JP6390697B2 - Magnification optical system, imaging apparatus equipped with magnifying optical system, and method for manufacturing magnifying optical system - Google Patents

Description

  The present invention relates to a variable magnification optical system suitable for a photographic camera, an electronic still camera, a video camera or the like using a film or a solid-state image pickup device, an imaging apparatus including the variable magnification optical system, and a method of manufacturing the variable magnification optical system About.

  Conventionally, a telephoto zoom lens having a zoom ratio of about 4 times has been proposed. For example, see JP-A-8-62541.

JP-A-8-62541

  Patent Document 1 describes a variable magnification optical system including five or six lens groups. In such a variable magnification optical system having a large number of lens groups, the zoom mechanism becomes complicated and the optical total length becomes large.

In the first aspect of the present invention, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a first lens group having a positive refractive power. And a distance between the first lens group and the second lens group is changed during zooming from the wide-angle end state to the telephoto end state, and the second lens group and the third lens The first lens group, the second lens group, and the third lens group move so that the distance from the group changes, and the first lens group, the second lens group, and the third lens group A zoom lens system that performs image plane correction at the time of image blurring by satisfying the following equation by moving at least a part of the image stabilization lens group to include a component in a direction orthogonal to the optical axis. did.
0.400 <(TLt−TLw) / (− f2) <0.880
2.00 <f1 / (− f2) <3.50
However,
TLt: optical total length of the variable magnification optical system in the telephoto end state TLw: total optical length of the variable magnification optical system in the wide angle end state f1: focal length of the first lens group f2: focal length of the second lens group In the first aspect of the present invention, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a first lens group having a positive refractive power. And a distance between the first lens group and the second lens group is changed during zooming from the wide-angle end state to the telephoto end state, and the second lens group and the third lens The first lens group, the second lens group, and the third lens group are moved so that the distance from the group changes, and a variable magnification optical system that satisfies the following condition is obtained.
0.400 <(TLt−TLw) / (− f2) <0.880
2.00 <f1 / (− f2) <3.50
4.90 <ft / f3 <5.90
1.50 <fw / (− f2) <2.50
However,
TLt: optical total length of the variable magnification optical system in the telephoto end state TLw: optical total length of the variable magnification optical system in the wide angle end state f1: focal length of the first lens group f2: focal length of the second lens group f3: Focal length of the third lens group ft: Focal length of the entire zooming optical system in the telephoto end state fw: Focal length of the entire zooming optical system in the wide-angle end state

  In the second aspect of the present invention, the imaging apparatus includes the variable magnification optical system according to the first aspect of the present invention.

1A and 1B are cross-sectional views showing a configuration of a variable magnification optical system according to a first example common to the first and second embodiments. FIG. 1A shows a wide-angle end state, and FIG. 1B shows a telephoto end. Indicates the state. 2A and 2B are graphs showing various aberrations of the variable magnification optical system according to the first example. FIG. 2A shows graphs showing various aberrations in the wide-angle end state when focusing on infinity, and FIG. 2B shows focusing at infinity. The aberration diagrams in the telephoto end state during focusing are shown. 3A and 3B are lateral aberration diagrams during camera shake correction of the variable magnification optical system according to the first example, FIG. 3A is a lateral aberration diagram in the wide-angle end state, and FIG. 3B is in the telephoto end state. The lateral aberration diagram is shown. 4A and 4B are cross-sectional views showing a configuration of a variable magnification optical system according to a second example common to the first and second embodiments. FIG. 4A shows a wide-angle end state, and FIG. 4B shows a telephoto end. Indicates the state. 5A and 5B are graphs showing various aberrations of the variable magnification optical system according to the second example. FIG. 5A shows graphs showing various aberrations at the wide-angle end state when focusing on infinity, and FIG. 5B shows focusing at infinity. The aberration diagrams in the telephoto end state during focusing are shown. 6A and 6B are lateral aberration diagrams during camera shake correction of the variable magnification optical system according to the second example. FIG. 6A is a lateral aberration diagram in the wide-angle end state, and FIG. 6B is in the telephoto end state. The lateral aberration diagram is shown. 7A and 7B are cross-sectional views showing a configuration of a variable magnification optical system according to a third example common to the first and second embodiments. FIG. 7A shows a wide-angle end state, and FIG. 7B shows a telephoto end. Indicates the state. 8A and 8B are graphs showing various aberrations of the variable magnification optical system according to the third example. FIG. 8A shows graphs showing various aberrations in the wide-angle end state at the time of focusing on infinity, and FIG. The aberration diagrams in the telephoto end state during focusing are shown. 9A and 9B are lateral aberration diagrams during camera shake correction of the variable magnification optical system according to the third example. FIG. 9A is a lateral aberration diagram in the wide-angle end state, and FIG. 9B is in the telephoto end state. The lateral aberration diagram is shown. 10A and 10B are cross-sectional views showing a configuration of a variable magnification optical system according to a fourth example common to the first and second embodiments. FIG. 10A shows a wide-angle end state, and FIG. 10B shows a telephoto end. Indicates the state. 11A and 11B are graphs showing various aberrations of the variable magnification optical system according to the fourth example. FIG. 11A shows graphs showing various aberrations in the wide-angle end state at the time of focusing on infinity, and FIG. The aberration diagrams in the telephoto end state during focusing are shown. 12A and 12B are lateral aberration diagrams during camera shake correction of the variable magnification optical system according to the fourth example. FIG. 12A is a lateral aberration diagram in the wide-angle end state, and FIG. 12B is in the telephoto end state. The lateral aberration diagram is shown. 13A and 13B are cross-sectional views showing a configuration of a variable magnification optical system according to a fifth example common to the first and second embodiments. FIG. 13A shows a wide-angle end state, and FIG. 13B shows a telephoto end. Indicates the state. FIGS. 14A and 14B are graphs showing various aberrations of the variable magnification optical system according to Example 5. FIG. 14A shows graphs showing various aberrations at the wide-angle end when focusing on infinity, and FIG. 14B shows focusing at infinity. The aberration diagrams in the telephoto end state during focusing are shown. 15A and 15B are lateral aberration diagrams during camera shake correction of the variable magnification optical system according to Example 5. FIG. 15A is a lateral aberration diagram in the wide-angle end state, and FIG. 15B is in the telephoto end state. The lateral aberration diagram is shown. 16A and 16B are cross-sectional views showing a configuration of a variable magnification optical system according to a sixth example common to the first and second embodiments. FIG. 16A shows a wide-angle end state, and FIG. 16B shows a telephoto end. Indicates the state. 17A and 17B are graphs showing various aberrations of the variable magnification optical system according to Example 6. FIG. 17A shows graphs showing various aberrations at the wide-angle end when focusing on infinity, and FIG. 17B shows focusing at infinity. The aberration diagrams in the telephoto end state during focusing are shown. 18A and 18B are lateral aberration diagrams during camera shake correction of the variable magnification optical system according to the sixth example. FIG. 18A is a lateral aberration diagram in the wide-angle end state, and FIG. 18B is the telephoto end state. The lateral aberration diagram is shown. FIG. 19 is a schematic diagram showing a configuration of a camera including the variable magnification optical system according to the first and second embodiments of the present invention. It is a flowchart which shows the outline of the manufacturing method of the variable magnification optical system which concerns on 1st Embodiment of this invention. It is a flowchart which shows the outline of the manufacturing method of the variable magnification optical system which concerns on 2nd Embodiment of this invention.

  Hereinafter, a variable magnification optical system, an imaging apparatus, and a method for manufacturing an optical variable magnification system according to the first embodiment of the present application will be described. First, the variable magnification optical system according to the first embodiment of the present application will be described.

The variable magnification optical system according to the first embodiment of the present application includes, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive And a third lens group having refractive power. The first lens group includes two lens components, the second lens group includes two lens components, and the third lens group includes two, five, or six lens components.
With such a configuration, the optical total length is reduced. The optical total length means the length on the optical axis from the lens surface closest to the object side to the image plane of the variable magnification optical system. The lens component refers to a single lens or a cemented lens.

In addition, the zoom optical system according to the first embodiment of the present application has the above-described configuration, and when the zoom is changed from the wide-angle end state to the telephoto end state, the first lens group, the second lens group, The first lens group, the second lens group, and the third lens group move so that the distance between the second lens group and the third lens group changes.
With such a configuration, it is possible to satisfactorily correct aberration fluctuations during zooming, particularly field curvature.

In addition, the zoom optical system according to the first embodiment of the present application preferably satisfies the following conditional expression (1-1) based on such a configuration.
(1-1) 0.400 <(TLt−TLw) / (− f2) <0.880
However,
TLt: optical total length of the variable magnification optical system in the telephoto end state TLw: optical total length of the variable magnification optical system in the wide angle end state f2: focal length of the second lens group

  Conditional expression (1-1) defines the amount of change in the total optical length with respect to the focal length of the second lens group, that is, the amount of extension of the first lens group when zooming from the wide-angle end state to the telephoto end state. Is an expression. By satisfying conditional expression (1-1), it is possible to achieve downsizing while maintaining optical performance.

  If the corresponding value of the conditional expression (1-1) exceeds the upper limit value, the refractive power of the second lens group becomes strong, and correction of coma and astigmatism becomes difficult, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1-1) to 0.870. In order to further secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1-1) to 0.860.

  If the corresponding value of conditional expression (1-1) is less than the lower limit value, the refractive power of the second lens group becomes weak, and a sufficient amount of light cannot be obtained, which is not preferable. If a sufficient amount of light is to be secured, the size of the first lens group is increased, and as a result, coma is deteriorated. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1-1) to 0.500. In order to further secure the effect of the present embodiment, it is preferable to set the lower limit value of conditional expression (1-1) to 0.600.

Moreover, it is preferable that the variable magnification optical system according to the first embodiment of the present application satisfies the following conditional expression (1-2).
(1-2) 2.00 <f1 / (− f2) <3.50
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group

  Conditional expression (1-2) is a conditional expression that defines the ratio of the focal length of the first lens group to the focal length of the second lens group. By satisfying conditional expression (1-2), it is possible to suppress aberration fluctuations during zooming and realize high optical performance.

  If the corresponding value of conditional expression (1-2) exceeds the upper limit, the refractive power of the second lens group becomes strong, and it becomes difficult to correct coma and astigmatism in the wide-angle end state. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1-2) to 3.40.

  If the corresponding value of conditional expression (1-2) is less than the lower limit, the refractive power of the first lens unit becomes strong, and it becomes difficult to correct spherical aberration and axial chromatic aberration in the telephoto end state, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1-2) to 2.50.

  In the variable magnification optical system according to the first embodiment of the present application, at least a part of the first lens group, the second lens group, and the third lens group is an anti-vibration lens group, and the direction is orthogonal to the optical axis. It is preferable to perform image plane correction at the time of image blurring by moving so as to include the above component. By adopting such a configuration, it is possible to satisfactorily perform image plane correction when image blur occurs due to camera shake, that is, image stabilization.

Moreover, it is preferable that the zoom optical system according to the first embodiment of the present application satisfies the following conditional expression (1-3).
(1-3) 1.82 <ft / f1 <3.00
However,
ft: focal length of the entire variable magnification optical system in the telephoto end state f1: focal length of the first lens group

  Conditional expression (1-3) is a conditional expression that defines an appropriate focal length of the first lens group in the telephoto end state. By satisfying conditional expression (1-3), it is possible to achieve downsizing and high optical performance.

  If the corresponding value of the conditional expression (1-3) exceeds the upper limit value, the refractive power of the first lens group becomes strong, and it becomes difficult to correct spherical aberration and axial chromatic aberration in the telephoto end state. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1-3) to 2.30.

  If the corresponding value of conditional expression (1-3) is less than the lower limit, the refractive power of the first lens group becomes weak, leading to an increase in the overall optical length, which is not preferable. Further, in order to reduce the total optical length in a state where the corresponding value of the conditional expression (1-3) is below the lower limit value, the refractive power of the second lens group and the third lens group is increased, and as a result, Coma and astigmatism are deteriorated, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1-3) to 1.90.

Moreover, it is preferable that the zoom optical system according to the first embodiment of the present application satisfies the following conditional expression (1-4).
(1-4) 3.50 <ft / f3 <5.90
However,
ft: focal length of the entire variable magnification optical system in the telephoto end state f3: focal length of the third lens group

  Conditional expression (1-4) is a conditional expression that defines an appropriate focal length of the third lens group in the telephoto end state. By satisfying conditional expression (1-4), it is possible to achieve downsizing and high optical performance.

  If the corresponding value of conditional expression (1-4) exceeds the upper limit value, the refractive power of the third lens group becomes strong, and it becomes difficult to correct spherical aberration and coma aberration, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1-4) to 5.60. In order to further secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1-4) to 5.50.

  If the corresponding value of conditional expression (1-4) is less than the lower limit, the refractive power of the third lens group becomes weak, leading to an increase in the overall optical length, which is not preferable. Further, in order to reduce the total optical length in a state where the corresponding value of the conditional expression (1-4) is below the lower limit value, the refractive power of the first lens group and the second lens group is increased, and as a result, Spherical aberration, coma aberration, and field curvature deteriorate, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1-4) to 4.50. In order to further secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1-4) to 4.90.

In addition, the zoom optical system according to the first embodiment of the present application preferably satisfies the following conditional expression (1-5).
(1-5) 1.50 <fw / (-f2) <2.50
However,
fw: focal length of the entire variable magnification optical system in the wide-angle end state f3: focal length of the third lens group

  Conditional expression (1-5) is a conditional expression that defines an appropriate focal length of the second lens group in the wide-angle end state. By satisfying conditional expression (1-5), high optical performance can be realized.

  If the corresponding value of the conditional expression (1-5) exceeds the upper limit value, the refractive power of the second lens group becomes strong, and correction of coma and astigmatism becomes difficult, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1-5) to 2.10.

  If the corresponding value of conditional expression (1-5) is less than the lower limit, the refractive power of the second lens group becomes weak, and a sufficient amount of light cannot be obtained, which is not preferable. If a sufficient amount of light is to be secured, the size of the first lens group is increased, and as a result, coma is deteriorated. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1-5) to 1.90.

  In addition, the variable magnification optical system according to the first embodiment of the present application moves image blurring so that at least a part of the third lens group includes a component in a direction perpendicular to the optical axis as a vibration-proof lens group. It is preferable to perform image plane correction at the time of occurrence. By adopting such a configuration, the diameter of the vibration-proof lens group can be reduced, and the entire lens barrel can be reduced in size.

  In the zoom optical system according to the first embodiment of the present application, focusing from an object at infinity to a near object is performed by moving at least a part of the first lens group along the optical axis. Is preferred. By adopting such a configuration, it is possible to effectively correct the spherical aberration at the time of focusing and the aberration fluctuation of the field curvature.

  Further, the imaging apparatus of the present application includes the variable magnification optical system according to the first embodiment having the above-described configuration. Thereby, it is possible to realize a small-sized image pickup apparatus having high optical performance.

In addition, in the manufacturing method of the variable magnification optical system according to the first embodiment of the present application, the first lens group having a positive refractive power and the second lens having a negative refractive power in order from the object side along the optical axis. And a third lens group having a positive refractive power, wherein the first lens group and the second lens group are zoomed from the wide-angle end state to the telephoto end state. The first lens group, the second lens group, and the third lens group move so that the distance between the lens group changes and the distance between the second lens group and the third lens group changes. And satisfying the following conditional expression (1-1).
(1-1) 0.400 <(TLt−TLw) / (− f2) <0.880
However,
TLt: full length of the variable magnification optical system in the telephoto end state TLw: full length of the variable magnification optical system in the wide angle end state f2: focal length of the second lens group

  With such a variable magnification optical system manufacturing method, a variable magnification optical system having a small size and high optical performance can be manufactured.

  Hereinafter, a variable magnification optical system, an imaging apparatus, and a method for manufacturing an optical variable magnification system according to the second embodiment of the present application will be described. First, the variable magnification optical system according to the second embodiment of the present application will be described.

The variable magnification optical system according to the second embodiment of the present application includes, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive And a third lens group having refractive power. The first lens group includes two lens components, the second lens group includes two lens components, and the third lens group includes two, five, or six lens components.
With such a configuration, the optical total length is reduced. The optical total length means the length on the optical axis from the lens surface closest to the object side to the image plane of the variable magnification optical system. The lens component refers to a single lens or a cemented lens.

In addition, the zoom optical system according to the second embodiment of the present application has the above-described configuration, and at the time of zooming from the wide-angle end state to the telephoto end state, the first lens group and the second lens group, The first lens group, the second lens group, and the third lens group move so that the distance between the second lens group and the third lens group changes.
With such a configuration, it is possible to satisfactorily correct aberration fluctuations during zooming, particularly field curvature.

Further, the variable magnification optical system according to the second embodiment of the present application has a short distance from an infinite object by moving at least a part of the first lens group along the optical axis in such a configuration. Focusing on objects.
With such a configuration, it is possible to satisfactorily correct aberration fluctuations during focusing, particularly spherical aberration.

Moreover, it is preferable that the variable magnification optical system according to the second embodiment of the present application satisfies the following conditional expression (2-1) based on such a configuration.
(2-1) 6.00 <ft / (-f2) <7.60
However,
ft: focal length of the entire variable magnification optical system in the telephoto end state f2: focal length of the second lens group

  Conditional expression (2-1) is a conditional expression that defines an appropriate focal length of the second lens group in the telephoto end state. By satisfying conditional expression (2-1), high optical performance can be realized.

  If the corresponding value of conditional expression (2-1) exceeds the upper limit value, the refractive power of the second lens group becomes strong, and it becomes difficult to correct coma and astigmatism, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2-1) to 7.10.

  If the corresponding value of conditional expression (2-1) is less than the lower limit value, the refractive power of the second lens group becomes weak, and a sufficient amount of light cannot be obtained, which is not preferable. If a sufficient amount of light is to be secured, the size of the first lens group is increased, and as a result, coma is deteriorated. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2-1) to 6.40.

  In the variable magnification optical system according to the second embodiment of the present application, at least a part of the first lens group, the second lens group, and the third lens group is an anti-vibration lens group and a direction orthogonal to the optical axis. It is preferable to perform image plane correction at the time of image blurring by moving so as to include the above component. By adopting such a configuration, it is possible to satisfactorily perform image plane correction when image blur occurs due to camera shake, that is, image stabilization.

In addition, the zoom optical system according to the second embodiment of the present application preferably satisfies the following conditional expression (2-2).
(2-2) 3.50 <ft / f3 <5.90
However,
ft: focal length of the entire variable magnification optical system in the telephoto end state f3: focal length of the third lens group

  Conditional expression (2-2) is a conditional expression that defines an appropriate focal length of the third lens group in the telephoto end state. By satisfying conditional expression (2-2), it is possible to achieve downsizing and high optical performance.

  If the corresponding value of conditional expression (2-2) exceeds the upper limit value, the refractive power of the third lens group becomes strong, and it becomes difficult to correct spherical aberration and coma aberration, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2-2) to 5.60. In order to further secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2-2) to 5.50.

  If the corresponding value of conditional expression (2-2) is less than the lower limit, the refractive power of the third lens group becomes weak, leading to an increase in the overall optical length, which is not preferable. Further, in order to reduce the total optical length in a state where the corresponding value of the conditional expression (2-2) is below the lower limit value, the refractive power of the first lens group and the second lens group is increased, and as a result, Spherical aberration, coma aberration, and field curvature deteriorate, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2-2) to 4.50. In order to further secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2-2) to 4.90.

In addition, the zoom optical system according to the second embodiment of the present application preferably satisfies the following conditional expression (2-3).
(2-3) 2.00 <f1 / (− f2) <3.50
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group

  Conditional expression (2-3) is a conditional expression that defines the ratio of the focal length of the first lens group to the focal length of the second lens group. By satisfying conditional expression (2-3), it is possible to suppress aberration fluctuation during zooming and realize high optical performance.

  If the corresponding value of the conditional expression (2-3) exceeds the upper limit value, the refractive power of the second lens group becomes strong, and it becomes difficult to correct coma and astigmatism in the wide-angle end state. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2-3) to 3.40.

  If the corresponding value of conditional expression (2-3) is less than the lower limit, the refractive power of the first lens group becomes strong, and it becomes difficult to correct spherical aberration and axial chromatic aberration in the telephoto end state, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2-3) to 2.50.

  In addition, the variable magnification optical system according to the second embodiment of the present application moves image blurring so that at least a part of the third lens group includes a component in a direction orthogonal to the optical axis as an anti-vibration lens group. It is preferable to perform image plane correction at the time of occurrence. By adopting such a configuration, the diameter of the vibration-proof lens group can be reduced, and the entire lens barrel can be reduced in size.

Moreover, it is preferable that the zoom optical system according to the second embodiment of the present application satisfies the following conditional expression (2-4).
(2-4) 0.400 <(TLt−TLw) / (− f2) <0.880
However,
TLt: optical total length of the variable magnification optical system in the telephoto end state TLw: optical total length of the variable magnification optical system in the wide angle end state f2: focal length of the second lens group

  Conditional expression (2-4) is a condition that defines the amount of change in the optical total length with respect to the focal length of the second lens unit, that is, the amount of extension of the first lens unit when zooming from the wide-angle end state to the telephoto end state. Is an expression. By satisfying conditional expression (2-4), it is possible to achieve downsizing while maintaining optical performance.

  If the corresponding value of the conditional expression (2-4) exceeds the upper limit value, the refractive power of the second lens group becomes strong, and it becomes difficult to correct coma and astigmatism, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2-4) to 0.870. In order to further secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2-4) to 0.860.

  If the corresponding value of conditional expression (2-4) is lower than the lower limit value, the refractive power of the second lens group becomes weak, and a sufficient amount of light cannot be obtained, which is not preferable. If a sufficient amount of light is to be secured, the size of the first lens group is increased, and as a result, coma is deteriorated. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2-4) to 0.500. In order to further secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2-4) to 0.600.

  Further, the imaging apparatus of the present application includes the variable magnification optical system according to the second embodiment having the above-described configuration. Thereby, it is possible to realize a small-sized image pickup apparatus having high optical performance.

In addition, the variable magnification optical system manufacturing method according to the second embodiment of the present application includes a first lens group having a positive refractive power and a second lens having a negative refractive power in order from the object side along the optical axis. And a third lens group having a positive refractive power, wherein the first lens group and the second lens group are zoomed from the wide-angle end state to the telephoto end state. The first lens group, the second lens group, and the third lens group move so that the distance between the lens group changes and the distance between the second lens group and the third lens group changes. And at least a part of the first lens group is moved along the optical axis to perform focusing from an infinitely distant object to a close object, and the following conditional expression (2-1) It is constituted so as to satisfy.
(2-1) 6.00 <ft / (-f2) <7.60
However,
ft: focal length of the entire variable magnification optical system in the telephoto end state f2: focal length of the second lens group

  With such a variable magnification optical system manufacturing method, a variable magnification optical system having a small size and high optical performance can be manufactured.

(Numerical example)
Hereinafter, a variable magnification optical system according to numerical examples of the first and second embodiments of the present application will be described with reference to the accompanying drawings. The first to sixth examples are examples common to the first and second embodiments.

(First embodiment)
1A and 1B are cross-sectional views showing a configuration of a variable magnification optical system ZL1 according to a first example common to the first and second embodiments of the present application. FIG. 1A shows a wide-angle end state, and FIG. Indicates the telephoto end state.
As shown in FIG. 1A, the variable magnification optical system ZL1 according to the present example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power in order from the object side along the optical axis. The lens group G2 includes a third lens group G3 having a positive refractive power.

  The first lens group G1 includes, in order from the object side along the optical axis, a biconvex lens L11, and a cemented lens of a negative meniscus lens L12 having a convex surface facing the object side and a biconvex lens L13.

  The second lens group G2 includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L21 and a positive meniscus lens L22 having a convex surface facing the object side, and a biconcave lens L23.

  The third lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a cemented lens of the biconvex lens L32 and the biconcave lens L33, an aperture stop S, and a positive meniscus lens having a concave surface facing the object side. The lens includes a cemented lens of L34 and a biconcave lens L35, a biconvex lens L36, and a negative meniscus lens L37 having a concave surface facing the object side.

  On the image plane I, an image sensor (not shown) made up of a CCD, a CMOS, or the like is disposed.

  In the variable magnification optical system ZL1 according to the present example, when the magnification is changed from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the second lens group G2 The first lens group G1 moves toward the object side with respect to the image plane I, and the second lens group G2 once moves toward the image plane I side with respect to the image plane I so that the distance from the three lens groups G3 decreases. The third lens group G3 moves to the object side. The aperture stop S moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The variable magnification optical system ZL1 according to the present example has a cemented lens of a positive meniscus lens L34 and a biconcave lens L35 out of the lens components constituting the third lens group G3, and is in a direction orthogonal to the optical axis. By moving in the direction including the component, image plane correction when image blur occurs, that is, image stabilization is performed. The vibration-proof lens group has a negative refractive power.

  Further, the variable magnification optical system ZL1 according to the present example moves along the optical axis by using, as a focus lens group, a cemented lens of a negative meniscus lens L12 and a biconvex lens L13 among the lens components constituting the first lens group G1. By doing so, focusing from the infinite object focusing state to the short distance object focusing state is performed. The focus lens group has a positive refractive power.

Table 1 below lists specifications of the variable magnification optical system ZL1 according to the first example.
In [Surface data] in Table 1, m is the order of the lens surfaces counted from the object side, r is the radius of curvature of the lens surfaces, d is the distance between the lens surfaces, and nd is for the d-line (wavelength λ = 587.6 nm). Refractive index and νd indicate Abbe numbers for d-line (wavelength λ = 587.6 nm), respectively. OP represents the object plane, S represents the aperture stop, and I represents the image plane. Note that the radius of curvature r = ∞ indicates a plane, and the description of the refractive index of air d = 1.0000 is omitted.

  In [various data], f represents a focal length, FNO represents an F number, 2ω represents an angle of view (unit: “°”), Y represents an image height, TL represents an optical total length, and BF represents a back focus. W indicates the wide-angle end state, M indicates the intermediate focal length state, and T indicates the respective focal length states in the telephoto end state.

  In [Variable interval data], di (i is an integer) indicates a surface interval between the i-th surface and the (i + 1) -th surface. Further, f represents a focal length, W represents a wide angle end state, M represents an intermediate focal length state, and T represents each focal length state in a telephoto end state.

[Lens Group Data] indicates the start surface ST and focal length f of each lens group.
[Conditional Expression Corresponding Value] indicates 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 described in Table 1. However, the optical system is not limited to this because an equivalent optical performance can be obtained even when proportionally enlarged or proportionally reduced.
In addition, the code | symbol of Table 1 described above shall be similarly used also in the table | surface of each Example mentioned later.

(Table 1) First Example [Surface Data]
m r d nd νd
OP ∞
1) 612.1430 2.90 1.51680 63.88
2) -277.5576 12.30
3) 52.9543 1.40 1.84666 23.80
4) 38.2262 6.20 1.48749 70.31
5) -328.7345 d5
6) -112.1355 1.20 1.69680 55.52
7) 19.1005 3.70 1.80518 25.45
8) 50.5611 2.55
9) -55.8178 1.20 1.77250 49.62
10) 193.6838 d10
11) 62.3977 3.50 1.60311 60.69
12) -62.3977 0.10
13) 29.6793 5.00 1.59282 68.69
14) -37.6135 1.10 1.78472 25.64
15) 166.8546 1.50
16) (S) ∞ 11.54
17) -174.6423 3.00 1.85026 32.35
18) -18.5976 1.10 1.77250 49.62
19) 33.5456 5.53
20) 43.1112 3.00 1.61720 53.97
21) -43.1112 7.40
22) -20.5806 1.20 1.79952 42.09
23) -36.8862 (BF)
I ∞

[Various data]
W M T
f 56.65 135.00 193.93
FNO 4.08 4.93 5.76
2ω 28.94 11.86 8.29
Y 14.25 14.25 14.25
TL 148.13 163.97 171.79
BF 39.47 52.80 65.87

[Variable interval data]
W M T
f 56.65 135.00 193.93
d5 2.19 25.13 29.02
d10 31.04 10.62 1.48

[Lens group data]
ST f
G1 1 94.79
G2 6 -28.34
G3 11 36.41

[Values for each conditional expression]
(1-1) (TLt−TLw) / (− f2) = 0.835
(1-2) f1 / (− f2) = 3.34
(1-3) ft / f1 = 2.05
(1-4) ft / f3 = 5.33
(1-5) fw / (-f2) = 2.00
(2-1) ft / (− f2) = 6.84
(2-2) ft / f3 = 5.33
(2-3) f1 / (− f2) = 3.34
(2-4) (TLt−TLw) / (− f2) = 0.835

2A and 2B are graphs showing various aberrations of the variable magnification optical system according to the first example. FIG. 2A shows graphs showing various aberrations in the wide-angle end state when focusing on infinity, and FIG. 2B shows focusing on infinity. The aberration diagrams in the telephoto end state at the time are shown.
FIGS. 3A and 3B are lateral aberration diagrams in the case where the image stabilization is performed with respect to a 0.3 ° rotational shake in the variable magnification optical system according to the first example. FIG. 3A is a lateral aberration diagram in the wide-angle end state. FIG. 3B shows a lateral aberration diagram in the telephoto end state.

  In each aberration diagram, FNO indicates an F number, and Y indicates an image height. In the figure, d indicates an aberration curve at the d-line (wavelength λ = 587.6 nm), g indicates an aberration curve at the g-line (wavelength λ = 435.8 nm), and those not described are d-line The aberration curve at is shown. In the spherical aberration diagram, the F-number value corresponding to the maximum aperture is shown, and in the astigmatism diagram and the distortion diagram, the maximum image height is shown. In the aberration diagram showing astigmatism, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. The aberration diagram showing the coma shows the meridional coma with respect to the d-line and the g-line. In addition, also in the various aberration diagrams of each example shown below, the same reference numerals as in this example are used, and the following description is omitted.

As is apparent from each aberration diagram, it is understood that the variable magnification optical system ZL1 according to the first example has excellent optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Second embodiment)
4A and 4B are cross-sectional views showing a configuration of a variable magnification optical system ZL2 according to a second example common to the first and second embodiments of the present application. FIG. 4A shows a wide-angle end state, and FIG. Indicates the telephoto end state.
As shown in FIG. 4A, the variable magnification optical system ZL2 according to this example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power in order from the object side along the optical axis. The lens group G2 includes a third lens group G3 having a positive refractive power.

  The first lens group G1 includes, in order from the object side along the optical axis, a biconvex lens L11, and a cemented lens of a negative meniscus lens L12 having a convex surface facing the object side and a biconvex lens L13.

  The second lens group G2 includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L21 and a positive meniscus lens L22 having a convex surface facing the object side, and a biconcave lens L23.

  The third lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a cemented lens of the biconvex lens L32 and the biconcave lens L33, an aperture stop S, and a positive meniscus lens having a concave surface facing the object side. The lens includes a cemented lens of L34 and a biconcave lens L35, a biconvex lens L36, and a negative meniscus lens L37 having a concave surface facing the object side.

  On the image plane I, an image sensor (not shown) made up of a CCD, a CMOS, or the like is disposed.

  In the variable magnification optical system ZL2 according to the present example, the distance between the first lens group G1 and the second lens group G2 increases during the variable magnification from the wide-angle end state to the telephoto end state, and the second lens group G2 and the second lens group G2 The first lens group G1 moves toward the object side with respect to the image plane I, and the second lens group G2 once moves toward the image plane I side with respect to the image plane I so that the distance from the three lens groups G3 decreases. The third lens group G3 moves to the object side. The aperture stop S moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The variable magnification optical system ZL2 according to the present example includes a cemented lens of a positive meniscus lens L34 and a biconcave lens L35 among the lens components constituting the third lens group G3, in a direction orthogonal to the optical axis using a vibration-proof lens group. By moving in the direction including the component, image plane correction when image blur occurs, that is, image stabilization is performed. The vibration-proof lens group has a negative refractive power.

  Further, the variable magnification optical system ZL2 according to the present example moves along the optical axis by using, as a focus lens group, a cemented lens of a negative meniscus lens L12 and a biconvex lens L13 among the lens components constituting the first lens group G1. By doing so, focusing from the infinite object focusing state to the short distance object focusing state is performed. The focus lens group has a positive refractive power.

  Table 2 below lists specifications of the variable magnification optical system ZL2 according to the second example.

(Table 2) Second Example [Surface Data]
m r d nd νd
OP ∞
1) 354.3437 2.90 1.51680 63.88
2) -354.3437 12.10
3) 53.5415 1.40 1.84666 23.80
4) 38.6340 6.17 1.48749 70.31
5) -339.2311 d5
6) -180.8776 1.20 1.69680 55.52
7) 18.8950 4.11 1.80518 25.45
8) 47.1527 2.54
9) -48.4021 1.00 1.77250 49.62
10) 189.6188 d10
11) 59.7109 3.80 1.60311 60.69
12) -59.7109 0.10
13) 27.1377 5.10 1.49782 82.57
14) -44.4450 1.00 1.80518 25.45
15) 328.7306 1.50
16) (S) ∞ 11.54
17) -131.5467 3.10 1.85026 32.35
18) -15.9850 1.00 1.79952 42.09
19) 39.3987 5.69
20) 51.6077 2.64 1.77250 49.62
21) -51.6077 7.75
22) -20.7941 1.10 1.77250 49.62
23) -39.0838 (BF)
I ∞

[Various data]
W M T
f 56.61 135.00 194.07
FNO 4.12 4.94 5.78
2ω 28.97 11.87 8.29
Y 14.25 14.25 14.25
TL 148.30 164.07 172.09
BF 39.90 52.90 66.23

[Variable interval data]
W M T
f 56.61 135.00 194.07
d5 2.10 24.96 28.67
d10 30.56 10.48 1.44

[Lens group data]
ST f
G1 1 94.19
G2 6 -27.78
G3 11 36.37

[Values for each conditional expression]
(1-1) (TLt−TLw) / (− f2) = 0.856
(1-2) f1 / (− f2) = 3.39
(1-3) ft / f1 = 2.06
(1-4) ft / f3 = 5.34
(1-5) fw / (-f2) = 2.04
(2-1) ft / (− f2) = 6.99
(2-2) ft / f3 = 5.34
(2-3) f1 / (− f2) = 3.39
(2-4) (TLt−TLw) / (− f2) = 0.856

5A and 5B are graphs showing various aberrations of the variable magnification optical system according to the second example. FIG. 5A shows graphs showing various aberrations at the wide-angle end state when focusing on infinity, and FIG. 5B shows focusing on infinity. The aberration diagrams in the telephoto end state at the time are shown.
FIGS. 6A and 6B are lateral aberration diagrams in the case of performing vibration isolation with respect to 0.3 ° rotational blur in the variable magnification optical system according to the second example. FIG. 6A is a lateral aberration diagram in the wide-angle end state. FIG. 6B shows a lateral aberration diagram in the telephoto end state.

As is apparent from each aberration diagram, it is understood that the variable magnification optical system ZL2 according to the second example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Third embodiment)
7A and 7B are cross-sectional views showing a configuration of a variable magnification optical system ZL3 according to a third example common to the first and second embodiments of the present application. FIG. 7A shows a wide-angle end state, and FIG. Indicates the telephoto end state.
As shown in FIG. 7A, the variable magnification optical system ZL3 according to the present embodiment includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power in order from the object side along the optical axis. The lens group G2 includes a third lens group G3 having a positive refractive power.

  The first lens group G1 includes, in order from the object side along the optical axis, a biconvex lens L11, and a cemented lens of a negative meniscus lens L12 having a convex surface facing the object side and a biconvex lens L13.

  The second lens group G2 includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L21 and a positive meniscus lens L22 having a convex surface facing the object side, and a biconcave lens L23.

  The third lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a cemented lens of the biconvex lens L32 and the biconcave lens L33, an aperture stop S, and a positive meniscus lens having a concave surface facing the object side. L34, a biconcave lens L35, a biconvex lens L36, and a negative meniscus lens L37 having a concave surface facing the object side.

  On the image plane I, an image sensor (not shown) made up of a CCD, a CMOS, or the like is disposed.

  In the variable magnification optical system ZL3 according to the present example, the distance between the first lens group G1 and the second lens group G2 increases during the magnification change from the wide-angle end state to the telephoto end state, and the second lens group G2 and the second lens group G2 The first lens group G1 moves toward the object side with respect to the image plane I, and the second lens group G2 once moves toward the image plane I side with respect to the image plane I so that the distance from the three lens groups G3 decreases. The third lens group G3 moves to the object side. The aperture stop S moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The variable magnification optical system ZL3 according to the present embodiment includes components in a direction orthogonal to the optical axis using the positive meniscus lens L34 and the biconcave lens L35 as a vibration-proof lens group among the lens components constituting the third lens group G3. By moving in the direction, image plane correction when image blur occurs, that is, image stabilization is performed. The vibration-proof lens group has a negative refractive power.

  In addition, the variable magnification optical system ZL3 according to the present example moves along the optical axis by using, as a focus lens group, a cemented lens of a negative meniscus lens L12 and a biconvex lens L13 among lens components constituting the first lens group G1. By doing so, focusing from the infinite object focusing state to the short distance object focusing state is performed. The focus lens group has a positive refractive power.

  Table 3 below lists specifications of the variable magnification optical system ZL3 according to the third example.

(Table 3) Third Example [Surface Data]
m r d nd νd
OP ∞
1) 306.0326 2.90 1.51680 63.88
2) -339.7962 12.13
3) 56.1912 1.40 1.84666 23.80
4) 40.2507 6.20 1.48749 70.31
5) -300.1780 d5
6) -114.0348 1.20 1.69680 55.52
7) 19.2118 3.80 1.80518 25.45
8) 47.9058 2.40
9) -48.6668 1.20 1.77250 49.62
10) 378.2718 d10
11) 117.7370 3.30 1.69680 55.52
12) -48.5775 0.10
13) 23.1922 5.00 1.49782 82.57
14) -51.2024 1.10 1.80518 25.45
15) 144.1914 1.50
16) (S) ∞ 12.27
17) -68.0139 2.00 1.82930 24.25
18) -24.1047 0.30
19) -25.2596 1.10 1.79952 42.09
20) 41.8712 5.00
21) 60.9585 3.00 1.63823 54.84
22) -39.3919 7.08
23) -17.5018 1.20 1.53326 65.34
24) -26.7545 (BF)
I ∞

[Various data]
W M T
f 56.65 135.00 194.00
FNO 4.07 4.90 5.64
2ω 28.83 11.82 8.26
Y 14.25 14.25 14.25
TL 147.91 164.38 171.52
BF 40.53 54.93 66.84

[Variable interval data]
W M T
f 56.65 135.00 194.00
d5 2.25 24.49 29.00
d10 30.95 10.79 1.50

[Lens group data]
ST f
G1 1 93.62
G2 6 -27.67
G3 11 37.38

[Values for each conditional expression]
(1-1) (TLt−TLw) / (− f2) = 0.653
(1-2) f1 / (− f2) = 3.38
(1-3) ft / f1 = 2.07
(1-4) ft / f3 = 5.19
(1-5) fw / (-f2) = 2.05
(2-1) ft / (− f2) = 7.01
(2-2) ft / f3 = 5.19
(2-3) f1 / (− f2) = 3.38
(2-4) (TLt−TLw) / (− f2) = 0.653

8A and 8B are graphs showing various aberrations of the variable magnification optical system according to the third example. FIG. 8A shows graphs showing various aberrations at the wide-angle end state when focusing on infinity, and FIG. 8B shows focusing on infinity. The aberration diagrams in the telephoto end state at the time are shown.
FIG. 9A and FIG. 9B are lateral aberration diagrams in the case of performing vibration isolation with respect to 0.3 ° rotational blur in the variable magnification optical system according to the third example. FIG. 9A is a lateral aberration diagram in the wide-angle end state. FIG. 9B shows a lateral aberration diagram in the telephoto end state.

As is apparent from each aberration diagram, it is understood that the variable magnification optical system ZL3 according to the third example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Fourth embodiment)
10A and 10B are cross-sectional views showing a configuration of a variable magnification optical system ZL4 according to a fourth example common to the first and second embodiments of the present application. FIG. 10A shows a wide-angle end state, and FIG. Indicates the telephoto end state.
As shown in FIG. 10A, the variable magnification optical system ZL4 according to the present example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power in order from the object side along the optical axis. The lens group G2 includes a third lens group G3 having a positive refractive power.

  The first lens group G1 includes, in order from the object side along the optical axis, a negative meniscus lens L11 having a convex surface directed toward the object side, and a biconvex lens L12.

  The second lens group G2 includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L21 and a positive meniscus lens L22 having a convex surface facing the object side, and a biconcave lens L23.

  The third lens group G3 includes, in order from the object side along the optical axis, a cemented lens of a biconvex lens L31, an aperture stop S, a biconvex lens L32, and a negative meniscus lens L33 having a concave surface facing the object side, and an object side. The lens includes a cemented lens of a positive meniscus lens L34 having a concave surface and a biconcave lens L35, a biconvex lens L36, and a negative meniscus lens L37 having a concave surface facing the object side.

  On the image plane I, an image sensor (not shown) made up of a CCD, a CMOS, or the like is disposed.

  In the variable magnification optical system ZL4 according to the present example, the distance between the first lens group G1 and the second lens group G2 increases during the magnification change from the wide-angle end state to the telephoto end state, and the second lens group G2 and the second lens group G2 The first lens group G1 moves toward the object side with respect to the image plane I, and the second lens group G2 once moves toward the image plane I side with respect to the image plane I so that the distance from the three lens groups G3 decreases. The third lens group G3 moves to the object side. The aperture stop S moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The variable magnification optical system ZL4 according to the present example is a lens component constituting the third lens group G3, and a cemented lens of a positive meniscus lens L34 and a biconcave lens L35 is used as an anti-vibration lens group in a direction orthogonal to the optical axis. By moving in the direction including the component, image plane correction when image blur occurs, that is, image stabilization is performed. The vibration-proof lens group has a negative refractive power.

  In addition, the variable magnification optical system ZL4 according to the present embodiment moves the first lens group G1 as the focus lens group along the optical axis, thereby focusing from the infinite object focusing state to the short distance object focusing state. It is carried out. The focus lens group has a positive refractive power.

  Table 4 below lists specifications of the variable magnification optical system ZL4 according to the fourth example.

(Table 4) Fourth Example [Surface Data]
m r d nd νd
OP ∞
1) 66.2043 1.50 1.78472 25.64
2) 38.6129 0.10
3) 38.5039 6.82 1.69680 55.52
4) -505.3576 d4
5) -142.2751 1.20 1.77250 49.62
6) 20.5806 3.78 1.80518 25.45
7) 72.3294 2.68
8) -51.2794 1.10 1.77250 49.62
9) 222.7953 d9
10) 82.8878 3.30 1.49782 82.57
11) -48.3083 11.77
12) (S) ∞ 0.10
13) 29.3302 5.05 1.58913 61.22
14) -31.9440 1.10 1.80518 25.45
15) -941.3496 13.42
16) -63.2265 3.26 1.85026 32.35
17) -14.8054 1.10 1.77250 49.62
18) 42.1348 4.15
19) 75.4770 2.66 1.65844 50.83
20) -30.8029 6.51
21) -20.0203 1.40 1.80610 40.97
22) -36.5377 (BF)
I ∞

[Various data]
W M T
f 55.00 135.00 196.54
FNO 4.14 4.93 5.82
2ω 30.10 11.86 8.17
Y 14.25 14.25 14.25
TL 148.32 163.22 171.32
BF 40.85 53.88 68.78

[Variable interval data]
W M T
f 55.00 135.00 196.54
d4 1.92 26.41 30.04
d9 34.55 11.94 1.50

[Lens group data]
ST f
G1 1 91.10
G2 5 -28.85
G3 10 39.78

[Values for each conditional expression]
(1-1) (TLt−TLw) / (− f2) = 0.797
(1-2) f1 / (− f2) = 3.16
(1-3) ft / f1 = 2.16
(1-4) ft / f3 = 4.94
(1-5) fw / (− f2) = 1.91
(2-1) ft / (− f2) = 6.81
(2-2) ft / f3 = 4.94
(2-3) f1 / (− f2) = 3.16
(2-4) (TLt−TLw) / (− f2) = 0.797

11A and 11B are graphs showing various aberrations of the variable magnification optical system according to the fourth example. FIG. 11A shows graphs showing various aberrations at the wide-angle end when focusing on infinity, and FIG. 11B shows focusing on infinity. The aberration diagrams in the telephoto end state at the time are shown.
FIGS. 12A and 12B are lateral aberration diagrams in the case of performing image stabilization for a 0.3 ° rotational shake in the variable magnification optical system according to the fourth example. FIG. 12A is a lateral aberration diagram in the wide-angle end state. An aberration diagram is shown, and FIG. 12B shows a lateral aberration diagram in the telephoto end state.

As is apparent from the respective aberration diagrams, it is understood that the variable magnification optical system ZL4 according to the fourth example has excellent optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(5th Example)
13A and 13B are cross-sectional views showing a configuration of a variable magnification optical system ZL5 according to a fifth example common to the first and second embodiments of the present application, FIG. 13A shows a wide-angle end state, and FIG. Indicates the telephoto end state.
As shown in FIG. 13A, the variable magnification optical system ZL5 according to the present embodiment includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power in order from the object side along the optical axis. The lens group G2 includes a third lens group G3 having a positive refractive power.

  The first lens group G1 includes, in order from the object side along the optical axis, a biconvex lens L11, and a cemented lens of a negative meniscus lens L12 having a convex surface facing the object side and a biconvex lens L13.

  The second lens group G2 includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L21 and a positive meniscus lens L22 having a convex surface facing the object side, and a biconcave lens L23.

  The third lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a cemented lens of the biconvex lens L32 and the biconcave lens L33, an aperture stop S, and a positive meniscus lens having a concave surface facing the object side. The lens includes a cemented lens of L34 and a biconcave lens L35, a biconvex lens L36, and a negative meniscus lens L37 having a concave surface facing the object side.

  On the image plane I, an image sensor (not shown) made up of a CCD, a CMOS, or the like is disposed.

  In the variable magnification optical system ZL5 according to the present example, the distance between the first lens group G1 and the second lens group G2 increases during the magnification change from the wide-angle end state to the telephoto end state, and the second lens group G2 and the second lens group G2 The first lens group G1 moves toward the object side with respect to the image plane I, and the second lens group G2 once moves toward the image plane I side with respect to the image plane I so that the distance from the three lens groups G3 decreases. The third lens group G3 moves to the object side. The aperture stop S moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The variable magnification optical system ZL5 according to the present embodiment moves the second lens group G2 in a direction including a component perpendicular to the optical axis as an anti-vibration lens group, thereby correcting image plane when an image blur occurs, that is, Anti-vibration is performed. The vibration-proof lens group has a negative refractive power.

  Further, the variable magnification optical system ZL5 according to the present example moves along the optical axis by using, as a focus lens group, a cemented lens of a negative meniscus lens L12 and a biconvex lens L13 among the lens components constituting the first lens group G1. By doing so, focusing from the infinite object focusing state to the short distance object focusing state is performed. The focus lens group has a positive refractive power.

  Table 5 below gives specifications of the variable magnification optical system ZL5 according to the fifth example.

(Table 5) Fifth Example [Surface data]
m r d nd νd
OP ∞
1) 612.1430 2.90 1.51680 63.88
2) -277.5576 12.30
3) 52.9543 1.40 1.84666 23.80
4) 38.2262 6.20 1.48749 70.31
5) -328.7345 d5
6) -112.1355 1.20 1.69680 55.52
7) 19.1005 3.70 1.80518 25.45
8) 50.5611 2.55
9) -55.8178 1.20 1.77250 49.62
10) 193.6838 d10
11) 62.3977 3.50 1.60311 60.69
12) -62.3977 0.10
13) 29.6793 5.00 1.59282 68.69
14) -37.6135 1.10 1.78472 25.64
15) 166.8546 1.50
16) (S) ∞ 11.54
17) -174.6423 3.00 1.85026 32.35
18) -18.5976 1.10 1.77250 49.62
19) 33.5456 5.53
20) 43.1112 3.00 1.61720 53.97
21) -43.1112 7.40
22) -20.5806 1.20 1.79952 42.09
23) -36.8862 (BF)
I ∞

[Various data]
W M T
f 56.65 135.00 193.93
FNO 4.08 4.93 5.76
2ω 28.94 11.86 8.29
Y 14.25 14.25 14.25
TL 148.13 163.97 171.79
BF 39.47 52.80 65.87

[Variable interval data]
W M T
f 56.65 135.00 193.93
d5 2.19 25.13 29.02
d10 31.04 10.62 1.48

[Lens group data]
ST f
G1 1 94.79
G2 6 -28.34
G3 11 36.41

[Values for each conditional expression]
(1-1) (TLt−TLw) / (− f2) = 0.835
(1-2) f1 / (− f2) = 3.34
(1-3) ft / f1 = 2.05
(1-4) ft / f3 = 5.33
(1-5) fw / (-f2) = 2.00
(2-1) ft / (− f2) = 6.84
(2-2) ft / f3 = 5.33
(2-3) f1 / (− f2) = 3.34
(2-4) (TLt−TLw) / (− f2) = 0.835

14A and 14B are graphs showing various aberrations of the variable magnification optical system according to the fifth example. FIG. 14A shows graphs showing various aberrations at the wide-angle end state when focusing on infinity, and FIG. 14B shows focusing on infinity. The aberration diagrams in the telephoto end state at the time are shown.
FIGS. 15A and 15B are lateral aberration diagrams in the case where the image stabilization is performed with respect to 0.3 ° rotational shake in the variable magnification optical system according to the fifth example. FIG. 15A is a lateral aberration diagram in the wide-angle end state. FIG. 15B shows a lateral aberration diagram in the telephoto end state.

As is apparent from the respective aberration diagrams, it is understood that the variable magnification optical system ZL5 according to the fifth example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Sixth embodiment)
16A and 16B are cross-sectional views showing a configuration of a variable magnification optical system ZL6 according to a sixth example common to the first and second embodiments of the present application, FIG. 16A shows a wide-angle end state, and FIG. Indicates the telephoto end state.
As shown in FIG. 16A, the variable magnification optical system ZL6 according to the present example includes a first lens group G1 having a positive refractive power and a second lens having a negative refractive power in order from the object side along the optical axis. The lens group G2 includes a third lens group G3 having a positive refractive power and a fourth lens group G4 having a negative refractive power.

  The first lens group G1 includes, in order from the object side along the optical axis, a negative meniscus lens L11 having a convex surface directed toward the object side, and a biconvex lens L12.

  The second lens group G2 includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L21 and a positive meniscus lens L22 having a convex surface facing the object side, and a biconcave lens L23.

  The third lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, an aperture stop S, and a cemented lens of a biconvex lens L32 and a negative meniscus lens L33 having a concave surface facing the object side. ing.

  The fourth lens group G4 has, in order from the object side along the optical axis, a cemented lens of a positive meniscus lens L41 having a concave surface directed toward the object side and a biconcave lens L42, a biconvex lens L43, and a concave surface directed toward the object side. It comprises a negative meniscus lens L44.

  On the image plane I, an image sensor (not shown) made up of a CCD, a CMOS, or the like is disposed.

  In the variable magnification optical system ZL6 according to the present example, the distance between the first lens group G1 and the second lens group G2 increases during the variable magnification from the wide-angle end state to the telephoto end state, and the second lens group G2 and the second lens group G2 The first lens group G1 moves toward the object side with respect to the image plane I, and the second lens group G2 once moves toward the image plane I side with respect to the image plane I so that the distance from the three lens groups G3 decreases. The third lens group G3 moves toward the object side, and the fourth lens group G4 moves toward the object side. The aperture stop S moves together with the third lens group G3 upon zooming from the wide-angle end state to the telephoto end state.

  The zoom optical system ZL6 according to the present example has a cemented lens of a positive meniscus lens L41 and a biconcave lens L42 out of the lens components constituting the fourth lens group G4, in a direction orthogonal to the optical axis. By moving in the direction including the component, image plane correction when image blur occurs, that is, image stabilization is performed. The vibration-proof lens group has a negative refractive power.

  In addition, the variable magnification optical system ZL6 according to the present embodiment moves the first lens group G1 as the focus lens group along the optical axis, thereby focusing from the infinite object focusing state to the short distance object focusing state. It is carried out. The focus lens group has a positive refractive power.

  Table 6 below provides specifications of the variable magnification optical system ZL6 according to the sixth example.

(Table 6) Sixth Example [Surface data]
m r d nd νd
OP ∞
1) 66.2043 1.50 1.78472 25.64
2) 38.6129 0.10
3) 38.5039 6.82 1.69680 55.52
4) -505.3576 d4
5) -142.2751 1.20 1.77250 49.62
6) 20.5806 3.78 1.80518 25.45
7) 72.3294 2.68
8) -51.2794 1.10 1.77250 49.62
9) 222.7953 d9
10) 82.8878 3.30 1.49782 82.57
11) -48.3083 11.77
12) (S) ∞ 0.10
13) 29.3302 5.05 1.58913 61.22
14) -31.9440 1.10 1.80518 25.45
15) -941.3496 d15
16) -63.2265 3.26 1.85026 32.35
17) -14.8054 1.10 1.77250 49.62
18) 42.1348 4.15
19) 75.4770 2.66 1.65844 50.83
20) -30.8029 6.51
21) -20.0203 1.40 1.80610 40.97
22) -36.5377 (BF)
I ∞

[Various data]
W M T
f 55.00 133.09 198.32
FNO 4.14 4.91 5.85
2ω 30.10 12.05 8.10
Y 14.25 14.25 14.25
TL 148.32 164.41 171.10
BF 40.85 55.07 68.56

[Variable interval data]
W M T
f 55.00 133.09 198.32
d4 1.92 26.41 30.04
d9 34.55 12.94 1.10
d15 13.42 12.42 13.82

[Lens group data]
ST f
G1 1 91.10
G2 5 -28.85
G3 10 35.67
G4 12 -85.48

[Values for each conditional expression]
(1-1) (TLt−TLw) / (− f2) = 0.790
(1-2) f1 / (− f2) = 3.16
(1-3) ft / f1 = 2.18
(1-4) ft / f3 = 5.56
(1-5) fw / (− f2) = 1.91
(2-1) ft / (− f2) = 6.87
(2-2) ft / f3 = 5.56
(2-3) f1 / (− f2) = 3.16
(2-4) (TLt−TLw) / (− f2) = 0.790

FIGS. 17A and 17B are graphs showing various aberrations of the variable magnification optical system according to Example 6. FIG. 17A shows graphs showing various aberrations at the wide-angle end when focusing on infinity, and FIG. 17B shows focusing on infinity. The aberration diagrams in the telephoto end state at the time are shown.
FIG. 18A and FIG. 18B are lateral aberration diagrams in the case of performing vibration isolation against a 0.3 ° rotational shake in the variable magnification optical system according to the sixth example, and FIG. 18A is a lateral view in the wide-angle end state. FIG. 18B shows a lateral aberration diagram in the telephoto end state.

As is apparent from the respective aberration diagrams, it is understood that the variable magnification optical system ZL6 according to the sixth example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

  As described above, according to the above-described embodiments, a variable magnification optical system having a small size and high optical performance can be realized. In particular, it is possible to realize a variable magnification optical system having a zoom ratio of about 3.0 to 4.5 times and an angle of view of 22 ° or more in the wide-angle end state and further provided with an image stabilization function. Further, by using the lens component of the second lens group G2, a part of the third lens group G3, or a part of the fourth lens group G4 as the anti-vibration group, the diameter of the anti-vibration group can be reduced. Miniaturization can be realized. The contents described below can be appropriately adopted as long as the optical performance is not impaired.

  As a numerical example of the variable magnification optical system of the present application, a three-group configuration or a four-group configuration is shown. However, the present application is not limited to this, and configures a variable magnification optical system of another group configuration (for example, five groups). It is also possible. Specifically, a configuration in which a lens or a lens group is added to the most object side of the variable magnification optical system of the present application, or a configuration in which a lens or a lens group is added to the most image side may be used. The lens group refers to a portion having at least one lens separated by an air interval that changes during zooming.

  In addition, the variable magnification optical system of the present application uses a part of a lens group, an entire lens group, or a plurality of lens groups as a focusing lens group for focusing from an object at infinity to a near object. It is good also as a structure moved to an axial direction. The focusing lens group can also be applied to autofocus, and is also suitable for driving by an autofocus motor, such as an ultrasonic motor.

  Further, in the zoom optical system of the present application, one lens group is moved so as to have a component in a direction perpendicular to the optical axis, or is rotated (oscillated) in an in-plane direction including the optical axis, and the hand is moved. It is possible to function as a vibration proof lens that corrects image blur caused by blur.

  Further, the lens surface of the lens constituting the variable magnification optical system of the present application may be a spherical surface, a flat surface, or an aspherical surface. When the lens surface is a spherical surface or a flat surface, it is preferable because lens processing and assembly adjustment are facilitated, and deterioration of optical performance due to errors in lens processing and assembly adjustment can be prevented. Further, even when the image plane is deviated, it is preferable because there is little deterioration in drawing performance. When the lens surface is aspheric, any of aspherical surfaces by grinding, a glass mold aspherical surface formed by molding glass into an aspherical surface, or a composite aspherical surface formed by forming resin on the glass surface into an aspherical surface An aspherical surface may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  In addition, the aperture stop S of the variable magnification optical system of the present application is preferably arranged in the third lens group G3, but the role may be substituted by a lens frame without providing a member as the aperture stop.

  Further, an antireflection film having a high transmittance in a wide wavelength range may be provided on the lens surface of the lens constituting the variable magnification optical system of the present application. Thereby, flare and ghost can be reduced and high contrast optical performance can be achieved.

  Next, an imaging apparatus including the variable magnification optical system according to the embodiment of the present application will be described.

  FIG. 19 is a diagram illustrating a configuration of a camera including the variable magnification optical system according to the embodiment of the present application. As shown in FIG. 19, the camera 1 is a so-called mirrorless camera of the interchangeable lens type that includes the variable magnification optical system ZL <b> 1 according to the first example as the photographing lens 2. In the camera 1, light from an object (not shown) (not shown) is collected by the photographing lens 2 and forms a subject image on the imaging surface of the imaging unit 3 via an optical low-pass filter (not shown). Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on the electronic viewfinder 4 provided in the camera 1. Thus, the photographer can observe the subject through the electronic viewfinder 4.

  When a release button (not shown) is pressed by the photographer, an image photoelectrically converted by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1.

  Here, the variable magnification optical system ZL1 according to the first embodiment mounted on the camera 1 as the photographing lens 2 has various aberrations well corrected from the wide-angle end state to the telephoto end state, and has a small size and high optical performance. A variable magnification optical system. Therefore, the camera 1 having a small size and high optical performance can be realized.

  Note that even if a camera in which any one of the variable magnification optical systems ZL2 to ZL6 according to the second to sixth examples is mounted as the photographing lens 2, the same effect as the camera 1 can be obtained. In this embodiment, an example of a mirrorless camera has been described. However, the photographic lens according to each of the above embodiments is mounted on a single-lens reflex camera that has a quick return mirror in the camera body and observes a subject with a finder optical system. Even in this case, the same effect as the camera 1 can be obtained.

  Next, a manufacturing method of the variable magnification optical system according to the first embodiment of the present application will be described. FIG. 20 is a flowchart showing an outline of the manufacturing method of the variable magnification optical system according to the first embodiment of the present application.

The variable magnification optical system manufacturing method according to the first embodiment of the present application includes a first lens group having a positive refractive power and a second lens group having a negative refractive power in order from the object side along the optical axis. A variable magnification optical system having a third lens group having a positive refractive power, and includes the following steps S1 to S2 as shown in FIG.
Step S1: At the time of zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group is changed, and the distance between the second lens group and the third lens group is changed. The first lens group, the second lens group, and the third lens group are configured to move so as to change.
Step S2: Configure so as to satisfy the following conditional expression (1-1).
(1-1) 0.400 <(TLt−TLw) / (− f2) <0.880
However,
TLt: full length of the variable magnification optical system in the telephoto end state TLw: full length of the variable magnification optical system in the wide angle end state f2: focal length of the second lens group

  According to the manufacturing method of the variable power optical system of the first embodiment of the present application, a small variable power optical system having good optical performance from the wide-angle end state to the telephoto end state can be manufactured.

  Next, a manufacturing method of the variable magnification optical system according to the second embodiment of the present application will be described. FIG. 21 is a flowchart showing an outline of a method for manufacturing a variable magnification optical system according to the second embodiment of the present application.

The variable magnification optical system manufacturing method according to the second embodiment of the present application includes, in order from the object side along the optical axis, a first lens group having a positive refractive power, and a second lens group having a negative refractive power. A variable magnification optical system having a third lens group having a positive refractive power, and includes the following steps S1 to S3 as shown in FIG.
Step S1: At the time of zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group is changed, and the distance between the second lens group and the third lens group is changed. The first lens group, the second lens group, and the third lens group are configured to move so as to change.
Step S2: It is configured to perform focusing from an object at infinity to a near object by moving at least a part of the first lens group along the optical axis.
Step S3: Configure so as to satisfy the following conditional expression (2-1).
(2-1) 6.00 <ft / (-f2) <7.60
However,
ft: focal length of the entire variable magnification optical system in the telephoto end state f2: focal length of the second lens group

According to the method for manufacturing the variable magnification optical system of the second embodiment of the present application, a small variable magnification optical system having good optical performance from the wide-angle end state to the telephoto end state can be manufactured.

Claims (9)

In order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power,
When zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group changes, and the distance between the second lens group and the third lens group changes. In addition, the first lens group, the second lens group, and the third lens group move,
By moving at least a part of the first lens group, the second lens group, and the third lens group so as to include a component in a direction orthogonal to the optical axis as an anti-vibration lens group, an image blur is generated. Perform image plane correction,
A variable magnification optical system that satisfies the following formula.
0.400 <(TLt−TLw) / (− f2) <0.880
2.00 <f1 / (− f2) <3.50
However,
TLt: optical total length of the variable magnification optical system in the telephoto end state TLw: total optical length of the variable magnification optical system in the wide angle end state f1: focal length of the first lens group f2: focal length of the second lens group In order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power,
When zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group changes, and the distance between the second lens group and the third lens group changes. In addition, the first lens group, the second lens group, and the third lens group move,
A variable magnification optical system that satisfies the following formula.
0.400 <(TLt−TLw) / (− f2) <0.880
2.00 <f1 / (− f2) <3.50
4.90 <ft / f3 <5.90
1.50 <fw / (− f2) <2.50
However,
TLt: optical total length of the variable magnification optical system in the telephoto end state TLw: optical total length of the variable magnification optical system in the wide angle end state f1: focal length of the first lens group f2: focal length of the second lens group f3: Focal length of the third lens group ft: Focal length of the entire zooming optical system in the telephoto end state fw: Focal length of the entire zooming optical system in the wide-angle end state By moving at least a part of the first lens group, the second lens group, and the third lens group so as to include a component in a direction orthogonal to the optical axis as an anti-vibration lens group, an image blur is generated. The zoom optical system according to claim 2 , wherein the image plane correction is performed. The variable power optical system according to claim 1 , wherein the zoom lens system satisfies the following formula.
3.50 <ft / f3 <5.90
However,
ft: focal length of the entire variable magnification optical system in the telephoto end state f3: focal length of the third lens group The variable power optical system according to claim 1 , wherein the zoom lens system satisfies the following formula.
1.50 <fw / (− f2) <2.50
However,
fw: focal length of the entire variable magnification optical system in the wide-angle end state f3: focal length of the third lens group   3. The zoom optical system according to claim 1, wherein focusing from an object at infinity to an object at a short distance is performed by moving at least a part of the first lens group along the optical axis. The zoom optical system according to any one of claims 1 to 6 , which satisfies a condition of the following formula.
1.82 <ft / f1 <3.00
However,
ft: focal length of the entire variable magnification optical system in the telephoto end state f1: focal length of the first lens group By moving in a direction including a component perpendicular to the optical axis at least a portion of the third lens group as a vibration reduction lens group, any one of claims 1 to perform image plane correction upon image blur occurs 7 The zoom optical system according to one item. An imaging apparatus comprising the variable magnification optical system according to any one of claims 1 to 8 .

Images