JPWO2020105107A1 - Magnification optical system, optical equipment, and manufacturing method of variable magnification optics - Google Patents

Abstract

It consists of a plurality of lens groups including a first negative lens group having a negative refractive force and a second negative lens group arranged on the image side of the first negative lens group, and the distance between adjacent lens groups at the time of magnification change. The first negative lens group and the second negative lens group move along the optical axis, and the first negative lens group can move as an anti-vibration lens group so as to include a component in a direction orthogonal to the optical axis. The second negative lens group moves along the optical axis at the time of focusing, and by satisfying a predetermined conditional expression, it has high optical performance and the anti-vibration lens group is miniaturized. A magnification optical system can be provided.

Description

The present invention relates to variable magnification optical systems, optical instruments, and methods for manufacturing variable magnification optical systems.

Conventionally, a variable magnification optical system including a group of anti-vibration lenses for correcting image blur has been proposed (see, for example, Patent Document 1). In a variable magnification optical system provided with such an anti-vibration lens group, further improvement in optical performance and miniaturization of the anti-vibration lens group are required.

Japanese Unexamined Patent Publication No. 11-316342

The first aspect of the present invention is
It has a plurality of lens groups including a first negative lens group having a negative refractive power and a second negative lens group having a negative refractive power arranged on the image side of the first negative lens group.
At the time of scaling, the distance between adjacent lens groups changes, and the first negative lens group and the second negative lens group move along the optical axis.
The first negative lens group can be moved as an anti-vibration lens group so as to include a component in a direction orthogonal to the optical axis.
The second negative lens group moves along the optical axis when in focus, and the second negative lens group moves along the optical axis.
It is a variable magnification optical system that satisfies the following conditional expression.
-2.00 <X1n / X2n <-0.500
However,
X1n: Amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction X2n: The direction of movement toward the image side is positive The amount of movement of the second negative lens group when the magnification is changed from the wide-angle end state to the telephoto end state when the direction is set.

The second aspect of the present invention is
A variable magnification optical system having a plurality of lens groups including a first negative lens group having a negative refractive power and a second negative lens group having a negative refractive power arranged on the image side of the first negative lens group. It is a manufacturing method of
At the time of scaling, the distance between adjacent lens groups changes, and the first negative lens group and the second negative lens group are configured to move along the optical axis.
The first negative lens group is configured to be movable as an anti-vibration lens group so as to include a component in a direction orthogonal to the optical axis.
The second negative lens group is configured to move along the optical axis when in focus.
It is a manufacturing method of a variable magnification optical system configured so as to satisfy the following conditional expression.
-2.00 <X1n / X2n <-0.500
However,
X1n: Amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction X2n: The direction of movement toward the image side is positive The amount of movement of the second negative lens group when the magnification is changed from the wide-angle end state to the telephoto end state when the direction is set.

1A, 1B, and 1C are cross-sectional views of the variable magnification optical system according to the first embodiment in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. 2A, 2B, and 2C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the first embodiment, respectively. 3A, 3B, and 3C are cross-sectional views of the variable magnification optical system according to the second embodiment in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. 4A, 4B, and 4C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the second embodiment, respectively. 5A, 5B and 5C are cross-sectional views of the variable magnification optical system according to the third embodiment in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. 6A, 6B, and 6C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the third embodiment, respectively. 7A, 7B, and 7C are cross-sectional views of the variable magnification optical system according to the fourth embodiment in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. 8A, 8B, and 8C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the fourth embodiment, respectively. 9A, 9B, and 9C are cross-sectional views of the variable magnification optical system according to the fifth embodiment in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. 10A, 10B, and 10C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the fifth embodiment, respectively. 11A, 11B, and 11C are cross-sectional views of the variable magnification optical system according to the sixth embodiment in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. 12A, 12B, and 12C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the sixth embodiment, respectively. 13A, 13B and 13C are cross-sectional views of the variable magnification optical system according to the seventh embodiment in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. 14A, 14B, and 14C are aberration diagrams of the variable magnification optical system according to the seventh embodiment at the time of focusing on an infinity object in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. FIG. 15 is a diagram showing a configuration of a camera provided with a variable magnification optical system. FIG. 16 is a flow chart showing an outline of a method for manufacturing a variable magnification optical system.

Hereinafter, a method for manufacturing a variable magnification optical system, an optical device, and a variable magnification optical system according to an embodiment of the present invention will be described.
The variable magnification optical system of the present embodiment includes a first negative lens group having a negative refractive force and a second negative lens group having a negative refractive force arranged on the image side of the first negative lens group. It has a plurality of lens groups, the distance between adjacent lens groups changes at the time of magnification change, the first negative lens group and the second negative lens group move along the optical axis, and the first negative lens group Is movable as an anti-vibration lens group so as to include a component in a direction orthogonal to the optical axis, and the second negative lens group moves along the optical axis at the time of focusing, and the following conditional expression (1) To be satisfied.
(1) -2.80 <X1n / X2n <-0.500
However,
X1n: Amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction X2n: The direction of movement toward the image side is positive The amount of movement of the second negative lens group when the magnification is changed from the wide-angle end state to the telephoto end state when the direction is set.

In the variable magnification optical system of the present embodiment, the distance between adjacent lens groups changes at the time of magnification change, and the first negative lens group and the second negative lens group move along the optical axis. With this configuration, the variable magnification optical system of the present embodiment realizes variable magnification and can satisfactorily correct various aberrations.

Further, the variable magnification optical system of the present embodiment can be moved so that the first negative lens group includes a component in a direction orthogonal to the optical axis as an anti-vibration lens group. With this configuration, image blurring due to camera shake can be satisfactorily corrected. Further, by setting the first negative lens group as the anti-vibration lens group, it is possible to realize the miniaturization of the anti-vibration lens group. As a result, the drive mechanism of the anti-vibration lens group can be miniaturized, and the performance of the anti-vibration lens group can be easily ensured.

Further, in the variable magnification optical system of the present embodiment, the second negative lens group moves along the optical axis when the second negative lens group is in focus. By using the second negative lens group arranged on the image side as the focusing lens group, the change in image magnification is suppressed, and the ratio of the amount of change in the image plane to the movement of the second negative lens group during focusing is set. It can be made larger.

The conditional equation (1) is the amount of movement of the first negative lens group in the optical axis direction when the magnification is changed from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction. An appropriate range is defined for the ratio of the amount of movement of the second negative lens group in the optical axis direction when the magnification is changed from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction. It is a conditional expression to do. By satisfying the conditional expression (1), the variable magnification optical system of the present embodiment can be miniaturized and various aberrations can be satisfactorily corrected.

When the corresponding value of the conditional expression (1) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the focal length of the first negative lens group becomes long, so that the amount of movement of the first negative lens group at the time of magnification change increases. As the size increases, the fluctuations of spherical aberration and curvature of field become large. Further, if an attempt is made to correct the fluctuation of these aberrations with another lens group, the focal length of the other lens group becomes short, and the spherical aberration generated in the other lens group becomes large. In addition, the amount of movement of the first negative lens group at the time of scaling becomes large, so that the diameter and the total length of the variable magnification optical system become large. By setting the upper limit value of the conditional expression (1) to −0.525, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (1) are set to −0.550, −0.575, −0.590, −0.600, −0.625, −. It is preferably 0.650, -0.660, -0.670, -0.680, and further -0.690.

On the other hand, when the corresponding value of the conditional expression (1) of the variable magnification optical system of the present embodiment is less than the lower limit value, the focal length of the first negative lens group becomes short, so that spherical aberration and spherical aberration generated in the first negative lens group occur. The curvature of field aberration becomes large. By setting the lower limit value of the conditional expression (1) to -1.900, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (1) are set to -1.800, -1.700, -1.600, -1.500, -1.450,-. It is preferably 1.400, -1.350, -1.300, -1.275, and more preferably -1.250.

Further, it is desirable that the variable magnification optical system of the present embodiment satisfies the following conditional expression (2).
(2) 0.200 <(-f1n) / √ (fw * ft) <0.400
However,
f1n: Focal length of the first negative lens group
fw: Focal length of the entire variable-magnification optical system in the wide-angle end state ft: Focal length of the entire variable-magnification optical system in the telephoto end state

Conditional expression (2) defines an appropriate range for the ratio of the focal length of the first negative lens group to the value of the synergistic average of the focal length in the wide-angle end state and the focal length in the telephoto end state of the variable magnification optical system. It is a conditional expression to do. By satisfying the conditional expression (2), the variable magnification optical system of the present embodiment has an appropriate lateral magnification of the first negative lens group, suppresses the influence of camera shake and the like at the time of vibration isolation, and causes image blur. It can be corrected satisfactorily.

When the corresponding value of the conditional expression (2) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the focal length of the first negative lens group becomes long, so that the amount of movement of the first negative lens group at the time of variable magnification increases. It becomes large and the total length of the variable magnification optical system becomes large. By setting the upper limit value of the conditional expression (2) to 0.390, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (2) are set to 0.380, 0.370, 0.360, 0.350, 0.340, 0.335, 0. It is preferably 330, 0.325, 0.320, and more preferably 0.315.

On the other hand, if the corresponding value of the conditional expression (2) of the variable magnification optical system of the present embodiment is less than the lower limit value, it becomes difficult to correct coma aberration and astigmatism. Further, as the focal length of the first negative lens group becomes shorter, the lateral magnification of the first negative lens group changes, and the influence on the image deviation due to the change in the direction perpendicular to the optical axis becomes large. By setting the lower limit value of the conditional expression (2) to 0.210, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (2) are set to 0.220, 0.230, 0.235, 0.240, 0.245, 0.250, 0. It is preferably 255, 0.260, 0.265, and more preferably 0.270.

Further, it is desirable that the variable magnification optical system of the present embodiment satisfies the following conditional expression (3).
(3) 0.200 <(-f2n) /√ (fw * ft) <1.000
However,
f2n: Focal length of the second negative lens group ww: Focal length of the entire variable magnification optical system in the wide-angle end state ft: Focal length of the entire variable magnification optical system in the telephoto end state

Conditional expression (3) defines an appropriate range for the ratio of the focal length of the second negative lens group to the value of the synergistic average of the focal length in the wide-angle end state and the focal length in the telephoto end state of the variable magnification optical system. It is a conditional expression to do. By satisfying the conditional expression (3), the variable magnification optical system of the present embodiment can satisfactorily correct various aberrations at the time of focusing and can reduce the size.

When the corresponding value of the conditional expression (3) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the focal length of the second negative lens group becomes long, so that the amount of movement of the second negative lens group at the time of magnification change increases. It becomes large and the total length of the variable magnification optical system becomes large. Further, at the time of focusing, the ratio of the image plane change to the movement of the second negative lens group becomes small. By setting the upper limit value of the conditional expression (3) to 0.950, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (3) are set to 0.900, 0.875, 0.850, 0.825, 0.800, 0.775, 0. It is preferably 750, 0.730, 0.725, and more preferably 0.720.

On the other hand, if the corresponding value of the conditional expression (3) of the variable magnification optical system of the present embodiment is less than the lower limit value, the focal length of the second negative lens group becomes short, so that the curvature of field occurs in the second negative lens group. The aberration becomes large, and it becomes difficult to correct the aberration at the time of focusing. By setting the lower limit value of the conditional expression (3) to 0.250, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (3) are set to 0.300, 0.350, 0.400, 0.425, 0.450, 0.475, 0. It is preferably 500, 0.510, 0.520, and more preferably 0.530.

Further, it is desirable that the variable magnification optical system of the present embodiment satisfies the following conditional expression (4).
(4) -1,000 <β1nt / β2nt <-0.300
However,
β1nt: lateral magnification of the first negative lens group in the telephoto end state β2nt: lateral magnification of the second negative lens group in the telephoto end state

The conditional expression (4) is a conditional expression for defining an appropriate range for the ratio of the lateral magnification of the first negative lens group in the telephoto end state to the lateral magnification of the second negative lens group in the telephoto end state. .. By satisfying the conditional equation (4), the variable magnification optical system of the present embodiment can suppress the occurrence of spherical aberration and image plane distortion in the first negative lens group and the second negative lens group.

When the corresponding value of the conditional expression (4) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the focal length of the first negative lens group becomes short, so that the spherical aberration and the image plane generated in the first negative lens group are shortened. Distortion becomes large. By setting the upper limit value of the conditional expression (4) to −0.325, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (4) are set to −0.350, −0.375, −0.400, −0.425, −0.450, −. It is preferably 0.475, -0.500, -0.510, -0.520, and further -0.530.

On the other hand, if the corresponding value of the conditional expression (4) of the variable magnification optical system of the present embodiment is less than the lower limit value, the focal length of the second negative lens group becomes short, so that the curvature of field occurs in the second negative lens group. The aberration becomes large, and it becomes difficult to correct the aberration at the time of focusing. By setting the lower limit value of the conditional expression (4) to −0.975, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (4) are set to −0.950, −0.925, −0.900, −0.880, −0.860, −. It is preferably 0.850, -0.840, -0.825, -0.810, and more preferably -0.800.

Further, it is desirable that the variable magnification optical system of the present embodiment satisfies the following conditional expression (5).
(5) 0.050 <X1n / √ (fw * ft) <0.250
However,
X1n: The amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction fw: The variable magnification optical system in the wide-angle end state Focal length of the entire system ft: Focal length of the entire variable magnification optical system in the telephoto end state

Conditional expression (5) shows the amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction, and the variable magnification optical system. It is a conditional expression for defining an appropriate range for the ratio of the focal length in the wide-angle end state and the focal length in the telephoto end state to the value of the synergistic average. The variable magnification optical system of the present embodiment can satisfactorily correct spherical aberration and curvature of field aberration by satisfying the conditional equation (5).

When the corresponding value of the conditional expression (5) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the focal length of the first negative lens group becomes long, so that the amount of movement of the first negative lens group at the time of magnification change increases. It becomes large, and the fluctuation of spherical aberration and image plane distortion becomes large. Further, if an attempt is made to correct the fluctuation of these aberrations with another lens group, the focal length of the other lens group becomes short, and the spherical aberration generated in the other lens group becomes large. Further, the large movement of the first negative lens group at the time of scaling increases the diameter and overall length of the variable magnification optical system. By setting the upper limit value of the conditional expression (5) to 0.240, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (5) are set to 0.230, 0.220, 0.210, 0.200, 0.195, 0.190, 0. It is preferably 185, 0.180, 0.175, and even 0.170.

On the other hand, when the corresponding value of the conditional expression (5) of the variable magnification optical system of the present embodiment is less than the lower limit value, the focal length of the first negative lens group becomes short, so that spherical aberration and spherical aberration generated in the first negative lens group occur. The curvature of field aberration becomes large. By setting the lower limit value of the conditional expression (5) to 0.060, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (5) are set to 0.070, 0.080, 0.090, 0.095, 0.100, 0.105, 0. It is preferably 110, 0.115, 0.120, and more preferably 0.125.

Further, in the variable magnification optical system of the present embodiment, it is desirable that the first negative lens group includes a first negative lens, a second negative lens, and a positive lens in order from the object side. With this configuration, the variable magnification optical system of the present embodiment can prevent light rays outside the angle of view from being multiple-reflected and reaching the imaging surface.

Further, in the variable magnification optical system of the present embodiment, it is desirable that the second negative lens group includes a positive lens and a negative lens. With this configuration, the variable magnification optical system of the present embodiment can suppress the occurrence of chromatic aberration and curvature of field aberration at the time of focusing at a close distance.

Further, in the variable magnification optical system of the present embodiment, it is desirable that an aperture diaphragm is arranged between the first negative lens group and the second negative lens group. By arranging the negative lens group after the aperture diaphragm in this way, the variable magnification optical system of the present embodiment can suppress the fluctuation of the angle of view at the time of focusing.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. , It is desirable to have the second negative lens group. As a result, the variable magnification optical system of the present embodiment is compact and can realize high optical performance capable of satisfactorily correcting various aberrations.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and satisfy the following conditional expression (6).
(6) 0.500 <f2p / (-f1n) <1.500
However,
f2p: Focal length of the second positive lens group f1n: Focal length of the first negative lens group

The variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the above, in order from the object side. By having the second negative lens group, it is possible to realize high optical performance that is compact and can satisfactorily correct various aberrations.

The conditional expression (6) is a conditional expression for defining an appropriate range for the ratio of the focal length of the second positive lens group to the focal length of the first negative lens group. The variable magnification optical system of the present embodiment can satisfactorily correct spherical aberration and curvature of field aberration by satisfying the conditional equation (6).

When the corresponding value of the conditional equation (6) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the focal length of the first negative lens group becomes short, and spherical aberration and curvature of field occur in the first negative lens group. Aberration becomes large. By setting the upper limit value of the conditional expression (6) to 1.450, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (6) are set to 1.400, 1.360, 1.330, 1.300, 1.275, 1.250, 1. It is preferably 225, 1.200, 1.175, and more preferably 1.150.

On the other hand, if the corresponding value of the conditional expression (6) of the variable magnification optical system of the present embodiment is less than the lower limit value, the focal length of the first negative lens group becomes long, so that the movement of the first negative lens group at the time of magnification change The amount becomes large, and the fluctuations of spherical aberration and curvature of field become large. In addition, the amount of movement of the first negative lens group at the time of scaling becomes large, so that the diameter and the total length of the variable magnification optical system become large. Further, since the focal length of the second positive lens group is shortened, the spherical aberration generated in the second positive lens group becomes large. By setting the lower limit value of the conditional expression (6) to 0.600, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (6) are set to 0.700, 0.750, 0.800, 0.850, 0.875, 0.900, 0. It is preferably 925, 0.950, 0.975, and more preferably 1.000.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and satisfy the following conditional expression (7).
(7) −0.300 <X2p / √ (fw * ft) <0.000
However,
X2p: Amount of movement of the second positive lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction fw: The variable magnification optical system in the wide-angle end state Focal distance of the entire system ft: Focal distance of the entire system of the variable magnification optical system in the telephoto end state

The variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the above, in order from the object side. By having the second negative lens group, it is possible to realize high optical performance that is compact and can satisfactorily correct various aberrations.

Conditional expression (7) shows the amount of movement of the second positive lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction, and the variable magnification optical system. It is a conditional expression for defining an appropriate range for the ratio of the focal length in the wide-angle end state and the focal length in the telephoto end state to the value of the synergistic average. The variable magnification optical system of the present embodiment can satisfactorily correct various aberrations including coma aberration by satisfying the conditional equation (7).

When the corresponding value of the conditional expression (7) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the power of the second positive lens group becomes weak. Therefore, in order to maintain the magnification ratio, the power of the first negative lens group becomes strong, and it becomes difficult to correct coma and astigmatism. By setting the upper limit value of the conditional expression (7) to −0.020, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (7) are set to −0.030, −0.040, −0.050, −0.060, −0.070, −. It is preferably 0.080, -0.090, -0.100, -0.110, and further -0.120.

On the other hand, when the corresponding value of the conditional expression (7) of the variable magnification optical system of the present embodiment is less than the lower limit value, the power of the second positive lens group becomes stronger and the spherical aberration is excessively corrected in the telephoto end state. .. In addition, it becomes difficult to correct coma aberration and curvature of field. By setting the lower limit value of the conditional expression (7) to −0.290, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (7) are set to −0.280, −0.270, −0.260, −0.250, −0.240, −. It is preferably 0.230, -0.220, -0.210, -0.205, and more preferably -0.200.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and the first positive lens group to move at the time of magnification change. With this configuration, the variable magnification optical system of the present embodiment suppresses fluctuations in spherical aberration and curvature of field aberration at the time of magnification change, enables efficient magnification change, and can realize miniaturization.

Further, it is desirable that the variable magnification optical system of the present embodiment satisfies the following conditional expression (8).
(8) 0.150 <Bfaw / fw <0.500
However,
Bfaw: Air-equivalent back focus of the entire variable-magnification optical system in the wide-angle end state fw: Focal length of the entire variable-magnification optical system in the wide-angle end state

Conditional expression (8) defines an appropriate range for the ratio of the air-equivalent back focus of the entire variable-magnification optical system in the wide-angle end state to the focal length of the entire variable-magnification optical system in the wide-angle end state. It is a conditional expression of. By satisfying the conditional expression (8), the variable magnification optical system of the present embodiment can satisfactorily correct various aberrations such as coma in the wide-angle end state.

If the corresponding value of the conditional expression (8) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the air-equivalent back focus becomes too large with respect to the focal length of the variable magnification optical system in the wide-angle end state, so that the wide-angle end It becomes difficult to correct various aberrations such as coma in the state. By setting the upper limit value of the conditional expression (8) to 0.480, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (8) are set to 0.460, 0.450, 0.440, 0.420, 0.400, 0.390, 0. It is preferably 380, 0.370, and more preferably 0.360.

On the other hand, if the corresponding value of the conditional expression (8) of the variable magnification optical system of the present embodiment is less than the lower limit value, the back focus becomes too small with respect to the focal length of the variable magnification optical system in the wide-angle end state, so that the wide-angle end It becomes difficult to correct various aberrations such as coma in the state. By setting the lower limit value of the conditional expression (8) to 0.160, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (8) are set to 0.170, 0.180, 0.190, 0.200, 0.210, and further 0.220. Is preferable.

Further, it is desirable that the variable magnification optical system of the present embodiment satisfies the following conditional expression (9).
(9) 20.000 ° <2ωw <45.000 °
However,
2ωw: Full angle of view of the variable magnification optical system in the wide-angle end state

The conditional expression (9) is a conditional expression for defining an appropriate range of the total angle of view of the variable magnification optical system in the wide-angle end state. By satisfying the conditional expression (9), the variable magnification optical system of the present embodiment can satisfactorily correct curvature of field aberration and distortion while having a wide angle of view.

In order to ensure the effect of this embodiment, it is preferable to set the upper limit value of the conditional expression (9) to 43.000 °. Further, in order to further ensure the effect of the present embodiment, it is preferable to set the upper limit values of the conditional expression (9) to 40.000 °, 38.000 °, 36.000 °, and further 35.000 °.
In order to ensure the effect of this embodiment, it is preferable to set the lower limit value of the conditional expression (9) to 22.000 °. Further, in order to further ensure the effect of the present embodiment, it is preferable to set the lower limit values of the conditional expression (9) to 24.000 °, 25.000 °, 26.000 °, and further 27.000 °.

Further, it is desirable that the variable magnification optical system of the present embodiment satisfies the following conditional expression (10).
(10) 1.500 <(β1nt-1) * βRt <4.500
However,
β1nt: Lateral magnification of the first negative lens group in the telephoto end state βRt: Composite lateral magnification of all lens groups arranged on the image side of the first negative lens group in the telephoto end state

Conditional expression (10) is a combination of the lateral magnification of the first negative lens group in the telephoto end state and the combined lateral magnification of all the lens groups arranged on the image side of the first negative lens group in the telephoto end state. It is a conditional expression for defining an appropriate range for the product. The variable magnification optical system of the present embodiment can satisfactorily correct coma aberration and curvature of field aberration by satisfying the conditional equation (10). Further, it is preferable because there is little deterioration in optical performance when eccentric.

When the corresponding value of the conditional expression (10) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the power of the first negative lens group becomes stronger, so that it becomes difficult to correct coma and astigmatism. By setting the upper limit value of the conditional expression (10) to 4.400, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit of the conditional expression (10) is set to 4.300, 4.200, 4.100, 4.000, 3.900, 3.800, 3. It is preferably 700, 3.600, and more preferably 3.500.

On the other hand, if the corresponding value of the conditional expression (10) of the variable magnification optical system of the present embodiment is less than the lower limit value, the power of the first negative lens group becomes weak, so that the amount of movement of the first negative lens group at the time of variable magnification Becomes larger. Therefore, if an attempt is made to increase the magnification ratio while reducing the amount of movement of the first negative lens group, the power of the other lens group becomes stronger. As a result, the spherical aberration in the telephoto end state is excessively corrected, and it becomes difficult to correct the coma aberration and the curvature of field. By setting the lower limit value of the conditional expression (10) to 1.600, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit of the conditional expression (10) is set to 1.700, 1.800, 1.900, 2.000, 2.100, 2.200, 2. It is preferably 300, 2.400, 2.500, and more preferably 2.600.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and satisfy the following conditional expression (11).
(11) 0.500 <m12tw / fw <2.000
However,
m12tw: Amount of change in distance between the first positive lens group and the first negative lens group when scaling from the wide-angle end state to the telephoto end state fw: Focal length of the entire variable magnification optical system in the wide-angle end state

The variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the above, in order from the object side. By having the second negative lens group, it is possible to realize high optical performance that is compact and can satisfactorily correct various aberrations.

The conditional equation (11) shows the amount of change in the distance between the first positive lens group and the first negative lens group when the magnification is changed from the wide-angle end state to the telephoto end state, and the variable magnification optical system in the wide-angle end state. This is a conditional expression for defining an appropriate range for the ratio to the focal length of the entire system. By satisfying the conditional expression (11), the variable magnification optical system of the present embodiment can satisfactorily correct various aberrations such as spherical aberration and chromatic aberration in the telephoto end state.

When the corresponding value of the conditional expression (11) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the power of the first positive lens group and the first negative lens group becomes weak, and it becomes difficult to correct spherical aberration. It ends up. In addition, the overall length of the variable magnification optical system increases. By setting the upper limit value of the conditional expression (11) to 1.900, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (11) are set to 1.800, 1.700, 1.650, 1.600, 1.550, 1.500, 1. It is preferably 450, 1.400, 1.350, and more preferably 1.300.

On the other hand, when the corresponding value of the conditional expression (11) of the variable magnification optical system of the present embodiment is less than the lower limit value, the power of the first positive lens group becomes stronger, and it is difficult to correct spherical aberration, axial chromatic aberration, and chromatic aberration of magnification. Become. By setting the lower limit value of the conditional expression (11) to 0.600, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (11) are set to 0.700, 0.800, 0.850, 0.900, 0.950, 1.000, 1. It is preferably 050 and further 1.100.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and satisfy the following conditional expression (12).
(12) 0.150 <(-f1n) /f1p<0.350
However,
f1n: Focal length of the first negative lens group
f1p: Focal length of the first positive lens group

The variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the above, in order from the object side. By having the second negative lens group, it is possible to realize high optical performance that is compact and can satisfactorily correct various aberrations.

The conditional expression (12) is a conditional expression for defining an appropriate range for the ratio of the focal length of the first negative lens group to the focal length of the first positive lens group. By satisfying the conditional equation (12), the variable magnification optical system of the present embodiment can suppress fluctuations in various aberrations such as spherical aberration when scaling from the wide-angle end state to the telephoto end state. ..

If the corresponding value of the conditional expression (12) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the refractive power of the first positive lens group becomes too strong, so that various factors such as spherical aberration at the time of magnification change It becomes difficult to suppress fluctuations in aberrations. By setting the upper limit value of the conditional expression (12) to 0.340, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (12) are set to 0.330, 0.320, 0.310, 0.300, 0.290, 0.280, 0. It is preferably 270, 0.260, and more preferably 0.250.

On the other hand, if the corresponding value of the conditional expression (12) of the variable magnification optical system of the present embodiment is less than the lower limit value, the refractive power of the first negative lens group becomes too strong, so that spherical aberration at the time of magnification change and the like. It becomes difficult to suppress fluctuations in various aberrations. By setting the lower limit value of the conditional expression (12) to 0.160, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, it is preferable to set the lower limit values of the conditional expression (12) to 0.170, 0.180, 0.190, 0.200, and further 0.210.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and the third negative lens group having a negative refractive power, and satisfy the following conditional expression (13).
(13) 0.010 <(-f3n) /f1p<3.000
However,
f3n: Focal length of the third negative lens group f1p: Focal length of the first positive lens group

The variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the above, in order from the object side. By having the second negative lens group and the third negative lens group having a negative refractive power, it is possible to realize high optical performance that is compact and can satisfactorily correct various aberrations.

The conditional expression (13) is a conditional expression for defining an appropriate range for the ratio of the focal length of the third negative lens group to the focal length of the first positive lens group. By satisfying the conditional equation (13), the variable magnification optical system of the present embodiment can suppress fluctuations in various aberrations such as coma when scaling from the wide-angle end state to the telephoto end state. ..

If the corresponding value of the conditional expression (13) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the refractive power of the first positive lens group becomes too strong, so that various factors such as coma aberration at the time of magnification change occur. It becomes difficult to suppress fluctuations in aberrations. By setting the upper limit value of the conditional expression (13) to 2.800, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit of the conditional expression (13) is set to 2.600, 2.400, 2.200, 2.000, 1.800, 1.700, 1. It is preferably 600, more preferably 1.500.

On the other hand, if the corresponding value of the conditional expression (13) of the variable magnification optical system of the present embodiment is less than the lower limit value, the refractive power of the first negative lens group becomes too strong, so that coma aberration at the time of magnification change and the like. It becomes difficult to suppress fluctuations in various aberrations. By setting the lower limit value of the conditional expression (13) to 0.050, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (13) are set to 0.100, 0.150, 0.200, 0.250, 0.300, 0.350, 0. It is preferably 400, 0.450, 0.500, and more preferably 0.550.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and the third negative lens group having a negative refractive power, and satisfy the following conditional expression (14).
(14) 0.050 <f2n / f3n <1.500
However,
f2n: Focal length of the second negative lens group f3n: Focal length of the third negative lens group

The variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the above, in order from the object side. By having the second negative lens group and the third negative lens group having a negative refractive power, it is possible to realize high optical performance that is compact and can satisfactorily correct various aberrations.

The conditional expression (14) is a conditional expression for defining an appropriate range for the ratio of the focal length of the second negative lens group to the focal length of the third negative lens group. By satisfying the conditional equation (14), the variable magnification optical system of the present embodiment satisfactorily corrects various aberrations such as curvature of field when scaling from the wide-angle end state to the telephoto end state. Can be done.

If the corresponding value of the conditional expression (14) of the variable magnification optical system of the present embodiment exceeds the upper limit value, the refractive power of the third negative lens group becomes too strong, so that curvature of field at the time of magnification change is started. It becomes difficult to satisfactorily correct the various aberrations. By setting the upper limit value of the conditional expression (14) to 1.400, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (14) are set to 1.300, 1.200, 1.100, 1.000, 0.950, and further 0.900. Is preferable.

On the other hand, if the corresponding value of the conditional expression (14) of the variable magnification optical system of the present embodiment is less than the lower limit value, the refractive power of the second negative lens group becomes too strong, and therefore the curvature of field at the time of magnification change. It becomes difficult to satisfactorily correct various aberrations such as. By setting the lower limit value of the conditional expression (14) to 0.100, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (14) are set to 0.150, 0.200, 0.225, 0.250, 0.275, 0.290, and further 0. It is preferably .300.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and the third negative lens group having a negative refractive power, and satisfy the following conditional expression (15).
(15) 0.080 <(RR-RF) / (RR + RF) <1.000
However,
RR: Radius of curvature of the lens surface on the most image side of the third negative lens group RF: Radius of curvature of the lens surface on the most object side of the third negative lens group

The variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the above, in order from the object side. By having the second negative lens group and the third negative lens group having a negative refractive power, it is possible to realize high optical performance that is compact and can satisfactorily correct various aberrations.

The conditional expression (15) is a conditional expression that defines the shape of the lens surface on the most image side of the third negative lens group and the shape of the lens surface on the most object side of the third negative lens group. The variable magnification optical system of the present embodiment can satisfactorily correct coma aberration and curvature of field in the telephoto end state by satisfying the conditional expression (15).

If the corresponding value of the conditional expression (15) of the variable magnification optical system of the present embodiment exceeds the upper limit value, it becomes difficult to correct various aberrations such as coma. By setting the upper limit value of the conditional expression (15) to 0.950, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (15) are set to 0.900, 0.850, 0.800, 0.775, 0.750, 0.725, 0. It is preferably 700, 0.690, and more preferably 0.680.

On the other hand, if the corresponding value of the conditional expression (15) of the variable magnification optical system of the present embodiment is less than the lower limit value, it becomes difficult to correct various aberrations such as curvature of field. By setting the lower limit value of the conditional expression (15) to 0.085, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (15) are set to 0.090, 0.095, 0.100, 0.105, 0.110, 0.115, and further 0. It is preferably .120.

Further, the variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, and a second positive lens group having a positive refractive power in order from the object side. It is desirable to have the second negative lens group and the third negative lens group having a negative refractive power, and satisfy the following conditional expression (16).
(16) -10.000 <RF / Bfaw <-1.500
RF: Radius of curvature of the lens surface on the most object side of the third negative lens group Bfaw: Air-equivalent back focus of the entire variable-magnification optical system in the wide-angle end state

The variable magnification optical system of the present embodiment includes a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the above, in order from the object side. By having the second negative lens group and the third negative lens group having a negative refractive power, it is possible to realize high optical performance that is compact and can satisfactorily correct various aberrations.

Conditional expression (16) defines an appropriate range for the ratio of the radius of curvature of the lens surface on the most object side of the third negative lens group to the air-equivalent back focus of the entire variable-magnification optical system in the wide-angle end state. It is a conditional expression for. The variable magnification optical system of the present embodiment can satisfactorily correct curvature of field by satisfying the conditional expression (16). It is also effective in reducing the occurrence of ghosts.

If the corresponding value of the conditional expression (16) of the variable magnification optical system of the present embodiment exceeds the upper limit value, it becomes difficult to correct various aberrations such as curvature of field. By setting the upper limit value of the conditional expression (16) to -1.600, the effect of this embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the upper limit values of the conditional expression (16) are set to -1.700, -1.80, -1.900, -2.00, and further -2.10. It is preferable to do so.

On the other hand, if the corresponding value of the conditional expression (16) of the variable magnification optical system of the present embodiment is less than the lower limit value, it becomes difficult to correct various aberrations such as curvature of field. By setting the lower limit value of the conditional expression (16) to −9.900, the effect of the present embodiment can be made more reliable. Further, in order to further ensure the effect of the present embodiment, the lower limit values of the conditional expression (16) are set to -8.00, -7000, -6.00, -5.5500, -5.000, -. It is preferably 4.500, -4.00, and more preferably -3.80.

The optical device of this embodiment has a variable magnification optical system having the above-described configuration. As a result, it is possible to realize an optical device in which the optical performance is improved and the anti-vibration lens group is miniaturized.

The method for manufacturing the variable magnification optical system of the present embodiment includes a first negative lens group having a negative refractive force and a second negative lens group having a negative refractive force arranged on the image side of the first negative lens group. This is a method for manufacturing a variable magnification optical system having a plurality of lens groups including The first negative lens group is configured to be movable so as to include a component in a direction orthogonal to the optical axis as an anti-vibration lens group, and the second negative lens group is combined. This is a method for manufacturing a variable magnification optical system, which is configured to move along the optical axis at the time of focusing and is configured to satisfy the following conditional expression (1).
(1) -2.80 <X1n / X2n <-0.500
However,
X1n: Amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction X2n: The direction of movement toward the image side is positive The amount of movement of the second negative lens group when the magnification is changed from the wide-angle end state to the telephoto end state when the direction is set.

As a result, it is possible to realize an optical device in which the optical performance is improved and the anti-vibration lens group is miniaturized.

Hereinafter, the variable magnification optical system according to the numerical embodiment of the present embodiment will be described with reference to the accompanying drawings.
(First Example)
1A, 1B and 1C are cross-sectional views of the variable magnification optical system according to the first embodiment in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively.
The arrow below each lens group in FIG. 1A indicates the moving direction of each lens group when scaling from the wide-angle end state to the intermediate focal length state. The arrow below each lens group in FIG. 1B indicates the moving direction of each lens group when scaling from the intermediate focal length state to the telephoto end state.

In the variable magnification optical system according to the present embodiment, the first positive lens group GP1 having a positive refractive force, which is the first lens group, and the first lens group having a negative refractive force, which is the second lens group, are arranged in this order from the object side. Negative lens group GN1, a second positive lens group GP2 having a positive refractive force, which is a third lens group, a second negative lens group GN2 having a negative refractive force, which is a fourth lens group, and a fifth lens group. It is composed of a third negative lens group GN3 having a negative refractive power.

The first positive lens group GP1 includes a positive meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side in order from the object side. Consists of a bonded positive lens.

The first negative lens group GN1 is composed of a negative meniscus lens L21 whose convex surface is directed toward the object side, a biconcave negative lens L22, and a biconvex positive lens L23 in this order from the object side.

The second positive lens group GP2 includes a positive meniscus lens L31 having a biconvex shape and a negative meniscus lens L32 having a concave surface facing the object side, and a positive meniscus lens L33 having a convex surface facing the object side, in this order from the object side. The aperture aperture ST, a negative meniscus lens L34 having a convex surface facing the object side, a biconvex positive lens L35, and a positive meniscus lens L36 having a convex surface facing the object side.

The second negative lens group GN2 is composed of a junction negative lens of a biconvex positive lens L41 and a biconcave negative lens L42 in order from the object side.

The third negative lens group GN3 is composed of a positive meniscus lens L51 having a concave surface facing the object side and a negative meniscus lens L52 having a concave surface facing the object side in order from the object side.

An image sensor (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

Based on the above configuration, in the variable magnification optical system according to the present embodiment, when the magnification is changed from the wide-angle end state to the telescopic end state, the distance between the first positive lens group GP1 and the first negative lens group GN1 is the first. The distance between the 1 negative lens group GN1 and the 2nd positive lens group GP2, the distance between the 2nd positive lens group GP2 and the 2nd negative lens group GN2, and the distance between the 2nd negative lens group GN2 and the 3rd negative lens group GN3 The first positive lens group GP1, the first negative lens group GN1, the second positive lens group GP2, the second negative lens group GN2, and the third negative lens group GN3 move along the optical axis so as to change. Specifically, the first positive lens group GP1 moves to the object side, the first negative lens group GN1 moves to the image side, the second positive lens group GP2 moves to the object side, and the second negative lens group GN2 It moves to the object side, and the third negative lens group GN3 moves to the object side.

The variable magnification optical system according to this embodiment focuses the second negative lens group GN2 from an infinity object to a short-range object by moving it toward the image side along the optical axis.

In the variable magnification optical system according to the present embodiment, the first negative lens group GN1 is moved as the anti-vibration lens group so as to include a component in the direction orthogonal to the optical axis to correct the image plane when image blurring occurs, that is, to prevent image blurring. Shake.

Table 1 below lists the specifications of the variable magnification optical system according to this embodiment.
In Table 1, f indicates the focal length, and BF indicates the back focus, that is, the distance on the optical axis from the lens surface on the image side to the image surface I.
In [plane data], m is the order of the optical planes counted from the object side, r is the radius of curvature, d is the plane spacing (distance between the nth plane (n is an integer) and the n + 1 plane), and nd is the d line (d line). The refractive index for wavelength 587.6 nm) and νd indicate the Abbe number for the d-line (wavelength 587.6 nm). Further, OP indicates an object surface, Dn (n is an integer) indicates a variable surface interval, ST indicates an aperture stop, and I indicates an image plane. The radius of curvature r = ∞ indicates a plane. The description of the refractive index nd of air = 1.00000 is omitted.

In [Various data], f is the focal length of the entire variable magnification optical system, FNo is the F number, ω is the half angle of view (unit is "°"), Y is the image height, and TL is the total length of the variable magnification optical system. The distance on the optical axis from the first surface to the image plane I, BF is the back focus, that is, the distance on the optical axis from the lens plane on the image side to the image plane I, and BF (air equivalent length) is the back focus converted to air. Are shown respectively. W indicates a wide-angle end state, M indicates an intermediate focal length state, and T indicates a telephoto end state.

In [variable interval data], D0 indicates the distance from the object to the lens surface closest to the object, and the magnification indicates the photographing magnification. Further, f indicates the focal length of the entire variable magnification optical system, and Dn (n is an integer) indicates the variable interval between the nth plane and the n + 1th plane. W indicates a wide-angle end state, M indicates an intermediate focal length state, and T indicates a telephoto end state.
[Lens group data] shows the start surface number ST and the focal length f of each lens group.
[Conditional expression corresponding value] shows the corresponding value of each conditional expression.

Here, "mm" is generally used as the unit of the focal length f, the radius of curvature r and other lengths listed in Table 1. However, the optical system is not limited to this because the same optical performance can be obtained even if the optical system is proportionally expanded or decreased.
The reference numerals in Table 1 described above shall be used in the same manner in the tables of the respective examples described later.

(Table 1) First Example [Surface data]
m r d nd ν d
OP ∞
1 87.93190 4.100 1.51680 64.1
2 303555.26000 0.100
3 121.99600 2.300 1.60342 38.0
4 42.16570 6.300 1.48749 70.3
5 450.00450 D5

6 539.75280 1.200 1.77250 49.6
7 44.56390 2.596
8 -40.08110 1.200 1.80610 41.0
9 53.94500 2.200 1.94595 18.0
10 -287.19930 D10

11 81.30600 4.750 1.49700 81.6
12 -24.71700 1.300 1.85026 32.4
13 -81.98450 0.100
14 35.58090 2.650 1.51823 58.8
15 66022.91900 2.000
16 ST 11.870
17 71.97160 1.700 1.90200 25.3
18 30.66560 0.965
19 82.45900 2.230 1.74400 44.8
20 -82.45900 0.100
21 32.77810 2.250 1.79500 45.3
22 115.59770 D22

23 38.49580 2.560 1.80518 25.4
24-75.09340 1.300 1.80610 41.0
25 21.42360 D25

26 -51.00010 3.420 1.58913 61.2
27 -20.93150 0.310
28 -24.80380 1.250 1.91082 35.2
29 -82.90360 D29
I ∞

[Various data]
Variable ratio 4.71
WMT
f 51.50 86.28 242.80
FNo 4.63 5.10 6.34
ω 16.1 9.4 3.3
Y 14.50 14.50 14.50
TL 161.202 176.253 204.667
BF 16.906 23.174 38.120
BF (air equivalent length) 16.906 23.174 38.120

[Variable interval data]
WMT
D0 ∞ ∞ ∞
Magnification -----
f 51.50 86.28 242.80
D5 11.800 36.593 73.195
D10 37.855 24.078 3.134
D22 6.151 8.639 3.000
D25 29.739 25.019 28.466
D29 16.906 23.174 38.120

[Lens group data]
ST f
1st positive lens group GP1 1 141.50
1st negative lens group GN1 6 -32.88
2nd positive lens group GP2 11 33.68
2nd negative lens group GN2 23 -66.49
3rd negative lens group GN3 26 -113.67

[Conditional expression correspondence value]
(1) X1n / X2n = -0.899
(2) (-f1n) /√ (fw * ft) = 0.294
(3) (-f2n) / √ (fw * ft) = 0.595
(4) β1nt / β2nt = -0.734
(5) X1n / √ (fw * ft) = 0.160
(6) f2p / (-f1n) = 1.024
(7) X2p / √ (fw * ft) =-0.150
(8) Bfaw / fw = 0.328
(9) 2ωw = 32.297 °
(10) (β1nt-1) * βRt = 2.990
(11) m12tw / fw = 1.192
(12) (-f1n) /f1p=0.232
(13) (-f3n) /f1p=0.803
(14) f2n / f3n = 0.585
(15) (RR-RF) / (RR + RF) = 0.238
(16) RF / Bfaw = -3.017

2A, 2B, and 2C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the first embodiment, respectively.

In each aberration diagram, FNO indicates an F number, and A indicates a ray incident angle, that is, a half angle of view (unit: “°”). Each aberration diagram shows an aberration curve on the d line (wavelength λ = 587.6 nm). The spherical aberration diagram shows the value of the F number corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the half angle of view, and the transverse aberration diagram shows the value of each half angle of view. In the astigmatism diagram, the solid line shows the sagittal image plane and the broken line shows the meridional image plane. Further, the lateral aberration diagram shows the meridional lateral aberration at each half angle of view A. In addition, in the various aberration diagrams of each embodiment shown below, the same reference numerals as those of this embodiment are used.

As is clear from each aberration diagram, it can be seen that the zoom lens according to the first embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(Second Example)
3A, 3B and 3C are cross-sectional views of the variable magnification optical system according to the second embodiment in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively.
The arrow below each lens group in FIG. 3A indicates the moving direction of each lens group when scaling from the wide-angle end state to the intermediate focal length state. The arrow below each lens group in FIG. 3B indicates the moving direction of each lens group when scaling from the intermediate focal length state to the telephoto end state.

In the variable magnification optical system according to the present embodiment, the first positive lens group GP1 having a positive refractive force, which is the first lens group, and the first lens group having a negative refractive force, which is the second lens group, are arranged in this order from the object side. Negative lens group GN1, a second positive lens group GP2 having a positive refractive force, which is a third lens group, a second negative lens group GN2 having a negative refractive force, which is a fourth lens group, and a fifth lens group. It is composed of a third negative lens group GN3 having a negative refractive power.

The first positive lens group GP1 includes, in order from the object side, a biconvex lens L11, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side. Consists of.

The first negative lens group GN1 is composed of a biconcave negative lens L21, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side, in this order from the object side.

The second positive lens group GP2 is a junction negative lens of a positive meniscus lens L31 with a concave surface facing the object side, a biconvex positive lens L32, and a negative meniscus lens L33 with a concave surface facing the object side in order from the object side. The aperture stop ST, a negative meniscus lens L34 with a convex surface facing the object side, a biconvex positive lens L35, and a positive meniscus lens L36 with a convex surface facing the object side.

The second negative lens group GN2 is composed of a junction negative lens of a biconvex positive lens L41 and a biconcave negative lens L42 in order from the object side.

The third negative lens group GN3 is composed of a positive meniscus lens L51 having a concave surface facing the object side and a negative meniscus lens L52 having a concave surface facing the object side in order from the object side.

An image sensor (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

Based on the above configuration, in the variable magnification optical system according to the present embodiment, when the magnification is changed from the wide-angle end state to the telescopic end state, the distance between the first positive lens group GP1 and the first negative lens group GN1 is the first. The distance between the 1 negative lens group GN1 and the 2nd positive lens group GP2, the distance between the 2nd positive lens group GP2 and the 2nd negative lens group GN2, and the distance between the 2nd negative lens group GN2 and the 3rd negative lens group GN3 The first positive lens group GP1, the first negative lens group GN1, the second positive lens group GP2, the second negative lens group GN2, and the third negative lens group GN3 move along the optical axis so as to change. Specifically, the first positive lens group GP1 moves to the object side, the first negative lens group GN1 moves to the image side, the second positive lens group GP2 moves to the object side, and the second negative lens group GN2 After moving to the image side once, it moves to the object side, and the third negative lens group GN3 moves to the object side.

The variable magnification optical system according to this embodiment focuses the second negative lens group GN2 from an infinity object to a short-range object by moving it toward the image side along the optical axis.

In the variable magnification optical system according to the present embodiment, the first negative lens group GN1 is moved as the anti-vibration lens group so as to include a component in the direction orthogonal to the optical axis to correct the image plane when image blurring occurs, that is, to prevent image blurring. Shake.

Table 2 below lists the specifications of the variable magnification optical system according to this embodiment.

(Table 2) Second Example [Surface data]
m r d nd ν d
OP ∞
1 93.89670 4.243 1.51680 64.1
2 -1137.60310 0.200
3 120.67270 2.300 1.60342 38.0
4 42.51470 6.300 1.48749 70.3
5 337.43420 D5

6 -92.89570 1.450 1.74400 44.8
7 62.46930 1.456
8-77.48380 1.450 1.79952 42.1
9 30.83830 2.780 1.92286 20.9
10 338.71580 D10

11 -904.06660 2.214 1.80610 41.0
12 -46.99250 0.100
13 44.29830 4.100 1.49700 81.6
14 -29.19740 1.300 2.00100 29.1
15 -197.75100 2.000
16 ST 15.500
17 84.89920 1.300 1.85026 32.4
18 48.64540 0.470 1.00000
19 99.43000 2.868 1.62299 58.1
20 -37.99330 0.100
21 61.34970 1.602 1.48749 70.3
22 200.00000 D22

23 41.49380 2.750 1.79504 28.7
24-39.97280 1.400 1.80440 39.6
25 23.36740 D25

26 -52.32020 2.766 1.53172 48.8
27 -24.78880 0.609
28 -27.81550 1.150 1.83400 37.2
29 -121.04380 D29
I ∞

[Various data]
Variable ratio 4.72
WMT
f 51.51 84.96 242.88
FNo 4.59 4.86 6.31
ω 15.9 9.4 3.3
Y 14.50 14.50 14.50
TL 160.482 175.164 203.122
BF 12.355 16.729 38.705
BF (air equivalent length) 12.355 16.729 38.705

[Variable interval data]
WMT
D0 ∞ ∞ ∞
Magnification -----
f 51.51 84.96 242.88
D5 11.800 38.203 72.641
D10 38.397 24.496 3.000
D22 3.618 6.802 3.000
D25 33.903 28.525 25.366
D29 12.355 16.729 38.705

[Lens group data]
ST f
1st positive lens group GP1 1 145.31
1st negative lens group GN1 6 -33.97
2nd positive lens group GP2 11 35.17
2nd negative lens group GN2 23 -71.56
3rd negative lens group GN3 26 -86.27

[Conditional expression correspondence value]
(1) X1n / X2n = -1.022
(2) (-f1n) / √ (fw * ft) = 0.304
(3) (-f2n) /√ (fw * ft) = 0.640
(4) β1nt / β2nt = -0.714
(5) X1n / √ (fw * ft) = 0.163
(6) f2p / (-f1n) = 1.035
(7) X2p / √ (fw * ft) =-0.154
(8) Bfaw / fw = 0.240
(9) 2ωw = 31.854 °
(10) (β1nt-1) * βRt = 3.040
(11) m12tw / fw = 1.181
(12) (-f1n) /f1p=0.234
(13) (-f3n) /f1p=0.594
(14) f2n / f3n = 0.829
(15) (RR-RF) / (RR + RF) = 0.396
(16) RF / Bfaw = -4.235

4A, 4B, and 4C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the second embodiment, respectively.
As is clear from each aberration diagram, it can be seen that the zoom lens according to the second embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(Third Example)
5A, 5B and 5C are cross-sectional views of the variable magnification optical system according to the third embodiment in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively.
The arrow below each lens group in FIG. 5A indicates the moving direction of each lens group when scaling from the wide-angle end state to the intermediate focal length state. The arrow below each lens group in FIG. 5B indicates the moving direction of each lens group when scaling from the intermediate focal length state to the telephoto end state.

In the variable magnification optical system according to the present embodiment, the first positive lens group GP1 having a positive refractive force, which is the first lens group, and the first lens group having a negative refractive force, which is the second lens group, are arranged in this order from the object side. Negative lens group GN1, a second positive lens group GP2 having a positive refractive force, which is a third lens group, a second negative lens group GN2 having a negative refractive force, which is a fourth lens group, and a fifth lens group. It is composed of a third negative lens group GN3 having a negative refractive power.

The first positive lens group GP1 includes, in order from the object side, a biconvex lens L11, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side. Consists of.

The first negative lens group GN1 is composed of a negative meniscus lens L21 whose convex surface is directed toward the object side, a biconcave negative lens L22, and a biconvex positive lens L23 in this order from the object side.

The second positive lens group GP2 includes a positive meniscus lens L31 having a biconvex shape and a negative meniscus lens L32 having a concave surface facing the object side, and a positive meniscus lens L33 having a convex surface facing the object side, in this order from the object side. The aperture aperture ST, a negative meniscus lens L34 having a convex surface facing the object side, a biconvex positive lens L35, and a positive meniscus lens L36 having a convex surface facing the object side.

The second negative lens group GN2 is composed of a junction negative lens of a biconvex positive lens L41 and a biconcave negative lens L42 in order from the object side.

The third negative lens group GN3 is composed of a positive meniscus lens L51 having a concave surface facing the object side and a negative meniscus lens L52 having a concave surface facing the object side in order from the object side.

An image sensor (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

Based on the above configuration, in the variable magnification optical system according to the present embodiment, when the magnification is changed from the wide-angle end state to the telescopic end state, the distance between the first positive lens group GP1 and the first negative lens group GN1 is the first. The distance between the 1 negative lens group GN1 and the 2nd positive lens group GP2, the distance between the 2nd positive lens group GP2 and the 2nd negative lens group GN2, and the distance between the 2nd negative lens group GN2 and the 3rd negative lens group GN3 The first positive lens group GP1, the first negative lens group GN1, the second positive lens group GP2, the second negative lens group GN2, and the third negative lens group GN3 move along the optical axis so as to change. Specifically, the first positive lens group GP1 moves to the object side, the first negative lens group GN1 moves to the image side, the second positive lens group GP2 moves to the object side, and the second negative lens group GN2 It moves to the object side, and the third negative lens group GN3 moves to the object side.

The variable magnification optical system according to this embodiment focuses the second negative lens group GN2 from an infinity object to a short-range object by moving it toward the image side along the optical axis.

In the variable magnification optical system according to the present embodiment, the first negative lens group GN1 is moved as the anti-vibration lens group so as to include a component in the direction orthogonal to the optical axis to correct the image plane when image blurring occurs, that is, to prevent image blurring. Shake.

Table 3 below lists the specifications of the variable magnification optical system according to this embodiment.

(Table 3) Third Example [Surface data]
m r d nd ν d
OP ∞
1 85.79135 4.163 1.51680 64.1
2 -21581.11600 0.200
3 106.31189 2.300 1.60342 38.0
4 40.99918 5.805 1.48749 70.3
5 217.68087 D5

6 116.23286 1.400 1.78590 44.2
7 34.74553 2.700
8-36.56350 1.400 1.78590 44.2
9 58.57482 2.025 1.94595 18.0
10 -215.47554 D10

11 78.51586 4.305 1.49700 81.6
12 -24.01014 1.300 2.00100 29.1
13 -69.47425 0.100
14 37.52112 2.769 1.74400 44.8
15 356.77312 2.000
16 ST 9.567
17 66.52484 1.300 1.95000 29.4
18 29.40073 1.300
19 135.60665 2.350 1.79952 42.1
20 -56.95917 0.100
21 30.08650 2.350 1.62299 58.1
22 114.10158 D22

23 36.98000 2.700 1.79504 28.7
24-38.17047 1.400 1.80440 39.6
25 21.71795 D25

26 -58.00000 3.400 1.53172 48.8
27 -21.24736 0.598
28 -27.04205 1.150 1.91082 35.2
29 -112.40885 D29
I ∞

[Various data]
Variable ratio 4.71
WMT
f 51.60 86.50 242.99
FNo 4.63 5.23 6.33
ω 16.2 9.5 3.4
Y 14.50 14.50 14.50
TL 159.517 176.163 204.962
BF 15.441 23.366 41.940
BF (air equivalent length) 15.441 23.366 41.940

[Variable interval data]
WMT
D0 ∞ ∞ ∞
Magnification -----
f 51.60 86.50 242.99
D5 11.800 36.104 75.112
D10 37.219 24.327 3.000
D22 3.874 5.974 3.000
D25 34.500 29.709 25.227
D29 15.441 23.366 41.940

[Lens group data]
ST f
1st positive lens group GP1 1 146.89
1st negative lens group GN1 6 -33.04
2nd positive lens group GP2 11 33.07
2nd negative lens group GN2 23 -71.59
3rd negative lens group GN3 26 -106.43

[Conditional expression correspondence value]
(1) X1n / X2n = -1.037
(2) (-f1n) /√ (fw * ft) = 0.295
(3) (-f2n) /√ (fw * ft) = 0.640
(4) β1nt / β2nt = -0.705
(5) X1n / √ (fw * ft) = 0.160
(6) f2p / (-f1n) = 1.001
(7) X2p / √ (fw * ft) =-0.146
(8) Bfaw / fw = 0.299
(9) 2ωw = 32.316 °
(10) (β1nt-1) * βRt = 2.991
(11) m12tw / fw = 1.227
(12) (-f1n) /f1p=0.225
(13) (-f3n) /f1p=0.725
(14) f2n / f3n = 0.673
(15) (RR-RF) / (RR + RF) = 0.319
(16) RF / Bfaw = -3.756

6A, 6B, and 6C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the third embodiment, respectively.
As is clear from each aberration diagram, it can be seen that the zoom lens according to the third embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(Fourth Example)
7A, 7B and 7C are cross-sectional views of the variable magnification optical system according to the fourth embodiment in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively.
The arrow below each lens group in FIG. 7A indicates the moving direction of each lens group when scaling from the wide-angle end state to the intermediate focal length state. The arrow below each lens group in FIG. 7B indicates the moving direction of each lens group when scaling from the intermediate focal length state to the telephoto end state.

In the variable magnification optical system according to the present embodiment, the first positive lens group GP1 having a positive refractive force, which is the first lens group, and the first lens group having a negative refractive force, which is the second lens group, are arranged in this order from the object side. Negative lens group GN1, a second positive lens group GP2 having a positive refractive force, which is a third lens group, a second negative lens group GN2 having a negative refractive force, which is a fourth lens group, and a fifth lens group. It is composed of a third negative lens group GN3 having a negative refractive power.

The first positive lens group GP1 includes a positive meniscus lens L11 having a convex surface facing the object side, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side in order from the object side. Consists of a bonded positive lens.

The first negative lens group GN1 is composed of a biconcave negative lens L21, a biconcave negative lens L22, and a positive meniscus lens L23 with a convex surface facing the object side, in this order from the object side.

The second positive lens group GP2 includes, in order from the object side, a biconvex positive lens L31, a biconvex positive lens L32, a negative meniscus lens L33 with a concave surface facing the object side, and an aperture aperture. It is composed of ST, a negative meniscus lens L34 having a convex surface facing the object side, a positive meniscus lens L35 having a concave surface facing the object side, and a positive meniscus lens L36 having a convex surface facing the object side.

The second negative lens group GN2 is composed of a junction negative lens of a biconvex positive lens L41 and a biconcave negative lens L42 in order from the object side.

The third negative lens group GN3 is composed of a positive meniscus lens L51 having a concave surface facing the object side and a negative meniscus lens L52 having a concave surface facing the object side in order from the object side.

An image sensor (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

Based on the above configuration, in the variable magnification optical system according to the present embodiment, when the magnification is changed from the wide-angle end state to the telescopic end state, the distance between the first positive lens group GP1 and the first negative lens group GN1 is the first. The distance between the 1 negative lens group GN1 and the 2nd positive lens group GP2, the distance between the 2nd positive lens group GP2 and the 2nd negative lens group GN2, and the distance between the 2nd negative lens group GN2 and the 3rd negative lens group GN3 The first positive lens group GP1, the first negative lens group GN1, the second positive lens group GP2, the second negative lens group GN2, and the third negative lens group GN3 move along the optical axis so as to change. Specifically, the first positive lens group GP1 moves to the object side, the first negative lens group GN1 moves to the image side, the second positive lens group GP2 moves to the object side, and the second negative lens group GN2 It moves to the object side, and the third negative lens group GN3 moves to the object side.

The variable magnification optical system according to this embodiment focuses the second negative lens group GN2 from an infinity object to a short-range object by moving it toward the image side along the optical axis.

In the variable magnification optical system according to the present embodiment, the first negative lens group GN1 is moved as the anti-vibration lens group so as to include a component in the direction orthogonal to the optical axis to correct the image plane when image blurring occurs, that is, to prevent image blurring. Shake.

Table 4 below lists the specifications of the variable magnification optical system according to this embodiment.

(Table 4) Fourth Example [Surface data]
m r d nd ν d
OP ∞
1 102.02360 4.018 1.51680 64.1
2 23725.55500 0.200
3 124.20660 2.300 1.62004 36.4
4 46.74590 6.448 1.48749 70.3
5 2520.57410 D5

6 -108.36330 1.500 1.71999 50.3
7 67.45060 1.732
8-93.87760 1.500 1.78590 44.2
9 25.84960 2.766 1.92286 20.9
10 95.38820 D10

11 356.21330 2.426 1.80610 41.0
12 -49.97960 0.100
13 43.50590 4.168 1.49700 81.6
14 -29.17280 1.300 2.00100 29.1
15 -549.62290 2.000
16 ST 14.664
17 102.25240 1.300 1.80518 25.4
18 61.57290 1.785
19 -112.53220 2.112 1.74100 52.8
20 -33.22100 0.100
21 44.64520 2.092 1.48749 70.3
22 3129.20700 D22

23 36.81260 2.689 1.79504 28.7
24-56.40380 1.400 1.80440 39.6
25 22.49860 D25

26 -105.25910 3.471 1.53172 48.8
27 -25.72550 0.100
28 -29.26300 1.117 1.83400 37.2
29 -519.07190 D29
I ∞

[Various data]
Variable ratio 4.72
WMT
f 51.51 85.02 242.99
FNo 4.56 5.08 6.30
ω 15.9 9.5 3.3
Y 14.50 14.50 14.50
TL 161.982 177.717 204.877
BF 12.355 21.015 38.805
BF (air equivalent length) 12.355 21.015 38.805

[Variable interval data]
WMT
D0 ∞ ∞ ∞
Magnification -----
f 51.51 85.02 242.99
D5 13.441 37.627 74.711
D10 35.676 23.863 2.974
D22 2.936 6.237 2.000
D25 36.287 27.687 25.101
D29 12.355 21.015 38.805

[Lens group data]
ST f
1st positive lens group GP1 1 142.30
1st negative lens group GN1 6 -32.29
2nd positive lens group GP2 11 35.53
2nd negative lens group GN2 23 -79.58
3rd negative lens group GN3 26 -88.56

[Conditional expression correspondence value]
(1) X1n / X2n = -1.204
(2) (-f1n) /√ (fw * ft) = 0.289
(3) (-f2n) / √ (fw * ft) = 0.712
(4) β1nt / β2nt = -0.797
(5) X1n / √ (fw * ft) = 0.164
(6) f2p / (-f1n) = 1.100
(7) X2p / √ (fw * ft) =-0.128
(8) Bfaw / fw = 0.240
(9) 2ωw = 31.780 °
(10) (β1nt-1) * βRt = 3.020
(11) m12tw / fw = 1.190
(12) (-f1n) /f1p=0.227
(13) (-f3n) /f1p=0.622
(14) f2n / f3n = 0.899
(15) (RR-RF) / (RR + RF) = 0.663
(16) RF / Bfaw = -8.520

8A, 8B, and 8C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the fourth embodiment, respectively.
As is clear from each aberration diagram, it can be seen that the zoom lens according to the fourth embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(Fifth Example)
9A, 9B and 9C are cross-sectional views of the variable magnification optical system according to the fifth embodiment in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively.
The arrow below each lens group in FIG. 9A indicates the moving direction of each lens group when scaling from the wide-angle end state to the intermediate focal length state. The arrow below each lens group in FIG. 9B indicates the moving direction of each lens group when scaling from the intermediate focal length state to the telephoto end state.

In the variable magnification optical system according to the present embodiment, the first positive lens group GP1 having a positive refractive force, which is the first lens group, and the first lens group having a negative refractive force, which is the second lens group, are arranged in this order from the object side. Negative lens group GN1, a second positive lens group GP2 having a positive refractive force, which is a third lens group, a second negative lens group GN2 having a negative refractive force, which is a fourth lens group, and a fifth lens group. It is composed of a third negative lens group GN3 having a negative refractive power.

The first positive lens group GP1 is a bonded positive lens consisting of a biconvex positive lens L11, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side, in order from the object side. It consists of.

The first negative lens group GN1 is composed of a negative meniscus lens L21 whose convex surface is directed toward the object side, a biconcave negative lens L22, and a biconvex positive lens L23 in this order from the object side.

The second positive lens group GP2 includes a positive meniscus lens L31 having a biconvex shape and a negative meniscus lens L32 having a concave surface facing the object side, and a positive meniscus lens L33 having a convex surface facing the object side, in this order from the object side. The aperture aperture ST, a negative meniscus lens L34 having a convex surface facing the object side, a biconvex positive lens L35, and a positive meniscus lens L36 having a convex surface facing the object side.

The second negative lens group GN2 is composed of a junction negative lens of a biconvex positive lens L41 and a biconcave negative lens L42 in order from the object side.

The third negative lens group GN3 is composed of a positive meniscus lens L51 having a concave surface facing the object side and a negative meniscus lens L52 having a concave surface facing the object side in order from the object side.

An image sensor (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

Based on the above configuration, in the variable magnification optical system according to the present embodiment, when the magnification is changed from the wide-angle end state to the telescopic end state, the distance between the first positive lens group GP1 and the first negative lens group GN1 is the first. The distance between the 1 negative lens group GN1 and the 2nd positive lens group GP2, the distance between the 2nd positive lens group GP2 and the 2nd negative lens group GN2, and the distance between the 2nd negative lens group GN2 and the 3rd negative lens group GN3 The first positive lens group GP1, the first negative lens group GN1, the second positive lens group GP2, the second negative lens group GN2, and the third negative lens group GN3 move along the optical axis so as to change. Specifically, the first positive lens group GP1 moves to the object side, the first negative lens group GN1 moves to the image side, the second positive lens group GP2 moves to the object side, and the second negative lens group GN2 It moves to the object side, and the third negative lens group GN3 moves to the object side.

The variable magnification optical system according to this embodiment focuses the second negative lens group GN2 from an infinity object to a short-range object by moving it toward the image side along the optical axis.

In the variable magnification optical system according to the present embodiment, the first negative lens group GN1 is moved as the anti-vibration lens group so as to include a component in the direction orthogonal to the optical axis to correct the image plane when image blurring occurs, that is, to prevent image blurring. Shake.

Table 5 below lists the specifications of the variable magnification optical system according to this embodiment.

(Table 5) Fifth Example [Surface data]
m r d nd ν d
OP ∞
1 89.51110 3.900 1.51680 64.1
2 -6223.14480 0.100
3 121.42130 2.300 1.60342 38.0
4 42.38070 6.292 1.48749 70.3
5 500.00010 D5

6 6605.01980 0.980 1.77250 49.6
7 45.10060 2.290
8-41.11830 1.200 1.78590 44.2
9 62.10660 2.079 1.94595 18.0
10 -284.90000 D10

11 90.49660 4.093 1.49700 81.6
12 -25.57740 1.300 1.85026 32.4
13 -63.88090 0.100
14 33.09670 2.552 1.51680 64.1
15 190.90280 2.000
16 ST 13.262
17 81.00000 1.300 1.71736 29.6
18 28.85130 1.055
19 90.00000 2.050 1.71999 50.3
20 -84.72400 0.100
21 30.60250 2.000 1.71999 50.3
22 101.01010 D22

23 40.74300 2.800 1.79504 28.7
24-34.71910 1.300 1.80440 39.6
25 22.08130 D25

26 -38.89500 3.054 1.61272 58.5
27 -21.08970 0.100
28 -25.00540 1.250 1.91082 35.2
29 -52.25280 D29
I ∞

[Various data]
Variable ratio 4.73
WMT
f 51.41 86.25 242.92
FNo 4.64 5.14 6.17
ω 16.1 9.4 3.3
Y 14.50 14.50 14.50
TL 161.541 175.521 204.303
BF 16.655 25.663 43.155
BF (air equivalent length) 16.655 25.663 43.155

[Variable interval data]
WMT
D0 ∞ ∞ ∞
Magnification -----
f 51.41 86.25 242.92
D5 11.800 35.130 72.602
D10 39.007 24.446 3.000
D22 6.543 9.225 3.000
D25 30.077 23.599 25.088
D29 16.655 25.663 43.155

[Lens group data]
ST f
1st positive lens group GP1 1 139.16
1st negative lens group GN1 6 -32.82
2nd positive lens group GP2 11 34.57
2nd negative lens group GN2 23 -64.26
3rd negative lens group GN3 26 -196.02

[Conditional expression correspondence value]
(1) X1n / X2n = -0.839
(2) (-f1n) /√ (fw * ft) = 0.293
(3) (-f2n) / √ (fw * ft) = 0.575
(4) β1nt / β2nt = -0.740
(5) X1n / √ (fw * ft) = 0.161
(6) f2p / (-f1n) = 1.054
(7) X2p / √ (fw * ft) =-0.161
(8) Bfaw / fw = 0.324
(9) 2ωw = 32.294 °
(10) (β1nt-1) * βRt = 2.990
(11) m12tw / fw = 1.183
(12) (-f1n) /f1p=0.236
(13) (-f3n) /f1p=1.409
(14) f2n / f3n = 0.328
(15) (RR-RF) / (RR + RF) = 0.147
(16) RF / Bfaw = -2.335

10A, 10B, and 10C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the fifth embodiment, respectively.
As is clear from each aberration diagram, it can be seen that the zoom lens according to the fifth embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(6th Example)
11A, 11B and 11C are cross-sectional views of the variable magnification optical system according to the sixth embodiment in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively.
The arrow below each lens group in FIG. 11A indicates the moving direction of each lens group when scaling from the wide-angle end state to the intermediate focal length state. The arrow below each lens group in FIG. 11B indicates the moving direction of each lens group when scaling from the intermediate focal length state to the telephoto end state.

In the variable magnification optical system according to the present embodiment, the first positive lens group GP1 having a positive refractive force, which is the first lens group, and the first lens group having a negative refractive force, which is the second lens group, are arranged in this order from the object side. Negative lens group GN1, a second positive lens group GP2 having a positive refractive force, which is a third lens group, a second negative lens group GN2 having a negative refractive force, which is a fourth lens group, and a fifth lens group. It is composed of a third negative lens group GN3 having a negative refractive power.

The first positive lens group GP1 is a bonded positive lens consisting of a biconvex positive lens L11, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side, in order from the object side. It consists of.

The first negative lens group GN1 includes a negative meniscus lens L21 whose convex surface is directed toward the object side, a negative lens L22 having a biconcave shape and a positive lens L23 having a biconvex shape, and an object side in this order from the object side. It consists of a negative meniscus lens L24 with a concave surface facing.

The second positive lens group GP2 includes a positive meniscus lens L31 having a biconvex shape and a negative meniscus lens L32 having a concave surface facing the object side, and a positive meniscus lens L33 having a convex surface facing the object side, in this order from the object side. The aperture aperture ST, a negative meniscus lens L34 having a convex surface facing the object side, a biconvex positive lens L35, and a positive meniscus lens L36 having a convex surface facing the object side.

The second negative lens group GN2 is composed of a junction negative lens of a biconvex positive lens L41 and a biconcave negative lens L42 in order from the object side.

The third negative lens group GN3 is composed of a positive meniscus lens L51 having a concave surface facing the object side and a negative meniscus lens L52 having a concave surface facing the object side in order from the object side.

An image sensor (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

Based on the above configuration, in the variable magnification optical system according to the present embodiment, when the magnification is changed from the wide-angle end state to the telescopic end state, the distance between the first positive lens group GP1 and the first negative lens group GN1 is the first. The distance between the 1 negative lens group GN1 and the 2nd positive lens group GP2, the distance between the 2nd positive lens group GP2 and the 2nd negative lens group GN2, and the distance between the 2nd negative lens group GN2 and the 3rd negative lens group GN3 The first positive lens group GP1, the first negative lens group GN1, the second positive lens group GP2, the second negative lens group GN2, and the third negative lens group GN3 move along the optical axis so as to change. Specifically, the first positive lens group GP1 moves to the object side, the first negative lens group GN1 moves to the image side, the second positive lens group GP2 moves to the object side, and the second negative lens group GN2 It moves to the object side, and the third negative lens group GN3 moves to the object side.

The variable magnification optical system according to this embodiment focuses the second negative lens group GN2 from an infinity object to a short-range object by moving it toward the image side along the optical axis.

In the variable magnification optical system according to the present embodiment, the first negative lens group GN1 is moved as the anti-vibration lens group so as to include a component in the direction orthogonal to the optical axis to correct the image plane when image blurring occurs, that is, to prevent image blurring. Shake.

Table 6 below lists the specifications of the variable magnification optical system according to this embodiment.

(Table 6) 6th Example [Surface data]
m r d nd ν d
OP ∞
1 93.47132 4.090 1.51680 64.1
2 -1133.57750 0.100
3 117.38090 2.300 1.60342 38.0
4 41.05760 6.300 1.48749 70.3
5 450.00000 D5

6 268.80000 1.200 1.79952 42.1
7 48.94615 2.300
8-47.17533 1.200 1.79500 45.3
9 47.57821 2.220 1.94595 18.0
10 -261.40114 0.650
11 -88.50282 1.000 1.95375 32.3
12 -457.30902 D12

13 74.45320 4.690 1.49700 81.6
14 -26.85628 1.250 1.90366 31.3
15 -70.82707 0.100
16 34.87737 2.530 1.56883 56.0
17 753.45804 2.000
18 ST 14.926
19 63.90081 1.650 1.90200 25.3
20 26.15260 0.955
21 85.00000 2.210 1.74400 44.8
22 -85.00010 0.100
23 24.32112 2.360 1.74400 44.8
24 64.74483 D24

25 40.01001 2.490 1.80518 25.4
26 -52.73825 1.250 1.80440 39.6
27 21.52211 D27

28 -39.08091 3.320 1.56384 60.7
29 -20.68916 0.320
30 -24.78916 1.250 1.91082 35.2
31 -53.86318 D31
I ∞

[Various data]
Variable ratio 4.77
WMT
f 51.27 86.15 244.63
FNo 4.64 5.28 6.43
ω 16.2 9.4 3.3
Y 14.50 14.50 14.50
TL 161.206 175.694 205.728
BF 17.347 23.137 40.477
BF (air equivalent length) 17.347 23.137 40.477

[Variable interval data]
WMT
D0 ∞ ∞ ∞
Magnification -----
f 51.27 86.15 244.63
D5 11.400 34.720 70.201
D12 36.081 22.431 3.000
D24 4.763 7.799 3.000
D27 28.854 24.848 26.290
D31 17.347 23.137 40.477

[Lens group data]
ST f
1st positive lens group GP1 1 137.12
1st negative lens group GN1 6 -30.39
2nd positive lens group GP2 13 33.93
2nd negative lens group GN2 25 -63.78
3rd negative lens group GN3 28 -155.58

[Conditional expression correspondence value]
(1) X1n / X2n = -0.694
(2) (-f1n) /√ (fw * ft) = 0.272
(3) (-f2n) / √ (fw * ft) = 0.570
(4) β1nt / β2nt = -0.645
(5) X1n / √ (fw * ft) = 0.128
(6) f2p / (-f1n) = 1.117
(7) X2p / √ (fw * ft) =-0.168
(8) Bfaw / fw = 0.338
(9) 2ωw = 32.329 °
(10) (β1nt-1) * βRt = 3.252
(11) m12tw / fw = 1.147
(12) (-f1n) /f1p=0.222
(13) (-f3n) /f1p=1.135
(14) f2n / f3n = 0.410
(15) (RR-RF) / (RR + RF) = 0.159
(16) RF / Bfaw = -2.253

12A, 12B, and 12C are aberration diagrams at the time of focusing an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the sixth embodiment, respectively.
As is clear from each aberration diagram, it can be seen that the zoom lens according to the sixth embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

(7th Example)
13A, 13B and 13C are cross-sectional views of the variable magnification optical system according to the seventh embodiment in the wide-angle end state, the intermediate focal length state and the telephoto end state, respectively.
The arrow below each lens group in FIG. 13A indicates the moving direction of each lens group when scaling from the wide-angle end state to the intermediate focal length state. The arrow below each lens group in FIG. 13B indicates the moving direction of each lens group when scaling from the intermediate focal length state to the telephoto end state.

In the variable magnification optical system according to the present embodiment, the first positive lens group GP1 having a positive refractive force, which is the first lens group, and the first lens group having a negative refractive force, which is the second lens group, are arranged in this order from the object side. Negative lens group GN1, a second positive lens group GP2 having a positive refractive force, which is a third lens group, a second negative lens group GN2 having a negative refractive force, which is a fourth lens group, and a fifth lens group. It is composed of a third negative lens group GN3 having a negative refractive power.

The first positive lens group GP1 is a bonded positive lens consisting of a biconvex positive lens L11, a negative meniscus lens L12 having a convex surface facing the object side, and a positive meniscus lens L13 having a convex surface facing the object side, in order from the object side. It consists of.

The first negative lens group GN1 is composed of a negative meniscus lens L21 whose convex surface is directed toward the object side, a biconcave negative lens L22, and a biconvex positive lens L23 in this order from the object side.

The second positive lens group GP2 includes a biconvex positive lens L31 and a negative meniscus lens L32 with a concave surface facing the object side in order from the object side, a biconvex positive lens L33, and an aperture aperture. It is composed of ST, a negative meniscus lens L34 having a convex surface facing the object side, a biconvex positive lens L35, and a positive meniscus lens L36 having a convex surface facing the object side.

The second negative lens group GN2 is composed of a junction negative lens of a biconvex positive lens L41 and a biconcave negative lens L42 in order from the object side.

The third negative lens group GN3 is composed of a positive meniscus lens L51 having a concave surface facing the object side and a negative meniscus lens L52 having a concave surface facing the object side in order from the object side.

An image sensor (not shown) composed of a CCD, CMOS, or the like is arranged on the image plane I.

Based on the above configuration, in the variable magnification optical system according to the present embodiment, when the magnification is changed from the wide-angle end state to the telescopic end state, the distance between the first positive lens group GP1 and the first negative lens group GN1 is the first. The distance between the 1 negative lens group GN1 and the 2nd positive lens group GP2, the distance between the 2nd positive lens group GP2 and the 2nd negative lens group GN2, and the distance between the 2nd negative lens group GN2 and the 3rd negative lens group GN3 The first positive lens group GP1, the first negative lens group GN1, the second positive lens group GP2, the second negative lens group GN2, and the third negative lens group GN3 move along the optical axis so as to change. Specifically, the first positive lens group GP1 moves to the object side, the first negative lens group GN1 moves to the image side, the second positive lens group GP2 moves to the object side, and the second negative lens group GN2 After moving to the image side once, it moves to the object side, and the third negative lens group GN3 moves to the object side.

The variable magnification optical system according to this embodiment focuses the second negative lens group GN2 from an infinity object to a short-range object by moving it toward the image side along the optical axis.

In the variable magnification optical system according to the present embodiment, the first negative lens group GN1 is moved as the anti-vibration lens group so as to include a component in the direction orthogonal to the optical axis to correct the image plane when image blurring occurs, that is, to prevent image blurring. Shake.

Table 7 below lists the specifications of the variable magnification optical system according to this embodiment.

(Table 7) 7th Example [Surface data]
m r d nd ν d
OP ∞
1 92.46664 4.090 1.51680 64.1
2 -1965.97730 0.100
3 130.30808 2.300 1.60342 38.0
4 43.48647 6.300 1.48749 70.3
5 450.00000 D5

6 268.80354 1.200 1.77250 49.6
7 44.43348 2.590
8-37.26227 1.200 1.80610 41.0
9 52.74280 2.220 1.94595 18.0
10 -328.24497 D10

11 49.79080 4.690 1.49700 81.6
12 -28.17550 1.250 1.90366 31.3
13 -81.07604 0.100
14 35.34536 2.530 1.56883 56.0
15 -578.67604 2.000
16 ST 12.554
17 44.40415 1.650 1.90200 25.3
18 21.10839 0.955
19 85.00000 2.210 1.74400 44.8
20 -85.00010 0.100
21 19.81161 2.360 1.74400 44.8
22 33.30793 D22

23 38.31794 2.490 1.80518 25.4
24-34.14118 1.250 1.80440 39.6
25 20.46917 D25

26 -37.68147 3.320 1.56384 60.7
27 -19.16939 0.320
28 -23.26939 1.250 1.91082 35.2
29 -48.50735 D29
I ∞

[Various data]
Variable ratio 4.77
WMT
f 51.25 86.18 244.50
FNo 4.64 5.26 6.42
ω 16.3 9.4 3.3
Y 14.50 14.50 14.50
TL 157.670 170.584 203.302
BF 17.052 20.583 40.472
BF (air equivalent length) 17.052 20.583 40.472

[Variable interval data]
WMT
D0 ∞ ∞ ∞
Magnification -----
f 51.25 86.18 244.50
D5 11.400 36.275 71.915
D10 39.608 23.775 3.000
D22 3.000 7.122 3.754
D25 27.581 23.800 25.132
D29 17.052 20.583 40.472

[Lens group data]
ST f
1st positive lens group GP1 1 146.90
1st negative lens group GN1 6 -32.36
2nd positive lens group GP2 11 33.16
2nd negative lens group GN2 23 -60.42
3rd negative lens group GN3 26 -191.47

[Conditional expression correspondence value]
(1) X1n / X2n = -0.710
(2) (-f1n) /√ (fw * ft) = 0.289
(3) (-f2n) / √ (fw * ft) = 0.540
(4) β1nt / β2nt = -0.533
(5) X1n / √ (fw * ft) = 0.133
(6) f2p / (-f1n) = 1.025
(7) X2p / √ (fw * ft) =-0.194
(8) Bfaw / fw = 0.333
(9) 2ωw = 32.519 °
(10) (β1nt-1) * βRt = 3.280
(11) m12tw / fw = 1.181
(12) (-f1n) /f1p=0.220
(13) (-f3n) /f1p=1.303
(14) f2n / f3n = 0.316
(15) (RR-RF) / (RR + RF) = 0.126
(16) RF / Bfaw = -2.210

14A, 14B, and 14C are aberration diagrams of the variable magnification optical system according to the seventh embodiment at the time of focusing on an infinity object in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively.
As is clear from each aberration diagram, it can be seen that the zoom lens according to the seventh embodiment has high optical performance with various aberrations satisfactorily corrected from the wide-angle end state to the telephoto end state.

According to each of the above embodiments, a variable magnification optical system having high optical performance capable of satisfactorily correcting various aberrations from the wide-angle end state to the telephoto end state and having a miniaturized anti-vibration lens group is realized. can do.

It should be noted that each of the above examples shows a specific example of the present invention, and the present invention is not limited thereto. The following contents can be appropriately adopted as long as the optical performance of the variable magnification optical system of the present embodiment is not impaired.
In the variable magnification optical system of the present application, the focal length in the wide-angle end state is about 50 to 70 mm in terms of 35 mm. Further, the variable magnification optical system of the present application has a magnification ratio of about 2.7 to 6 times. Further, the variable magnification optical system of the present application has an F number of about 3.5 to 4.5 in the wide-angle end state and about 5.6 to 7.0 in the telephoto end state.

As a numerical example of the variable magnification optical system of the present embodiment, a five-group configuration is shown, but the present embodiment is not limited to this, and other group configurations (for example, six groups, etc.) of the variable magnification optical system are configured. You can also do it. Specifically, a lens or a lens group may be added to the most object side or the most image side of the variable magnification optical system of each of the above embodiments. Alternatively, a lens or a lens group may be added between adjacent lens groups. The lens group may be composed of at least one or more lenses.

Further, in each of the above embodiments, the second negative lens group is 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, for example, an ultrasonic motor, a stepping motor, a VCM motor, or the like.

Further, in each of the above embodiments, the first negative lens group is used as the anti-vibration lens group, but the present invention is not limited to this, and the entire or a part of any of the lens groups is set as the anti-vibration lens group and is perpendicular to the optical axis. It is also possible to provide vibration isolation by moving the lens so as to include components in the same direction, or by rotating (swinging) in the in-plane direction including the optical axis.

Further, it is preferable that the aperture diaphragm of the variable magnification optical system of each of the above embodiments is arranged in the second positive lens group. The aperture diaphragm may be configured such that the lens frame substitutes the role of the aperture diaphragm without providing a member.

Further, the lens surface of the lens constituting the variable magnification optical system of each of the above embodiments may be a spherical surface or a flat surface, or may be an aspherical surface. When the lens surface is spherical or flat, lens processing and assembly adjustment can be facilitated, and deterioration of optical performance due to errors in lens processing and assembly adjustment can be prevented, which is preferable. Further, even if the image plane is deviated, the depiction performance is less deteriorated, which is preferable. When the lens surface is aspherical, it can be either an aspherical surface obtained by grinding, a glass molded aspherical surface formed by molding glass into an aspherical shape, or a composite aspherical surface formed by forming a resin provided on the glass surface into an aspherical shape. good. Further, the lens surface may be a diffraction surface, and the lens may be a refractive index distribution type lens (GRIN lens) or a plastic lens.

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

Next, the camera provided with the variable magnification optical system of the present embodiment will be described with reference to FIG.
FIG. 15 is a diagram showing a configuration of a camera provided with the variable magnification optical system of the present embodiment.
As shown in FIG. 15, the camera 1 is a lens-interchangeable mirrorless camera provided with the variable magnification optical system according to the first embodiment as the photographing lens 2.

In the present camera 1, the light from an object (subject) (not shown) is collected by the photographing lens 2 and passed through an OLPF (Optical low pass filter) (not shown) on the imaging surface of the imaging unit 3. Form a subject image. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3, and the image of the subject is generated. This image is displayed on the EVF (Electronic viewfinder) 4 provided in the camera 1. This allows the photographer to observe the subject via the EVF4.
Further, when the photographer presses the release button (not shown), the image of the subject generated by the imaging unit 3 is stored in the memory (not shown). In this way, the photographer can shoot the subject with the camera 1.

Here, the variable magnification optical system according to the first embodiment mounted on the camera 1 as a photographing lens 2 has high optical ability capable of satisfactorily correcting various aberrations from the wide-angle end state to the telephoto end state as described above. It has performance and the anti-vibration lens group has been downsized. That is, the present camera 1 has high optical performance capable of satisfactorily correcting various aberrations, and can realize miniaturization of the anti-vibration lens group. Even if a camera equipped with the variable magnification optical system according to the second to seventh embodiments is configured as the photographing lens 2, the same effect as that of the camera 1 can be obtained. Further, even when the single-lens reflex type camera having a quick return mirror and observing the subject by the finder optical system is equipped with the variable magnification optical system according to each of the above embodiments, the same effect as that of the camera 1 can be obtained. can.

Next, the outline of the manufacturing method of the variable magnification optical system of the present embodiment will be described with reference to FIG.
FIG. 16 is a flow chart showing an outline of the manufacturing method of the optical system of the present embodiment.
The method for manufacturing the optical system of the present embodiment shown in FIG. 16 includes a first negative lens group having a negative refractive power and a second negative lens group having a negative refractive power arranged on the image side of the first negative lens group. It is a method for manufacturing a variable magnification optical system having a plurality of lens groups including a lens group, and includes the following steps S1 to S4.

Step S1: At the time of scaling, the distance between adjacent lens groups changes, and the first negative lens group and the second negative lens group are configured to move along the optical axis.
Step S2: The first negative lens group is configured to be movable as a vibration-proof lens group so as to include a component in a direction orthogonal to the optical axis.
Step S3: The second negative lens group is configured to move along the optical axis at the time of focusing.
Step S4: Configure so as to satisfy the following conditional expression (1).
(1) -2.80 <X1n / X2n <-0.500
However,
X1n: Amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction X2n: The direction of movement toward the image side is positive The amount of movement of the second negative lens group when the magnification is changed from the wide-angle end state to the telephoto end state when the direction is set.

According to the method for manufacturing the variable magnification optical system of the present embodiment, the variable magnification optical system having high optical performance capable of satisfactorily correcting various aberrations and having a miniaturized anti-vibration lens group can be obtained. Can be manufactured.

GP1 1st positive lens group GN1 1st negative lens group GP2 2nd positive lens group GN2 2nd negative lens group GN3 3rd negative lens group ST Aperture aperture I Image plane 1 Camera 2 Shooting lens

Claims (23)

It has a plurality of lens groups including a first negative lens group having a negative refractive power and a second negative lens group having a negative refractive power arranged on the image side of the first negative lens group.
At the time of scaling, the distance between adjacent lens groups changes, and the first negative lens group and the second negative lens group move along the optical axis.
The first negative lens group can be moved as an anti-vibration lens group so as to include a component in a direction orthogonal to the optical axis.
The second negative lens group moves along the optical axis when in focus, and the second negative lens group moves along the optical axis.
A variable magnification optical system that satisfies the following conditional expression.
-2.00 <X1n / X2n <-0.500
However,
X1n: Amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction X2n: The direction of movement toward the image side is positive The amount of movement of the second negative lens group when the magnification is changed from the wide-angle end state to the telephoto end state when the direction is set. The variable magnification optical system according to claim 1, which satisfies the following conditional expression.
0.200 <(-f1n) / √ (fw * ft) <0.400
However,
f1n: Focal length of the first negative lens group
fw: Focal length of the entire variable-magnification optical system in the wide-angle end state ft: Focal length of the entire variable-magnification optical system in the telephoto end state The variable magnification optical system according to claim 1 or 2, which satisfies the following conditional expression.
0.200 <(-f2n) /√ (fw * ft) <1.000
However,
f2n: Focal length of the second negative lens group
fw: Focal length of the entire variable-magnification optical system in the wide-angle end state ft: Focal length of the entire variable-magnification optical system in the telephoto end state The variable magnification optical system according to any one of claims 1 to 3, which satisfies the following conditional expression.
-1.00 <β1nt / β2nt <-0.300
However,
β1nt: lateral magnification of the first negative lens group in the telephoto end state β2nt: lateral magnification of the second negative lens group in the telephoto end state The variable magnification optical system according to any one of claims 1 to 4, which satisfies the following conditional expression.
0.050 <X1n / √ (fw * ft) <0.250
However,
X1n: The amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction fw: The variable magnification optical system in the wide-angle end state Focal length of the entire system ft: Focal length of the entire variable magnification optical system in the telephoto end state The variable magnification optical system according to any one of claims 1 to 5, wherein the first negative lens group includes a first negative lens, a second negative lens, and a positive lens in order from the object side. The variable magnification optical system according to any one of claims 1 to 6, wherein the second negative lens group comprises a positive lens and a negative lens in this order from the object side. The variable magnification optical system according to any one of claims 1 to 7, wherein an aperture diaphragm is arranged between the first negative lens group and the second negative lens group. A claim having a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the second negative lens group in order from the object side. The variable magnification optical system according to any one of 1 to 8. In order from the object side, it has a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the second negative lens group.
The variable magnification optical system according to any one of claims 1 to 9, which satisfies the following conditional expression.
0.500 <f2p / (-f1n) <1.500
However,
f2p: Focal length of the second positive lens group f1n: Focal length of the first negative lens group In order from the object side, it has a first positive lens group having a positive refractive force, the first negative lens group, a second positive lens group having a positive refractive force, and the second negative lens group.
The variable magnification optical system according to any one of claims 1 to 10, which satisfies the following conditional expression.
−0.300 <X2p / √ (fw * ft) <0.000
However,
X2p: Movement amount of the second positive lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction fw: The variable magnification optical system in the wide-angle end state Focal length of the entire system ft: Focal length of the entire variable magnification optical system in the telephoto end state In order from the object side, it has a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the second negative lens group.
The variable magnification optical system according to any one of claims 1 to 11, wherein the first positive lens group moves at the time of magnification change. The variable magnification optical system according to any one of claims 1 to 12, which satisfies the following conditional expression.
0.150 <Bfaw / fw <0.500
However,
Bfaw: Air-equivalent back focus of the entire variable-magnification optical system in the wide-angle end state fw: Focal length of the entire variable-magnification optical system in the wide-angle end state The variable magnification optical system according to any one of claims 1 to 13, which satisfies the following conditional expression.
20.000 ° <2ωw <45.000 °
However,
2ωw: Full angle of view of the variable magnification optical system in the wide-angle end state The variable magnification optical system according to any one of claims 1 to 14, which satisfies the following conditional expression.
1.500 <(β1nt-1) * βRt <4.500
However,
β1nt: Lateral magnification of the first negative lens group in the telephoto end state βRt: Composite lateral magnification of all lens groups arranged on the image side of the first negative lens group in the telephoto end state In order from the object side, it has a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the second negative lens group.
The variable magnification optical system according to any one of claims 1 to 15, which satisfies the following conditional expression.
0.500 <m12tw / fw <2.000
However,
m12tw: Amount of change in distance between the first positive lens group and the first negative lens group when scaling from the wide-angle end state to the telephoto end state fw: Focal length of the entire variable magnification optical system in the wide-angle end state In order from the object side, it has a first positive lens group having a positive refractive power, the first negative lens group, a second positive lens group having a positive refractive power, and the second negative lens group.
The variable magnification optical system according to any one of claims 1 to 16, which satisfies the following conditional expression.
0.150 <(-f1n) /f1p<0.350
However,
f1n: Focal length of the first negative lens group
f1p: Focal length of the first positive lens group From the object side, the first positive lens group having a positive refractive power, the first negative lens group, the second positive lens group having a positive refractive power, the second negative lens group, and the negative refraction. It has a third negative lens group with power,
The variable magnification optical system according to any one of claims 1 to 17, which satisfies the following conditional expression.
0.010 <(-f3n) /f1p<3.000
However,
f3n: Focal length of the third negative lens group f1p: Focal length of the first positive lens group From the object side, the first positive lens group having a positive refractive power, the first negative lens group, the second positive lens group having a positive refractive power, the second negative lens group, and the negative refraction. It has a third negative lens group with power,
The variable magnification optical system according to any one of claims 1 to 18, which satisfies the following conditional expression.
0.050 <f2n / f3n <1.500
However,
f2n: Focal length of the second negative lens group f3n: Focal length of the third negative lens group From the object side, the first positive lens group having a positive refractive power, the first negative lens group, the second positive lens group having a positive refractive power, the second negative lens group, and the negative refraction. It has a third negative lens group with power,
The variable magnification optical system according to any one of claims 1 to 19, which satisfies the following conditional expression.
0.080 <(RR-RF) / (RR + RF) <1.000
However,
RR: Radius of curvature of the lens surface on the most image side of the third negative lens group RF: Radius of curvature of the lens surface on the most object side of the third negative lens group From the object side, the first positive lens group having a positive refractive power, the first negative lens group, the second positive lens group having a positive refractive power, the second negative lens group, and the negative refraction. It has a third negative lens group with power,
The variable magnification optical system according to any one of claims 1 to 20, which satisfies the following conditional expression.
-10.000 <RF / Bfaw <-1.500
RF: Radius of curvature of the lens surface on the most object side of the third negative lens group Bfaw: Air-equivalent back focus of the entire variable-magnification optical system in the wide-angle end state An optical device provided with the variable magnification optical system according to any one of claims 1 to 21. A variable magnification optical system having a plurality of lens groups including a first negative lens group having a negative refractive power and a second negative lens group having a negative refractive power arranged on the image side of the first negative lens group. It is a manufacturing method of
At the time of scaling, the distance between adjacent lens groups changes, and the first negative lens group and the second negative lens group are configured to move along the optical axis.
The first negative lens group is configured to be movable as an anti-vibration lens group so as to include a component in a direction orthogonal to the optical axis.
The second negative lens group is configured to move along the optical axis when in focus.
A method for manufacturing a variable magnification optical system that satisfies the following conditional expression.
-2.00 <X1n / X2n <-0.500
However,
X1n: Amount of movement of the first negative lens group at the time of scaling from the wide-angle end state to the telephoto end state when the direction of movement toward the image side is the positive direction X2n: The direction of movement toward the image side is positive The amount of movement of the second negative lens group when the magnification is changed from the wide-angle end state to the telephoto end state when the direction is set.

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