JP5488061B2 - Variable-magnification optical system, optical device, and variable-magnification optical system manufacturing method - Google Patents

Description

  The present invention relates to a variable magnification optical system, an optical apparatus having the variable magnification optical system, and a method for manufacturing the variable magnification optical system.

  Conventionally, as a variable magnification optical system used for an interchangeable lens for a single-lens reflex camera or the like, many optical systems in which the lens group closest to the object side has a positive refractive power have been proposed (for example, see Patent Document 1).

JP 2008-3195 A

  If the conventional variable magnification optical system is further increased in magnification, aberration fluctuations increase, making it difficult to obtain sufficiently high optical performance.

  The present invention has been made in view of the above problems, and an object thereof is to provide a variable magnification optical system that suppresses aberration fluctuation and has high optical performance, an optical apparatus having the same, and a method for manufacturing the variable magnification optical system. To do.

In order to solve the above problems, the present invention provides:
In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, Consists of substantially 5 lens groups with the 3C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third A lens group decreases, The interval between the 3A lens group and the 3B lens group changes, the interval between the 3B lens group and the 3C lens group changes,
The third A lens group includes a first positive lens, a second positive lens, and a cemented lens in order from the object side along the optical axis.
The cemented lens has a third positive lens and a negative lens,
A variable magnification optical system characterized by satisfying the following conditional expression is provided.
0.90 <f3A / (− f3B) <1.30
νd31−νd34> 35.0
0.50 <r32a / r31a <10.00
However,
f3A: focal length of the third A lens group f3B: focal length of the third B lens group
νd31: Abbe number of the d-line of the first positive lens
νd34: Abbe number of d-line of the negative lens
r31a: radius of curvature of the object-side surface of the first positive lens
r32a: the radius of curvature of the object-side surface of the second positive lens .
In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, Consists of substantially 5 lens groups with the 3C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third A lens group decreases, The interval between the 3A lens group and the 3B lens group changes, the interval between the 3B lens group and the 3C lens group changes,
The third A lens group includes a first positive lens, a second positive lens, and a cemented lens in order from the object side along the optical axis.
The cemented lens has a third positive lens and a negative lens,
A variable magnification optical system characterized by satisfying the following conditional expression is provided.
(Νd31 + νd32 + νd33) / 3−νd34> 35.0
0.90 <f3A / (− f3B) <1.30
0.50 <r32a / r31a <10.00
However,
νd31: d-line Abbe number of the first positive lens νd32: d-line Abbe number of the second positive lens νd33: d-line Abbe number of the third positive lens νd34: d-line Abbe number of the negative lens f3A: focal length of the third A lens group f3B: focal length of the third B lens group
r31a: radius of curvature of the object-side surface of the first positive lens
r32a: the radius of curvature of the object-side surface of the second positive lens .
In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, Consists of substantially 5 lens groups with the 3C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third A lens group decreases, The interval between the 3A lens group and the 3B lens group changes, the interval between the 3B lens group and the 3C lens group changes,
The third A lens group includes a first positive lens, a second positive lens, and a cemented lens in order from the object side along the optical axis.
The cemented lens has a third positive lens and a negative lens,
The third positive lens has a biconvex shape, and the negative lens has a negative meniscus shape;
A variable magnification optical system characterized by satisfying the following conditional expression is provided.
νd33−νd34> 35.0
0.90 <f3A / (− f3B) <1.30
0.50 <r32a / r31a <10.00
However,
νd33: d-line Abbe number of the third positive lens νd34: d-line Abbe number of the negative lens
f3A: focal length of the third A lens group
f3B: focal length of the third B lens group
r31a: radius of curvature of the object-side surface of the first positive lens
r32a: the radius of curvature of the object-side surface of the second positive lens .
In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, Consists of substantially 5 lens groups with the 3C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third A lens group decreases, The interval between the 3A lens group and the 3B lens group changes, the interval between the 3B lens group and the 3C lens group changes,
The third A lens group includes a first positive lens, a second positive lens, and a cemented lens in order from the object side along the optical axis.
The cemented lens has a third positive lens and a negative lens,
A variable magnification optical system characterized by satisfying the following conditional expression is provided.
40.0 <νd32−νd34 <65.0
40.0 <νd33−νd34
νd31−νd34> 35.0
However,
νd32: Abbe number of d-line of the second positive lens νd33: Abbe number of d-line of the third positive lens νd34: Abbe number of d-line of the negative lens
νd31: Abbe number of the d-line of the first positive lens
νd34: Abbe number of d-line of the negative lens

  The present invention also provides an optical apparatus comprising the variable magnification optical system.

The present invention also provides:
In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, A method of manufacturing a variable magnification optical system substantially consisting of five lens groups with a third C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refracting power,
When the first lens group, the second lens group, the 3A lens group, the 3B lens group, and the 3C lens group are changed from the wide-angle end state to the telephoto end state, the first lens group The distance between the second lens group and the second lens group can be increased, the distance between the second lens group and the third A lens group can be decreased, and the distance between the third A lens group and the third B lens group can be changed, An interval between the third B lens group and the third C lens group is arranged to be variable,
In order from the object side along the optical axis, the first positive lens, the second positive lens, and the cemented lens are disposed in the third A lens group, and the third positive lens and the negative lens are included in the cemented lens.
Provided is a variable magnification optical system manufacturing method in which the third A lens group and the third B lens group satisfy the following conditional expression.
0.90 <f3A / (− f3B) <1.30
νd31−νd34> 35.0
0.50 <r32a / r31a <10.00
However,
f3A: focal length of the third A lens group f3B: focal length of the third B lens group
νd31: Abbe number of the d-line of the first positive lens
νd34: Abbe number of d-line of the negative lens
r31a: radius of curvature of the object-side surface of the first positive lens
r32a: radius of curvature of the object-side surface of the second positive lens

  According to the present invention, it is possible to provide a variable magnification optical system that suppresses aberration fluctuation and has high optical performance, an optical apparatus having the variable magnification optical system, and a method for manufacturing the variable magnification optical system.

It is sectional drawing which shows the structure of the variable magnification optical system which concerns on 1st Example. FIG. 4A illustrates various aberration diagrams of the variable magnification optical system according to Example 1 in an infinitely focused state, where (a) is a wide-angle end state, (b) is a first intermediate focal length state, and (c) is a second intermediate state. Each focal length state is shown. FIG. 5A illustrates various aberration diagrams of the zoom optical system according to the first example in an infinitely focused state, where (a) is a third intermediate focal length state, (b) is a fourth intermediate focal length state, and (c) is a graph. Each telephoto end state is shown. It is sectional drawing which shows the structure of the variable magnification optical system which concerns on 2nd Example. The aberration diagrams in the infinite focus state of the variable magnification optical system according to the second example are shown, (a) is a wide-angle end state, (b) is a first intermediate focal length state, and (c) is a second intermediate state. Each focal length state is shown. The aberration diagrams in the infinite focus state of the variable magnification optical system according to the second example are shown, (a) is the third intermediate focal length state, (b) is the fourth intermediate focal length state, (c) is Each telephoto end state is shown. It is sectional drawing which shows the structure of the variable magnification optical system which concerns on 3rd Example. The aberration diagrams in the infinite focus state of the variable magnification optical system according to the third example are shown, (a) is a wide-angle end state, (b) is a first intermediate focal length state, and (c) is a second intermediate state. Each focal length state is shown. The aberration diagrams in the infinite focus state of the variable magnification optical system according to the third example are shown, (a) is the third intermediate focal length state, (b) is the fourth intermediate focal length state, (c) is Each telephoto end state is shown. It is sectional drawing which shows the structure of the variable magnification optical system which concerns on 4th Example. FIG. 6A shows various aberration diagrams of the zoom optical system according to Example 4 in the infinitely focused state, where (a) is a wide-angle end state, (b) is a first intermediate focal length state, and (c) is a second intermediate state. Each focal length state is shown. The aberration diagrams in the infinite focus state of the variable magnification optical system according to the fourth example are shown, (a) is the third intermediate focal length state, (b) is the fourth intermediate focal length state, (c) is Each telephoto end state is shown. It is sectional drawing which shows the structure of the variable magnification optical system which concerns on 5th Example. FIG. 6A shows various aberration diagrams of the variable magnification optical system according to Example 5 in the infinitely focused state, where (a) is a wide-angle end state, (b) is a first intermediate focal length state, and (c) is a second intermediate state. Each focal length state is shown. The aberration diagrams in the infinite focus state of the variable magnification optical system according to the fifth example are shown, (a) is the third intermediate focal length state, (b) is the fourth intermediate focal length state, (c) is Each telephoto end state is shown. It is a figure which shows the structure of the camera provided with the variable magnification optical system which concerns on 1st Example. It is a figure which shows the manufacturing method of the variable magnification optical system of this application.

  Hereinafter, a variable magnification optical system according to an embodiment of the present application will be described.

  The variable magnification optical system according to this embodiment 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 third lens group having a positive refractive power. And the distance between the first lens group and the second lens group increases and the distance between the second lens group and the third lens group decreases during zooming from the wide-angle end state to the telephoto end state. By doing so, an optical system capable of zooming is realized, and fluctuations in distortion due to zooming are suppressed.

Further, the variable magnification optical system according to this embodiment, the third lens group, in order from the object along the optical axis, a first 3A lens unit having a positive refractive power, a third 3B lens unit having a negative refractive power, a 3C lens group, and when changing magnification from the wide-angle end state to the telephoto end state, the distance between the 3A lens group and the 3B lens group changes, and the distance between the 3B lens group and the 3C lens group is By changing the configuration, it is possible to increase the zoom ratio of the third lens unit rather than moving the third lens unit as a unit, and to suppress fluctuations in spherical aberration, coma and astigmatism, and high optical performance. Can be realized. Hereinafter, in the present specification, “third A lens group”, “third B lens group”, and “third C lens group” are referred to as “first partial lens group”, “second partial lens group”, and “third partial lens”. Also referred to as “group”.

  In the variable magnification optical system according to the present embodiment, the first partial lens group includes a first positive lens, a second positive lens, and a cemented lens in order from the object side along the optical axis. Is configured to have a third positive lens and a negative lens, so that each of the first partial lens groups has at least three positive lenses while having a predetermined positive refractive power necessary for zooming. It can weaken the refractive power of the lens, suppress the occurrence of negative spherical aberration that occurs from the positive lens, while suppressing the occurrence of decentration coma aberration and spherical aberration due to manufacturing errors such as lens decentering and spacing deviation, High optical performance can be realized.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (1).
(1) (νd31 + νd32 + νd33) / 3−νd34> 35.0
Where νd31 is the Abbe number of the d-line of the first positive lens, νd32 is the Abbe number of the d-line of the second positive lens, νd33 is the Abbe number of the d-line of the third positive lens, and νd34 is the Abbe number of the d-line of the negative lens. Is a number.

  Conditional expression (1) is a conditional expression for correcting axial chromatic aberration in a balanced manner and obtaining high optical performance.

  If the lower limit of conditional expression (1) is not reached, correction of axial chromatic aberration and chromatic spherical aberration in the telephoto end state becomes difficult, and high optical performance cannot be realized.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (1) to 38.0. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (1) to 41.0.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (1) to 70.0. Exceeding the preferable upper limit value of conditional expression (1) causes excessive correction of secondary axial chromatic aberration and spherical spherical aberration in the telephoto end state in existing optical materials, resulting in chromatic aberration and high optical performance. Cannot be realized. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (1) to 65.0.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (2).
(2) νd31−νd34> 35.0
Here, νd31 is the Abbe number of the d-line of the first positive lens, and νd34 is the Abbe number of the d-line of the negative lens.

  Conditional expression (2) is a conditional expression for obtaining a high optical performance by correcting axial chromatic aberration in a balanced manner by optimizing the chromatic aberration correction state of the first positive lens and the negative lens.

  If the lower limit value of conditional expression (2) is not reached, it is difficult to correct axial chromatic aberration and spherical spherical aberration in the telephoto end state, and high optical performance cannot be realized.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (2) to 40.0. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (2) to 44.0.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (2) to 70.0. Exceeding the preferred upper limit value of conditional expression (2) causes excessive correction of secondary axial chromatic aberration and spherical aberration of color in the telephoto end state in existing optical materials, resulting in chromatic aberration and high optical performance. Cannot be realized. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (2) to 65.0.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (3).
(3) νd32−νd34> 35.0
However, νd32 is the Abbe number of the d-line of the second positive lens, and νd34 is the Abbe number of the d-line of the negative lens.

  Conditional expression (3) is a conditional expression for obtaining high optical performance by correcting axial chromatic aberration in a balanced manner by optimizing the chromatic aberration correction state of the second positive lens and the negative lens.

  If the lower limit value of conditional expression (3) is not reached, correction of axial chromatic aberration and chromatic spherical aberration in the telephoto end state becomes difficult, and high optical performance cannot be realized.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (3) to 40.0. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (3) to 44.0.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (3) to 70.0. Exceeding the preferable upper limit value of conditional expression (3) causes excessive correction of secondary axial chromatic aberration and spherical aberration of color in the telephoto end state in existing optical materials, resulting in chromatic aberration and high optical performance. Cannot be realized. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (3) to 65.0.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (4).
(4) νd33−νd34> 35.0
However, νd33 is the Abbe number of the d-line of the third positive lens, and νd34 is the Abbe number of the d-line of the negative lens.

  Conditional expression (4) is a conditional expression for obtaining a high optical performance by correcting axial chromatic aberration in a balanced manner by optimizing the chromatic aberration correction state of the third positive lens and the negative lens.

  If the lower limit of conditional expression (4) is not reached, correction of axial chromatic aberration and chromatic spherical aberration in the telephoto end state becomes difficult, and high optical performance cannot be realized.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (4) to 40.0. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (4) to 44.0.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (4) to 70.0. Exceeding the preferable upper limit value of conditional expression (4) causes excessive correction of secondary axial chromatic aberration and spherical spherical aberration in the telephoto end state in existing optical materials, resulting in chromatic aberration and high optical performance. Cannot be realized. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (4) to 65.0.

  In the variable magnification optical system according to this embodiment, it is desirable that the cemented lens includes a third positive lens and a negative lens in order from the object side along the optical axis.

  With this configuration, the color spherical aberration can be corrected satisfactorily.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (5).
(5) 0.80 <f3A / (− f3B) <1.30
Here, f3A is the focal length of the first partial lens group, and f3B is the focal length of the second partial lens group.

  Conditional expression (5) defines an appropriate range of the focal length of the second partial lens group relative to the focal length of the first partial lens group, and is a conditional expression for realizing high optical performance over the entire zooming range. It is.

  When the lower limit of conditional expression (5) is not reached, the focal length of the first partial lens group becomes too small relative to the focal length of the second partial lens group, and the first partial lens group in the wide-angle end state is Correction of the generated negative spherical aberration becomes difficult, and high optical performance cannot be realized.

  When the upper limit of conditional expression (5) is exceeded, the focal length of the second partial lens group becomes too small relative to the focal length of the first partial lens group, and the second partial lens group in the telephoto end state Correction of the generated positive spherical aberration becomes difficult, and high optical performance cannot be realized.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (5) to 0.90.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (5) to 1.20.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (6).
(6) 0.50 <f32 / f31 <10.00
Here, f31 is the focal length of the first positive lens, and f32 is the focal length of the second positive lens.

  Conditional expression (6) defines an appropriate range of the focal length of the second positive lens with respect to the focal length of the first positive lens, and is a conditional expression for realizing high optical performance over the entire zooming range. .

  When the lower limit of conditional expression (6) is not reached, the focal length of the second positive lens becomes too small relative to the focal length of the first positive lens, and negative spherical aberration that occurs in the second positive lens. Correction becomes difficult and high optical performance cannot be realized.

  When the upper limit of conditional expression (6) is exceeded, the focal length of the first positive lens becomes too small relative to the focal length of the second positive lens, and negative spherical aberration that occurs in the first positive lens. Correction becomes difficult and high optical performance cannot be realized.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (6) to 0.67.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (6) to 6.50.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (7).
(7) 0.50 <r32a / r31a <10.00
However, r31a is the radius of curvature of the object side surface of the first positive lens, and r32a is the radius of curvature of the object side surface of the second positive lens.

  Conditional expression (7) defines an appropriate range of the radius of curvature of the object-side surface of the second positive lens with respect to the radius of curvature of the object-side surface of the first positive lens, and is highly optical over the entire zooming range. It is a conditional expression for realizing performance.

  If the lower limit of conditional expression (7) is not reached, the negative spherical aberration that occurs on the object-side surface of the second positive lens becomes excessive and correction within the third lens group becomes difficult, thus realizing high optical performance. Can not.

  If the upper limit of conditional expression (7) is exceeded, the negative spherical aberration that occurs on the object-side surface of the first positive lens becomes excessive, making correction within the third lens group difficult and realizing high optical performance. Can not.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (7) to 0.65.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (7) to 6.50.

  In the variable magnification optical system according to this embodiment, it is desirable that the first positive lens has a biconvex shape.

  By adopting this shape, negative spherical aberration generated in the first positive lens is suppressed, and generation of decentration coma aberration, spherical aberration and the like due to manufacturing errors such as lens eccentricity and gap in the first partial lens group is prevented. Further suppression can achieve high optical performance.

  In the variable magnification optical system according to the present embodiment, it is desirable that the second positive lens has a biconvex shape.

  By adopting this shape, negative spherical aberration generated in the second positive lens is suppressed, and occurrence of decentration coma aberration and spherical aberration due to manufacturing errors such as lens eccentricity and interval deviation in the first partial lens group is prevented. Further suppression can achieve high optical performance.

  In the zoom optical system according to the present embodiment, it is desirable that the third positive lens has a biconvex shape and the negative lens has a negative meniscus shape.

  By adopting this shape, high optical performance can be realized by suppressing over-correction of negative spherical aberration and chromatic spherical aberration generated in the cemented lens having the third positive lens and the negative lens.

  Further, in the zoom optical system according to the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the distance between the first partial lens group and the second partial lens group increases, and the second partial lens group and It is desirable to reduce the distance from the third partial lens group.

  With this configuration, the principal point position of the third lens group in the third lens group can be moved so that the telephoto end state is closer to the object side than the wide-angle end state. A variable magnification optical system with high performance can be realized.

  In the variable magnification optical system according to the present embodiment, it is desirable that the third partial lens group has a positive refractive power.

  With this configuration, the principal point position of the third lens group in the third lens group can be moved so that the telephoto end state is closer to the object side than the wide-angle end state. The positive refracting power of the third lens group can be shared by the first partial lens group and the third partial lens group, and negative spherical aberration generated in the first partial lens group is suppressed to cover the entire zooming range. Suppression of spherical aberration can be suppressed and high optical performance can be realized.

  In addition, it is desirable that the variable magnification optical system according to the present embodiment has an aperture stop on the image side from the second lens group.

  With this configuration, high optical performance can be realized by suppressing an increase in the outer diameter of the third lens group and suppressing a variation in distortion during zooming from the wide-angle end state to the telephoto end state.

  In the variable power optical system according to the present embodiment, it is desirable to have an aperture stop between the second lens group and the third lens group.

  With this configuration, high optical performance can be realized by suppressing an increase in the outer diameter of the first and second lens groups and suppressing a variation in distortion during zooming from the wide-angle end state to the telephoto end state.

  In addition, the zoom optical system according to the present embodiment has an aperture stop, and the aperture stop can move integrally with the first partial lens group when zooming from the wide-angle end state to the telephoto end state. desirable.

  With this configuration, it is possible to suppress changes in off-axis rays passing through the third lens unit upon zooming from the wide-angle end state to the telephoto end state, and to suppress fluctuations in coma, field curvature, and astigmatism. Optical performance can be realized.

(Example)
Hereinafter, each example according to the present embodiment will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view showing a configuration of a variable magnification optical system according to the first example.

  As shown in FIG. 1, the variable magnification optical system according to the first example includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power in order from the object side along the optical axis. And a third lens group G3 having a positive refractive power. The third lens group G3 includes a third A lens group G3A having a positive refractive power, a third B lens group G3B having a negative refractive power, and a third C lens group G3C having a positive refractive power.

  When zooming from the wide-angle end state W to the telephoto end state T, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases. Thus, with respect to the image plane I, the first lens group G1 moves monotonously to the object side, and the second lens group G2 moves to the image side up to the first intermediate focal length state M1, and the first intermediate focal length state From M1 to the telephoto end state T, it moves to the object side. Further, the third A lens group G3A and the third B lens group are arranged such that the distance between the third A lens group G3A and the third B lens group G3B increases and the distance between the third B lens group G3B and the third C lens group G3C decreases. G3B and the third C lens group G3C move to the object side monotonously with respect to the image plane I. Further, the third A lens group G3A and the third C lens group G3C move integrally with the image plane I.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the third A lens group G3A.

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

  The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave lens L22, a biconvex lens L23, a biconcave lens L24, and a biconvex lens L25. It consists of a lens. The negative meniscus lens L21 located closest to the object side in the second lens group G2 is a composite aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The third A lens group G3A includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, a cemented lens of a biconvex lens L33, and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The third B lens group G3B includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L41 and a positive meniscus lens L42 having a convex surface facing the object side, and a negative meniscus lens L43 having a concave surface facing the object side. It is composed of The biconcave lens L41 located closest to the object side of the third B lens group G3B is a glass mold aspheric lens having an aspheric lens surface on the object side.

  The third C lens group G3C is composed of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface directed toward the object side, a biconvex lens L52, and a cemented lens of the biconcave lens L53 and the biconvex lens L54. ing. The positive meniscus lens L51 located closest to the object side in the third C lens group G3C is a glass mold aspheric lens having an aspheric lens surface on the object side. Light rays emitted from the biconvex lens L54 form an image on the image plane I.

  The image plane I is formed on an image sensor (not shown), and the image sensor is composed of a CCD, a CMOS, or the like (the same applies to the following embodiments).

  Table 1 below lists specifications of the variable magnification optical system according to the first example.

  In (surface data) in the table, the object surface is the object surface, the surface number is the lens surface number from the object side, r is the radius of curvature, d is the surface spacing, and nd is the d-line (wavelength λ = 587.6 nm). Refractive index, νd represents the Abbe number in the d-line (wavelength λ = 587.6 nm), (variable) represents the variable surface interval, (diaphragm) represents the aperture stop S, and the image surface represents the image surface I. Note that the refractive index of air nd = 1.000 000 is omitted. Further, “∞” in the radius of curvature r column indicates a plane.

In (Aspheric data), the aspheric surface is expressed by the following equation.
X (y) = (y ² / r) / [1+ [1-κ (y ² / r ² )] ^1/2 ]
+ A4 × y ⁴ + A6 × y ⁶ + A8 × y ⁸ + A10 × y ¹⁰
Here, the height in the direction perpendicular to the optical axis is y, and the amount of displacement in the optical axis direction at the height y (the distance along the optical axis from the tangential plane of each aspheric surface to each aspheric surface) is X ( y) Let r be the radius of curvature (paraxial radius of curvature) of the reference sphere, κ be the conic coefficient, and An be the n-th aspherical coefficient. “En” represents “× 10 ⁻ⁿ ”, for example “1.234E-05” represents “1.234 × 10 ⁻⁵ ”. Each aspherical surface is indicated with “*” on the right side of the surface number in (surface data).

  In (various data), the zoom ratio is the zoom ratio of the zoom optical system, W is the wide-angle end state, M1 is the first intermediate focal length state, M2 is the second intermediate focal length state, and M3 is the third intermediate focal length state. , M4 is the fourth intermediate focal length state, T is the telephoto end state, f is the focal length of the entire system, FNO is the F number, ω is the half field angle (unit: “°”), Y is the image height, and TL is infinite. The entire length of the lens system from the most object-side surface of the first lens group G1 to the image plane I in the far-focus state, Bf is the back focus, φ is the maximum aperture stop diameter, and di is the variable surface interval value at surface number i. Respectively.

  (Zoom lens group data) indicates the start surface number of each lens group and the focal length of the lens group.

  (Conditional expression corresponding value) indicates the corresponding value of each conditional expression.

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

(Table 1)

(Surface data)
Surface number rd nd νd
Object ∞ ∞
1 205.09180 2.00000 1.882997 40.76
2 67.52420 9.07190 1.456000 91.20
3 -361.42710 0.10000
4 70.10040 6.86700 1.603001 65.46
5 -2470.83790 (variable)

6 * 84.76870 0.15000 1.553890 38.09
7 73.93750 1.20000 1.834807 42.72
8 17.03670 6.46970
9 -49.48220 1.00000 1.816000 46.62
10 52.14060 0.15000
11 31.61490 5.45080 1.761820 26.56
12 -44.44820 1.19350
13 -25.13580 1.00000 1.816000 46.62
14 64.50360 2.42190 1.808090 22.79
15 -166.54310 (variable)

16 (Aperture) ∞ 1.00000
17 63.10220 3.49130 1.593190 67.87
18 -50.22150 0.10000
19 58.68260 2.72200 1.487490 70.41
20 -121.43450 0.10000
21 48.64320 4.10420 1.487490 70.41
22 -34.50080 1.00000 1.808090 22.79
23 -205.15990 (variable)

24 * -66.96860 1.00000 1.693501 53.20
25 26.57120 2.15810 1.761820 26.56
26 63.33840 4.78730
27 -24.70410 1.00000 1.729157 54.66
28 -74.86360 (variable)

29 * -569.79420 3.96090 1.589130 61.16
30 -23.53500 0.10000
31 37.14850 5.00600 1.487490 70.41
32 -45.19690 1.71640
33 -107.03630 1.00000 1.882997 40.76
34 23.36210 4.50160 1.548141 45.79
35 -637.55850 (Bf)
Image plane ∞

(Aspheric data)
6th surface κ = 1.0000
A4 = 3.61880E-06
A6 = -6.10680E-09
A8 = -4.67380E-12
A10 = 5.77660E-14
24th surface κ = 1.0000
A4 = 3.81940E-06
A6 = -1.72450E-09
A8 = 0.00000E + 00
A10 = 0.00000E + 00
29th surface κ = 1.0000
A4 = -1.63630E-05
A6 = 8.94380E-09
A8 = -2.98150E-11
A10 = 2.87630E-14

(Various data)
Zoom ratio 15.71
W M1 M2 M3 M4 T
f = 18.56080 27.61236 50.16122 104.15546 280.42469 291.57422
FNO = 3.60018 4.14587 5.56795 5.60084 5.86110 5.87404
ω = 38.95554 26.62942 15.36461 7.45367 2.81770 2.71157
Y = 14.20 14.20 14.20 14.20 14.20 14.20
TL = 163.30 170.24 188.45 255.60 252.27 252.97
Bf = 39.15242 46.48061 63.58078 70.61280 82.17689 82.77641
φ = 16.20 16.20 16.20 18.00 19.80 19.90

d5 2.14670 11.21590 21.46790 55.86030 79.96320 80.53690
d15 34.33830 24.88030 15.73730 11.46250 2.46860 2.00000
d23 3.38750 5.60850 9.43760 10.66930 11.77830 11.83690
d28 9.44940 7.22840 3.39920 2.16760 1.05860 1.00000

(Zoom lens group data)
Group Start surface Focal length 1 1 122.10406
2 6-15.86654
3 16 39.50539 (W) 38.07702 (M1)
34.51367 (M2) 33.18380 (M3)
31.94773 (M4) 31.88175 (T)
3A 16 26.56694
3B 24-24.00147
3C 29 33.81791

(Values for conditional expressions)
(1) (νd31 + νd32 + νd33) /3−νd34=46.77
(2) νd31−νd34 = 45.08
(3) νd32−νd34 = 47.62
(4) νd33−νd34 = 47.62
(5) f3A / (− f3B) = 1.107
(6) f32 / f31 = 1.710
(7) r32a / r31a = 0.930

  2A and 2B are graphs showing various aberrations of the variable magnification optical system according to the first example in the infinitely focused state, where FIG. 2A is a wide-angle end state, FIG. 2B is a first intermediate focal length state, and FIG. Indicates the second intermediate focal length state.

  FIGS. 3A and 3B are graphs showing various aberrations in the infinitely focused state of the variable magnification optical system according to the first example. FIG. 3A is a third intermediate focal length state, and FIG. 3B is a fourth intermediate focal length state. (C) shows a telephoto end state, respectively.

  In each aberration diagram, FNO represents an F number, and A represents a half angle of view (unit: “°”). Further, d represents d-line (wavelength 587.6 nm), g represents various aberrations with respect to g-line (wavelength 435.8 nm), and those not described represent various aberrations with respect to d-line. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane.

  In the following examples, the same symbols are used, and the following description is omitted.

  From each aberration diagram, it is understood that the variable magnification optical system according to the first example has various optical aberrations corrected and high optical performance.

(Second embodiment)
FIG. 4 is a cross-sectional view showing the configuration of the variable magnification optical system according to the second example.

  As shown in FIG. 4, the variable magnification optical system according to the second example includes, in order from the object side along the optical axis, a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power. And a third lens group G3 having a positive refractive power. The third lens group G3 includes a third A lens group G3A having a positive refractive power, a third B lens group G3B having a negative refractive power, and a third C lens group G3C having a positive refractive power.

  When zooming from the wide-angle end state W to the telephoto end state T, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases. Thus, with respect to the image plane I, the first lens group G1 moves monotonously to the object side, and the second lens group G2 moves to the image side up to the first intermediate focal length state M1, and the first intermediate focal length state From M1 to the telephoto end state T, it moves to the object side. Further, the third A lens group G3A and the third B lens group are arranged such that the distance between the third A lens group G3A and the third B lens group G3B increases and the distance between the third B lens group G3B and the third C lens group G3C decreases. G3B and the third C lens group G3C move to the object side monotonously with respect to the image plane I. Further, the third A lens group G3A and the third C lens group G3C move integrally with the image plane I.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the third A lens group G3A.

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

  The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave lens L22, a biconvex lens L23, a biconcave lens L24, and a biconvex lens L25. It consists of a lens. The negative meniscus lens L21 located closest to the object side in the second lens group G2 is a composite aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The third A lens group G3A includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, a cemented lens of a biconvex lens L33, and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The third B lens group G3B includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L41 and a positive meniscus lens L42 having a convex surface facing the object side, and a negative meniscus lens L43 having a concave surface facing the object side. It is composed of The biconcave lens L41 located closest to the object side of the third B lens group G3B is a composite aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The third C lens group G3C is composed of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface directed toward the object side, a biconvex lens L52, and a cemented lens of the biconcave lens L53 and the biconvex lens L54. ing. The positive meniscus lens L51 located closest to the object side in the third C lens group G3C is a glass mold aspheric lens having an aspheric lens surface on the object side. Light rays emitted from the biconvex lens L54 form an image on the image plane I.

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

(Table 2)

(Surface data)
Surface number rd nd νd
Object ∞ ∞
1 186.59960 2.20000 1.834000 37.17
2 69.08900 8.80000 1.497820 82.56
3 -494.44545 0.10000
4 73.40222 6.45000 1.593190 67.87
5 2016.71160 (variable)

6 * 84.85000 0.10000 1.553890 38.09
7 74.02192 1.20000 1.834810 42.72
8 17.09747 6.95000
9 -37.97970 1.00000 1.816000 46.63
10 77.67127 0.15000
11 36.26557 5.30000 1.784720 25.68
12 -36.26557 0.80000
13 -25.69642 1.00000 1.816000 46.63
14 66.08300 2.05000 1.808090 22.79
15 -666.70366 (variable)

16 (Aperture) ∞ 1.00000
17 68.30727 3.40000 1.593190 67.87
18 -47.99596 0.10000
19 68.52367 2.45000 1.487490 70.45
20 -136.98392 0.10000
21 46.52671 4.20000 1.487490 70.45
22 -36.16400 1.00000 1.808090 22.79
23 -202.95328 (variable)

24 * -55.09840 0.20000 1.553890 38.09
25 -57.24715 0.90000 1.696800 55.52
26 28.15100 2.15000 1.728250 28.46
27 87.70856 4.35000
28 -26.69877 1.00000 1.729160 54.66
29 -76.47707 (variable)

30 * -333.89500 4.65000 1.589130 61.18
31 -24.64395 0.10000
32 31.19625 5.85000 1.487490 70.45
33 -43.38887 1.45000
34 -109.71645 1.00000 1.883000 40.77
35 20.29920 5.30000 1.548140 45.79
36 -808.81321 (Bf)
Image plane ∞

(Aspheric data)
6th surface κ = 1.0000
A4 = 3.13350E-06
A6 = 4.73080E-10
A8 = -3.40500E-11
A10 = 1.16620E-13
24th surface κ = 1.0000
A4 = 5.24030E-06
A6 = -2.00730E-09
A8 = 0.00000E + 00
A10 = 0.00000E + 00
30th surface κ = 1.0000
A4 = -1.54020E-05
A6 = 1.69500E-09
A8 = 1.34490E-11
A10 = -2.07220E-13

(Various data)
Zoom ratio 15.72
W M1 M2 M3 M4 T
f = 18.52363 27.14081 48.93259 104.52143 279.97293 291.21725
FNO = 3.60558 4.11071 5.47222 5.69344 5.89216 5.89616
ω = 38.89095 26.92688 15.68138 7.41882 2.81880 2.71146
Y = 14.20 14.20 14.20 14.20 14.20 14.20
TL = 164.74 171.75 188.90 225.49 250.78 251.39
Bf = 39.44250 46.21988 62.15925 71.57530 82.59962 83.10134
φ = 15.80 15.80 15.80 17.50 19.50 19.60

d5 2.15700 11.18630 21.31960 53.25650 76.35561 76.94960
d15 33.80140 24.99560 16.07940 11.31350 2.48461 2.00000
d23 3.45650 5.73730 9.97480 11.60170 12.99717 13.04330
d29 10.58680 8.30600 4.06850 2.44160 1.04613 1.00000

(Zoom lens group data)
Group Start surface Focal length 1 1 118.96910
2 6-15.5622
3 16 40.88868 (W) 38.97852 (M1)
35.53907 (M2) 33.90635 (M3)
32.43302 (M4) 32.38356 (T)
3A 16 27.17463
3B 24-25.41506
3C 30 34.39022

(Values for conditional expressions)
(1) (νd31 + νd32 + νd33) /3−νd34=46.80
(2) νd31−νd34 = 45.08
(3) νd32−νd34 = 47.66
(4) νd33−νd34 = 47.66
(5) f3A / (-f3B) = 1.069
(6) f32 / f31 = 1.958
(7) r32a / r31a = 1.003

  FIG. 5 shows various aberration diagrams of the zoom optical system according to the second example in the infinite focus state, where (a) is a wide-angle end state, (b) is a first intermediate focal length state, and (c). Indicates the second intermediate focal length state.

  FIG. 6 shows various aberration diagrams of the zoom optical system according to the second example in an infinitely focused state, where (a) is a third intermediate focal length state, (b) is a fourth intermediate focal length state, (C) shows a telephoto end state, respectively.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the second example has various optical aberrations corrected and high optical performance.

(Third embodiment)
FIG. 7 is a cross-sectional view showing the configuration of the variable magnification optical system according to the third example.

  As shown in FIG. 7, the variable magnification optical system according to the third example includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power in order from the object side along the optical axis. And a third lens group G3 having a positive refractive power. The third lens group G3 includes a third A lens group G3A having a positive refractive power, a third B lens group G3B having a negative refractive power, and a third C lens group G3C having a positive refractive power.

  When zooming from the wide-angle end state W to the telephoto end state T, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases. Thus, with respect to the image plane I, the first lens group G1 moves monotonously to the object side, and the second lens group G2 moves to the image side up to the first intermediate focal length state M1, and the first intermediate focal length state From M1 to the telephoto end state T, it moves to the object side. Further, the third A lens group G3A and the third B lens group are arranged such that the distance between the third A lens group G3A and the third B lens group G3B increases and the distance between the third B lens group G3B and the third C lens group G3C decreases. G3B and the third C lens group G3C move to the object side monotonously with respect to the image plane I. Further, the third A lens group G3A and the third C lens group G3C move integrally with the image plane I.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the third A lens group G3A.

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

  The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave lens L22, a biconvex lens L23, a biconcave lens L24, and a biconvex lens L25. It consists of a lens. The negative meniscus lens L21 located closest to the object side in the second lens group G2 is a composite aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The third A lens group G3A includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, a cemented lens of a biconvex lens L33, and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The third B lens group G3B includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L41 and a positive meniscus lens L42 having a convex surface facing the object side, and a negative meniscus lens L43 having a concave surface facing the object side. It is composed of The positive meniscus lens L42 located at the center of the third B lens group G3B is a glass mold aspheric lens having an aspheric lens surface on the image side.

  The third C lens group G3C is composed of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface directed toward the object side, a biconvex lens L52, and a cemented lens of the biconcave lens L53 and the biconvex lens L54. ing. The positive meniscus lens L51 located closest to the object side in the third C lens group G3C is a glass mold aspheric lens having an aspheric lens surface on the object side. Light rays emitted from the biconvex lens L54 form an image on the image plane I.

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

(Table 3)

(Surface data)
Surface number rd nd νd
Object ∞ ∞
1 192.86460 2.20000 1.834000 37.16
2 71.04740 9.00410 1.497820 82.52
3 -459.57820 0.10000
4 73.87410 6.67930 1.593190 67.87
5 1334.48060 (variable)

6 * 84.76870 0.10000 1.553890 38.09
7 73.93750 1.25000 1.834807 42.72
8 16.85860 6.41100
9 -43.47510 1.00000 1.816000 46.62
10 57.52320 0.15000
11 33.20000 5.23710 1.784723 25.68
12 -42.33520 1.08530
13 -25.03850 1.00000 1.816000 46.62
14 74.32200 2.14790 1.808090 22.79
15 -196.76990 (variable)

16 (Aperture) ∞ 1.00000
17 70.66380 3.23230 1.593190 67.87
18 -52.37330 0.10000
19 73.76600 2.71810 1.487490 70.41
20 -83.31450 0.10000
21 45.54460 4.17150 1.487490 70.41
22 -35.11250 1.00000 1.808090 22.79
23 -188.15270 (variable)

24 -63.85980 1.00000 1.696797 55.52
25 31.67440 1.86210 1.804855 24.73
26 * 64.32250 4.66290
27 -26.08000 1.00000 1.729157 54.66
28 -73.30510 (variable)

29 * -227.36510 4.17540 1.589130 61.16
30 -24.31080 0.10000
31 31.50890 5.72340 1.487490 70.41
32 -46.90920 1.38940
33 -141.28220 1.00000 1.882997 40.76
34 20.03510 5.37700 1.548141 45.79
35 -602.91670 (Bf)
Image plane ∞

(Aspheric data)
6th surface κ = 1.0000
A4 = 3.84520E-06
A6 = -3.19400E-09
A8 = -2.44510E-11
A10 = 1.16080E-13
26th surface κ = 1.0000
A4 = -3.46580E-06
A6 = 6.73460E-10
A8 = 0.00000E + 00
A10 = 0.00000E + 00
29th surface κ = 1.0000
A4 = -1.44010E-05
A6 = 5.94450E-09
A8 = -3.11020E-11
A10 = -4.07130E-14

(Various data)
Zoom ratio 15.72
W M1 M2 M3 M4 T
f = 18.53645 27.58219 49.59390 104.29638 280.11936 291.48464
FNO = 3.48547 4.01900 5.38724 5.99810 6.59072 6.59436
ω = 39.03040 26.66707 15.52780 7.42798 2.81545 2.70726
Y = 14.20 14.20 14.20 14.20 14.20 14.20
TL = 163.55 170.26 187.72 224.86 250.69 251.38
Bf = 39.23508 46.33384 63.02959 70.07809 81.49952 82.08045
φ = 16.40 16.40 16.40 16.40 17.20 17.30

d5 2.13850 10.94060 20.49340 54.83910 78.05500 78.64320
d15 33.51210 24.32490 15.53470 11.28210 2.48000 2.00000
d23 3.41920 5.91090 10.06530 11.33700 12.63700 12.68280
d28 10.26360 7.77190 3.61750 2.34580 1.04580 1.00000

(Zoom lens group data)
Group Start surface Focal length 1 1 120.82876
2 6-15.55570
3 16 39.66938 (W) 38.28864 (M1)
34.69117 (M2) 33.38573 (M3)
32.00045 (M4) 31.95102 (T)
3A 16 26.728858
3B 24-25.10440
3C 29 34.49933

(Values for conditional expressions)
(1) (νd31 + νd32 + νd33) /3−νd34=46.77
(2) νd31−νd34 = 45.08
(3) νd32−νd34 = 47.62
(4) νd33−νd34 = 47.62
(5) f3A / (− f3B) = 1.065
(6) f32 / f31 = 1.576
(7) r32a / r31a = 1.04

  FIG. 8 shows various aberration diagrams of the zoom optical system according to the third example in the infinitely focused state, where (a) is a wide-angle end state, (b) is a first intermediate focal length state, and (c). Indicates the second intermediate focal length state.

  FIG. 9 shows various aberration diagrams of the zoom optical system according to the third example in the infinitely focused state, where (a) is a third intermediate focal length state, (b) is a fourth intermediate focal length state, (C) shows a telephoto end state, respectively.

  From each aberration diagram, it can be seen that the variable magnification optical system according to the third example has various optical aberrations corrected and high optical performance.

(Fourth embodiment)
FIG. 10 is a cross-sectional view showing the configuration of the variable magnification optical system according to the fourth example.

  As shown in FIG. 10, the zoom optical system according to the fourth example includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power in order from the object side along the optical axis. And a third lens group G3 having a positive refractive power. The third lens group G3 includes a third A lens group G3A having a positive refractive power, a third B lens group G3B having a negative refractive power, and a third C lens group G3C having a positive refractive power.

  When zooming from the wide-angle end state W to the telephoto end state T, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases. Thus, with respect to the image plane I, the first lens group G1 moves monotonously to the object side, and the second lens group G2 moves to the image side up to the first intermediate focal length state M1, and the first intermediate focal length state From M1 to the telephoto end state T, it moves to the object side. Further, the third A lens group G3A and the third B lens group are arranged such that the distance between the third A lens group G3A and the third B lens group G3B increases and the distance between the third B lens group G3B and the third C lens group G3C decreases. G3B and the third C lens group G3C move to the object side monotonously with respect to the image plane I. Further, the third A lens group G3A and the third C lens group G3C move integrally with the image plane I.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the third A lens group G3A.

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

  The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave lens L22, a biconvex lens L23, a biconcave lens L24, and a biconvex lens L25. It consists of a lens. The negative meniscus lens L21 located closest to the object side in the second lens group G2 is a composite aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The third A lens group G3A includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, a cemented lens of a biconvex lens L33, and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The third B lens group G3B includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L41 and a positive meniscus lens L42 having a convex surface facing the object side, and a negative meniscus lens L43 having a concave surface facing the object side. It is composed of The biconcave lens L41 located closest to the object side of the third B lens group G3B is a glass mold aspheric lens having an aspheric lens surface on the object side.

  The third C lens group G3C is composed of, in order from the object side along the optical axis, a positive meniscus lens L51 having a concave surface directed toward the object side, a biconvex lens L52, and a cemented lens of the biconcave lens L53 and the biconvex lens L54. ing. The positive meniscus lens L51 located closest to the object side in the third C lens group G3C is a glass mold aspheric lens having an aspheric lens surface on the object side. Light rays emitted from the biconvex lens L54 form an image on the image plane I.

  Table 4 below lists various values of the variable magnification optical system according to the fourth example.

(Table 4)

(Surface data)
Surface number rd nd νd
Object ∞ ∞
1 185.24410 2.20000 1.834000 37.16
2 68.75480 8.80000 1.497820 82.52
3 -497.29190 0.10000
4 71.28350 6.45000 1.593190 67.87
5 1172.32230 (variable)

6 * 84.76870 0.10000 1.553890 38.09
7 73.93750 1.20000 1.834807 42.72
8 16.75000 6.90150
9 -39.27190 1.00000 1.816000 46.62
10 66.81930 0.15000
11 34.96200 5.30000 1.784723 25.68
12 -38.10160 0.85100
13 -25.92810 1.00000 1.816000 46.62
14 73.51020 2.05000 1.808090 22.79
15 -287.76490 (variable)

16 (Aperture) ∞ 1.00000
17 67.56430 3.40000 1.593190 67.87
18 -48.87440 0.10000
19 67.50290 2.45000 1.487490 70.41
20 -148.37490 0.10000
21 48.80470 4.10000 1.487490 70.41
22 -34.96390 1.00000 1.808090 22.79
23 -151.08370 (variable)

24 * -60.11270 1.00000 1.693500 53.31
25 28.34580 2.15000 1.728250 28.46
26 78.30380 4.62360
27 -25.31330 1.00000 1.729157 54.66
28 -74.02640 (variable)

29 * -258.20790 4.30000 1.589130 61.18
30 -24.20710 0.10000
31 31.58110 5.85000 1.487490 70.41
32 -43.77790 1.99120
33 -117.57770 1.00000 1.882997 40.76
34 20.29060 5.20000 1.548141 45.79
35 -725.37280 (Bf)
Image plane ∞

(Aspheric data)
6th surface κ = 1.0000
A4 = 3.04550E-06
A6 = -3.32430E-09
A8 = -1.97490E-11
A10 = 7.65670E-14
24th surface κ = 1.0000
A4 = 3.99640E-06
A6 = -1.46410E-09
A8 = 0.00000E + 00
A10 = 0.00000E + 00
29th surface κ = 1.0000
A4 = -1.52760E-05
A6 = 3.24870E-09
A8 = -4.79200E-12
A10 = -1.47520E-13

(Various data)
Zoom ratio 15.72
W M1 M2 M3 M4 T
f = 18.53407 28.28311 49.61061 104.44333 280.42014 291.31408
FNO = 4.19822 4.84518 5.60962 5.63139 5.64795 5.65065
ω = 39.09871 25.91447 15.52706 7.44054 2.81841 2.71459
Y = 14.20 14.20 14.20 14.20 14.20 14.20
TL = 163.83 172.73 188.63 224.05 249.11 249.82
Bf = 39.11654 46.29035 62.64242 69.74259 81.54926 82.19687
φ = 13.60 13.60 15.70 17.60 20.35 20.50

d5 2.15320 13.04850 21.16970 53.87340 76.26610 76.78310
d15 33.72460 24.55710 15.98250 11.59370 2.46300 2.00000
d23 3.38090 5.75490 9.65610 11.06770 12.30820 12.36930
d28 9.98840 7.61440 3.71320 2.30160 1.06110 1.00000

(Zoom lens group data)
Group Start surface Focal length 1 1 118.41983
2 6-15.62139
3 16 39.52889 (W) 38.28789 (M1)
35.01838 (M2) 33.58746 (M3)
32.26976 (M4) 32.0385 (T)
3A 16 27.10600
3B 24-244.65991
3C 29 335.6757

(Values for conditional expressions)
(1) (νd31 + νd32 + νd33) /3−νd34=46.77
(2) νd31−νd34 = 45.08
(3) νd32−νd34 = 47.62
(4) νd33−νd34 = 47.62
(5) f3A / (− f3B) = 1.0099
(6) f32 / f31 = 1.976
(7) r32a / r31a = 0.999

  FIG. 11 shows various aberration diagrams of the zoom optical system according to the fourth example in the infinitely focused state, where (a) is the wide-angle end state, (b) is the first intermediate focal length state, and (c). Indicates the second intermediate focal length state.

  FIG. 12 shows various aberration diagrams of the zoom optical system according to the fourth example in the infinitely focused state, where (a) is a third intermediate focal length state, (b) is a fourth intermediate focal length state, (C) shows a telephoto end state, respectively.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the fourth example has various aberrations corrected well and high optical performance.

(5th Example)
FIG. 13 is a cross-sectional view showing the configuration of the variable magnification optical system according to the fifth example.

  As shown in FIG. 13, the variable magnification optical system according to the fifth example includes a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power in order from the object side along the optical axis. And a third lens group G3 having a positive refractive power. The third lens group G3 includes a third A lens group G3A having a positive refractive power, a third B lens group G3B having a negative refractive power, and a third C lens group G3C having a positive refractive power.

  When zooming from the wide-angle end state W to the telephoto end state T, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases. Thus, with respect to the image plane I, the first lens group G1 moves monotonously to the object side, and the second lens group G2 moves to the image side up to the first intermediate focal length state M1, and the first intermediate focal length state From M1 to the telephoto end state T, it moves to the object side. Further, the third A lens group G3A and the third B lens group are arranged such that the distance between the third A lens group G3A and the third B lens group G3B increases and the distance between the third B lens group G3B and the third C lens group G3C decreases. G3B and the third C lens group G3C move to the object side monotonously with respect to the image plane I.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the third A lens group G3A.

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

  The second lens group G2 includes, in order from the object side along the optical axis, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave lens L22, a biconvex lens L23, a biconcave lens L24, and a biconvex lens L25. It consists of a lens. The negative meniscus lens L21 located closest to the object side in the second lens group G2 is a composite aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The third A lens group G3A includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, a cemented lens of a biconvex lens L33, and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The third B lens group G3B includes, in order from the object side along the optical axis, a cemented lens of a biconcave lens L41 and a positive meniscus lens L42 having a convex surface facing the object side, and a negative meniscus lens L43 having a concave surface facing the object side. It is composed of The biconcave lens L41 located closest to the object side of the third B lens group G3B is a composite aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The third C lens group G3C includes, in order from the object side along the optical axis, a biconvex lens L51, a biconvex lens L52, and a cemented lens of a biconcave lens L53 and a biconvex lens L54. The biconvex lens L51 located closest to the object side in the third C lens group G3C is a glass mold aspheric lens having an aspheric lens surface on the object side. Light rays emitted from the biconvex lens L54 form an image on the image plane I.

  Table 5 below provides specification values of the variable magnification optical system according to the fifth example.

(Table 5)

(Surface data)
Surface number rd nd νd
Object ∞ ∞
1 175.60560 2.20000 1.834000 37.16
2 67.43020 8.80000 1.497820 82.52
3 -587.78480 0.10000
4 72.27100 6.45000 1.593190 67.87
5 1826.13880 (variable)

6 * 84.76870 0.10000 1.553890 38.09
7 73.93750 1.20000 1.834807 42.72
8 17.18730 6.95000
9 -36.98220 1.00000 1.816000 46.62
10 77.92630 0.15000
11 36.63460 5.30000 1.784723 25.68
12 -36.63460 0.80000
13 -26.19910 1.00000 1.816000 46.62
14 63.73960 2.05000 1.808090 22.79
15 -643.27060 (variable)

16 (Aperture) ∞ 1.00000
17 65.83650 3.40000 1.593190 67.87
18 -50.15460 0.10000
19 65.68170 2.45000 1.487490 70.41
20 -154.97430 0.10000
21 46.73330 4.20000 1.487490 70.41
22 -35.78330 1.00000 1.808090 22.79
23 -191.93180 (variable)

24 * -57.29660 0.20000 1.553890 38.09
25 -59.72500 0.90000 1.696797 55.52
26 28.51000 2.15000 1.728250 28.46
27 91.99760 4.14020
28 -32.89540 1.00000 1.729157 54.66
29 -144.33150 (variable)

30 * 6427.19190 4.65000 1.589130 61.18
31 -27.38180 0.10000
32 31.47760 5.85000 1.487490 70.41
33 -43.75390 1.45000
34 -113.58970 1.00000 1.882997 40.76
35 20.34810 5.30000 1.548141 45.79
36 -709.14530 (Bf)
Image plane ∞

(Aspheric data)
6th surface κ = 1.0000
A4 = 2.88220E-06
A6 = -2.29350E-11
A8 = -2.35280E-11
A10 = 9.21570E-14
24th surface κ = 1.0000
A4 = 4.32780E-06
A6 = 1.88460E-09
A8 = 0.00000E + 00
A10 = 0.00000E + 00
30th surface κ = 1.0000
A4 = -1.36170E-05
A6 = -3.55860E-10
A8 = 1.83080E-11
A10 = -1.86790E-13

(Various data)
Zoom ratio 15.70
W M1 M2 M3 M4 T
f = 18.56060 27.94799 48.95245 104.65150 280.18763 291.42454
FNO = 3.57565 4.13253 5.36204 5.62482 5.80434 5.81064
ω = 38.80191 26.18802 15.68652 7.44205 2.82863 2.72113
Y = 14.20 14.20 14.20 14.20 14.20 14.20
TL = 164.76 171.03 189.45 225.29 249.99 250.61
Bf = 38.84705 44.06807 62.50183 73.57929 86.00428 86.64770
φ = 15.80 15.80 15.80 17.50 19.50 19.60

d5 2.15700 11.13190 22.22690 53.01000 75.67850 76.25220
d15 33.36360 23.94380 15.96870 11.30360 2.48130 2.00000
d23 3.46820 7.42730 8.95240 9.64300 9.67390 9.62460
d29 11.83830 9.36420 4.70680 2.66290 1.06600 1.00000

(Zoom lens group data)
Group Start surface Focal length 1 1 117.7729
2 6 -15.60945
3 16 40.44771 (W) 39.66103 (M1)
35.67164 (M2) 33.95695 (M3)
32.73988 (M4) 32.70088 (T)
3A 16 27.35473
3B 24-26.50041
3C 30 35.423

(Values for conditional expressions)
(1) (νd31 + νd32 + νd33) /3−νd34=46.77
(2) νd31−νd34 = 45.08
(3) νd32−νd34 = 47.62
(4) νd33−νd34 = 47.62
(5) f3A / (− f3B) = 1.032
(6) f32 / f31 = 1.957
(7) r32a / r31a = 0.998

  FIGS. 14A and 14B are graphs showing various aberrations of the variable magnification optical system according to Example 5 in the infinite focus state, where FIG. 14A is a wide-angle end state, FIG. 14B is a first intermediate focal length state, and FIG. Indicates the second intermediate focal length state.

  FIG. 15 shows various aberration diagrams of the zoom optical system according to Example 5 in the infinitely focused state, where (a) is the third intermediate focal length state, (b) is the fourth intermediate focal length state, (C) shows a telephoto end state, respectively.

  From each aberration diagram, it can be seen that the variable magnification optical system according to the fifth example has various optical aberrations corrected and high optical performance.

  As described above, according to the present embodiment, it is possible to provide a variable magnification optical system that suppresses aberration fluctuation and has high optical performance.

  Next, a camera equipped with the variable magnification optical system according to the present embodiment will be described. Although the case where the variable magnification optical system according to the first example is mounted will be described, the same applies to other examples.

  FIG. 16 is a diagram illustrating a configuration of a camera including the variable magnification optical system according to the first example.

  In FIG. 16, a camera 1 is a digital single-lens reflex camera provided with a variable magnification optical system according to the first example as a photographing lens 2. In the camera 1, light from an object (subject) (not shown) is collected by the taking lens 2 and is focused on the focusing screen 4 via the quick return mirror 3. The light imaged on the focusing screen 4 is reflected in the pentaprism 5 a plurality of times and guided to the eyepiece lens 6. Thus, the photographer can observe the subject image as an erect image through the eyepiece 6.

  When the release button (not shown) is pressed by the photographer, the quick return mirror 3 is retracted out of the optical path, and light from the subject (not shown) reaches the image sensor 7. As a result, light from the subject is picked up by the image sensor 7 and recorded as a subject image in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1.

  By mounting the zoom optical system according to the first example as the photographing lens 2 on the camera 1, a camera having high performance can be realized.

  The outline of the manufacturing method of the variable magnification optical system of the present application will be described below.

  FIG. 17 is a diagram showing a manufacturing method of the variable magnification optical system of the present application.

  The variable magnification optical system manufacturing method 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 third lens group having a positive refractive power. Is a method for manufacturing a variable magnification optical system including the steps S1, S2 and S3 shown in FIG.

  Step S1: When changing the magnification of the first lens group, the second lens group, and the third lens group from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group can be increased. The distance between the second lens group and the third lens group is arranged so as to be reduced.

  Step S2: In order from the object side along the optical axis, the first partial lens group with positive refractive power, the second partial lens group with negative refractive power, and the third partial lens group are changed from the wide-angle end state to the telephoto end state. In zooming, the distance between the first partial lens group and the second partial lens group can be changed, and the distance between the second partial lens group and the third partial lens group can be changed.

  Step S3: In order from the object side along the optical axis, the first positive lens, the second positive lens, and the cemented lens are arranged in the first partial lens group, and the third positive lens and the negative lens are used as the cemented lens. include.

  According to the manufacturing method of the variable magnification optical system of the present application, it is possible to manufacture a variable magnification optical system that suppresses aberration fluctuation and has high optical performance.

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

  Although the five-group configuration is shown in the embodiment, the present invention can be applied to other group configurations such as a six-group configuration. Further, a configuration in which a lens or a lens group is added to the most object side, 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.

  A single lens group, a plurality of lens groups, or a partial lens group may be moved in the optical axis direction to be a focusing lens group that performs focusing from an object at infinity to a near object. The focusing lens group can be applied to autofocus, and is also suitable for driving a motor for autofocus (using an ultrasonic motor or the like). In particular, it is preferable that at least a part of the second lens group is a focusing lens group.

  In addition, the lens group or the partial lens group is moved so as to have a component in a direction perpendicular to the optical axis, or is rotated (swayed) in the in-plane direction including the optical axis to reduce image blur caused by camera shake. A vibration-proof lens group to be corrected may be used. In particular, it is preferable that at least a part of the 3B lens group is an anti-vibration lens group.

  Further, the lens surface may be formed as a spherical surface, a flat surface, or an aspheric surface.

  When the lens surface is a spherical surface or a flat surface, lens processing and assembly adjustment are facilitated, and optical performance deterioration due to processing and assembly adjustment errors 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 an aspheric surface, the aspheric surface is an aspheric surface by grinding, a glass mold aspheric surface made of glass with an aspheric shape, or a composite aspheric surface made of resin with an aspheric shape on the glass surface. Any 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.

  Further, each lens surface may be provided with an antireflection film having a high transmittance in a wide wavelength region in order to reduce flare and ghost and achieve high optical performance with high contrast.

  The variable magnification optical system of the present embodiment has a variable magnification ratio of about 7 to 25.

  In the variable magnification optical system of the present embodiment, it is preferable that the first lens group has two positive lens components. In the first lens group, it is preferable that lens components are arranged in order of positive and negative in order from the object side with an air gap interposed therebetween.

  In the variable power optical system of the present embodiment, it is preferable that the second lens group has one positive lens component and three negative lens components. In the second lens group, it is preferable that the lens components are arranged in order of negative, positive and negative in order from the object side with an air gap interposed therebetween.

  In the variable magnification optical system of the present embodiment, it is preferable that the 3A lens group has three positive lens components.

  In the zoom optical system according to the present embodiment, it is preferable that the third lens group B has two negative lens components.

  In the variable power optical system of the present embodiment, it is preferable that the third C lens group has two positive lens components. In the third C lens group, it is preferable that lens components are arranged in order of positive and negative in order from the object side with an air gap interposed therebetween.

  In addition, in order to explain the present invention in an easy-to-understand manner, the configuration requirements of the embodiment have been described, but the present invention is not limited to this.

G1 1st lens group G2 2nd lens group G3 3rd lens group G3A 3A lens group G3B 3B lens group G3C 3C lens group S Aperture stop I Image plane 1 Camera

Claims (22)

In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, Consists of substantially 5 lens groups with the 3C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third A lens group decreases, The interval between the 3A lens group and the 3B lens group changes, the interval between the 3B lens group and the 3C lens group changes,
The third A lens group includes, in order from the object side along the optical axis, a first positive lens, a second positive lens, and a cemented lens.
The cemented lens has a third positive lens and a negative lens,
A zoom optical system characterized by satisfying the following conditional expression:
0.90 <f3A / (− f3B) <1.30
νd31−νd34> 35.0
0.50 <r32a / r31a <10.00
However,
f3A: focal length of the third A lens group f3B: focal length of the third B lens group
νd31: Abbe number of the d-line of the first positive lens
νd34: Abbe number of d-line of the negative lens
r31a: radius of curvature of the object-side surface of the first positive lens
r32a: radius of curvature of the object-side surface of the second positive lens In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, Consists of substantially 5 lens groups with the 3C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third A lens group decreases, The interval between the 3A lens group and the 3B lens group changes, the interval between the 3B lens group and the 3C lens group changes,
The third A lens group includes, in order from the object side along the optical axis, a first positive lens, a second positive lens, and a cemented lens.
The cemented lens has a third positive lens and a negative lens,
A zoom optical system characterized by satisfying the following conditional expression:
(Νd31 + νd32 + νd33) / 3−νd34> 35.0
0.90 <f3A / (− f3B) <1.30
0.50 <r32a / r31a <10.00
However,
νd31: d-line Abbe number of the first positive lens νd32: d-line Abbe number of the second positive lens νd33: d-line Abbe number of the third positive lens νd34: d-line Abbe number of the negative lens f3A: focal length of the third A lens group f3B: focal length of the third B lens group
r31a: radius of curvature of the object-side surface of the first positive lens
r32a: radius of curvature of the object-side surface of the second positive lens In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, Consists of substantially 5 lens groups with the 3C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third A lens group decreases, The interval between the 3A lens group and the 3B lens group changes, the interval between the 3B lens group and the 3C lens group changes,
The third A lens group includes a first positive lens, a second positive lens, and a cemented lens in order from the object side along the optical axis.
The cemented lens has a third positive lens and a negative lens,
The third positive lens has a biconvex shape, and the negative lens has a negative meniscus shape;
A zoom optical system characterized by satisfying the following conditional expression:
νd33−νd34> 35.0
0.90 <f3A / (− f3B) <1.30
0.50 <r32a / r31a <10.00
However,
νd33: d-line Abbe number of the third positive lens νd34: d-line Abbe number of the negative lens
f3A: focal length of the third A lens group
f3B: focal length of the third B lens group
r31a: radius of curvature of the object-side surface of the first positive lens
r32a: radius of curvature of the object-side surface of the second positive lens In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, Consists of substantially 5 lens groups with the 3C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refractive power,
Upon zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third A lens group decreases, The interval between the 3A lens group and the 3B lens group changes, the interval between the 3B lens group and the 3C lens group changes,
The third A lens group includes, in order from the object side along the optical axis, a first positive lens, a second positive lens, and a cemented lens.
The cemented lens has a third positive lens and a negative lens,
A zoom optical system characterized by satisfying the following conditional expression:
40.0 <νd32−νd34 <65.0
40.0 <νd33−νd34
νd31−νd34> 35.0
However,
νd32: Abbe number of d-line of the second positive lens νd33: Abbe number of d-line of the third positive lens νd34: Abbe number of d-line of the negative lens
νd31: Abbe number of the d-line of the first positive lens
νd34: Abbe number of d-line of the negative lens The zoom lens system according to claim 4 , wherein the following conditional expression is satisfied.
(Νd31 + νd32 + νd33) / 3−νd34> 35.0
However,
νd31: d-line Abbe number of the first positive lens νd32: d-line Abbe number of the second positive lens νd33: d-line Abbe number of the third positive lens νd34: d-line Abbe number of the negative lens 4. The variable magnification optical system according to claim 1, wherein the following conditional expression is satisfied: 5.
νd32−νd34> 35.0
However,
νd32: Abbe number of d-line of the second positive lens νd34: Abbe number of d-line of the negative lens The zoom lens system according to claim 1 or 2, wherein the following conditional expression is satisfied.
νd33−νd34> 35.0
However,
νd33: Abbe number of d-line of the third positive lens νd34: Abbe number of d-line of the negative lens The zoom lens system according to claim 4 , wherein the following conditional expression is satisfied.
0.80 <f3A / (− f3B) <1.30
However,
f3A: focal length of the third A lens group f3B: focal length of the third B lens group   3. The variable magnification optical system according to claim 1, wherein the third positive lens has a biconvex shape, and the negative lens has a negative meniscus shape. The variable magnification optical system according to claim 2 , wherein the following conditional expression is satisfied.
νd31−νd34> 35.0
However,
νd31: d-line Abbe number of the first positive lens νd34: d-line Abbe number of the negative lens The zoom lens system according to claim 4 , wherein the following conditional expression is satisfied.
0.50 <r32a / r31a <10.00
However,
r31a: radius of curvature of the object side surface of the first positive lens r32a: radius of curvature of the object side surface of the second positive lens The variable magnification optical system according to any one of claims 1 to 11 , wherein the cemented lens includes the third positive lens and the negative lens in order from the object side along the optical axis. The zoom lens system according to any one of claims 1 to 12 , wherein the following conditional expression is satisfied.
0.50 <f32 / f31 <10.00
However,
f31: focal length of the first positive lens f32: focal length of the second positive lens   The variable magnification optical system according to claim 1, wherein the first positive lens has a biconvex shape.   The variable power optical system according to claim 1, wherein the second positive lens has a biconvex shape.   In zooming from the wide-angle end state to the telephoto end state, the distance between the third A lens group and the third B lens group increases, and the distance between the third B lens group and the third C lens group decreases. 16. The variable magnification optical system according to claim 1, wherein the variable magnification optical system is characterized in that:   The variable power optical system according to any one of claims 1 to 16, wherein the third C lens group has a positive refractive power.   18. The variable magnification optical system according to claim 1, further comprising an aperture stop closer to the image side than the second lens group.   The variable magnification optical system according to any one of claims 1 to 18, further comprising an aperture stop between the second lens group and the third A lens group. Having an aperture stop,
The zooming according to any one of claims 1 to 19, wherein the aperture stop moves integrally with the third A lens group when zooming from the wide-angle end state to the telephoto end state. Optical system.   21. An optical apparatus comprising the variable magnification optical system according to claim 1. In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a 3A lens group having a positive refractive power, and a third B lens group having a negative refractive power, A method of manufacturing a variable magnification optical system substantially consisting of five lens groups with a third C lens group,
The 3A lens group, the 3B lens group, and the 3C lens group as a whole have positive refracting power,
When the first lens group, the second lens group, the 3A lens group, the 3B lens group, and the 3C lens group are changed from the wide-angle end state to the telephoto end state, the first lens group The distance between the second lens group and the second lens group can be increased, the distance between the second lens group and the third A lens group can be decreased, and the distance between the third A lens group and the third B lens group can be changed, An interval between the third B lens group and the third C lens group is arranged to be variable,
In order from the object side along the optical axis, the first positive lens, the second positive lens, and the cemented lens are disposed in the third A lens group, and the third positive lens and the negative lens are included in the cemented lens.
A method for manufacturing a variable magnification optical system, characterized in that the third A lens group and the third B lens group satisfy the following conditional expression:
0.90 <f3A / (− f3B) <1.30
νd31−νd34> 35.0
0.50 <r32a / r31a <10.00
However,
f3A: focal length of the third A lens group f3B: focal length of the third B lens group
νd31: Abbe number of the d-line of the first positive lens
νd34: Abbe number of d-line of the negative lens
r31a: radius of curvature of the object-side surface of the first positive lens
r32a: radius of curvature of the object-side surface of the second positive lens

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