JP2011186161A - Variable power optical system, optical device, and method for manufacturing variable power optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable power optical system for suppressing aberration variation and having high optical performance, and also to provide an optical device having it, and a method for manufacturing the variable power optical system. <P>SOLUTION: The variable power optical system has: a first lens group G1 of positive reflective power; a second lens group G2 of negative reflective power; a third lens group G3 of positive refractive power; and a fourth lens group G4 of negative refractive power; a fifth lens group G5 of positive refractive power in order from an object side along an optical axis, and also has an aperture diaphragm S on an image side from the second lens group G2. In variable power from a wide angle end state W to a telephoto end state T, an interval between the first lens group G1 and the second lens group G2 is increased, an interval between the second lens group G2 and the third lens group G3 is decreased, an interval between the third lens group G3 and the fourth lens group G4 is changed, and an interval between the fourth lens group G4 and the fifth lens group G5 is changed, and the variable power optical system satisfies prescribed conditional inequalities. <P>COPYRIGHT: (C)2011,JPO&INPIT

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-described problems, the present invention provides 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 in order from the object side along the optical axis. A fourth lens group having a negative refractive power and a fifth lens group having a positive refractive power, and having an aperture stop closer to the image side than the second lens group, and changing from the wide-angle end state to the telephoto end state. At the time of magnification, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the third lens group and the fourth lens group. And the distance between the fourth lens group and the fifth lens group varies, and the zoom lens system satisfies the following conditional expression.
0.17 <f1 / fT <0.60
1.03 <φT / φW <1.70
However,
fT: focal length of the entire system in the telephoto end state f1: focal length φW of the first lens group: maximum aperture diameter of the aperture stop in the wide angle end state φT: maximum aperture diameter of the aperture stop in the telephoto end state

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

Further, according to the present invention, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative refractive power. A variable magnification optical system manufacturing method having a fourth lens group and a fifth lens group having a positive refractive power, wherein an aperture stop is disposed on the image side of the second lens group, and the first lens group and the When changing the second lens group, the third lens group, the fourth lens group, and the fifth lens group from the wide-angle end state to the telephoto end state, the first lens group, the second lens group, The distance between the second lens group and the third lens group can be decreased, the distance between the third lens group and the fourth lens group can be changed, and the fourth lens group and the fourth lens group can be changed. A variable magnification light characterized by being arranged so that the distance from the five lens groups can be changed and satisfying the following conditional expression: To provide a process for the preparation of the system.
0.17 <f1 / fT <0.60
1.03 <φT / φW <1.70
However,
fT: focal length of the entire system in the telephoto end state f1: focal length φW of the first lens group: maximum aperture diameter of the aperture stop in the wide angle end state φT: maximum aperture diameter of the aperture stop in the telephoto end state

  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 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. A fourth lens group having a negative refractive power and a fifth lens group having a positive refractive power, an aperture stop on the image side of the second lens group, and 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 lens group decreases, the distance between the third lens group and the fourth lens group changes, and By adopting a configuration in which the distance between the fourth lens group and the fifth lens group is changed, an optical system capable of zooming is realized, and distortion is appropriately corrected from the wide-angle end state to the telephoto end state.

In addition, the variable magnification optical system according to the present embodiment satisfies the following conditional expressions (1) and (2).
(1) 0.17 <f1 / fT <0.60
(2) 1.03 <φT / φW <1.70
Where fT is the focal length of the entire system in the telephoto end state, f1 is the focal length of the first lens group, φW is the maximum aperture diameter of the aperture stop in the wide-angle end state, and φT is the maximum aperture diameter of the aperture stop in the telephoto end state is there.

  Conditional expression (1) is a conditional expression for satisfactorily correcting spherical aberration and curvature of field generated in the variable magnification optical system and obtaining high optical performance.

  When the lower limit value of conditional expression (1) is not satisfied, that is, when the refractive power of the first lens unit becomes excessively large, negative spherical aberration at the telephoto end state and negative field curvature at the wide-angle end state are greatly generated. High optical performance cannot be obtained.

  If the upper limit of conditional expression (1) is exceeded, that is, if the refractive power of the first lens group becomes excessively small, it is necessary to move the first lens group with respect to the image plane to maintain the variable magnification. In addition, it is difficult to secure the amount of peripheral light in the telephoto end state, and it becomes difficult to correct positive spherical aberration generated in the second lens group in the telephoto end state, and high optical performance cannot be obtained.

  In order to secure the effect of the embodiment, it is preferable to set the lower limit of conditional expression (1) to 0.23. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (1) to 0.25. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (1) to 0.28.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (1) to 0.53. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit value of conditional expression (1) to 0.48. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (1) to 0.43.

  Conditional expression (2) is a conditional expression for obtaining a high optical performance by appropriately correcting the spherical aberration and the coma aberration in the telephoto end state with an appropriately small F number. By satisfying conditional expression (2), the amount of change in the F-number that changes when zooming from the wide-angle end state to the telephoto end state is optimized, and fluctuations in spherical aberration and coma aberration over the entire zoom range. It becomes possible to suppress.

  When the lower limit of conditional expression (2) is not reached, the maximum aperture diameter of the aperture stop in the telephoto end state becomes too small. Then, the F number in the telephoto end state becomes too large, and spherical aberration and coma aberration are greatly generated in the wide-angle end state, so that high optical performance cannot be realized.

  If the upper limit of conditional expression (2) is exceeded, large spherical aberration and coma occur 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 1.05. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (2) to 1.08. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (2) to 1.12.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (2) to 1.58. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (2) to 1.45.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (3).
(3) 1.02 <φM10 / φW <1.70
However, φM10 is the maximum aperture diameter of the aperture stop in the intermediate focal length state where the focal length of the entire system is 10 times or more of fW, where fW is the focal length of the entire system in the wide-angle end state.

  Conditional expression (3) indicates that the variable power optical system has a sufficient F value in the variable power region in the intermediate focal length state where the focal length of the entire variable power optical system is 10 times or more of fW, and has high optical performance. It is a conditional expression for realizing.

  When the lower limit value of conditional expression (3) is not reached, the maximum aperture diameter of the aperture stop becomes too small in the variable magnification region in the intermediate focal length state where the focal length of the entire variable magnification optical system is 10 times or more of fW. Then, the F number in this variable magnification region becomes too large, and spherical aberration and coma aberration are greatly generated in the wide-angle end state, so that high optical performance cannot be realized.

  When the upper limit of conditional expression (3) is exceeded, spherical aberration and coma are greatly generated and high in the variable magnification region in the intermediate focal length state where the focal length of the entire variable magnification optical system is 10 times or more of fW. 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 1.03. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (3) to 1.06.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (3) to 1.60. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (3) to 1.55. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (3) to 1.40.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (4).
(4) 1.02 <φM15 / φW <1.70
However, φM15 is the maximum aperture diameter of the aperture stop in the intermediate focal length state where the focal length of the entire system is 15 times or more of fW, where fW is the focal length of the entire system in the wide-angle end state.

  Conditional expression (4) gives a high optical performance by giving the variable magnification optical system a sufficient F value in the variable magnification region in the intermediate focal length state where the focal length of the entire variable magnification optical system is 15 times or more of fW. It is a conditional expression for realizing.

  When the lower limit of conditional expression (4) is not reached, the maximum aperture diameter of the aperture stop becomes too small in the variable magnification region in the intermediate focal length state where the focal length of the entire variable magnification optical system is 15 times or more of fW. Then, the F number in this variable magnification region becomes too large, and spherical aberration and coma aberration are greatly generated in the wide-angle end state, so that high optical performance cannot be realized.

  When the upper limit of conditional expression (4) is exceeded, large spherical aberration and coma occur in the variable magnification region in the intermediate focal length state where the focal length of the entire variable magnification optical system is 15 times or more of fW, which is 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 1.04. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (4) to 1.07.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (4) to 1.60. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (4) to 1.55. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (4) to 1.40.

In addition, it is desirable that the variable magnification optical system according to the present embodiment satisfies the following conditional expression (5).
(5) 1.00 ≦ φM5 / φW <1.40
However, φM5 is the maximum aperture diameter of the aperture stop in the intermediate focal length state where the focal length of the entire system is 5 to 8 times fW when the focal length of the entire system in the wide-angle end state is fW.

  Conditional expression (5) is a conditional expression for realizing high optical performance in a variable magnification region of the intermediate focal length where the focal length of the entire system is not less than 5 times and not more than 8 times fW.

  When the lower limit value of conditional expression (5) is not reached, the maximum aperture diameter of the aperture stop becomes too small in the variable range of the intermediate focal length where the focal length of the entire system is 5 to 8 times fW. Then, the F number in this variable magnification region becomes too large, and spherical aberration and coma aberration are greatly generated in the wide-angle end state, so that high optical performance cannot be realized.

  When the upper limit value of conditional expression (5) is exceeded, large spherical aberration and coma aberration occur in the variable focal range of the intermediate focal length where the focal length of the entire system is 5 to 8 times fW, 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 1.01. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (5) to 1.03.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (5) to 1.32. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (5) to 1.25.

In the zoom optical system according to the present embodiment, the aperture stop is in the wide-angle end state from the wide-angle end state to the intermediate focal length state of the focal length fM of the entire system when zooming from the wide-angle end state to the telephoto end state. It is desirable to maintain the maximum opening diameter and satisfy the following conditional expression (6).
(6) 1.50 <fM / fW <15.00
However, fW is the focal length of the entire system in the wide-angle end state.

  Conditional expression (6) is a conditional expression for realizing high optical performance in a variable magnification region of any intermediate focal length.

  If the lower limit value of conditional expression (6) is not reached, spherical aberration and coma are greatly generated in a variable magnification region of any intermediate focal length, and high optical performance cannot be realized.

  If the upper limit value of conditional expression (6) is exceeded, the F number becomes too large in the variable focal region of any intermediate focal length, and spherical aberration and coma aberration occur at the wide-angle end state, resulting in 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 1.80. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (6) to 2.30.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (6) to 12.00. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (6) to 8.50.

  In the zoom optical system according to the present embodiment, it is desirable that the maximum aperture diameter of the aperture stop monotonously increases when the focal length fM is changed from the intermediate focal length state to the telephoto end state. The maximum aperture diameter of the aperture stop is the maximum aperture stop diameter in each focal length state.

  With this configuration, it is possible to simplify the mechanical configuration of the variable magnification optical system, and to suppress variations in spherical aberration in the variable magnification region from the intermediate focal length state to the telephoto end state with the focal length fM. Thus, 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 (7).
(7) 0.032 <−f2 / fT <0.064
Here, f2 is the focal length of the second lens group.

  Conditional expression (7) is a conditional expression for realizing high optical performance by suppressing aberration fluctuations occurring in the second lens group upon zooming from the wide-angle end state to the telephoto end state.

  When the lower limit value of conditional expression (7) is not reached, the refractive power of the second lens group becomes excessively large. As a result, during zooming from the wide-angle end state to the telephoto end state, variations in spherical aberration and astigmatism occur greatly, and high optical performance cannot be realized.

  When the upper limit of conditional expression (7) is exceeded, the refractive power of the second lens group becomes excessively small, and the amount of movement of the second lens group increases. Then, at the time of zooming from the wide-angle end state to the telephoto end state, it becomes difficult to suppress spherical aberration and astigmatism fluctuations that occur in the second lens group, 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 (7) to 0.038. In order to further secure the effect of the embodiment, it is more preferable to set the lower limit of conditional expression (7) to 0.042.

  In order to secure the effect of the embodiment, it is preferable to set the upper limit of conditional expression (7) to 0.061. In order to further secure the effect of the embodiment, it is more preferable to set the upper limit of conditional expression (7) to 0.057.

  In the zoom optical system according to the present embodiment, it is desirable that the F number of the entire system increases monotonously when zooming from the wide-angle end state to the telephoto end state.

  With this configuration, when zooming from the wide-angle end state to the telephoto end state, an excessive increase in the axial ray height passing through the lens group in the vicinity of the stop, for example, the third lens group, is suppressed, and the spherical surface is accordingly accompanied. It becomes possible to suppress fluctuations such as aberration, and high optical performance can be realized.

  In the zoom optical system according to the present embodiment, it is desirable that the first lens unit moves toward the object side with respect to the image plane when zooming from the wide-angle end state to the telephoto end state.

  With this configuration, the diameter of the first lens group can be reduced, and the height of the off-axis light beam passing through the first lens group in the wide-angle end state from the optical axis can be suppressed to suppress field curvature and astigmatism. The fluctuation at the time of zooming can be suppressed.

  In the zoom optical system according to the present embodiment, it is desirable that the aperture stop moves integrally with at least a part of the third lens group when zooming from the wide-angle end state to the telephoto end state.

  With this configuration, the mechanical configuration of the variable magnification optical system can be simplified, and fluctuations in spherical aberration can be suppressed, thereby realizing high optical performance.

  In the variable magnification optical system according to this embodiment, it is desirable that the aperture stop be disposed on the object side of the third lens group.

  With this configuration, the diameter of the first lens group can be reduced, and the height of the off-axis light beam passing through the first lens group in the wide-angle end state from the optical axis can be suppressed to suppress field curvature and astigmatism. The fluctuation at the time of zooming can be suppressed.

  In the zoom optical system according to the present embodiment, it is desirable that the third lens unit and the fifth lens unit move together when zooming from the wide-angle end state to the telephoto end state.

  With this configuration, the third lens group and the fifth lens group can be configured integrally, and the amount of mutual eccentricity between the third lens group and the fifth lens group due to manufacturing errors is suppressed, and the third lens group It is possible to suppress the occurrence of decentration coma that occurs between the fifth lens groups, thereby realizing high optical performance.

(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. The third lens group G3 having positive refractive power, the fourth lens group G4 having negative refractive power, and the fifth lens group G5 having 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, the lens moves toward the object side, and the third lens group G3 monotonously moves toward the object side. Furthermore, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases so that the fourth lens group G4 and the fifth lens group. G5 moves to the object side monotonously with respect to the image plane I. Further, the third lens group G3 and the fifth lens group G5 move integrally with the image plane I.

  The aperture stop S is disposed on the most 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 lens group G3. Further, upon zooming from the wide-angle end state W to the telephoto end state T, the aperture stop S maintains the maximum aperture diameter of the wide-angle end state W from the wide-angle end state W to the second intermediate focal length state M2, and the second intermediate From the focal length state M2 to the telephoto end state T, the maximum aperture diameter increases monotonously.

  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 lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, and a cemented lens of a biconvex lens L33 and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The fourth lens group G4 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 in the fourth lens group G4 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 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 a biconcave lens L53 and a biconvex lens L54. ing. The positive meniscus lens L51 located closest to the object side in the fifth lens group G5 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. The fourth intermediate focal length state M4 has a focal length that exceeds 15 times the focal length of the wide-angle end state W.

  (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 26.56694
4 24-24.00147
5 29 33.81791

(Values for conditional expressions)
(1) f1 / fT = 0.419
(2) φT / φW = 1.228
(3) φM10 / φW = 1.222 (φM10 is the value of the fourth intermediate focal length state M4)
(4) φM15 / φW = 1.222 (φM15 is the value of the fourth intermediate focal length state M4)
(5) φM5 / φW = 1.111 (φM5 is the value of the third intermediate focal length state M3)
(6) fM / fW = 2.703 (fM is the value of the second intermediate focal length state M2)
(7) -f2 / fT = 0.0544

  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. The third lens group G3 having positive refractive power, the fourth lens group G4 having negative refractive power, and the fifth lens group G5 having 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, the lens moves toward the object side, and the third lens group G3 monotonously moves toward the object side. Furthermore, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases so that the fourth lens group G4 and the fifth lens group. G5 moves to the object side monotonously with respect to the image plane I. Further, the third lens group G3 and the fifth lens group G5 move integrally with the image plane I.

  The aperture stop S is disposed on the most 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 lens group G3. Further, upon zooming from the wide-angle end state W to the telephoto end state T, the aperture stop S maintains the maximum aperture diameter of the wide-angle end state W from the wide-angle end state W to the second intermediate focal length state M2, and the second intermediate From the focal length state M2 to the telephoto end state T, the maximum aperture diameter increases monotonously.

  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 lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, and a cemented lens of a biconvex lens L33 and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The fourth lens group G4 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 in the fourth lens group G4 is a composite aspheric lens in which an aspheric surface is formed by providing a resin layer on the lens surface on the object side.

  The fifth lens group G5 includes, 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 a biconcave lens L53 and a biconvex lens L54. ing. The positive meniscus lens L51 located closest to the object side in the fifth lens group G5 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 27.17463
4 24-25.4506
5 30 34.39022

(Values for conditional expressions)
(1) f1 / fT = 0.409
(2) φT / φW = 1.241
(3) φM10 / φW = 1.234 (φM10 is the value of the fourth intermediate focal length state M4)
(4) φM15 / φW = 1.234 (φM15 is the value of the fourth intermediate focal length state M4)
(5) φM5 / φW = 1.108 (φM5 is the value of the third intermediate focal length state M3)
(6) fM / fW = 2.642 (fM is the value of the second intermediate focal length state M2)
(7) -f2 / fT = 0.0537

  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. The third lens group G3 having positive refractive power, the fourth lens group G4 having negative refractive power, and the fifth lens group G5 having 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, the lens moves toward the object side, and the third lens group G3 monotonously moves toward the object side. Furthermore, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases so that the fourth lens group G4 and the fifth lens group. G5 moves to the object side monotonously with respect to the image plane I. Further, the third lens group G3 and the fifth lens group G5 move integrally with the image plane I.

  The aperture stop S is disposed on the most 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 lens group G3. When zooming from the wide-angle end state W to the telephoto end state T, the aperture stop S maintains the maximum aperture diameter of the wide-angle end state W from the wide-angle end state W to the third intermediate focal length state M3. From the focal length state M3 to the telephoto end state T, the maximum aperture diameter increases monotonously.

  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 lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, and a cemented lens of a biconvex lens L33 and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The fourth lens group G4 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 fourth lens group G4 is a glass mold aspheric lens having an aspheric lens surface on the image side.

  The fifth lens group G5 includes, 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 a biconcave lens L53 and a biconvex lens L54. ing. The positive meniscus lens L51 located closest to the object side in the fifth lens group G5 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 26.728858
4 24-25.10440
5 29 34.4993

(Values for conditional expressions)
(1) f1 / fT = 0.415
(2) φT / φW = 1.055
(3) φM10 / φW = 1.049 (φM10 is the value of the fourth intermediate focal length state M4)
(4) φM15 / φW = 1.049 (φM15 is the value of the fourth intermediate focal length state M4)
(5) φM5 / φW = 1.000 (φM5 is the value of the third intermediate focal length state M3)
(6) fM / fW = 5.627 (fM is the value of the third intermediate focal length state M3)
(7) -f2 / fT = 0.0533

  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. The third lens group G3 having positive refractive power, the fourth lens group G4 having negative refractive power, and the fifth lens group G5 having 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, the lens moves toward the object side, and the third lens group G3 monotonously moves toward the object side. Furthermore, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases so that the fourth lens group G4 and the fifth lens group. G5 moves to the object side monotonously with respect to the image plane I. Further, the third lens group G3 and the fifth lens group G5 move integrally with the image plane I.

  The aperture stop S is disposed on the most 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 lens group G3. When zooming from the wide-angle end state W to the telephoto end state T, the aperture stop S maintains the maximum aperture diameter of the wide-angle end state W from the wide-angle end state W to the first intermediate focal length state M1. From the focal length state M1 to the telephoto end state T, the maximum aperture diameter increases monotonously.

  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 lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, and a cemented lens of a biconvex lens L33 and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The fourth lens group G4 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 in the fourth lens group G4 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 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 a biconcave lens L53 and a biconvex lens L54. ing. The positive meniscus lens L51 located closest to the object side in the fifth lens group G5 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 27.10600
4 24 -24.659991
5 29 33.5757

(Values for conditional expressions)
(1) f1 / fT = 0.407
(2) φT / φW = 1.507
(3) φM10 / φW = 1.396 (φM10 is the value of the fourth intermediate focal length state M4)
(4) φM15 / φW = 1.396 (φM15 is the value of the fourth intermediate focal length state M4)
(5) φM5 / φW = 1.294 (φM5 is the value of the third intermediate focal length state M3)
(6) fM / fW = 1.526 (fM is the value of the first intermediate focal length state M1)
(7) -f2 / fT = 0.0536

  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. The third lens group G3 having positive refractive power, the fourth lens group G4 having negative refractive power, and the fifth lens group G5 having 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, the lens moves toward the object side, and the third lens group G3 monotonously moves toward the object side. Furthermore, the distance between the third lens group G3 and the fourth lens group G4 increases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases so that the fourth lens group G4 and the fifth lens group. G5 moves to the object side monotonously with respect to the image plane I.

  The aperture stop S is disposed on the most 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 lens group G3. Further, upon zooming from the wide-angle end state W to the telephoto end state T, the aperture stop S maintains the maximum aperture diameter of the wide-angle end state W from the wide-angle end state W to the second intermediate focal length state M2, and the second intermediate From the focal length state M2 to the telephoto end state T, the maximum aperture diameter increases monotonously.

  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 lens group G3 includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, and a cemented lens of a biconvex lens L33 and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The fourth lens group G4 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 in the fourth lens group G4 is a composite aspheric lens in which an aspheric surface is formed by providing a resin layer on the lens surface on the object side.

  The fifth lens group G5 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 fifth lens group G5 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 27.35473
4 24-26.50041
5 30 35.423

(Values for conditional expressions)
(1) f1 / fT = 0.404
(2) φT / φW = 1.241
(3) φM10 / φW = 1.234 (φM10 is the value of the fourth intermediate focal length state M4)
(4) φM15 / φW = 1.234 (φM15 is the value of the fourth intermediate focal length state M4)
(5) φM5 / φW = 1.108 (φM5 is the value of the third intermediate focal length state M3)
(6) fM / fW = 2.636 (fM is the value of the second intermediate focal length state M2)
(7) -f2 / fT = 0.0536

  FIGS. 14A and 14B show various aberration diagrams of the zoom optical system according to the fifth example in the infinitely focused 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. , A method for manufacturing a variable magnification optical system having a fourth lens group having negative refractive power and a fifth lens group having positive refractive power, and includes steps S1, S2, and S3 shown in FIG.

  Step S1: An aperture stop is disposed on the image side from the second lens group.

  Step S2: When the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group are changed from the wide-angle end state to the telephoto end state, the first lens group and the second lens group The distance between the lens group can be increased, the distance between the second lens group and the third lens group can be decreased, the distance between the third lens group and the fourth lens group can be changed, the fourth lens group and the fifth lens group It arranges so that the interval with can be changed.

Step S3: The following conditional expressions (1) and (2) are satisfied.
(1) 0.17 <f1 / fT <0.60
(2) 1.03 <φT / φW <1.70
Where fT is the focal length of the entire system in the telephoto end state, f1 is the focal length of the first lens group, φW is the maximum aperture diameter of the aperture stop in the wide-angle end state, and φT is the maximum aperture diameter of the aperture stop in the telephoto end state is there.

  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 fourth 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 errors in 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 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 third lens group has three positive lens components.

  In the variable power optical system of the present embodiment, it is preferable that the fourth lens group has two negative lens components.

  In the variable magnification optical system of the present embodiment, it is preferable that the fifth lens group has two positive lens components. In the fifth 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 G4 4th lens group G5 5th lens group S Aperture stop I Image surface 1 Camera

Claims (14)

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 group having a negative refractive power in order from the object side along the optical axis. A fifth lens unit having positive refractive power,
An aperture stop on the image side of the second lens group;
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 lens group decreases, The interval between the third lens group and the fourth lens group changes, the interval between the fourth lens group and the fifth lens group changes,
A zoom optical system characterized by satisfying the following conditional expression:
0.17 <f1 / fT <0.60
1.03 <φT / φW <1.70
However,
fT: focal length of the entire system in the telephoto end state f1: focal length φW of the first lens group: maximum aperture diameter of the aperture stop in the wide angle end state φT: maximum aperture diameter of the aperture stop in the telephoto end state The variable magnification optical system according to claim 1, wherein the following conditional expression is satisfied.
1.02 <φM10 / φW <1.70
However,
φM10: When the focal length of the entire system in the wide-angle end state is fW, the maximum aperture diameter of the aperture stop in the intermediate focal length state where the focal length of the entire system is 10 times or more of fW The variable magnification optical system according to claim 1, wherein the following conditional expression is satisfied.
1.02 <φM15 / φW <1.70
However,
φM15: Maximum aperture diameter of the aperture stop in an intermediate focal length state where the focal length of the whole system is 15 times or more of fW when the focal length of the whole system in the wide-angle end state is fW 4. The variable magnification optical system according to claim 1, wherein the following conditional expression is satisfied: 5.
1.00 ≦ φM5 / φW <1.40
However,
φM5: When the focal length of the entire system in the wide-angle end state is fW, the maximum aperture diameter of the aperture stop in the intermediate focal length state where the focal length of the entire system is 5 to 8 times fW During zooming from the wide-angle end state to the telephoto end state, the aperture stop maintains the maximum aperture diameter in the wide-angle end state from the wide-angle end state to the intermediate focal length state of the focal length fM of the entire system.
5. The variable magnification optical system according to claim 1, wherein the following conditional expression is satisfied.
1.50 <fM / fW <15.00
However,
fW: focal length of the entire system in the wide-angle end state   6. The variable magnification optical system according to claim 5, wherein the maximum aperture diameter of the aperture stop monotonously increases when the focal length fM is changed from the intermediate focal length state to the telephoto end state. The variable power optical system according to claim 1, wherein the following conditional expression is satisfied.
0.032 <−f2 / fT <0.064
However,
f2: Focal length of the second lens group   8. The variable magnification optical system according to claim 1, wherein the F number of the entire system monotonously increases upon zooming from the wide-angle end state to the telephoto end state.   9. The zoom optical system according to claim 1, wherein the first lens unit moves toward the object side with respect to the image plane during zooming from the wide-angle end state to the telephoto end state. system.   10. The zoom lens according to claim 1, wherein the aperture stop moves integrally with at least a part of the third lens group during zooming from the wide-angle end state to the telephoto end state. Variable magnification optical system.   11. The zoom optical system according to claim 1, wherein the aperture stop is disposed on the object side of the third lens group. 11.   12. The variable power optical system according to claim 1, wherein the third lens unit and the fifth lens unit move together when zooming from the wide-angle end state to the telephoto end state. system.   An optical apparatus comprising the variable magnification optical system according to claim 1. 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 group having a negative refractive power in order from the object side along the optical axis. A method of manufacturing a variable magnification optical system having a fifth lens unit having positive refractive power,
An aperture stop is disposed on the image side from the second lens group,
When changing the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group 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 lens group can be decreased, the distance between the third lens group and the fourth lens group can be changed, The distance between the fourth lens group and the fifth lens group is arranged to be variable,
A variable magnification optical system manufacturing method characterized by satisfying the following conditional expression:
0.17 <f1 / fT <0.60
1.03 <φT / φW <1.70
However,
fT: focal length of the entire system in the telephoto end state f1: focal length φW of the first lens group: maximum aperture diameter of the aperture stop in the wide angle end state φT: maximum aperture diameter of the aperture stop in the telephoto end state

Images