JP2014085495A - Variable magnification optical system, optical device, and manufacturing method for variable magnification optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact variable magnification optical system and an optical device which exhibit superior optical performances, and to provide a manufacturing method for the variable magnification optical system.SOLUTION: A variable magnification optical system: comprises a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power in this order from the object side, where the first lens group G1 includes at least one lens having a positive refractive power and at least one lens having a negative refractive power; is configured such that a distance between the first lens group G1 and the second lens group G2, a distance between the second lens group G2 and the third lens group G3, a distance between the third lens group G3 and the fourth lens group G4, and a distance between the fourth lens group G4 and the fifth lens group G5 are changed when magnification from a wide-angle end state to a telephoto end state; and fulfills a prescribed formula.

Description

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

  Conventionally, as a variable power optical system suitable for an interchangeable lens for a camera, a digital camera, a video camera, and the like, many lenses having a positive refractive power in the most object side lens group have been proposed (for example, Patent Document 1). reference.).

JP 2010-237455 A

  However, the conventional variable power optical system as described above has a problem that it is difficult to obtain sufficiently high optical performance if it is attempted to reduce the size.

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a variable magnification optical system, an optical device, and a method for manufacturing the variable magnification optical system that are small and have high optical performance.

In order to solve the above problems, the present invention
In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a negative refractive power A group and a fifth lens group having a positive refractive power,
The first lens group includes at least one positive lens and at least one negative lens;
At the time of zooming from the wide angle end state to the telephoto end state, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, the third lens group and the The distance between the fourth lens group and the distance between the fourth lens group and the fifth lens group change,
A variable magnification optical system characterized by satisfying the following conditional expression is provided.
0.00 <Δνd1 <15.60
However,
Δνd1: Abbe number with respect to d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group, and refraction among the negative lenses in the first lens group. Difference of Abbe number with respect to d-line (wavelength: 587.6 nm) of the negative lens with the highest rate

The present invention also provides
Provided is an optical device comprising the variable magnification optical system.

The present invention also provides
In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a negative refractive power A variable magnification optical system having a group and a fifth lens group having a positive refractive power,
The first lens group includes at least one positive lens and at least one negative lens;
The first lens group satisfies the following conditional expression:
At the time of zooming from the wide angle end state to the telephoto end state, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, the third lens group and the There is provided a variable magnification optical system manufacturing method characterized in that an interval between a fourth lens group and an interval between the fourth lens group and the fifth lens group are changed.
0.00 <Δνd1 <15.60
However,
Δνd1: Abbe number with respect to d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group, and refraction among the negative lenses in the first lens group. Difference of Abbe number with respect to d-line (wavelength: 587.6 nm) of the negative lens with the highest rate

  According to the present invention, it is possible to provide a variable magnification optical system, an optical apparatus, and a variable magnification optical system that are small and have high optical performance.

(A), (b), and (c) are sectional views in the wide-angle end state, intermediate focal length state, and telephoto end state, respectively, of the variable magnification optical system according to the first example of the present application. (A), (b), and (c) are various figures at the time of focusing on an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the first example of the present application, respectively. It is an aberration diagram. (A), (b), and (c) are sectional views of the variable magnification optical system according to the second example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. (A), (b), and (c) are various values at the time of focusing on an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the second example of the present application, respectively. It is an aberration diagram. (A), (b), and (c) are sectional views of the variable magnification optical system according to the third example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. (A), (b), and (c) are various values at the time of focusing on an object at infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the third example of the present application, respectively. It is an aberration diagram. It is a figure which shows the structure of the camera provided with the variable magnification optical system of this application. It is a figure which shows the outline of the manufacturing method of the variable magnification optical system of this application.

Hereinafter, a variable magnification optical system, an optical apparatus, and a method for manufacturing the variable magnification optical system of the present application will be described.
The variable magnification optical system of the present application includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative lens power. A fourth lens group having a refractive power of 5 and a fifth lens group having a positive refractive power, and the first lens group has at least one positive lens and at least one negative lens, At the time of zooming from the wide angle end state to the telephoto end state, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, the third lens group and the The distance between the fourth lens group and the distance between the fourth lens group and the fifth lens group vary. With this configuration, the variable magnification optical system of the present application realizes variable magnification from the wide-angle end state to the telephoto end state, and can suppress fluctuations in distortion and astigmatism due to the variable magnification.

The variable magnification optical system of the present application is characterized by satisfying the following conditional expression (1).
(1) 0.00 <Δνd1 <15.60
However,
Δνd1: Abbe number with respect to d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group, and refraction among the negative lenses in the first lens group. Difference of Abbe number with respect to d-line (wavelength: 587.6 nm) of the negative lens with the highest rate

Conditional expression (1) satisfies the Abbe number of the positive lens having the largest refractive index among the positive lenses in the first lens group and the Abbe number of the negative lens having the largest refractive index among the negative lenses in the first lens group. It defines the difference in numbers. The variable magnification optical system of the present application satisfies the conditional expression (1), and achieves miniaturization, while reducing variations in chromatic aberration, spherical aberration, and astigmatism that occur in the first lens group during zooming. Can be suppressed.
If the corresponding value of the conditional expression (1) of the variable magnification optical system of the present application is less than the lower limit value, if an attempt is made to suppress chromatic aberration that occurs in the first lens group, spherical aberration and astigmatism that occur in the first lens group. Becomes excessive. For this reason, it becomes difficult to simultaneously suppress the variation of spherical aberration and the variation of astigmatism and the variation of chromatic aberration at the time of zooming, and high optical performance cannot be realized. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (1) to 4.00.
On the other hand, if the corresponding value of the conditional expression (1) of the variable magnification optical system of the present application exceeds the upper limit value, if the variable magnification optical system of the present application is to be miniaturized, the second order generated in the first lens group at the time of variable magnification. Therefore, it becomes difficult to suppress fluctuations in the chromatic aberration of magnification, and high optical performance cannot be realized. In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (1) to 15.00.
With the above configuration, a variable magnification optical system having a small size and high optical performance can be realized.

Moreover, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (2).
(2) 1.820 <ndph
However,
ndph: refractive index with respect to d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group.

Conditional expression (2) defines the refractive index of the positive lens having the largest refractive index among the positive lenses in the first lens group. The variable magnification optical system of the present application satisfies the conditional expression (2), thereby reducing the thickness of the first lens unit to achieve miniaturization, while reducing variations in spherical aberration and astigmatism during zooming. Can be suppressed.
If the corresponding value of the conditional expression (2) of the zoom optical system of the present application is below the lower limit value, if the zoom ratio of the zoom optical system of the present application is maintained without increasing the size of the first lens group, The refractive power of one lens unit becomes small, and the amount of movement of the first lens unit during zooming increases. For this reason, while suppressing the enlargement of the variable magnification optical system of the present application, the variation of spherical aberration and the variation of astigmatism that occur at the time of magnification variation in the lens unit located on the image side of the first lens unit is suppressed. This makes it difficult to achieve high optical performance. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (2) to 1.850.
In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (2) to 2.800. By making the corresponding value of conditional expression (2) of the variable magnification optical system of the present application smaller than 2.800, transmission of visible light to the material of the positive lens having the highest refractive index among the positive lenses in the first lens group. A sufficient rate can be secured.

Moreover, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (3).
(3) 30.50 <νdph
However,
νdph: Abbe number for the d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group

Conditional expression (3) defines the Abbe number of the positive lens having the largest refractive index among the positive lenses in the first lens group. The variable magnification optical system of the present application satisfies the conditional expression (3), so that it is possible to suppress the variation in chromatic aberration that occurs in the first lens group at the time of zooming.
If the corresponding value of conditional expression (3) of the variable magnification optical system of the present application is below the lower limit value, the chromatic aberration generated in the positive lens of the first lens group becomes excessive, and it is difficult to suppress the variation of chromatic aberration at the time of zooming. Become. For this reason, high optical performance cannot be realized. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (3) to 34.50.

Moreover, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (4).
(4) 0.039 <Δnd1 <0.190
However,
Δnd1: Among the negative lenses in the first lens group, the refractive index with respect to the d-line (wavelength 587.6 nm) of the negative lens having the largest refractive index, and the refractive index among the positive lenses in the first lens group. Difference in refractive index with respect to d-line (wavelength: 587.6 nm) of a positive lens having the largest refractive index

Conditional expression (4) indicates that the negative lens having the largest refractive index among the negative lenses in the first lens group and the refraction of the positive lens having the largest refractive index among the positive lenses in the first lens group. It defines the difference in rate. By satisfying conditional expression (4), the variable magnification optical system of the present application can suppress variations in spherical aberration and astigmatism that occur in the first lens group during magnification.
If the corresponding value of conditional expression (4) of the variable magnification optical system of the present application is less than the lower limit value, it becomes difficult to suppress positive spherical aberration generated in the negative lens of the first lens group, and high optical performance is realized. It becomes impossible to do. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (4) to 0.043.
On the other hand, when the corresponding value of conditional expression (4) of the variable magnification optical system of the present application exceeds the upper limit value, the refractive index of the positive lens in the first lens group becomes relatively small. For this reason, the curvature of the positive lens in the first lens group becomes large, and it becomes difficult to suppress fluctuations in spherical aberration and astigmatism during zooming. Therefore, high optical performance cannot be realized. In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (4) to 0.175.

In the variable magnification optical system of the present application, it is desirable that at least one positive lens among the positive lenses in the first lens group satisfies the following conditional expression (5).
(5) 75.00 <νdp1
However,
νdp1: Abbe number with respect to d-line (wavelength: 587.6 nm) of at least one positive lens among the positive lenses in the first lens group

Conditional expression (5) defines an optimum Abbe number of at least one positive lens among the positive lenses in the first lens group. By satisfying conditional expression (5), the variable magnification optical system of the present application can suppress variations in longitudinal chromatic aberration and magnification chromatic aberration during magnification.
If the corresponding value of conditional expression (5) of the variable magnification optical system of the present application is lower than the lower limit value, it is difficult to suppress fluctuations in axial chromatic aberration and magnification chromatic aberration during zooming, and high optical performance is realized. Will not be able to.
In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (5) to 99.00. When the corresponding value of conditional expression (5) of the variable magnification optical system of the present application is smaller than 99.00, fluctuations in axial chromatic aberration and magnification chromatic aberration that occur in lenses other than the at least one positive lens at the time of magnification change. And high optical performance can be realized.

Further, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (6).
(6) 5.50 <f1 / (− f2) <15.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group

Conditional expression (6) defines an appropriate range of the focal length ratio between the first lens group and the second lens group. By satisfying conditional expression (6), the zoom optical system of the present application can suppress fluctuations in astigmatism during zooming while maintaining a high zoom ratio.
If the corresponding value of conditional expression (6) of the variable magnification optical system of the present application is below the lower limit value, astigmatism is greatly generated in the wide-angle end state, and high optical performance cannot be realized. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (6) to 5.60. In order to further secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (6) to 5.90.
On the other hand, if the corresponding value of conditional expression (6) of the variable magnification optical system of the present application exceeds the upper limit value, it becomes difficult to suppress fluctuations in astigmatism that occurs in the second lens group at the time of zooming. In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (6) to 11.50. In order to further secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (6) to 10.20.

Moreover, it is desirable that the variable magnification optical system of the present application satisfies the following conditional expression (7).
(7) 0.220 <(− f2) / f3 <0.530
However,
f2: focal length of the second lens group f3: focal length of the third lens group

Conditional expression (7) defines an appropriate range of the focal length ratio between the second lens group and the third lens group. By satisfying conditional expression (7), the zooming optical system of the present application can suppress fluctuations in spherical aberration and astigmatism during zooming while maintaining a high zoom ratio.
If the corresponding value of conditional expression (7) of the variable magnification optical system of the present application is less than the lower limit value, it will be difficult to suppress fluctuations in astigmatism that occurs in the second lens group during zooming. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (7) to 0.270.
On the other hand, if the corresponding value of conditional expression (7) of the variable magnification optical system of the present application exceeds the upper limit value, it becomes difficult to suppress the variation of spherical aberration that occurs in the third lens group at the time of zooming. In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (7) to 0.490. Furthermore, in order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (7) to 0.450.

  In the zoom optical system of the present application, it is desirable that the distance between the first lens group and the second lens group is increased when zooming from the wide-angle end state to the telephoto end state. With this configuration, the focal length of the first lens group and the focal length of the second lens group can be made appropriate. Then, spherical aberration and astigmatism occurring in each lens group can be suppressed, and fluctuations in spherical aberration and astigmatism can be suppressed during zooming.

  In the variable power optical system of the present application, it is desirable that the distance between the second lens group and the third lens group is reduced when zooming from the wide-angle end state to the telephoto end state. With this configuration, the focal length of the second lens group and the focal length of the third lens group can be made appropriate. Then, spherical aberration and astigmatism occurring in each lens group can be suppressed, and fluctuations in spherical aberration and astigmatism can be suppressed during zooming.

  In the zoom optical system of the present application, it is desirable that the distance between the third lens group and the fourth lens group is increased when zooming from the wide-angle end state to the telephoto end state. With this configuration, it is possible to suppress variations in spherical aberration and astigmatism that occur in the third lens group and the fourth lens group during zooming.

The variable magnification optical system of the present application desirably includes at least one lens that satisfies the following conditional expressions (8) and (9).
(8) 1.929 <ndh
(9) 28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to d-line (wavelength 587.6 nm) of the lens

Conditional expression (8) defines the optimum refractive index of the lens. By satisfying conditional expression (8), the variable magnification optical system of the present application can suppress variations in spherical aberration and astigmatism during magnification while achieving miniaturization.
If the corresponding value of conditional expression (8) of the variable magnification optical system of the present application is below the lower limit value, it becomes difficult to suppress fluctuations in spherical aberration and astigmatism during zooming, and high optical performance is realized. Will not be able to. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (8) to 1.940.
In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (8) to 2.800. By making the corresponding value of conditional expression (8) of the variable magnification optical system of the present application smaller than 2.800, it is possible to sufficiently ensure the transmittance of visible light to the lens material.

Conditional expression (9) defines the optimal Abbe number of the lens. By satisfying conditional expression (9), the variable magnification optical system of the present application can suppress variations in longitudinal chromatic aberration and magnification chromatic aberration during magnification while achieving miniaturization.
If the corresponding value of conditional expression (9) of the variable magnification optical system of the present application is below the lower limit value, it will be difficult to suppress the fluctuation of axial chromatic aberration and the fluctuation of lateral chromatic aberration at the time of zooming, and high optical performance will be realized. Will not be able to. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (9) to 29.00. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (9) to 30.00. In order to secure the effect of the present application, it is more preferable to set the lower limit of conditional expression (9) to 32.00.
In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (9) to 50.00. By reducing the corresponding value of conditional expression (9) of the variable magnification optical system of the present application to less than 50.00, it is possible to suppress variations in axial chromatic aberration and magnification chromatic aberration that occur in lenses other than the lens during zooming. And high optical performance can be realized.

  In the variable magnification optical system of the present application, it is preferable that the first lens group has at least one lens. With this configuration, it is possible to suppress variations in spherical aberration, astigmatism, axial chromatic aberration, and lateral chromatic aberration that occur in the first lens group during zooming.

  In the variable magnification optical system of the present application, it is desirable that the fifth lens group has at least one lens. With this configuration, spherical aberration, astigmatism, axial chromatic aberration, and lateral chromatic aberration that occur in the fifth lens group can be suppressed from the wide-angle end state to the telephoto end state.

In the zoom optical system according to the present application, it is preferable that the fourth lens group includes a positive lens that satisfies the following conditional expression (10).
(10) 75.00 <νdp4
However,
νdp4: Abbe number for the d-line (wavelength 587.6 nm) of the material of the positive lens in the fourth lens group

Conditional expression (10) defines an optimum Abbe number of the positive lens in the fourth lens group. By satisfying conditional expression (10), the variable magnification optical system of the present application can suppress variations in longitudinal chromatic aberration and magnification chromatic aberration during magnification.
If the corresponding value of conditional expression (10) of the variable magnification optical system of the present application is less than the lower limit value, it becomes difficult to suppress the variation of axial chromatic aberration at the time of zooming, and high optical performance cannot be realized. .
In order to secure the effect of the present application, it is more preferable to set the upper limit of conditional expression (10) to 99.00. By reducing the corresponding value of conditional expression (10) of the variable magnification optical system of the present application from 99.00, it is possible to suppress axial chromatic aberration occurring in lenses other than the positive lens, and to realize high optical performance. Can do.

  The optical device of the present application is characterized by having the variable magnification optical system having the above-described configuration. Thereby, it is possible to realize an optical device that is small and has high optical performance.

The variable magnification optical system manufacturing method of the present application includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. And a fourth variable lens unit having a negative refractive power and a fifth lens unit having a positive refractive power, wherein the first lens group is at least one positive lens. And at least one negative lens, and the first lens group satisfies the following conditional expression (1), and the first lens is changed upon zooming from the wide-angle end state to the telephoto end state: A distance between the second lens group and the second lens group, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group, and the fourth lens group and the second lens group. It is characterized in that the interval between the five lens groups is changed. Thereby, a variable magnification optical system having a small size and high optical performance can be manufactured.
(1) 0.00 <Δνd1 <15.60
However,
Δνd1: Abbe number with respect to d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group, and refraction among the negative lenses in the first lens group. Difference of Abbe number with respect to d-line (wavelength: 587.6 nm) of the negative lens with the highest rate

Hereinafter, a variable magnification optical system according to numerical examples of the present application will be described with reference to the accompanying drawings.
(First embodiment)
1A, 1B, and 1C are cross-sectional views of the zoom optical system according to the first example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is.
The variable magnification optical system according to the present example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens having a positive refractive power. The lens group G3 includes a fourth lens group G4 having a negative refractive power and a fifth lens group G5 having a positive refractive power.

The first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side. Become.
The second lens group G2 has a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a concave surface directed toward the object side, in order from the object side. And a negative meniscus lens L24. The negative meniscus lens L21 is a glass mold aspheric lens having an aspheric lens surface on the object side.
The third lens group G3 is composed of a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32 in order from the object side. An aperture stop S is provided on the object side of the third lens group G3.

The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L41 and a biconcave negative lens L42, and a positive meniscus having a biconcave negative lens L43 and a convex surface facing the object side. It consists of a cemented lens with lens L44. The negative lens L43 is a glass mold aspheric lens having an aspheric lens surface on the object side.
The fifth lens group G5 includes, in order from the object side, a cemented lens of a biconvex positive lens L51, a biconvex positive lens L52, and a negative meniscus lens L53 with a concave surface facing the object, and a convex surface on the object side A negative meniscus lens L54 having a convex surface and a biconvex positive lens L55, and a negative meniscus lens L56 having a convex surface facing the image side. The negative meniscus lens L56 is a glass mold aspheric lens having an aspheric lens surface on the image side.
In the zoom optical system according to the present embodiment, a low-pass filter, a sensor cover glass, or the like may be disposed between the fifth lens group G5 and the image plane I.

  With the above-described configuration, in the variable magnification optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 increases when the magnification is changed from the wide-angle end state to the telephoto end state. The air gap between the second lens group G2 and the third lens group G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 increases, and the fourth lens group G4 and the fifth lens group G5 The first to fifth lens groups G1 to G5 move along the optical axis so that the air gap decreases and the air gap between the aperture stop S and the third lens group G3 decreases. It moves integrally with the lens group G4. Specifically, the first lens group G1 and the third lens group G3 move to the object side during zooming. The second lens group G2, the fourth lens group G4, and the fifth lens group G5 move toward the object side from the wide-angle end state to the intermediate focal length state, and move toward the image side from the intermediate focal length state to the telephoto end state.

Table 1 below lists values of specifications of the variable magnification optical system according to the present example.
In Table 1, f indicates the focal length, and BF indicates the back focus (the distance on the optical axis between the lens surface closest to the image side and the image plane I).
In [Surface data], the surface number is the order of the optical surfaces counted from the object side, r is the radius of curvature, d is the surface interval (the interval between the nth surface (n is an integer) and the n + 1th surface), and nd is The refractive index for d-line (wavelength 587.6 nm) and νd indicate the Abbe number for d-line (wavelength 587.6 nm), respectively. In addition, the object plane indicates the object plane, the variable indicates the variable plane spacing, the stop S indicates the aperture stop S, and the image plane indicates the image plane I. The radius of curvature r = ∞ indicates a plane. For the aspherical surface, * is added to the surface number, and the value of the paraxial radius of curvature is indicated in the column of the radius of curvature r. The description of the refractive index of air nd = 1.00000 is omitted.

[Aspherical data] shows an aspherical coefficient and a conic constant when the shape of the aspherical surface shown in [Surface data] is expressed by the following equation.
x = (h ² / r) / [1+ {1−κ (h / r) ² } ^1/2 ]
+ A4h ⁴ + A6h ⁶ + A8h ⁸ + A10h ¹⁰
Here, h is the height in the direction perpendicular to the optical axis, x is the distance (sag amount) from the tangent plane of the apex of the aspheric surface to the aspheric surface at the height h, and κ is the conic constant. , A4, A6, A8, A10 are aspherical coefficients, and r is the radius of curvature of the reference sphere (paraxial radius of curvature). “E−n” (n is an integer) indicates “× 10 ⁻ⁿ ”, for example “1.234E-05” indicates “1.234 × 10 ⁻⁵ ”. The secondary aspherical coefficient A2 is 0 and is not shown.

In [Various data], FNO is the F number, ω is the half angle of view (unit is “°”), Y is the image height, TL is the total length of the variable magnification optical system (image from the first surface when focusing on an object at infinity) (Distance on the optical axis to the surface I), dn represents the variable distance between the nth surface and the (n + 1) th surface, and φ represents the diameter of the aperture stop S. W represents the wide-angle end state, M represents the intermediate focal length state, and T represents the telephoto end state.
[Lens Group Data] indicates the start surface and focal length of each lens group.
[Conditional Expression Corresponding Value] shows the corresponding value of each conditional expression of the variable magnification optical system according to the present example.

Here, the focal length f, the radius of curvature r, and other length units listed in Table 1 are generally “mm”. However, the optical system is not limited to this because an equivalent optical performance can be obtained even when proportionally enlarged or proportionally reduced.
In addition, the code | symbol of Table 1 described above shall be similarly used also in the table | surface of each Example mentioned later.

(Table 1) First Example
[Surface data]
Surface number r d nd νd
Object ∞

1 104.5118 1.6000 2.003300 28.27
2 39.3751 7.4000 1.497820 82.57
3 -463.5701 0.1000
4 40.3116 5.4000 1.834810 42.73
5 241.9089 Variable

* 6 79.9711 1.0000 1.851350 40.10
7 8.1252 4.8500
8 -14.2116 1.0000 1.883000 40.66
9 124.9279 0.1000
10 30.8124 3.3500 1.808090 22.74
11 -15.1873 0.3000
12 -13.2222 1.0000 1.883000 40.66
13 -23.0302 Variable

14 (Aperture S) ∞ Variable

15 26.1923 1.0000 1.954000 33.46
16 12.2483 2.8500 1.719990 50.27
17 -43.5073 Variable

18 14.5527 2.8500 1.497820 82.57
19 -40.3302 1.0000 1.950000 29.37
20 173.4596 2.1500
* 21 -105.0156 1.0000 1.806100 40.71
22 10.9037 2.2000 1.808090 22.74
23 28.6084 Variable

24 30.6882 2.8500 1.579570 53.74
25 -18.3905 0.1000
26 18.8919 3.6000 1.518230 58.82
27 -13.1344 1.0000 2.000690 25.46
28 -2198.5412 0.7500
29 412.2295 1.0000 1.954000 33.46
30 12.8823 3.5000 1.755200 27.57
31 -23.7185 1.1500
32 -16.1296 1.0000 1.806100 40.71
* 33 -97.3104 BF

Image plane ∞

[Aspherical data]
6th surface κ -8.7294
A4 4.64796E-05
A6 -4.09659E-07
A8 2.44519E-09
A10 -9.90503E-12

21st surface κ -1.5760
A4 1.72590E-05
A6 9.45415E-08
A8 -1.00397E-09
A10 0.00000E + 00

33rd surface κ -19.8082
A4 -1.67719E-05
A6 -2.11776E-07
A8 -4.15932E-10
A10 -1.15008E-11

[Various data]
Scaling ratio 9.42

W T
f 10.30 to 97.00
FNO 4.09 to 5.81
ω 40.21 〜 4.76 °
Y 8.19-8.19

W M T
f 10.30000 50.00013 97.00039
ω 40.21337 9.15519 4.75685
FNO 4.09 5.78 5.81
φ 7.68 8.50 9.20
TL 100.29944 130.25093 139.59967
d5 2.10000 28.50000 39.66696
d13 17.38897 3.31447 2.00000
d14 4.87082 3.98262 1.60000
d17 2.59389 3.48209 5.86471
d23 5.29632 3.42829 3.30000
BF 13.94944 33.44346 33.06800

[Lens group data]
Group start surface f
1 1 64.38705
2 6 -9.57903
3 15 29.91408
4 18 -81.48313
5 24 28.77173

[Conditional expression values]
(1) Δνd1 = 14.46
(2) ndph = 1.835 (L13)
(3) νdph = 42.73 (L13)
(4) Δnd1 = 0.169
(5) νdp1 = 82.57 (L12)
(6) f1 / (− f2) = 6.72
(7) (−f2) /f3=0.320
(8) ndh = 1.954 (L31), 1.950 (L42), 1.954 (L54)
(9) νdh = 33.46 (L31), 29.37 (L42), 33.46 (L54)
(10) νdp4 = 82.57 (L41)

  2 (a), 2 (b), and 2 (c) respectively show infinity in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable magnification optical system according to the first example of the present application. It is an aberration diagram at the time of focusing on an object.

  In each aberration diagram, FNO denotes an F number, and A denotes a light incident angle, that is, a half angle of view (unit: “°”). d indicates the aberration at the d-line (wavelength 587.6 nm), g indicates the aberration at the g-line (wavelength 435.8 nm), and those without d and g indicate the aberration at the d-line. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. Note that the same reference numerals as in this embodiment are used in the aberration diagrams of each embodiment described later.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the present example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Second embodiment)
FIGS. 3A, 3B, and 3C are cross-sectional views of the zoom optical system according to the second example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is.
The variable magnification optical system according to the present example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens having a positive refractive power. The lens group G3 includes a fourth lens group G4 having a negative refractive power and a fifth lens group G5 having a positive refractive power.

The first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side. Become.
The second lens group G2 includes, in order from the object side, a biconcave negative lens L21, a biconcave negative lens L22, a biconvex positive lens L23, and a negative meniscus lens L24 with a concave surface facing the object side. It consists of.
The third lens group G3 is composed of a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32 in order from the object side. An aperture stop S is provided on the object side of the third lens group G3.

The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L41 and a biconcave negative lens L42, and a positive meniscus having a biconcave negative lens L43 and a convex surface facing the object side. It consists of a cemented lens with lens L44. The negative lens L43 is a glass mold aspheric lens having an aspheric lens surface on the object side.
The fifth lens group G5 includes, in order from the object side, a biconvex positive lens L51, a cemented lens of a positive meniscus lens L52 having a concave surface facing the object side, and a negative meniscus lens L53 having a concave surface facing the object side. Become. The positive lens L51 is a glass mold aspheric lens having an aspheric lens surface on the object side.
In the zoom optical system according to the present embodiment, a low-pass filter, a sensor cover glass, or the like may be disposed between the fifth lens group G5 and the image plane I.

With the above-described configuration, in the variable magnification optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 increases when the magnification is changed from the wide-angle end state to the telephoto end state. The air gap between the second lens group G2 and the third lens group G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 increases, and the fourth lens group G4 and the fifth lens group G5 The first to fifth lens groups G1 to G5 move along the optical axis so that the air gap decreases and the air gap between the aperture stop S and the third lens group G3 decreases. It moves integrally with the lens group G4. Specifically, the first lens group G1, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move to the object side during zooming. The second lens group G2 moves toward the object side from the wide-angle end state to the intermediate focal length state, and moves toward the image side from the intermediate focal length state to the telephoto end state.
Table 2 below provides values of specifications of the variable magnification optical system according to the present example.

(Table 2) Second Example
[Surface data]
Surface number r d nd νd
Object ∞

1 251.8446 1.6000 1.950000 29.37
2 36.8495 7.9000 1.497820 82.57
3 -162.8867 0.1000
4 41.6898 5.7500 1.883000 40.66
5 7827.2710 Variable

6 -808.8261 1.0000 1.883000 40.66
7 9.5148 3.6000
8 -15.5435 1.0000 1.883000 40.66
9 143.0303 0.1000
10 28.6318 3.0500 1.808090 22.74
11 -13.3111 0.2500
12 -12.1771 1.0000 1.834810 42.73
13 -36.4394 Variable

14 (Aperture S) ∞ Variable

15 27.0772 1.0000 2.000690 25.46
16 15.7705 2.5000 1.744000 44.80
17 -35.2142 Variable

18 12.6941 2.9500 1.497820 82.57
19 -24.8876 1.0000 1.846660 23.80
20 775.1758 2.1500
* 21 -227.6550 1.0000 1.806100 40.97
22 8.8217 2.2000 1.846660 23.80
23 19.5840 Variable

* 24 15.0000 3.1500 1.583130 59.42
25 -23.9888 0.1000
26 -509.6518 4.2000 1.581440 40.98
27 -7.8594 1.0000 1.954000 33.46
28 -200.0000 BF

Image plane ∞

[Aspherical data]
21st surface κ -20.0000
A4 1.61374E-05
A6 -2.79859E-08
A8 -1.22068E-09
A10 0.00000E + 00

24th surface κ 3.6281
A4 -1.21377E-04
A6 -7.10924E-07
A8 1.36403E-08
A10 -4.10781E-10

[Various data]
Scaling ratio 9.42

W T
f 10.30 to 97.00
FNO 4.12 to 6.48
ω 43.07 〜 4.70 °
Y 8.19-8.19

W M T
f 10.30000 50.00001 96.99995
ω 43.07103 9.11914 4.70123
FNO 4.12 5.81 6.48
φ 6.80 7.90 7.90
TL 90.80323 122.13334 131.09941
d5 2.28937 28.97477 38.62002
d13 13.12572 3.71901 2.00000
d14 6.29895 3.32684 1.40000
d17 2.43367 5.40578 7.33262
d23 6.60623 3.30000 3.30000
BF 13.44928 30.80693 31.84677

[Lens group data]
Group start surface f
1 1 59.94630
2 6 -8.99248
3 15 24.34092
4 18 -112.21259
5 24 35.78226

[Conditional expression values]
(1) Δνd1 = 11.29
(2) ndph = 1.883 (L13)
(3) νdph = 40.66 (L13)
(4) Δnd1 = 0.067
(5) νdp1 = 82.57 (L12)
(6) f1 / (− f2) = 6.67
(7) (−f2) /f3=0.369
(8) ndh = 1.950 (L11), 1.904 (L53)
(9) νdh = 29.37 (L11), 33.46 (L53)
(10) νdp4 = 82.57 (L41)

  4 (a), 4 (b), and 4 (c) respectively show infinity in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the second example of the present application. It is an aberration diagram at the time of focusing on an object.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the present example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

(Third embodiment)
5A, 5B, and 5C are cross-sectional views of the zoom optical system according to the third example of the present application in the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively. It is.
The variable magnification optical system according to the present example includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens having a positive refractive power. The lens group G3 includes a fourth lens group G4 having a negative refractive power and a fifth lens group G5 having a positive refractive power.

The first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex positive lens L12, and a positive meniscus lens L13 having a convex surface facing the object side. Become.
The second lens group G2 has a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave negative lens L22, a biconvex positive lens L23, and a concave surface directed toward the object side, in order from the object side. And a negative meniscus lens L24. The negative meniscus lens L21 is a glass mold aspheric lens having an aspheric lens surface on the object side.
The third lens group G3 is composed of a cemented lens of a negative meniscus lens L31 having a convex surface directed toward the object side and a biconvex positive lens L32 in order from the object side. An aperture stop S is provided on the object side of the third lens group G3.

The fourth lens group G4 includes, in order from the object side, a cemented lens of a biconvex positive lens L41 and a negative meniscus lens L42 having a convex surface directed toward the image side, and a biconcave negative lens L43 and a convex surface toward the object side. It consists of a cemented lens with a directed positive meniscus lens L44. The negative lens L43 is a glass mold aspheric lens having an aspheric lens surface on the object side.
The fifth lens group G5 includes, in order from the object side, a biconvex positive lens L51, a cemented lens of a biconvex positive lens L52, and a negative meniscus lens L53 having a concave surface facing the object. The positive lens L51 is a glass mold aspheric lens having an aspheric lens surface on the object side.
In the zoom optical system according to the present embodiment, a low-pass filter, a sensor cover glass, or the like may be disposed between the fifth lens group G5 and the image plane I.

With the above-described configuration, in the variable magnification optical system according to the present embodiment, the air gap between the first lens group G1 and the second lens group G2 increases when the magnification is changed from the wide-angle end state to the telephoto end state. The air gap between the second lens group G2 and the third lens group G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 increases, and the fourth lens group G4 and the fifth lens group G5 The first to fifth lens groups G1 to G5 move along the optical axis so that the air gap decreases and the air gap between the aperture stop S and the third lens group G3 decreases. It moves integrally with the lens group G4. Specifically, the first lens group G1, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 move to the object side during zooming. The second lens group G2 moves toward the object side from the wide-angle end state to the intermediate focal length state, and moves toward the image side from the intermediate focal length state to the telephoto end state.
Table 3 below lists values of specifications of the variable magnification optical system according to the present example.

(Table 3) Third Example
[Surface data]
Surface number r d nd νd
Object ∞

1 149.8692 1.6000 1.949665 27.56
2 44.3736 6.8398 1.497820 82.51
3 -243.5058 0.1000
4 45.3756 5.3508 1.867900 41.78
5 311.4136 Variable

* 6 89.0243 1.2000 1.834810 42.73
7 8.4900 3.7581
8 -15.7255 1.0000 1.834810 42.73
9 250.0000 0.1000
10 25.2749 3.2925 1.808090 22.74
11 -17.4750 0.5480
12 -12.6196 1.0000 1.816000 46.59
13 -33.4252 Variable

14 (Aperture S) ∞ Variable

15 29.1681 1.0000 1.889044 39.77
16 18.2404 3.2071 1.593125 66.16
17 -26.5261 Variable

18 14.2857 3.5654 1.497820 82.51
19 -21.9776 1.0000 1.902000 25.23
20 -82.8398 2.2052
* 21 -52.3071 1.0000 1.848976 43.01
22 9.1414 2.6915 1.950000 29.37
23 25.8642 Variable

* 24 35.4414 3.3350 1.589130 61.22
25 -21.3191 0.3000
26 42.3100 4.4029 1.581440 40.98
27 -10.1979 1.2000 1.954000 33.46
28 -300.4717 BF

Image plane ∞

[Aspherical data]
6th surface κ 1.0000
A4 3.45801E-05
A6 -1.38520E-07
A8 -5.59965E-11
A10 1.26030E-11

21st surface κ 1.0000
A4 1.74477E-06
A6 1.28096E-07
A8 -2.63692E-09
A10 0.00000E + 00

24th surface κ 1.0000
A4 -1.22983E-05
A6 1.47314E-07
A8 -5.48742E-10
A10 0.00000E + 00

[Various data]
Scaling ratio 9.42

W T
f 10.30 to 97.00
FNO 3.50 to 5.62
ω 39.90 〜 4.69 °
Y 8.19-8.19

W M T
f 10.30001 49.99971 96.99932
ω 39.90076 9.01930 4.68610
FNO 3.50 5.20 5.62
φ 8.99 8.81 9.00
TL 99.25773 129.21001 139.67596
d5 1.99991 30.68218 41.26022
d13 18.53440 4.14191 2.00000
d14 3.76478 2.96318 1.40000
d17 3.54181 4.34341 5.90655
d23 8.01786 3.30678 3.30001
BF 14.70262 35.07621 37.11281

[Lens group data]
Group start surface f
1 1 66.85483
2 6 -9.36043
3 15 27.88295
4 18 -160.91663
5 24 33.55859

[Conditional expression values]
(1) Δνd1 = 14.22
(2) ndph = 1.868 (L13)
(3) νdph = 41.78 (L13)
(4) Δnd1 = 0.082
(5) νdp1 = 82.51 (L12)
(6) f1 / (− f2) = 7.14
(7) (−f2) /f3=0.336
(8) ndh = 1.950 (L44), 1.904 (L53)
(9) νdh = 29.37 (L44), 33.46 (L53)
(10) νdp4 = 82.51 (L41)

  FIGS. 6A, 6B, and 6C are infinite at the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system according to the third example of the present application, respectively. It is an aberration diagram at the time of focusing on an object.

  From the respective aberration diagrams, it can be seen that the variable magnification optical system according to the present example has high optical performance with various aberrations corrected well from the wide-angle end state to the telephoto end state.

  According to each of the above embodiments, a variable magnification optical system having a small size and high optical performance can be realized. In addition, each said Example has shown one specific example of this invention, and this invention is not limited to these. The following contents can be adopted as appropriate as long as the optical performance of the variable magnification optical system of the present application is not impaired.

  A numerical example of the variable magnification optical system of the present application is shown as having a five-group configuration, but the present application is not limited to this, and constitutes a variable magnification optical system of other group configurations (for example, six groups, seven groups, etc.). You can also. Specifically, a configuration in which a lens or a lens group is added to the most object side or the most image side of the variable magnification optical system of the present application may be used. The lens group refers to a portion having at least one lens separated by an air interval that changes during zooming.

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

  Further, in the variable magnification optical system of the present application, any lens group or a part thereof is moved as a vibration-proof lens group so as to include a component in a direction perpendicular to the optical axis, or a surface including the optical axis A configuration in which image blur caused by camera shake or the like is corrected by rotationally moving (swinging) inward is also possible. In particular, in the variable magnification optical system of the present application, it is preferable that at least a part of the third lens group, at least a part of the fourth lens group, or at least a part of the fifth lens group be an anti-vibration lens group.

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

In the variable magnification optical system of the present application, the aperture stop is preferably arranged in the third lens group or in the vicinity of the third lens group, and the role of the aperture stop is replaced by a lens frame without providing a member. Also good.
Further, an antireflection film having a high transmittance in a wide wavelength range may be applied to the lens surface of the lens constituting the variable magnification optical system of the present application. Thereby, flare and ghost can be reduced, and high optical performance with high contrast can be achieved.

Next, a camera provided with the variable magnification optical system of the present application will be described with reference to FIG.
FIG. 7 is a diagram illustrating a configuration of a camera including the variable magnification optical system of the present application.
As shown in FIG. 7, the camera 1 is a so-called mirrorless camera of an interchangeable lens provided with the variable magnification optical system according to the first example as the photographing lens 2.
In the camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and is on the imaging surface of the imaging unit 3 via an OLPF (Optical low pass filter) (not shown). A subject image is formed on the screen. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. Thus, the photographer can observe the subject via the EVF 4.
When the release button (not shown) is pressed by the photographer, the subject image generated by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1.

  Here, the variable magnification optical system according to the first embodiment mounted as the photographing lens 2 in the camera 1 is a variable magnification optical system that is small in size and has high optical performance. Therefore, the present camera 1 can achieve high optical performance while achieving downsizing. Even if a camera equipped with the variable magnification optical system according to the second and third examples as the photographing lens 2 is configured, the same effect as the camera 1 can be obtained. Further, even when the variable magnification optical system according to each of the above embodiments is mounted on a single-lens reflex camera that has a quick return mirror and observes a subject with a finder optical system, the same effect as the camera 1 can be obtained. it can.

Finally, the outline of the manufacturing method of the variable magnification optical system of this application is demonstrated based on FIG.
The zoom optical system manufacturing method of the present application shown in FIG. 8 has, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a positive refractive power. A method for manufacturing a variable magnification optical system having a third lens group, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, including the following steps S1 to S3. It is a waste.

Step S1: The first lens group has at least one positive lens and at least one negative lens.
Step S2: The first lens group is made to satisfy the following conditional expression (1), and each lens group is sequentially arranged in the lens barrel from the object side.
(1) 0.00 <Δνd1 <15.60
However,
Δνd1: Abbe number with respect to the d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group, and the largest refractive index among the negative lenses in the first lens group Abbe number difference for d-line (wavelength 587.6nm) of negative lens

  Step S3: By providing a known moving mechanism in the lens barrel, the distance between the first lens group and the second lens group, the second lens group and the first lens group at the time of zooming from the wide-angle end state to the telephoto end state. The distance between the third lens group, the distance between the third lens group and the fourth lens group, and the distance between the fourth lens group and the fifth lens group are changed.

  According to the method for manufacturing a variable magnification optical system of the present application, a variable magnification optical system having a small size and high optical performance can be manufactured.

G1 1st lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group S Aperture stop I Image surface

Claims (16)

In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a negative refractive power A group and a fifth lens group having a positive refractive power,
The first lens group includes at least one positive lens and at least one negative lens;
At the time of zooming from the wide angle end state to the telephoto end state, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, the third lens group and the The distance between the fourth lens group and the distance between the fourth lens group and the fifth lens group change,
A zoom optical system characterized by satisfying the following conditional expression:
0.00 <Δνd1 <15.60
However,
Δνd1: Abbe number with respect to d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group, and refraction among the negative lenses in the first lens group. Difference of Abbe number with respect to d-line (wavelength: 587.6 nm) of the negative lens with the highest rate The variable magnification optical system according to claim 1, wherein the following conditional expression is satisfied.
1.820 <ndph
However,
ndph: refractive index with respect to d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group. The zoom lens system according to claim 1 or 2, wherein the following conditional expression is satisfied.
30.50 <νdph
However,
νdph: Abbe number for the d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group The zoom lens system according to any one of claims 1 to 3, wherein the following conditional expression is satisfied.
0.039 <Δnd1 <0.190
However,
Δnd1: Among the negative lenses in the first lens group, the refractive index with respect to the d-line (wavelength 587.6 nm) of the negative lens having the largest refractive index, and the refractive index among the positive lenses in the first lens group. Difference in refractive index with respect to d-line (wavelength: 587.6 nm) of a positive lens having the largest refractive index 5. The variable magnification optical system according to claim 1, wherein at least one positive lens among the positive lenses in the first lens group satisfies the following conditional expression. 6. .
75.00 <νdp1
However,
νdp1: Abbe number with respect to d-line (wavelength: 587.6 nm) of at least one positive lens among the positive lenses in the first lens group The zoom lens system according to any one of claims 1 to 5, wherein the following conditional expression is satisfied.
5.50 <f1 / (− f2) <15.00
However,
f1: Focal length of the first lens group f2: Focal length of the second lens group The zoom lens system according to any one of claims 1 to 6, wherein the following conditional expression is satisfied.
0.220 <(− f2) / f3 <0.530
However,
f2: focal length of the second lens group f3: focal length of the third lens group   8. The distance between the first lens group and the second lens group increases at the time of zooming from the wide-angle end state to the telephoto end state. Variable magnification optical system.   9. 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. Variable magnification optical system.   10. The space between the third lens group and the fourth lens group increases during zooming from the wide-angle end state to the telephoto end state, according to claim 1. Variable magnification optical system. 11. The variable magnification optical system according to claim 1, comprising at least one lens satisfying the following conditional expression.
1.928 <ndh
28.60 <νdh
However,
ndh: refractive index with respect to d-line (wavelength 587.6 nm) of the lens νdh: Abbe number with respect to d-line (wavelength 587.6 nm) of the lens   The variable magnification optical system according to claim 11, wherein the first lens group includes at least one of the lenses.   The variable power optical system according to claim 11 or 12, wherein the fifth lens group includes at least one of the lenses. The variable power optical system according to any one of claims 1 to 13, wherein the fourth lens group includes a positive lens that satisfies the following conditional expression.
75.00 <νdp4
However,
νdp4: Abbe number for the d-line (wavelength 587.6 nm) of the material of the positive lens in the fourth lens group   An optical apparatus comprising the variable magnification optical system according to any one of claims 1 to 14. In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a negative refractive power A variable magnification optical system having a group and a fifth lens group having a positive refractive power,
The first lens group includes at least one positive lens and at least one negative lens;
The first lens group satisfies the following conditional expression:
At the time of zooming from the wide angle end state to the telephoto end state, the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, the third lens group and the A method of manufacturing a zoom optical system, characterized in that an interval between the fourth lens group and an interval between the fourth lens group and the fifth lens group are changed.
0.00 <Δνd1 <15.60
However,
Δνd1: Abbe number with respect to d-line (wavelength 587.6 nm) of the positive lens having the largest refractive index among the positive lenses in the first lens group, and refraction among the negative lenses in the first lens group. Difference of Abbe number with respect to d-line (wavelength: 587.6 nm) of the negative lens with the highest rate

Images