(h/r) ² } ^1/2 ]
+ ^A4h4 + ^A6h6 + ^A8h8 + ^A10h10
Here, h is the height in the direction perpendicular to the optical axis, x is the sag amount which is the distance along the optical axis from the tangent plane of the apex of the aspherical surface to the aspherical surface at height h, and κ is the conic constant. , A4, A6, A8, and A10 are the aspheric coefficients, and r is the paraxial radius of curvature of the reference sphere. "En" (n is an integer) indicates "×10 ^-n ", for example "1.234E-05" indicates "1.234×10 ^-5 ". The second-order aspheric coefficient A2 is 0 and is omitted.

In [Variable distance data], Dn (n is an integer) indicates the surface distance between the n-th surface and the (n+1)-th surface. W is the wide-angle end state, M is the intermediate focal length state, T is the telephoto end state, infinity is when focusing on an infinite distance object, and short distance is when focusing on a short distance object.
[Value corresponding to conditional expression] shows the corresponding value for each conditional expression.

Here, the unit of focal length f, radius of curvature r, and other lengths described in Table 1 is generally "mm". However, the optical system is not limited to this because equivalent optical performance can be obtained even if it is proportionally enlarged or proportionally reduced.
Note that the reference numerals in Table 1 described above are also used in the tables of the embodiments described later.

(Table 1) First embodiment [Surface data]
m r d nd νd
OP ∞
1 73.00000 2.150 1.84666 23.8
2 47.49515 8.600 1.75500 52.3
3 417.04330 D3

4 400.00000 1.800 1.74353 49.5
*5 17.04241 8.087
6 -181.13172 1.350 1.75500 52.3
7 49.98466 2.108
8 37.80684 3.693 2.00069 25.5
9 235.22758 D9

10(S) ∞ 1.500
*11 25.88353 4.048 1.55332 71.7
12 -254.63176 0.800
13 52.19394 1.000 1.83481 42.7
14 26.38369 3.546 1.61800 63.3
15 -150.00000 3.743
16 -33.68615 1.000 1.81600 46.6
17 17.28639 6.494 1.59319 67.9
18 -23.04098 D18

19 -22.45485 1.000 1.80100 34.9
20 -41.05177 0.103
21 59.92172 6.115 1.59201 67.0
*22 -26.25646 D22

23 -40.60645 3.489 1.58913 61.2
*24 -24.00000 5.786
25 -24.36536 1.500 1.61800 63.3
26 107.45414 D26

27 ∞ 1.600 1.51680 64.1
28∞D28
I ∞

[Various data]
Zoom ratio: 2.75
WMT
f 24.72 46.31 67.91
FNo 4.00 4.00 4.00
ω 43.3 24.0 16.7
Y 21.70 21.70 21.70
TL 121.583 134.978 151.029
BF 15.558 28.486 36.144
BF (air conversion length) 15.013 27.941 35.599

[Lens group data]
Lens group ST f
1st lens group 1 125.09
2nd lens group 4 -28.96
Third lens group 10 39.65
4th lens group 19 56.05
5th lens group 23 -51.52

[Aspheric data]
Face κ A4 A6 A8 A10
5 0.00000e+00 2.11342e-05 4.21453e-08 -3.77216e-11 4.44697e-13
11 1.00000e+00 -5.01541e-06 1.10914e-09 4.72876e-11 -3.55280e-13
22 1.00000e+00 1.52181e-05 -2.09730e-08 -1.77284e-11 -1.36838e-13
24 1.00000e+00 3.09258e-06 3.56902e-08 -3.36788e-11 3.80333e-13

[Variable interval data]
WMT WMT
Infinity Infinity Infinity Close Close Close
D3 1.600 17.195 31.254 1.600 17.195 31.254
D9 23.690 8.562 2.895 23.690 8.562 2.895
D18 4.579 8.446 10.823 2.148 3.205 2.313
D22 8.245 4.378 2.000 10.675 9.619 10.510
D26 13.858 26.785 34.444 13.858 26.785 34.444
D28 0.100 0.101 0.101 0.100 0.101 0.101

[Value corresponding to conditional expression]
(1) f1/fw = 5.0602
(2) BFw/fw = 0.6901
(3) βFw = 0.5234
(4) f5/f3 = -1.2993
(5) f1/f1Rw = 5.7747
(6) nd3fp = 1.5533
(7) νd3p = 71.6835
(8) 1/βRw = 0.7853
(9) f2fn/f2 = 0.8285
(10) fF/ft = 0.8254
(11) ωw = 43.3420°

2A, 2B, and 2C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the first embodiment, respectively, when focusing on an object at infinity.
3A, 3B, and 3C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the first embodiment, respectively, when focusing on a short-distance object.

In each aberration diagram, FNO indicates the F-number, NA the numerical aperture, A the angle of incidence of rays, that is, the half angle of view (unit: "°"), and H0 the height of the object (unit: mm). In more detail, the spherical aberration chart shows the value of the F number FNO or numerical aperture NA corresponding to the maximum aperture, the astigmatism chart and the distortion chart show the maximum value of the half angle of view or the maximum object height, respectively, and the coma chart shows Indicates the value of each half angle of view or each object height. d indicates aberration at the d-line (wavelength: 587.6 nm), g indicates aberration at the g-line (wavelength: 435.8 nm), and those without d and g indicate aberration at the d-line. In the astigmatism diagrams, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. The coma diagram shows the coma or lateral aberration at each half angle of view or each object height. Note that the same reference numerals as in this embodiment are used in the aberration diagrams of each embodiment described later.

From the aberration diagrams, it can be seen that the variable power optical system according to this example has excellent imaging performance with good correction of various aberrations from the wide-angle end state to the telephoto end state. It can be seen that they have excellent imaging performance.

(Second embodiment)
4A, 4B, and 4C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to Example 2 of the present embodiment. The arrow under each lens group in FIG. 4A indicates the moving direction of each lens group during zooming from the wide-angle end state to the intermediate focal length state. The arrows under each lens group in FIG. 4B indicate the locus of movement of each lens group during zooming from the intermediate focal length state to the telephoto end state.

The variable power optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S , a third lens group G3 having positive refractive power, and a subsequent lens group GR having positive refractive power.

The first lens group G1 is composed of, in order from the object side along the optical axis, a cemented lens constructed by cementing 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.
The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Consists of The negative meniscus lens L21 is a glass mold aspherical lens having an aspherical lens surface on the image plane I side.
The third lens group G3 comprises, in order from the object side along the optical axis, a biconvex positive lens L31, a cemented lens constructed by a negative meniscus lens L32 having a convex surface facing the object side, and a biconvex positive lens L33. , a cemented lens of a biconcave negative lens L34 and a biconvex positive lens L35. The biconvex positive lens L31 is a glass-molded aspherical lens having an aspherical surface on the object side.

The subsequent lens group GR is composed of, in order from the object side along the optical axis, a fourth lens group G4 having positive refractive power and a fifth lens group G5 having negative refractive power.
The fourth lens group G4 is composed of, in order from the object side along the optical axis, a negative meniscus lens L41 having a concave surface facing the object side, and a biconvex positive lens L42. The biconvex positive lens L42 is a glass-molded aspherical lens having an aspherical lens surface on the image plane I side.
The fifth lens group G5 consists of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface facing the object side, and a biconcave negative lens L52. The positive meniscus lens L51 is a glass molded aspherical lens having an aspherical lens surface on the image plane I side.

Between the fifth lens group G5 and the image plane I, a filter FL such as a low-pass filter is arranged.
An imaging device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I. FIG.

The variable-magnification optical system according to the present embodiment has a distance between the first lens group G1 and the second lens group G2, and a distance between the second lens group G2 and the third lens group G3 during zooming from the wide-angle end state to the telephoto end state. , the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5. move along the optical axis. Also, the aperture stop S moves integrally with the third lens group G3 during zooming from the wide-angle end state to the telephoto end state.
In the variable-magnification optical system according to the present embodiment, the fourth lens group G4 as a focusing lens group is moved along the optical axis toward the object, thereby focusing from an infinity object to a short distance object.
Table 2 below shows the values of the specifications of the variable-magnification optical system according to this example.

(Table 2) Second embodiment [Surface data]
m r d nd νd
OP ∞
1 71.32483 2.150 1.84666 23.8
2 47.40907 8.400 1.75500 52.3
3 322.63295 D3

4 400.00000 1.800 1.74353 49.5
*5 16.36859 9.475
6 -167.05753 2.029 1.75500 52.3
7 52.89355 0.797
8 36.08835 4.010 2.00069 25.5
9 256.44936 D9

10(S) ∞ 1.500
*11 25.91417 3.857 1.55332 71.7
12 -275.22572 1.078
13 51.71743 1.000 1.83481 42.7
14 21.38295 4.402 1.61800 63.3
15 -80.10599 3.539
16 -29.70942 1.000 1.81600 46.6
17 18.35723 5.582 1.59349 67.0
18 -21.31475 D18

19 -21.98830 1.000 1.74950 35.2
20 -53.12352 0.100
21 62.90338 5.816 1.62263 58.2
*22 -25.22856 D22

23 -35.90246 3.521 1.62263 58.2
*24 -23.00000 6.177
25 -23.30716 1.500 1.61800 63.3
26 150.39447 D26

27 ∞ 1.600 1.51680 64.1
28∞D28
I ∞

[Various data]
Zoom ratio: 2.75
WMT
f 24.72 46.31 67.90
FNo 4.00 4.00 4.00
ω 43.6 24.3 16.8
Y 21.70 21.70 21.70
TL 122.013 134.611 152.248
BF 15.085 29.244 35.661
BF (air conversion length) 14.540 28.699 35.116

[Lens group data]
Lens group ST f
1st lens group 1 128.74
2nd lens group 4 -28.81
3rd lens group 10 38.09
4th lens group 19 60.73
5th lens group 23 -52.48

[Aspheric data]
Face κ A4 A6 A8 A10
5 0.00000e+00 2.31089e-05 3.91931e-08 8.80919e-12 3.83889e-13
11 1.00000e+00 -6.11034e-06 4.65530e-09 -7.97458e-11 3.48297e-13
22 1.00000e+00 1.49147e-05 -1.52664e-08 -4.38703e-11 -3.36461e-14
24 1.00000e+00 3.38657e-06 2.78770e-08 3.43065e-11 1.67177e-13

[Variable interval data]
WMT WMT
Infinity Infinity Infinity Close Close Close
D3 1.607 15.176 31.798 1.607 15.176 31.798
D9 23.402 8.272 2.870 23.402 8.272 2.870
D18 4.665 9.193 11.184 2.019 3.622 2.045
D22 8.519 3.992 2.000 11.165 9.562 11.139
D26 13.385 27.544 33.962 13.385 27.544 33.962
D28 0.100 0.099 0.099 0.099 0.099 0.099

[Value corresponding to conditional expression]
(1) f1/fw = 5.2079
(2) BFw/fw = 0.6709
(3) βFw = 0.5717
(4) f5/f3 = -1.3777
(5) f1/f1Rw = 5.9279
(6) nd3fp = 1.5533
(7) νd3p = 71.6835
(8) 1/βRw = 0.7923
(9) f2 fn/f2 = 0.7983
(10) fF/ft = 0.8944
(11) ωw = 43.6046°

5A, 5B, and 5C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the second embodiment, respectively, when focusing on an object at infinity.
6A, 6B, and 6C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the second embodiment, respectively, when focusing on a short-distance object.

From the aberration diagrams, it can be seen that the variable power optical system according to this example has excellent imaging performance with good correction of various aberrations from the wide-angle end state to the telephoto end state. It can be seen that they have excellent imaging performance.

(Third embodiment)
7A, 7B, and 7C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to Example 3 of the present embodiment. The arrow under each lens group in FIG. 7A indicates the moving direction of each lens group during zooming from the wide-angle end state to the intermediate focal length state. The arrows under each lens group in FIG. 7B indicate the locus of movement of each lens group during zooming from the intermediate focal length state to the telephoto end state.

The variable power optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S , a third lens group G3 having positive refractive power, and a subsequent lens group GR having positive refractive power.

The first lens group G1 is composed of, in order from the object side along the optical axis, a cemented lens constructed by cementing 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.
The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Consists of The negative meniscus lens L21 is a glass mold aspherical lens having an aspherical lens surface on the image plane I side.
The third lens group G3 includes, in order from the object side along the optical axis, a positive meniscus lens L31 with a convex surface facing the object side, a negative meniscus lens L32 with a convex surface facing the object side, and a biconvex positive lens L33. and a cemented lens of a biconcave negative lens L34 and a biconvex positive lens L35. The positive meniscus lens L31 is a glass-molded aspherical lens having an aspherical surface on the object side.

The subsequent lens group GR is composed of, in order from the object side along the optical axis, a fourth lens group G4 having positive refractive power and a fifth lens group G5 having negative refractive power.
The fourth lens group G4 is composed of, in order from the object side along the optical axis, a negative meniscus lens L41 having a concave surface facing the object side, and a biconvex positive lens L42. The biconvex positive lens L42 is a glass-molded aspherical lens having an aspherical lens surface on the image plane I side.
The fifth lens group G5 consists of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface facing the object side, and a biconcave negative lens L52. The positive meniscus lens L51 is a glass molded aspherical lens having an aspherical lens surface on the image plane I side.

Between the fifth lens group G5 and the image plane I, a filter FL such as a low-pass filter is arranged.
An imaging device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I. FIG.

The variable-magnification optical system according to the present embodiment has a distance between the first lens group G1 and the second lens group G2, and a distance between the second lens group G2 and the third lens group G3 during zooming from the wide-angle end state to the telephoto end state. , the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5. move along the optical axis. Also, the aperture stop S moves integrally with the third lens group G3 during zooming from the wide-angle end state to the telephoto end state.
In the variable-magnification optical system according to the present embodiment, the fourth lens group G4 as a focusing lens group is moved along the optical axis toward the object, thereby focusing from an infinity object to a short distance object.
Table 3 below shows the values of the specifications of the variable magnification optical system according to this example.

(Table 3) Third embodiment [Surface data]
m r d nd νd
OP ∞
1 77.74447 2.150 1.84666 23.8
2 53.55851 8.020 1.72916 54.6
3 478.39025 D3

4 1000.00000 2.000 1.74250 49.4
*5 17.13499 9.008
6 -103.78967 1.500 1.75500 52.3
7 80.88445 0.942
8 41.82797 3.959 2.00069 25.5
9 874.65992 D9

10(S) ∞ 1.500
*11 25.63046 3.669 1.55332 71.7
12 649.10845 0.500
13 43.22955 1.000 1.83481 42.7
14 18.28418 4.715 1.61800 63.3
15 -90.27190 4.286
16 -32.75074 1.000 1.81600 46.6
17 18.81533 5.331 1.59349 67.0
18-22.38426 D18

19 -20.95545 1.000 1.80610 33.3
20 -38.43736 0.450
21 70.13258 6.000 1.62263 58.2
*22 -25.20560 D22

23 -28.47777 3.307 1.69350 53.3
*24 -21.27208 6.193
25 -24.27627 1.500 1.61881 63.9
26 106.34326 D26

27 ∞ 1.600 1.51680 64.1
28∞D28
I ∞

[Various data]
Zoom ratio: 2.75
WMT
f 24.72 46.31 67.90
FNo 4.00 4.28 4.00
ω 43.9 24.1 16.6
Y 21.70 21.70 21.70
TL 121.939 132.931 151.948
BF 14.546 28.656 35.001
BF (air conversion length) 14.000 28.111 34.456

[Lens group data]
Lens group ST f
1st lens group 1 137.34
2nd lens group 4 -31.18
Third lens group 10 38.77
4th lens group 19 54.86
5th lens group 23 -47.21

[Aspheric data]
Face κ A4 A6 A8 A10
5 0.00000e+00 2.00686e-05 2.97810e-08 2.98043e-11 1.72509e-13
11 1.00000e+00 -5.31955e-06 1.45892e-09 2.19477e-11 -2.48946e-13
22 1.00000e+00 1.44228e-05 -1.30721e-08 5.35466e-12 -2.19209e-13
24 1.00000e+00 5.35295e-06 2.89950e-08 -2.95842e-11 3.75280e-13

[Variable interval data]
WMT WMT
Infinity Infinity Infinity Close Close Close
D3 1.704 15.094 33.353 1.704 15.094 33.353
D9 24.986 8.476 2.890 24.986 8.476 2.890
D18 4.613 8.792 10.677 2.183 3.795 2.527
D22 8.064 3.886 2.000 10.494 8.882 10.150
D26 12.846 26.958 33.303 12.846 26.958 33.303
D28 0.100 0.099 0.098 0.099 0.098 0.098

[Value corresponding to conditional expression]
(1) f1/fw = 5.5559
(2) BFw/fw = 0.6491
(3) βFw = 0.5546
(4) f5/f3 = -1.2178
(5) f1/f1Rw = 6.2478
(6) nd3fp = 1.5533
(7) νd3p = 71.6835
(8) 1/βRw = 0.7706
(9) f2 fn/f2 = 0.7537
(10) fF/ft = 0.8080
(11) ωw = 43.9044°

8A, 8B, and 8C are diagrams of various aberrations when focusing on an object at infinity in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the third embodiment, respectively.
9A, 9B, and 9C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the third embodiment, respectively, when focusing on a short-distance object.

From the aberration diagrams, it can be seen that the variable power optical system according to this example has excellent imaging performance with good correction of various aberrations from the wide-angle end state to the telephoto end state. It can be seen that they have excellent imaging performance.

(Fourth embodiment)
10A, 10B, and 10C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to Example 4 of the present embodiment. The arrow under each lens group in FIG. 10A indicates the moving direction of each lens group during zooming from the wide-angle end state to the intermediate focal length state. The arrows under each lens group in FIG. 10B indicate the locus of movement of each lens group during zooming from the intermediate focal length state to the telephoto end state.

The variable power optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S , a third lens group G3 having positive refractive power, and a subsequent lens group GR having positive refractive power.

The first lens group G1 is composed of, in order from the object side along the optical axis, a cemented lens constructed by cementing 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.
The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Consists of The negative meniscus lens L21 is a glass mold aspherical lens having an aspherical lens surface on the image plane I side.
The third lens group G3 includes, in order from the object side along the optical axis, a positive meniscus lens L31 with a convex surface facing the object side, a negative meniscus lens L32 with a convex surface facing the object side, and a biconvex positive lens L33. and a cemented lens of a biconcave negative lens L34 and a biconvex positive lens L35. The positive meniscus lens L31 is a glass-molded aspherical lens having an aspherical surface on the object side.

The subsequent lens group GR is composed of, in order from the object side along the optical axis, a fourth lens group G4 having positive refractive power and a fifth lens group G5 having negative refractive power.
The fourth lens group G4 is composed of, in order from the object side along the optical axis, a negative meniscus lens L41 having a concave surface facing the object side, and a biconvex positive lens L42. The biconvex positive lens L42 is a glass-molded aspherical lens having an aspherical lens surface on the image plane I side.
The fifth lens group G5 consists of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface facing the object side, and a biconcave negative lens L52. The positive meniscus lens L51 is a glass molded aspherical lens having an aspherical lens surface on the image plane I side.

Between the fifth lens group G5 and the image plane I, a filter FL such as a low-pass filter is arranged.
An imaging device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I. FIG.

The variable-magnification optical system according to the present embodiment has a distance between the first lens group G1 and the second lens group G2, and a distance between the second lens group G2 and the third lens group G3 during zooming from the wide-angle end state to the telephoto end state. , the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5. move along the optical axis. Also, the aperture stop S moves integrally with the third lens group G3 during zooming from the wide-angle end state to the telephoto end state.
In the variable-magnification optical system according to the present embodiment, the fourth lens group G4 as a focusing lens group is moved along the optical axis toward the object, thereby focusing from an infinity object to a short distance object.
Table 4 below lists the values of the specifications of the variable magnification optical system according to this example.

(Table 4) Fourth embodiment [Surface data]
m r d nd νd
OP ∞
1 76.69882 2.150 1.84666 23.8
2 49.37863 8.183 1.75500 52.3
3 439.48582 D3

4 1000.00000 2.000 1.74250 49.4
*5 17.13499 9.947
6 -92.86562 1.500 1.75500 52.3
7 89.43926 1.284
8 45.22218 3.631 2.00069 25.5
9 1279.93050 D9

10(S) ∞ 1.500
*11 25.91677 3.597 1.55332 71.7
12 261.64746 0.300
13 38.95443 1.000 1.83481 42.7
14 23.18065 4.122 1.61800 63.3
15 -155.71305 4.035
16 -65.68195 1.000 1.83481 42.7
17 15.75952 5.135 1.61800 63.3
18-32.57355 D18

19 -20.56363 2.000 1.80100 34.9
20 -34.41474 1.000
21 89.46436 6.000 1.59201 67.0
*22 -24.96683 D22

23 -34.33374 3.425 1.55332 71.7
*24 -23.28316 4.520
25 -24.47581 1.500 1.61881 63.9
26 132.00709 D26

27 ∞ 1.500 1.51680 64.1
28∞D28
I ∞

[Various data]
Zoom ratio: 2.75
WMT
f 24.72 46.31 67.90
FNo 4.00 4.18 4.00
ω 43.6 23.8 16.5
Y 21.70 21.70 21.70
TL 121.051 133.285 149.815
BF 14.060 26.434 33.679
BF (air conversion length) 13.549 25.923 33.168

[Lens group data]
Lens group ST f
1st lens group 1 131.85
2nd lens group 4 -29.95
Third lens group 10 35.73
4th lens group 19 55.25
5th lens group 23 -46.59

[Aspheric data]
Face κ A4 A6 A8 A10
5 0.00000e+00 1.93492e-05 2.97056e-08 3.40451e-11 1.36704e-13
11 1.00000e+00 -5.53738e-06 5.67727e-10 5.02317e-11 -4.30689e-13
22 1.00000e+00 1.49131e-05 -1.16787e-08 1.79818e-12 -2.00447e-13
24 1.00000e+00 3.34976e-06 2.85281e-08 -3.37056e-11 3.81301e-13

[Variable interval data]
WMT WMT
Infinity Infinity Infinity Close Close Close
D3 1.800 17.426 32.352 1.800 17.426 32.352
D9 23.692 7.926 2.285 23.692 7.926 2.285
D18 5.643 9.324 11.669 2.987 3.852 2.996
D22 8.025 4.345 2.000 10.681 9.817 10.673
D26 12.460 24.834 32.078 12.460 24.834 32.078
D28 0.100 0.101 0.101 0.100 0.101 0.101

[Value corresponding to conditional expression]
(1) f1/fw = 5.3337
(2) BFw/fw = 0.6294
(3) βFw = 0.6214
(4) f5/f3 = -1.3040
(5) f1/f1Rw = 6.0287
(6) nd3fp = 1.5533
(7) νd3p = 71.6835
(8) 1/βRw = 0.7672
(9) f2 fn/f2 = 0.7846
(10) fF/ft = 0.8135
(11) ωw = 43.5536°

11A, 11B, and 11C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the fourth embodiment, respectively, when focusing on an object at infinity.
12A, 12B, and 12C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the fourth embodiment, respectively, when focusing on a close object.

From the aberration diagrams, it can be seen that the variable power optical system according to this example has excellent imaging performance with good correction of various aberrations from the wide-angle end state to the telephoto end state. It can be seen that they have excellent imaging performance.

(Fifth embodiment)
13A, 13B, and 13C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to Example 5 of the present embodiment. The arrow under each lens group in FIG. 13A indicates the moving direction of each lens group during zooming from the wide-angle end state to the intermediate focal length state. The arrows under each lens group in FIG. 13B indicate the locus of movement of each lens group during zooming from the intermediate focal length state to the telephoto end state.

The variable power optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S , a third lens group G3 having positive refractive power, and a subsequent lens group GR having positive refractive power.

The first lens group G1 is composed of, in order from the object side along the optical axis, a cemented lens constructed by cementing 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.
The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Consists of The negative meniscus lens L21 is a glass-molded aspherical lens in which the lens surface on the object side and the lens surface on the image plane I side are aspherical surfaces.
The third lens group G3 includes, in order from the object side along the optical axis, a positive meniscus lens L31 with a convex surface facing the object side, a biconvex positive lens L32, and a negative meniscus lens L33 with a concave surface facing the object side. and a cemented lens of a biconcave negative lens L34 and a biconvex positive lens L35. The positive meniscus lens L31 is a glass-molded aspherical lens having an aspherical surface on the object side.

The subsequent lens group GR is composed of, in order from the object side along the optical axis, a fourth lens group G4 having positive refractive power and a fifth lens group G5 having negative refractive power.
The fourth lens group G4 is composed of, in order from the object side along the optical axis, a negative meniscus lens L41 having a concave surface facing the object side, and a biconvex positive lens L42. The biconvex positive lens L42 is a glass-molded aspherical lens having an aspherical lens surface on the image plane I side.
The fifth lens group G5 consists of, in order from the object side along the optical axis, a biconcave negative lens L51 and a positive meniscus lens L52 having a convex surface facing the object side.

Between the fifth lens group G5 and the image plane I, a filter FL such as a low-pass filter is arranged.
An imaging device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I. FIG.

The variable-magnification optical system according to the present embodiment has a distance between the first lens group G1 and the second lens group G2, and a distance between the second lens group G2 and the third lens group G3 during zooming from the wide-angle end state to the telephoto end state. , the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5. move along the optical axis. Also, the aperture stop S moves integrally with the third lens group G3 during zooming from the wide-angle end state to the telephoto end state.
In the variable-magnification optical system according to the present embodiment, the fourth lens group G4 as a focusing lens group is moved along the optical axis toward the object, thereby focusing from an infinity object to a short distance object.
Table 5 below lists the values of the specifications of the variable magnification optical system according to this example.

(Table 5) Fifth embodiment [Surface data]
m r d nd νd
OP ∞
1 78.28661 2.200 1.94595 18.0
2 55.12139 7.465 1.83481 42.7
3 416.58751 D3

*4 600.00000 2.000 1.74330 49.3
*5 14.79065 9.268
6 -80.00000 1.500 1.49782 82.6
7 112.11004 0.150
8 35.97822 3.589 2.00069 25.5
9 115.26124 D9

10(S) ∞ 1.500
*11 22.34807 3.756 1.61881 63.9
12 215.30357 4.534
13 116.19602 4.736 1.61800 63.3
14 -16.99559 1.000 1.61266 44.5
15 -42.70583 0.150
16 -3080.10830 1.000 1.83481 42.7
17 14.42589 4.664 1.49782 82.6
18 -73.51276 D18

19 -32.33307 1.000 1.80100 34.9
20 -94.44385 0.415
21 34.51492 5.500 1.69350 53.2
*22 -39.28206 D22

23 -146.73735 1.500 1.59319 67.9
24 27.39699 2.426
25 58.23961 2.594 1.69895 30.1
26 100.00000 D26

27 ∞ 1.500 1.51680 64.1
28∞D28
I ∞

[Various data]
Zoom ratio: 2.75
WMT
f 24.71 46.30 67.86
FNo 4.00 4.16 4.00
ω 43.3 23.8 16.5
Y 21.70 21.70 21.70
TL 117.744 130.814 147.913
BF 19.640 33.380 41.487
BF (air conversion length) 19.129 32.869 40.976

[Lens group data]
Lens group ST f
1st lens group 1 121.95
2nd lens group 4 -27.81
Third lens group 10 36.02
4th lens group 19 45.26
5th lens group 23 -48.61

[Aspheric data]
Face κ A4 A6 A8 A10
4 1.00000e+00 1.94041e-06 -1.27348e-08 2.13014e-11 -1.37676e-14
5 0.00000e+00 2.59781e-05 6.01951e-08 -1.23842e-10 2.09998e-13
11 1.00000e+00 -1.43227e-05 1.69157e-08 -3.97283e-10 1.27743e-12
22 1.00000e+00 1.66914e-05 -1.21729e-08 -1.24851e-12 9.57183e-15

[Variable interval data]
WMT WMT
Infinity Infinity Infinity Close Close Close
D3 2.000 16.993 31.289 2.000 16.993 31.289
D9 24.595 8.932 3.628 24.595 8.932 3.628
D18 4.555 7.160 9.062 2.811 3.351 2.811
D22 6.007 3.402 1.500 7.751 7.211 7.751
D26 18.040 31.781 39.888 18.040 31.781 39.888
D28 0.100 0.100 0.100 0.100 0.099 0.100

[Value corresponding to conditional expression]
(1) f1/fw = 4.9349
(2) BFw/fw = 0.8998
(3) βFw = 0.5108
(4) f5/f3 = -1.3496
(5) f1/f1Rw = 5.6533
(6) nd3fp = 1.6188
(7) νd3p = 63.8544
(8) 1/βRw = 0.6758
(9) f2fn/f2 = 0.7346
(10) fF/ft = 0.6668
(11) ωw = 43.2711°

14A, 14B, and 14C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the fifth embodiment, respectively, when focusing on an object at infinity.
15A, 15B, and 15C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the fifth embodiment, respectively, when focusing on a short distance object.

From the aberration diagrams, it can be seen that the variable power optical system according to this example has excellent imaging performance with good correction of various aberrations from the wide-angle end state to the telephoto end state. It can be seen that they have excellent imaging performance.

(Sixth embodiment)
16A, 16B, and 16C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to Example 6 of the present embodiment. The arrows under each lens group in FIG. 16A indicate the moving direction of each lens group during zooming from the wide-angle end state to the intermediate focal length state. The arrows under each lens group in FIG. 16B indicate the locus of movement of each lens group during zooming from the intermediate focal length state to the telephoto end state.

The variable power optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S , a third lens group G3 having positive refractive power, and a subsequent lens group GR having positive refractive power.

The first lens group G1 is composed of, in order from the object side along the optical axis, a cemented lens constructed by cementing 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.
The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Consists of The negative meniscus lens L21 is a glass mold aspherical lens having an aspherical lens surface on the image plane I side.
The third lens group G3 includes, in order from the object side along the optical axis, a biconvex positive lens L31, a positive meniscus lens L32 with a concave surface facing the object side, and a negative meniscus lens L33 with a concave surface facing the object side. and a cemented lens composed of a negative meniscus lens L34 having a convex surface facing the object side and a positive meniscus lens L35 having a convex surface facing the object side. The biconvex positive lens L31 is a glass-molded aspherical lens having an aspherical surface on the object side.

The subsequent lens group GR is composed of, in order from the object side along the optical axis, a fourth lens group G4 having positive refractive power and a fifth lens group G5 having negative refractive power.
The fourth lens group G4 consists of, in order from the object side along the optical axis, a negative meniscus lens L41 with a concave surface facing the object side and a positive meniscus lens L42 with a concave surface facing the object side. The negative meniscus lens L41 is a glass-molded aspherical lens having an aspherical surface on the object side. The positive meniscus lens L42 is a glass molded aspherical lens having an aspherical lens surface on the image plane I side.
The fifth lens group G5 consists of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface facing the object side, and a biconcave negative lens L52.

Between the fifth lens group G5 and the image plane I, a filter FL such as a low-pass filter is arranged.
An imaging device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I. FIG.

The variable-magnification optical system according to the present embodiment has a distance between the first lens group G1 and the second lens group G2, and a distance between the second lens group G2 and the third lens group G3 during zooming from the wide-angle end state to the telephoto end state. , the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5. move along the optical axis. Also, the aperture stop S moves integrally with the third lens group G3 during zooming from the wide-angle end state to the telephoto end state.
In the variable-magnification optical system according to the present embodiment, the fourth lens group G4 as a focusing lens group is moved along the optical axis toward the object, thereby focusing from an infinity object to a short distance object.
Table 6 below lists the values of the specifications of the variable power optical system according to this example.

(Table 6) Sixth embodiment [Surface data]
m r d nd νd
OP ∞
1 60.32635 2.039 1.80809 22.7
2 41.97920 8.268 1.75500 52.3
3 207.34902 D3

4 1000.00000 2.000 1.82886 42.3
*5 15.73567 8.461
6 -59.96573 1.500 1.49782 82.6
7 49.78382 0.150
8 35.18437 4.075 1.98917 26.2
9 1619.58040 D9

10(S) ∞ 1.500
*11 25.50000 4.170 1.55332 71.7
12 -65.45591 3.367
13 -32.91804 3.671 1.83645 42.6
14 -14.77178 1.500 1.94754 27.1
15 -26.35178 0.150
16 26.26299 1.500 1.99662 26.6
17 13.56251 3.695 1.64836 33.2
18 37.92217 D18

*19 -45.13942 1.500 1.58313 59.4
20 -55.10622 4.314
21 -45.22291 5.000 1.55332 71.7
*22 -17.65257 D22

23 -60.30075 8.069 1.65648 32.5
24 -15.50000 1.500 1.75698 36.7
25 290.03399 D25

26 ∞ 1.500 1.51680 64.1
27 ∞ D27
I ∞

[Various data]
Zoom ratio: 2.75
WMT
f 24.72 46.31 67.90
FNo 4.00 4.09 4.00
ω 44.7 24.0 16.7
Y 21.70 21.70 21.70
TL 116.526 128.486 142.973
BF 14.627 25.478 33.218
BF (air conversion length) 14.116 24.967 32.707

[Lens group data]
Lens group ST f
1st lens group 1 114.00
2nd lens group 4 -26.90
Third lens group 10 31.86
4th lens group 19 53.18
5th lens group 23 -48.77

[Aspheric data]
Face κ A4 A6 A8 A10
5 0.00000e+00 2.28397e-05 5.52091e-08 -3.85159e-11 3.96575e-13
11 1.00000e+00 -1.02420e-05 -5.12185e-09 -2.80701e-11 -2.18997e-13
19 1.00000e+00 -3.49441e-05 -2.07361e-07 1.87328e-09 -1.70790e-11
22 1.00000e+00 7.10600e-06 -6.76172e-08 4.93526e-10 -2.53168e-12

[Variable interval data]
WMT WMT
Infinity Infinity Infinity Close Close Close
D3 2.000 17.776 29.427 2.000 17.776 29.427
D9 21.834 7.167 2.262 21.834 7.167 2.262
D18 4.820 7.522 10.636 2.245 2.026 1.830
D22 6.816 4.114 1.000 9.392 9.610 9.806
D25 13.027 23.878 31.619 13.027 23.878 31.619
D27 0.100 0.100 0.100 0.100 0.100 0.100

[Value corresponding to conditional expression]
(1) f1/fw = 4.6115
(2) BFw/fw = 0.6524
(3) βFw = 0.6567
(4) f5/f3 = -1.5310
(5) f1/f1Rw = 5.3365
(6) nd3fp = 1.5533
(7) νd3p = 71.6835
(8) 1/βRw = 0.7366
(9) f2 fn/f2 = 0.7177
(10) fF/ft = 0.7832
(11) ωw = 44.7194°

17A, 17B, and 17C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the sixth embodiment, respectively, when focusing on an object at infinity.
18A, 18B, and 18C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the sixth embodiment, respectively, when focusing on a short distance object.

From the aberration diagrams, it can be seen that the variable power optical system according to this example has excellent imaging performance with good correction of various aberrations from the wide-angle end state to the telephoto end state. It can be seen that they have excellent imaging performance.

(Seventh embodiment)
19A, 19B, and 19C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to Example 7 of the present embodiment. The arrow under each lens group in FIG. 19A indicates the moving direction of each lens group during zooming from the wide-angle end state to the intermediate focal length state. The arrows under each lens group in FIG. 19B indicate the locus of movement of each lens group during zooming from the intermediate focal length state to the telephoto end state.

The variable power optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S , a third lens group G3 having positive refractive power, and a subsequent lens group GR having positive refractive power.

The first lens group G1 is composed of, in order from the object side along the optical axis, a cemented lens constructed by cementing a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12.
The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 having a convex surface facing the object side, a negative meniscus lens L22 having a concave surface facing the object side, and a negative meniscus lens L22 having a concave surface facing the object side. and a positive meniscus lens L23. The negative meniscus lens L21 is a glass-molded aspherical lens in which the lens surface on the object side and the lens surface on the image plane I side are aspherical surfaces.
The third lens group G3 includes, in order from the object side along the optical axis, a positive meniscus lens L31 having a convex surface facing the object side, a positive meniscus lens L32 having a convex surface facing the object side, and a positive meniscus lens L32 having a convex surface facing the object side. It consists of a cemented lens of a positive meniscus lens L33 and a negative meniscus lens L34 having a convex surface facing the object side. The positive meniscus lens L31 is a glass-molded aspherical lens having an aspherical surface on the object side.

The subsequent lens group GR includes, in order from the object side along the optical axis, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G5 having negative refractive power. and a lens group G6.
The fourth lens group G4 is composed of a biconvex positive lens L41. The biconvex positive lens L41 is a glass-molded aspherical lens in which the lens surface on the object side and the lens surface on the image plane I side are aspherical.
The fifth lens group G5 is composed of a negative meniscus lens L51 having a convex surface facing the object side. The negative meniscus lens L51 is a glass-molded aspherical lens having an aspherical surface on the object side.
The sixth lens group G6 is composed of a negative meniscus lens L61 having a concave surface facing the object side.

Between the sixth lens group G6 and the image plane I, a filter FL such as a low-pass filter is arranged.
An imaging device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I. FIG.

The variable-magnification optical system according to the present embodiment has a distance between the first lens group G1 and the second lens group G2, and a distance between the second lens group G2 and the third lens group G3 during zooming from the wide-angle end state to the telephoto end state. , the distance between the third lens group G3 and the fourth lens group G4, the distance between the fourth lens group G4 and the fifth lens group G5, and the distance between the fifth lens group G5 and the sixth lens group G6. , the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move along the optical axis. At this time, the position of the sixth lens group G6 with respect to the image plane I is fixed. Also, the aperture stop S moves integrally with the third lens group G3 during zooming from the wide-angle end state to the telephoto end state.
In the variable-magnification optical system according to the present embodiment, the fourth lens group G4 as a focusing lens group is moved along the optical axis toward the object, thereby focusing from an infinity object to a short distance object.
Table 7 below lists the values of the specifications of the variable power optical system according to this example.

(Table 7) Seventh embodiment [Surface data]
m r d nd νd
OP ∞
1 101.78373 2.263 1.84666 23.8
2 64.09488 8.457 1.75500 52.3
3-4649.78570 D3

*4 338.09183 2.000 1.85135 40.1
*5 17.62582 9.239
6 -31.88780 1.500 1.49782 82.6
7 -480.92591 0.150
8 48.76651 3.362 2.00069 25.5
9 1462.00720 D9

10(S) ∞ 1.500
*11 40.00000 3.061 1.49710 81.5
12 746.47149 0.150
13 56.62003 3.000 1.85896 22.7
14 1991.68980 0.150
15 22.31377 3.732 1.49782 82.6
16 102.88645 1.500 1.85896 22.7
17 20.13958 D17

*18 25.58334 5.130 1.49710 81.5
*19 -26.20789 D19

*20 44.84857 1.500 1.74330 49.3
21 19.56479 D21

22 -58.99276 0.839 1.61800 63.3
23 -84.99207 21.000
24 0.00000 1.500 1.51680 64.1
25 0.00000 D25
I ∞

[Various data]
Zoom ratio: 2.75
WMT
f 24.72 46.32 67.90
FNo 4.02 4.01 4.02
ω 43.5 23.3 16.4
Y 21.70 21.70 21.70
TL 115.000 129.999 145.678
BF 22.601 22.601 22.602
BF (air conversion length) 22.090 22.090 22.091

[Lens group data]
Lens group ST f
1st lens group 1 141.68
2nd lens group 4 -27.31
Third lens group 10 59.45
4th lens group 18 26.93
5th lens group 20 -47.90
6th lens group 22 -315.95

[Aspheric data]
Face κ A4 A6 A8 A10
4 1.00000e+00 1.12967e-05 -4.46018e-08 1.00140e-10 -1.05741e-13
5 0.00000e+00 3.44021e-05 7.39481e-08 -2.03619e-10 1.51680e-12
11 1.00000e+00 -6.99848e-06 -1.23976e-08 1.83746e-10 -4.96062e-13
18 1.00000e+00 -1.46574e-05 2.12049e-07 -8.82713e-10 -5.22530e-12
19 1.00000e+00 2.32857e-05 1.32158e-07 -5.88648e-10 -6.83977e-12
20 1.00000e+00 4.54779e-06 -1.12679e-08 -3.81570e-10 0.00000e+00

[Variable interval data]
WMT WMT
Infinity Infinity Infinity Close Close Close
D3 2.000 22.166 34.570 2.000 22.166 34.570
D9 24.510 8.331 2.222 24.510 8.331 2.222
D17 5.931 5.867 5.409 4.929 3.275 0.788
D19 4.569 3.472 1.944 5.571 6.063 6.565
D21 7.856 20.029 31.398 7.856 20.029 31.398
D25 0.101 0.101 0.102 0.101 0.101 0.103

[Value corresponding to conditional expression]
(1) f1/fw = 5.7316
(2) BFw/fw = 0.9668
(3) βFw = 0.0452
(4) f5/f3 = -0.8058
(5) f1/f1Rw = 6.3640
(6) nd3fp = 1.4971
(7) νd3p = 81.5584
(8) 1/βRw = 0.9286
(9) f2 fn/f2 = 0.8021
(10) fF/ft = 0.3965
(11) ωw = 43.4833°

20A, 20B, and 20C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the seventh embodiment, respectively, when focusing on an object at infinity.
21A, 21B, and 21C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable magnification optical system according to the seventh embodiment, respectively, when focusing on a short-distance object.

From the aberration diagrams, it can be seen that the variable power optical system according to this example has excellent imaging performance with good correction of various aberrations from the wide-angle end state to the telephoto end state. It can be seen that they have excellent imaging performance.

(Eighth embodiment)
22A, 22B, and 22C are cross-sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable power optical system according to Example 8 of the present embodiment. The arrow under each lens group in FIG. 22A indicates the moving direction of each lens group during zooming from the wide-angle end state to the intermediate focal length state. The arrows under each lens group in FIG. 22B indicate the locus of movement of each lens group during zooming from the intermediate focal length state to the telephoto end state.

The variable power optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S , a third lens group G3 having positive refractive power, and a subsequent lens group GR having positive refractive power.

The first lens group G1 is composed of, in order from the object side along the optical axis, a cemented lens constructed by cementing a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12.
The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 with a convex surface facing the object side, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side. Consists of The negative meniscus lens L21 is a glass mold aspherical lens having an aspherical lens surface on the image plane I side.
The third lens group G3 comprises, in order from the object side along the optical axis, a biconvex positive lens L31, a cemented lens constructed by a negative meniscus lens L32 having a convex surface facing the object side, and a biconvex positive lens L33. , a cemented lens of a positive meniscus lens L34 having a concave surface facing the object side cemented with a biconcave negative lens L35. The biconvex positive lens L31 is a glass-molded aspherical lens having an aspherical surface on the object side.

The subsequent lens group GR is composed of, in order from the object side along the optical axis, a fourth lens group G4 having positive refractive power and a fifth lens group G5 having negative refractive power.
The fourth lens group G4 is composed of, in order from the object side along the optical axis, a positive meniscus lens L41 having a convex surface facing the object side, and a biconvex positive lens L42. The biconvex positive lens L42 is a glass-molded aspherical lens in which the lens surface on the object side and the lens surface on the image plane I side are aspherical.
The fifth lens group G5 is composed of a cemented lens constructed by cementing a biconvex positive lens L51 and a biconcave negative lens L52 in order from the object side along the optical axis. The biconcave negative lens L52 is a glass-molded aspherical lens having an aspherical surface on the object side.

Between the fifth lens group G5 and the image plane I, a filter FL such as a low-pass filter is arranged.
An imaging device (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I. FIG.

The variable-magnification optical system according to the present embodiment has a distance between the first lens group G1 and the second lens group G2, and a distance between the second lens group G2 and the third lens group G3 during zooming from the wide-angle end state to the telephoto end state. , the distance between the third lens group G3 and the fourth lens group G4, and the distance between the fourth lens group G4 and the fifth lens group G5. move along the optical axis. Also, the aperture stop S moves integrally with the third lens group G3 during zooming from the wide-angle end state to the telephoto end state.
In the variable-magnification optical system according to this embodiment, the positive meniscus lens L41 of the fourth lens group G4 as a focusing lens group is moved along the optical axis toward the object, thereby focusing from an infinity object to a short distance object. do the charcoal.
Table 8 below lists the values of the specifications of the variable magnification optical system according to this example.

(Table 8) Eighth embodiment [Surface data]
m r d nd νd
OP ∞
1 116.51174 2.150 1.84666 23.8
2 68.14169 8.500 1.75500 52.3
3-1607.21650 D3

4 643.64333 2.000 1.85135 40.1
*5 22.47852 12.291
6 -49.00635 1.500 1.49782 82.6
7 35.41428 0.100
8 32.93414 4.000 2.00069 25.5
9 134.12564 D9

10(S) ∞ 1.500
*11 23.68026 5.000 1.55332 71.7
12 -51.23473 1.136
13 87.42815 1.000 1.97484 25.9
14 48.00600 5.000 1.61800 63.3
15 -93.41134 1.653
16 -27.67767 4.500 1.61800 63.3
17 -14.25207 1.000 1.63137 35.1
18 3549.62960 D18

19 34.01132 1.500 1.83858 33.3
20 52.01107 6.500
*21 505.55440 4.000 1.59201 67.0
*22 -61.72425 D22

23 106.95458 10.000 1.51680 64.1
24 -20.00000 1.500 1.74330 49.3
*25 144.50680 D25

26 0.00000 1.500 1.51680 64.1
27 0.00000 D27
I ∞

[Various data]
Zoom ratio: 2.75
WMT
f 24.72 46.31 67.89
FNo 4.00 4.00 4.00
ω 44.9 23.8 16.5
Y 21.70 21.70 21.70
TL 121.839 134.775 154.929
BF 14.062 27.994 39.252
BF (air conversion length) 13.551 27.483 38.741

[Lens group data]
Lens group ST f
1st lens group 1 156.61
2nd lens group 4 -26.22
Third lens group 10 38.65
4th lens group 19 53.93
5th lens group 23 -89.77

[Aspheric data]
Face κ A4 A6 A8 A10
5 0.00000e+00 1.29856e-05 3.72807e-08 -9.91643e-11 5.62653e-13
11 1.00000e+00 -6.13337e-06 1.52342e-08 -1.33494e-10 5.07280e-13
21 1.00000e+00 -1.56957e-05 -4.44053e-08 -8.01823e-10 -6.52474e-14
22 1.00000e+00 6.23173e-06 -4.75716e-08 -5.19265e-10 -1.02402e-13
25 1.00000e+00 1.25490e-06 3.00760e-08 -1.22687e-10 3.40306e-13

[Variable interval data]
WMT WMT
Infinity Infinity Infinity Close Close Close
D3 2.000 19.945 36.744 2.000 19.945 36.744
D9 20.989 5.771 1.000 20.989 5.771 1.000
D18 4.914 2.181 2.103 4.914 2.181 2.103
D22 5.044 4.055 1.000 6.288 6.671 5.279
D25 12.462 26.394 37.651 12.462 26.394 37.651
D27 0.100 0.100 0.101 0.100 0.100 0.101

[Value corresponding to conditional expression]
(1) f1/fw = 6.3354
(2) BFw/fw = 0.6275
(3) βFw = 0.7271
(4) f5/f3 = -2.3229
(5) f1/f1Rw = 8.1273
(6) nd3fp = 1.5533
(7) νd3p = 71.6835
(8) 1/βRw = 0.8894
(9) f2 fn/f2 = 1.0450
(10) fF/ft=1.3722
(11) ωw = 45.6019°

23A, 23B, and 23C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable power optical system according to the eighth embodiment, respectively, when focusing on an object at infinity.
24A, 24B, and 24C are diagrams of various aberrations in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable magnification optical system according to the eighth embodiment, respectively, when focusing on a close object.

From the aberration diagrams, it can be seen that the variable power optical system according to this example has excellent imaging performance with good correction of various aberrations from the wide-angle end state to the telephoto end state. It can be seen that they have excellent imaging performance.

According to each of the above-described embodiments, it is possible to cope with a large-sized image pickup device while being compact, to correct various aberrations from the wide-angle end state to the telephoto end state, and to achieve excellent results even when focusing on a short-distance object. A variable power optical system having image performance can be realized.

The variable power optical system according to the present embodiment has a variable power ratio of about 2 to 10 times, and a focal length in the wide-angle end state of about 20 to 30 mm in terms of 35 mm. Further, the variable power optical system according to the present embodiment has an F-number of about f/2.0 to f/4.5 in the wide-angle end state, and an F-number of about f/2.0 to f/4.5 in the telephoto end state. It is about 6.3.
Moreover, each of the above examples shows a specific example of the present embodiment, and the present embodiment is not limited to these. The following content can be appropriately adopted within a range that does not impair the optical performance of the variable power optical system of this embodiment.

Numerical examples of the variable magnification optical system according to the present embodiment have been shown with a 5-group configuration or a 6-group configuration, but the present embodiment is not limited to this, and other group configurations (for example, 7 groups, etc.) can be used for variable magnification. An optical system can also be constructed. Specifically, a configuration in which a lens or lens group is added to the most object side or most image side of the variable power optical system of each of the above embodiments may be used. Alternatively, a lens or lens group may be added between the first lens group G1 and the second lens group G2. Alternatively, a lens or lens group may be added between the second lens group G2 and the third lens group G3. Alternatively, a lens or lens group may be added between the third lens group G3 and the subsequent lens group GR.

Further, in each of the above embodiments, the fourth lens group G4 and the fifth lens group G5, or the fourth lens group G4, the fifth lens group G5 and the sixth lens group G6 are shown as the lens groups constituting the subsequent lens group GR. However, it is not limited to this.

Further, in each of the above embodiments, one lens group or part of the lens group is used as the focusing lens group, but two or more lens groups may be used as the focusing lens group. Such a focusing lens group can also be applied to autofocus, and is also suitable for driving by a motor for autofocus, such as an ultrasonic motor, a stepping motor, a VCM motor, or the like.

Further, in the variable power optical system of each of the above embodiments, any one of the lens groups in whole or in part may be moved as a vibration reduction group so as to include a component in the direction perpendicular to the optical axis, or the optical axis may be shifted. It is also possible to adopt a configuration in which vibration isolation is performed by rotationally moving (swinging) in an in-plane direction including.

Further, the lens surfaces of the lenses constituting the variable power optical system of each of the above embodiments may be spherical, planar, or aspherical. When the lens surface is spherical or flat, it is preferable because it facilitates lens processing and assembly adjustment, and can prevent deterioration of optical performance due to errors in lens processing and assembly adjustment. In addition, even when the image plane is shifted, deterioration in rendering performance is small, which is preferable. If the lens surface is aspherical, it can be aspherical by grinding, glass molded aspherical by molding glass into an aspherical shape, or composite aspherical by forming resin on the glass surface into an aspherical shape. good. Further, 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 power optical system of each of the above embodiments, the aperture stop S is preferably arranged between the second lens group G2 and the third lens group G3. may be substituted for the role.

Further, an antireflection film having a high transmittance in a wide wavelength range may be applied to the lens surfaces of the lenses constituting the variable power optical system of each of the above embodiments. As a result, flare and ghost can be reduced, and high contrast and high optical performance can be achieved.

Next, a camera provided with the variable-magnification optical system of this embodiment will be described with reference to FIG.
FIG. 25 is a diagram showing the configuration of a camera provided with the variable magnification optical system of this embodiment.
As shown in FIG. 25, the camera 1 is a so-called mirrorless camera of an interchangeable lens type provided with the variable-magnification optical system according to the first embodiment as a photographing lens 2 .

In this camera 1, light from an unillustrated object (subject) is condensed by a photographing lens 2 and passed through an unillustrated OLPF (Optical low pass filter) onto an imaging surface of an imaging unit 3. to form an image of the subject. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1 . This allows the photographer to observe the subject through the EVF4.
Also, when a release button (not shown) is pressed by the photographer, the image of the subject generated by the imaging section 3 is stored in a memory (not shown). In this manner, the photographer can photograph the subject with the camera 1. FIG.

Here, the variable-magnification optical system according to the first embodiment mounted as the photographing lens 2 in the camera 1 has excellent optical performance as described above and is compact. In other words, this camera 1 can be made compact, and achieves high optical performance with good correction of various aberrations from the wide-angle end state to the telephoto end state, and excellent imaging performance even when focusing on a close object. can do. It should be noted that even if a camera equipped with the variable magnification optical system according to the above-described second to eighth embodiments as the photographing lens 2 is constructed, the same effect as that of the above-described camera 1 can be obtained. Further, even when the variable magnification optical system according to each of the above embodiments is mounted on a single-lens reflex camera that has a quick return mirror and observes a subject through a finder optical system, the same effect as that of camera 1 can be obtained. can.

Next, the outline of the manufacturing method of the variable-magnification optical system of this embodiment will be described with reference to FIG.
FIG. 26 is a flowchart showing an outline of the method for manufacturing the variable power optical system of this embodiment.

The method of manufacturing the variable magnification optical system of this embodiment shown in FIG. and a subsequent lens group having positive refractive power, the method including the following steps S1 to S3.

Step S1: 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. and the distance between the third lens group and the subsequent lens group is changed.
Step S2: Configure the trailing lens group to have a focusing lens group that moves when focusing from an infinity object to a close object.
Step S3: Make the variable magnification optical system satisfy the following conditional expressions (1) and (2).
(1) 2.00 < f1/fw < 8.000
(2) 0.100<BFw/fw<1.00
however,
f1: focal length of the first lens group fw: focal length of the variable power optical system in the wide-angle end state BFw: back focus of the variable power optical system in the wide-angle end state fw: focal length of the variable power optical system in the wide-angle end state Focal length

According to the method for manufacturing a variable magnification optical system of the present embodiment, it is possible to cope with a large imaging device while being compact, to correct various aberrations well from the wide-angle end state to the telephoto end state, and to further improve the close-up. It is possible to realize a variable magnification optical system having high optical performance with excellent imaging performance even when focusing on a distance object.

G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group G6 Sixth lens group GR Subsequent lens group S Aperture stop I Image plane

Claims (15)

In order from the object side, a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a subsequent lens group with positive refractive power. Consists of
The subsequent lens group consists of, in order from the object side, a fourth lens group having positive refractive power and a fifth lens group having negative refractive power,
During zooming, the distance between the first lens group and the second lens group changes, the distance between the second lens group and the third lens group changes, and the distance between the third lens group and the fourth lens changes. the distance between the groups changes, the distance between the fourth lens group and the fifth lens group changes,
the trailing lens group has a focusing lens group that moves during focusing;
A variable magnification optical system that satisfies the following conditional expressions.
2.00 < f1/fw < 8.000
0.100<BFw/fw<1.00
however,
f1: focal length of the first lens group fw: focal length of the variable power optical system in the wide-angle end state BFw: back focus of the variable power optical system in the wide-angle end state fw: focal length of the variable power optical system in the wide-angle end state Focal length 2. A variable magnification optical system according to claim 1, which satisfies the following conditional expression.
4.000 < f1/f1Rw < 9.000
however,
f1Rw: Composite focal length in the wide-angle end state of the lens group arranged closer to the image plane than the first lens group 3. A variable magnification optical system according to claim 1, wherein the negative lens is arranged closest to the object side. 4. The variable magnification optical system according to claim 1, wherein the negative lens is arranged closest to the image plane. 5. The variable power optical system according to claim 1, wherein the third lens group has, in order from the object side, a positive lens and a cemented lens. 6. A variable power optical system according to claim 1, which satisfies the following conditional expression.
nd3fp < 1.800
however,
nd3fp: refractive index of the lens with the highest refractive index in the third lens group 7. A variable power optical system according to claim 1, which satisfies the following conditional expression.
50.000 < vd3p
however,
νd3p: Abbe number of the lens with the smallest Abbe number in the third lens group The variable magnification optical system according to any one of claims 1 to 7, wherein the fourth lens group has the focusing lens group. 9. The variable magnification optical system according to claim 1, wherein the following conditional expression is satisfied.
40.00° < ωw < 85.00°
however,
ωw: Half angle of view of the variable magnification optical system in the wide-angle end state 10. The variable power optical system according to claim 1, wherein the following conditional expression is satisfied.
0.040 < βFw < 0.800
however,
βFw: Lateral magnification of the focusing lens group in the wide-angle end state 11. The variable power optical system according to claim 1, wherein the following conditional expression is satisfied.
-3.000 < f5/f3 < -0.500
however,
f3: focal length of the third lens group f5: focal length of the fifth lens group 12. The variable-magnification optical system according to claim 1, which satisfies the following conditional expression.
0.500 < 1/βRw < 1.000
however,
βRw: Lateral magnification of the lens group closest to the image plane in the wide-angle end state 13. The variable-magnification optical system according to claim 1, which satisfies the following conditional expression.
0.500 < f2fn/f2 < 1.100
however,
f2fn: focal length of the most object side lens component in the second lens group f2: focal length of the second lens group 14. The variable-magnification optical system according to claim 1, which satisfies the following conditional expression.
0.300 < fF/ft < 1.400
however,
fF: focal length of the focusing lens group ft: focal length of the variable magnification optical system in the telephoto end state An optical apparatus comprising the variable magnification optical system according to any one of claims 1 to 14.

Images