JP5724189B2 - Variable magnification optical system, optical device - Google Patents

Description

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

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

JP 2008-3195 A

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

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

In order to solve the above-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 F1 lens group having a positive refractive power in order from the object side along the optical axis. And the third B1 lens group having a positive refractive power substantially comprises four lens groups, and the third F1 lens group and the third B1 lens group have a positive refractive power as a whole, and telephoto from the wide-angle end state. Upon zooming to the end state, the first lens group moves monotonously to the object side with respect to the image plane, the distance between the first lens group and the second lens group increases, and the second lens group And the third F1 lens group decrease, the distance between the third F1 lens group and the third B1 lens group changes, and has an aperture stop on the image side from the second lens group. A variable magnification optical system characterized by satisfying
0.17 <f1 / fT <0.60
1.03 <φT / φW <1.70
1.02 <φM15 / φW <1.70
0.032 <−f2 / fT ≦ 0.0475
However,
fT: focal length of the entire system in the telephoto end state f1: focal length of the first lens group φW: 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 φM15: wide angle When the focal length of the entire system in the end state is fW, the maximum aperture diameter f2 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: the focal length of the second lens group In the present invention, in order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third F1 lens group having a positive refractive power, and a first lens unit having a positive refractive power. The third F1 lens group and the third B1 lens group have a positive refractive power as a whole, and the zoom lens changes from the wide-angle end state to the telephoto end state. The first lens group and the second lens The first lens group moves to the object side and the second lens group temporarily moves to the image side so that the distance to the group increases and the distance between the second lens group and the third F1 lens group decreases. Then, it moves to the object side, and the distance between the third F1 lens group and the third B1 lens group changes, or the first lens group having positive refractive power and negative refraction in order from the object side along the optical axis. The second lens group having the positive power, the third F2 lens group having the positive refractive power, the third M lens group having the negative refractive power, and the third B2 lens group having the positive refractive power substantially include five lens groups, The third F2 lens group, the third M lens group, and the third B2 lens group have positive refractive power as a whole, and the first lens group and the second lens group upon zooming from the wide-angle end state to the telephoto end state. And the distance between the second lens group and the third F2 lens group is The first lens group moves toward the object side, the second lens group moves once toward the image side and then moves toward the object side, and the distance between the third F2 lens group and the third M lens group is small. The distance between the third M lens group and the third B2 lens group changes, the aperture stop is located on the image side of the second lens group, and the following conditional expression is satisfied: An optical system is provided.
0.17 <f1 / fT ≦ 0.355
1.03 <φT / φW <1.70
1.02 <φM15 / φW <1.70
However,
fT: focal length of the entire system in the telephoto end state f1: focal length of the first lens group φW: 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 φM15: wide angle When the focal length of the entire system in the end state is fW, the maximum aperture diameter of the aperture stop in the intermediate focal length state in which the focal length of the entire system is 15 times or more of fW
Also, the present invention includes, in order from the object side along the optical axis, a first lens group having positive refractive power, a second lens unit having a negative refractive power, a third 3F1 lens group having positive refractive power, positive refractive power The third F1 lens group substantially comprises four lens groups, and the third F1 lens group and the third B1 lens group as a whole have positive refracting power and are more open to the image side than the second lens group. The first lens unit moves to the object side monotonously with respect to the image plane during zooming from the wide-angle end state to the telephoto end state, and the first lens unit and the second lens unit The distance increases, the distance between the second lens group and the third F1 lens group decreases, the distance between the third F1 lens group and the third B1 lens group changes, and the following conditional expression is satisfied: A variable magnification optical system is provided.
0.17 <f1 / fT <0.60
1.03 <φT / φW <1.70
0.032 <−f2 / fT ≦ 0.0394
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 f2: the above The focal length of the second lens group In the present invention, in order from the object side along the optical axis, the first lens group having a positive refractive power, the second lens group having a negative refractive power, and the third F2 lens having a positive refractive power. The third F2 lens group, the third M lens group, and the third B2 lens group. The third F2 lens group, the third M lens group, and the third B2 lens group. Has a positive refracting power as a whole, has an aperture stop closer to the image side than the second lens group, and the first lens group and the second lens group upon zooming from the wide-angle end state to the telephoto end state The distance between the second lens group and the third F2 is increased. The first lens group moves to the object side so that the distance from the lens group decreases, the second lens group temporarily moves to the image side, and then moves to the object side, and the third F2 lens group and the third M There is provided a variable magnification optical system characterized in that the distance between the lens group is changed, and the distance between the third M lens group and the third B2 lens group is changed to satisfy the following conditional expression.
0.17 <f1 / fT <0.60
1.03 <φT / φW <1.70
0.032 <−f2 / fT <0.057
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 f2: the above Focal length of the second lens group

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

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

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

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

  The variable magnification optical system according to this embodiment includes, in order from the object side along the optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. And having an aperture stop closer to the image side than the second lens group, and during 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, and the second lens group The distance between the first lens group and the third lens group is reduced, so that 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 variable power optical system according to the present embodiment, the third lens group has two positive refractive power subgroups, and two positive refractive powers are used for zooming from the wide-angle end state to the telephoto end state. It is desirable that the subgroup spacing changes.

  With this configuration, it becomes possible to increase the zooming power of the third lens group, and the zooming optical system can be miniaturized. In addition, when zooming from the wide-angle end state to the telephoto end state, it is possible to suppress variations in spherical aberration and astigmatism that occur in the third lens group, thereby realizing high optical performance.

  In the variable magnification optical system according to the present embodiment, the third lens group has a positive refractive power partial group, a negative refractive power partial group, and a positive refractive power partial group, from the wide-angle end state to the telephoto end. It is desirable to change the interval between the positive refractive power subgroup, the negative refractive power subgroup, and the positive refractive power subgroup upon zooming into the state.

  With this configuration, it becomes possible to increase the zooming power of the third lens group, and the zooming optical system can be miniaturized. In addition, when zooming from the wide-angle end state to the telephoto end state, it is possible to suppress variations in spherical aberration and astigmatism that occur in the third lens group, 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. And a third lens group G3 having a positive refractive power.

  When zooming from the wide-angle end state W to the telephoto end state T, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 decreases. Thus, with respect to the image plane I, the first lens group G1 moves monotonously to the object side, the second lens group G2 moves to the object side, and the third lens group G3 moves monotonously to the object side.

  Further, the third lens group G3 is composed of a 31st lens group G31 having a positive refractive power and a 32nd lens group G32 having a positive refractive power, and in the zooming from the wide angle end state W to the telephoto end state T, The 31st lens group G31 and the 32nd lens group G32 move monotonously with respect to the image plane I toward the object side so that the distance between the 31st lens group G31 and the 32nd lens group G32 decreases.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the 31st lens group G31. 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, and a negative meniscus lens having a convex surface directed toward the image side. It consists of a cemented lens of L24 and a positive meniscus lens L25 having a convex surface facing the image side. 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 thirty-first lens group G31 includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, a cemented lens of the biconvex lens L33 and the biconcave lens L34, and a cemented structure of the biconcave lens L35 and the biconvex lens L36. The lens includes a negative meniscus lens L37 having a concave surface facing the object side. The biconcave lens L35 is a glass mold aspheric lens having an aspheric lens surface on the object side.

  The thirty-second lens group G32 includes, in order from the object side along the optical axis, a biconvex lens L41, and a cemented lens of a negative meniscus lens L42 having a convex surface facing the object side and a biconvex lens L43. The biconvex lens L41 located closest to the object side in the thirty-second lens group G32 is a glass mold aspheric lens having an aspheric lens surface on the object side. Light rays emitted from the biconvex lens L43 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 ∞ ∞
1 127.9445 2.0000 1.850260 32.35
2 66.5460 7.8500 1.497820 82.52
3 -596.2307 0.1000
4 67.4403 5.4000 1.593190 67.87
5 436.1899 (variable)

6 * 135.2961 0.1500 1.553890 38.09
7 107.2597 1.0000 1.804000 46.58
8 15.2626 6.7000
9 -34.5499 1.0000 1.834807 42.72
10 51.8990 0.1000
11 34.0967 4.5000 1.784723 25.68
12 -32.1245 0.9000
13 -21.1157 1.0000 1.882997 40.76
14 -2390.2062 2.1000 1.922860 20.50
15 -67.6125 (variable)

16 (Aperture) ∞ 1.0000
17 31.6133 3.6500 1.593190 67.87
18 -218.5545 0.1000
19 49.1304 3.2000 1.487490 70.41
20 -63.6210 0.1000
21 35.3573 4.2500 1.487490 70.41
22 -34.0783 1.0000 1.846660 23.78
23 659.9606 3.9000
24 * -35.0367 1.0000 1.756998 47.82
25 17.5822 3.9000 1.698947 30.13
26 -95.2623 3.3500
27 -55.5200 1.0000 1.882997 40.76
28 -585.5172 (variable)

29 * 439.7935 2.2000 1.589130 61.16
30 -53.2069 0.1000
31 65.1340 1.0000 1.834000 37.16
32 27.7296 4.1000 1.487490 70.41
33 -58.1329 (Bf)
Image plane ∞

(Aspheric data)
6th surface κ = 4.3350
A4 = 9.45630E-06
A6 = -1.51470E-08
A8 = -1.16860E-12
A10 = 1.65790E-13
24th surface κ = -0.3009
A4 = 6.23810E-06
A6 = 8.96820E-09
A8 = 0.00000E + 00
A10 = 0.00000E + 00
29th surface κ = -20.0000
A4 = -1.92960E-05
A6 = 5.96200E-09
A8 = -1.65600E-10
A10 = 4.18100E-13

(Various data)
Zoom ratio 15.698
W M1 M2 M3 M4 T
f = 18.53928 27.99917 49.99950 105.00169 278.75308 291.02949
FNO = 3.60631 4.19068 5.39086 5.76130 5.78421 5.78825
ω = 39.00856 26.78890 15.55965 7.48510 2.85557 2.73699
Y = 14.20 14.20 14.20 14.20 14.20 14.20
TL = 148.79923 157.22054 181.95557 217.34659 241.72065 242.82932
Bf = 39.00067 52.54373 76.57450 91.11965 104.16125 105.34665
φ = 17.20 17.20 17.20 18.40 20.40 20.59

d5 2.10000 9.42195 20.39318 46.65937 66.86210 67.33267
d15 33.50310 24.00476 15.75155 10.98454 2.49980 2.00000
d28 7.54546 4.60010 2.58634 1.93303 1.54750 1.50000

(Zoom lens group data)
Group Start surface Focal length 1 1 104.3654
2 6-13.81152
3 16 36.1068 (W) 34.3169 (M1)
33.03282 (M2) 32.66171 (M3)
32.4464 (M4) 32.4030 (T)
31 16 39.54020
32 29 48.03635

(Values for conditional expressions)
(1) f1 / fT = 0.358
(2) φT / φW = 1.197
(3) φM10 / φW = 1.186 (φM10 is the value of the fourth intermediate focal length state M4)
(4) φM15 / φW = 1.186 (φM15 is the value of the fourth intermediate focal length state M4)
(5) φM5 / φW = 1.070 (φM5 is the value of the third intermediate focal length state M3)
(6) fM / fW = 2.70 (fM is the value of the second intermediate focal length state M2)
(7) -f2 / fT = 0.0475

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

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

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

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

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

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

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

  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, the second lens group G2 moves to the object side, and the third lens group G3 moves monotonously to the object side.

  Further, the third lens group G3 is composed of a 31st lens group G31 having a positive refractive power and a 32nd lens group G32 having a positive refractive power, and in the zooming from the wide angle end state W to the telephoto end state T, The 31st lens group G31 and the 32nd lens group G32 move monotonously with respect to the image plane I toward the object side so that the distance between the 31st lens group G31 and the 32nd lens group G32 decreases.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the 31st lens group G31. 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, and a biconcave lens L24. 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 thirty-first lens group G31 includes, in order from the object side along the optical axis, a cemented lens of a biconvex lens L31, a biconvex lens L32, and a negative meniscus lens L33 having a concave surface facing the object side, and a biconcave lens L34 and the object side. It is composed of a cemented lens with a positive meniscus lens L35 having a convex surface. The biconcave lens L34 is a composite aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The thirty-second lens group G32 includes, in order from the object side along the optical axis, a biconvex lens L41, a cemented lens of a biconvex lens L42 and a biconcave lens L43, and a biconvex lens L44. The biconvex lens L41 located closest to the object side in the thirty-second lens group G32 is a glass mold aspheric lens having an aspheric lens surface on the object side. The light beam emitted from the biconvex lens L44 forms 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 ∞ ∞
1 107.0206 1.8000 1.903658 31.31
2 61.2968 9.0132 1.456500 90.27
3 -505.7797 0.1000
4 56.5708 6.5660 1.603001 65.44
5 263.1448 (variable)

6 * 107.6633 0.1500 1.553890 38.09
7 79.4357 1.2000 1.816000 46.62
8 12.5498 5.8961
9 -28.1361 1.0000 1.816000 46.62
10 76.8103 0.1000
11 29.0330 5.0805 1.846660 23.78
12 -28.2941 0.7021
13 -20.3234 1.0000 1.788001 47.37
14 328.3222 (variable)

15 (Aperture) ∞ 0.5000
16 38.5144 4.3804 1.527510 66.72
17 -31.0868 0.1000
18 24.8278 5.7092 1.497000 81.64
19 -22.4849 1.0000 1.850260 32.35
20 -1199.4167 3.0000
21 * -52.5575 0.1000 1.553890 38.09
22 -56.7769 1.0000 1.772499 49.60
23 32.9354 1.9482 1.805181 25.42
24 83.4259 (variable)

25 * 38.1701 5.1517 1.677900 54.89
26 -30.3075 0.1000
27 119.1216 5.7937 1.511790 49.72
28 -16.9262 1.0000 1.878780 41.73
29 40.2625 0.7994
30 88.7687 4.0188 1.497970 53.26
31 -31.8725 (Bf)
Image plane ∞

(Aspheric data)
6th surface κ = 1.0000
A4 = 8.23600E-06
A6 = 2.68070E-08
A8 = -2.85680E-10
A10 = 8.96110E-13
21st surface κ = 1.0000
A4 = 8.39680E-06
A6 = 4.90050E-09
A8 = 0.00000E + 00
A10 = 0.00000E + 00
25th surface κ = 1.0000
A4 = -1.05940E-05
A6 = 2.60370E-08
A8 = 0.00000E + 00
A10 = 0.00000E + 00

(Various data)
Zoom ratio 15.666
W M1 M2 M3 M4 T
f = 18.57581 27.79158 50.03219 134.79308 281.38675 291.01598
FNO = 3.58467 4.09252 5.03317 6.30198 6.35021 6.35739
ω = 38.75301 26.53439 15.40656 5.90773 2.83943 2.74550
Y = 14.20 14.20 14.20 14.20 14.20 14.20
TL = 141.06118 153.60481 176.97503 214.13726 226.92995 227.18745
Bf = 38.02328 48.03831 64.55253 85.33826 92.38485 92.60805
φ = 15.40 15.40 15.40 15.40 16.20 16.20

d5 2.12080 12.45490 26.91570 50.67230 62.28300 62.67010
d14 23.69130 18.40230 13.31350 7.80730 2.14860 1.80000
d24 10.01650 7.50000 4.98400 3.11010 2.90420 2.90000

(Zoom lens group data)
Group Start surface Focal length 1 1 95.68946
2 6 -11.14695
3 15 31.13029 (W) 29.77152 (M1)
28.52664 (M2) 27.66506 (M3)
277.5355 (M4) 277.5169 (T)
31 15 42.77504
32 25 40.12768

(Values for conditional expressions)
(1) f1 / fT = 0.329
(2) φT / φW = 1.052
(3) φM10 / φW = 1.052 (φM10 is the value of the fourth intermediate focal length state M4)
(4) φM15 / φW = 1.052 (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 = 7.256 (fM is the value of the third intermediate focal length state M3)
(7) -f2 / fT = 0.0394

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

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

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

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

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

  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.

  Further, the third lens group G3 is composed of a 31st lens group G31 having a positive refractive power and a 32nd lens group G32 having a positive refractive power, and in the zooming from the wide angle end state W to the telephoto end state T, The 31st lens group G31 and the 32nd lens group G32 move monotonously with respect to the image plane I toward the object side so that the distance between the 31st lens group G31 and the 32nd lens group G32 decreases.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the 31st lens group G31. 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, and a negative meniscus lens having a convex surface directed toward the image side. It consists of a cemented lens of L24 and a positive meniscus lens L25 having a convex surface facing the image side. 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 thirty-first lens group G31 has, in order from the object side along the optical axis, a convex surface facing the biconvex lens L31, the biconvex lens L32, the cemented lens of the biconvex lens L33 and the biconcave lens L34, and the biconcave lens L35. Further, it is composed of a cemented lens with the positive meniscus lens L36 and a negative meniscus lens L37 having a concave surface facing the object side. The biconcave lens L35 is a glass mold aspheric lens having an aspheric lens surface on the object side.

  The thirty-second lens group G32 includes, in order from the object side along the optical axis, a biconvex lens L41 and a cemented lens of a biconcave lens L42 and a biconvex lens L43. The biconvex lens L41 located closest to the object side in the thirty-second lens group G32 is a glass mold aspheric lens having an aspheric lens surface on the object side. Light rays emitted from the biconvex lens L43 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 ∞ ∞
1 123.9595 2.0000 1.850260 32.35
2 65.8189 9.3000 1.497820 82.52
3 -679.8190 0.1000
4 66.6349 6.2000 1.593190 67.87
5 419.9308 (variable)

6 * 162.3242 0.1500 1.553890 38.09
7 146.0754 1.0000 1.834807 42.72
8 16.1304 6.5500
9 -35.2760 1.0000 1.882997 40.76
10 60.4450 0.1000
11 37.3723 5.2000 1.846660 23.78
12 -32.7279 0.8214
13 -23.9463 1.0000 1.882997 40.76
14 -252.4150 2.0000 1.808090 22.79
15 -72.4479 (variable)

16 (Aperture) ∞ 1.0000
17 36.7222 3.3000 1.593190 67.87
18 -118.1963 0.1000
19 41.3768 3.1500 1.487490 70.41
20 -92.3429 0.1000
21 42.3403 3.8000 1.487490 70.41
22 -41.0036 1.0000 1.805181 25.43
23 259.3609 3.8191
24 * -63.6485 1.0000 1.806100 40.94
25 22.0000 2.9000 1.805181 25.43
26 150.5781 4.2000
27 -45.8244 1.0000 1.882997 40.76
28 -215.9895 (variable)

29 * 77.1794 3.1500 1.589130 61.16
30 -37.1187 0.1000
31 -261.2949 1.0000 1.882997 40.76
32 39.9808 4.4000 1.518229 58.93
33 -48.5209 (Bf)
Image plane ∞

(Aspheric data)
6th surface κ = -5.7774
A4 = 6.79980E-06
A6 = -2.52730E-08
A8 = 8.26150E-11
A10 = -1.02860E-13
24th surface κ = 2.8196
A4 = 4.59750E-06
A6 = 4.28350E-09
A8 = 0.00000E + 00
A10 = 0.00000E + 00
29th surface κ = -6.5363
A4 = -1.95310E-05
A6 = 1.79050E-08
A8 = -1.55070E-10
A10 = 4.13770E-13

(Various data)
Zoom ratio 15.696
W M1 M2 M3 M4 T
f = 18.53979 27.99960 49.99905 104.99746 281.99442 290.99204
FNO = 4.10702 4.69307 5.38961 5.39973 5.39860 5.39939
ω = 38.99845 26.65869 15.38789 7.50128 2.82458 2.73812
Y = 14.20 14.20 14.20 14.20 14.20 14.20
TL = 160.00885 165.81325 187.27349 218.99165 237.63297 237.79997
Bf = 39.11693 51.53459 69.40178 89.39051 98.87896 99.16649
φ = 15.60 15.60 16.50 20.00 21.72 21.78

d5 2.15153 10.22614 25.00000 45.02627 65.29400 65.69297
d15 40.45482 29.25621 20.27964 13.14016 2.48000 2.00000
d28 8.84506 5.35580 3.15156 1.99420 1.53950 1.50000

(Zoom lens group data)
Group Start surface Focal length 1 1 103.25223
2 6-15.13084
3 16 39.5369 (W) 37.13627 (M1)
35.75578 (M2) 35.07124 (M3)
34.80941 (M4) 34.78685 (T)
31 16 44.74649
32 29 47.36030

(Values for conditional expressions)
(1) f1 / fT = 0.355
(2) φT / φW = 1.396
(3) φM10 / φW = 1.392 (φM10 is the value of the fourth intermediate focal length state M4)
(4) φM15 / φW = 1.392 (φM15 is the value of the fourth intermediate focal length state M4)
(5) φM5 / φW = 1.282 (φM5 is the value of the third intermediate focal length state M3)
(6) fM / fW = 1.510 (fM is the value of the first intermediate focal length state M1)
(7) -f2 / fT = 0.0520

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

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

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

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

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

  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.

  Further, the third lens group G3 includes a 31st lens group G31 having a positive refractive power, a 32nd lens group G32 having a negative refractive power, and a 33rd lens group G33 having a positive refractive power. At the time of zooming to the telephoto end state T, the distance between the 31st lens group G31 and the 32nd lens group G32 increases, and the distance between the 32nd lens group G32 and the 33rd lens group G33 decreases. The lens group G31, the thirty-second lens group G32, and the thirty-third lens group G33 move toward the object side with respect to the image plane I.

  The aperture stop S is disposed closest to the object side of the third lens group G3 on the image side of the second lens group G2, and is configured integrally with the 31st lens group G31. 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 thirty-first lens group G31 includes, in order from the object side along the optical axis, a biconvex lens L31, a biconvex lens L32, a cemented lens of a biconvex lens L33, and a negative meniscus lens L34 having a concave surface facing the object side. ing.

  The thirty-second lens group G32 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 thirty-second lens group G32 is a compound aspherical lens in which an aspherical surface is formed by providing a resin layer on the object-side lens surface.

  The thirty-third lens group G33 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 thirty-third lens group G33 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 ∞ ∞
1 175.6056 2.2000 1.834000 37.16
2 67.4302 8.8000 1.497820 82.52
3 -587.7848 0.1000
4 72.2710 6.4500 1.593190 67.87
5 1826.1388 (variable)

6 * 84.7687 0.1000 1.553890 38.09
7 73.9375 1.2000 1.834807 42.72
8 17.1873 6.9500
9 -36.9822 1.0000 1.816000 46.62
10 77.9263 0.1500
11 36.6346 5.3000 1.784723 25.68
12 -36.6346 0.8000
13 -26.1991 1.0000 1.816000 46.62
14 63.7396 2.0500 1.808090 22.79
15 -643.2706 (variable)

16 (Aperture) ∞ 1.0000
17 65.8365 3.4000 1.593190 67.87
18 -50.1546 0.1000
19 65.6817 2.4500 1.487490 70.41
20 -154.9743 0.1000
21 46.7333 4.2000 1.487490 70.41
22 -35.7833 1.0000 1.808090 22.79
23 -191.9318 (variable)

24 * -57.2966 0.2000 1.553890 38.09
25 -59.7250 0.9000 1.696797 55.52
26 28.5100 2.1500 1.728250 28.46
27 91.9976 4.1402
28 -32.8954 1.0000 1.729157 54.66
29 -144.3315 (variable)

30 * 6427.1919 4.6500 1.589130 61.18
31 -27.3818 0.1000
32 31.4776 5.8500 1.487490 70.41
33 -43.7539 1.4500
34 -113.5897 1.0000 1.882997 40.76
35 20.3481 5.3000 1.548141 45.79
36 -709.1453 (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 15.701
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 = 164.76435 171.02547 189.44683 225.28899 249.99418 250.61470
Bf = 38.84705 44.06807 62.50183 73.57929 86.00428 86.64770
φ = 15.80 15.80 15.80 17.50 19.50 19.60

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

(Zoom lens group data)
Group Start surface Focal length 1 1 117.7729
2 6 -15.60945
3 16 40.44771 (W) 39.66103 (M1)
35.67164 (M2) 33.95695 (M3)
32.73988 (M4) 32.70088 (T)
31 16 27.35473
32 24 -26.50041
33 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

  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.

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

  In FIG. 13, 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. 14 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 variable magnification optical system manufacturing method comprising 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 changing the magnification of the first lens group, the second lens group, and the third lens group from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group can be increased. The distance between the second lens group and the third lens group is arranged so as to be reduced.

Step 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.

In the embodiment, the 4-group and 5-group configurations are shown, but the present invention can be applied to other group configurations such as the 6- 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 third 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 and one negative lens component.

  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 G31 31st lens group G32 32nd lens group G33 33rd lens group S Aperture stop I Image plane 1 Camera

Claims (14)

In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a third F1 lens group having a positive refractive power, and a third B1 lens group having a positive refractive power It consists essentially of four lens groups,
The third F1 lens group and the third B1 lens group have positive refracting power as a whole,
When zooming from the wide-angle end state to the telephoto end state, the first lens group moves monotonously to the object side with respect to the image plane, and the distance between the first lens group and the second lens group increases. The distance between the second lens group and the third F1 lens group decreases, and the distance between the third F1 lens group and the third B1 lens group changes,
An aperture stop on the image side of the second lens group;
A zoom optical system characterized by satisfying the following conditional expression:
0.17 <f1 / fT <0.60
1.03 <φT / φW <1.70
1.02 <φM15 / φW <1.70
0.032 <−f2 / fT ≦ 0.0475
However,
fT: focal length of the entire system in the telephoto end state f1: focal length of the first lens group φW: 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 φM15: wide angle When the focal length of the entire system in the end state is fW, the maximum aperture diameter f2 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: the focal length of the second lens group In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a third F1 lens group having a positive refractive power, and a third B1 lens group having a positive refractive power It consists essentially of four lens groups,
The third F1 lens group and the third B1 lens group have positive refracting power as a whole,
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 increases, and the distance between the second lens group and the third F1 lens group decreases. The first lens group moves toward the object side, the second lens group moves once toward the image side and then moves toward the object side, and the distance between the third F1 lens group and the third B1 lens group changes,
Or
A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third F2 lens group having a positive refractive power, and a third M lens group having a negative refractive power in order from the object side along the optical axis; It consists of substantially five lens groups by the third B2 lens group having positive refractive power,
The third F2 lens group, the third M lens group, and the third B2 lens group have positive refracting power as a whole,
During zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group is increased, and the distance between the second lens group and the third F2 lens group is decreased. The first lens group moves toward the object side, the second lens group moves once toward the image side and then moves toward the object side, and the distance between the third F2 lens group and the third M lens group changes, The distance between the third M lens group and the third B2 lens group changes,
An aperture stop on the image side of the second lens group;
A zoom optical system characterized by satisfying the following conditional expression:
0.17 <f1 / fT ≦ 0.355
1.03 <φT / φW <1.70
1.02 <φM15 / φW <1.70
However,
fT: focal length of the entire system in the telephoto end state f1: focal length of the first lens group φW: 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 φM15: wide angle When the focal length of the entire system in the end state is fW, the maximum aperture diameter of the aperture stop in the intermediate focal length state in which the focal length of the entire system is 15 times or more of fW In order from the object side along the optical axis, a first lens unit having a positive refractive power, a second lens group having a negative refractive power, a third F1 lens group having a positive refractive power, and a third B1 lens group having a positive refractive power It consists essentially of four lens groups,
The third F1 lens group and the third B1 lens group have positive refracting power as a whole,
An aperture stop on the image side of the second lens group;
When zooming from the wide-angle end state to the telephoto end state, the first lens group moves monotonously to the object side with respect to the image plane, and the distance between the first lens group and the second lens group increases. The distance between the second lens group and the third F1 lens group decreases, and the distance between the third F1 lens group and the third B1 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
0.032 <−f2 / fT ≦ 0.0394
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 f2: the above Focal length of the second lens group A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third F2 lens group having a positive refractive power, and a third M lens group having a negative refractive power in order from the object side along the optical axis; It consists of substantially five lens groups by the third B2 lens group having positive refractive power,
The third F2 lens group, the third M lens group, and the third B2 lens group have positive refracting power as a whole,
An aperture stop on the image side of the second lens group;
During zooming from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group is increased, and the distance between the second lens group and the third F2 lens group is decreased. The first lens group moves toward the object side, the second lens group moves once toward the image side and then moves toward the object side, and the distance between the third F2 lens group and the third M lens group changes, The distance between the third M lens group and the third B2 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
0.032 <−f2 / fT <0.057
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 f2: the above Focal length of the second lens group 5. The zoom optical system according to claim 3, 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 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.
Variable-power optical system according to claim 1, any one of 4, characterized by satisfying the following conditional expression.
1.50 <fM / fW <15.00
However,
fW: focal length of the entire system in the wide-angle end state 7. The variable magnification optical system according to claim 6 , 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 magnification optical system according to claim 2, wherein the following conditional expression is satisfied.
0.032 <−f2 / fT <0.064
However,
f2: Focal length of the second lens group Variable-power optical system according to any one of claims 1 8, characterized by satisfying the following conditional expression.
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 Variable-power optical system according to any one of claims 1 9, characterized by satisfying the following conditional expression.
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 Angle end state to the telephoto end state, the entire system variable magnification optical system according to claim 1, any one of 10 F-number, characterized in that the monotonically increasing in. In zooming from the wide-angle end state to the telephoto end state, the aperture stop has at least one of the third F1 lens group and the 3B1 lens group when the zooming optical system is substantially composed of four lens groups. When the variable magnification optical system is substantially composed of five lens groups, it is integrated with at least a part of the third F2 lens group, the third M lens group, and the 3B2 lens group. variable power optical system according to any one of claims 1 to 11, characterized in that movement. The aperture stop is disposed on the object side of the third F1 lens group when the variable magnification optical system is substantially composed of four lens groups, and the variable magnification optical system is substantially composed of five lens groups. variable power optical system according to any one of claims 1 to 12, characterized in that arranged on the object side of the first 3F2 lens group when made. Optical apparatus characterized by having a variable magnification optical system according to any one of claims 1 to 13.

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