JP2017129668A - Variable magnification optical system, optical instrument, and variable magnification optical system manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable magnification optical system, an optical instrument, and a variable magnification optical system manufacturing method that include an excellent optical performance.SOLUTION: A variable magnification optical system ZL including a plurality of lens groups in which an interval among the lens groups varies upon varying magnification comprises: an aperture stop S; at least one object side focusing group GfF that is disposed on an object side further than the aperture stop S, and moves in an optical axis direction upon focusing; and at least one image side focusing group DfR that is disposed on an image side further than the aperture stop, and moves in the optical axis direction upon focusing. Upon focusing, the object side focusing group GfF is different in a movement trajectory from the image side focusing group DfR, and a prescribed condition is satisfied.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, a variable magnification optical system having a short-distance focusing function by focusing on a plurality of groups has been proposed (for example, see Patent Document 1). However, Patent Document 1 has a problem that further improvement in optical performance is desired.

JP 2009-271471 A

A variable magnification optical system according to the present invention is a variable magnification optical system having a plurality of lens groups, and the distance between the lens groups changes at the time of zooming, and is disposed on the object side of the aperture stop and the aperture stop. And at least one object-side focusing group that moves in the optical axis direction during focusing, and at least one image-side focusing group that is disposed closer to the image side than the aperture stop and moves in the optical axis direction during focusing, At the time of focusing, the movement trajectory of the object-side focusing group and the image-side focusing group is different, and one of the object-side focusing group and one of the image-side focusing group is set as the first focusing group, When the other is the second focusing group, the following condition is satisfied.
| Ff1 / ff2 | <1.00
0.010 <| FZ2T / FZ1T | <1.00
0.050 <| FZ2W / FZ2T | <0.950
However,
ff1: Focal length of the first focusing group ff2: Focal length of the second focusing group FZ1T: When the first focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state Fluctuation amount of axial focusing position [mm]
FZ2W: On-axis focal position fluctuation amount [mm] when the second focus group moves 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focus state
FZ2T: On-axis focal position variation amount [mm] when the second focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and infinitely focused state

Further, the variable magnification optical system according to the present invention is a variable magnification optical system having a plurality of lens groups, and the distance between the lens groups changes at the time of zooming, and is arranged on the object side from the aperture stop. And at least one object-side focusing group that moves in the optical axis direction during focusing, and at least one image-side focusing group that is disposed closer to the image side than the aperture stop and moves in the optical axis direction during focusing. However, at the time of focusing, the movement trajectory of the object-side focusing group and the image-side focusing group are different, and one of the image-side focusing groups is set as the first focusing group, and one of the object-side focusing groups is set as the first focusing group. When two focusing groups are used, the following condition is satisfied.
| Ff1 / ff2 | <1.00
However,
ff1: Focal length of the first focusing group ff2: Focal length of the second focusing group

A method for manufacturing a variable magnification optical system according to the present invention is a method for manufacturing a variable magnification optical system having a plurality of lens groups, and the distance between the lens groups changes at the time of zooming. At least one object-side focusing group that is arranged closer to the object side and moves in the optical axis direction during focusing, and at least one image-side focusing group that is arranged closer to the image side than the aperture stop and moves in the optical axis direction during focusing Are arranged so that the movement trajectories of the object-side focusing group and the image-side focusing group are different during focusing, and one of the object-side focusing group and one of the image-side focusing group is arranged. Of these, when one is a first focusing group and the other is a second focusing group, they are arranged so as to satisfy the following condition.
| Ff1 / ff2 | <1.00
0.010 <| FZ2T / FZ1T | <1.00
0.050 <| FZ2W / FZ2T | <0.950
However,
ff1: Focal length of the first focusing group ff2: Focal length of the second focusing group FZ1T: When the first focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state Fluctuation amount of axial focusing position [mm]
FZ2W: On-axis focal position fluctuation amount [mm] when the second focus group moves 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focus state
FZ2T: On-axis focal position variation amount [mm] when the second focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and infinitely focused state

FIG. 4 is a cross-sectional view illustrating a lens configuration in an infinitely focused state of the variable magnification optical system according to the first example, where (W) represents a wide-angle end state, (M) represents an intermediate focal length state, and (T ) Indicates the telephoto end state. FIG. 4 is a diagram showing various aberrations of the zoom optical system according to the first embodiment in an infinitely focused state, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T) shows telephoto. Indicates the end state. FIG. 5A is a diagram illustrating various aberrations of the zoom optical system according to the first embodiment in a close-up focus state, where (W) represents a wide-angle end state, (M) represents an intermediate focal length state, and (T) represents a telephoto end. Indicates the state. FIG. 6 is a cross-sectional view showing a lens configuration of an infinitely focused state of a variable magnification optical system according to a second example, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T ) Indicates the telephoto end state. FIG. 6 is a diagram illustrating various aberrations of the zoom optical system according to the second embodiment in an infinitely focused state, where (W) indicates a wide-angle end state, (M) indicates an intermediate focal length state, and (T) indicates telephoto. Indicates the end state. FIG. 6 is a diagram illustrating various aberrations in the close-up focus state of the variable magnification optical system according to the second embodiment, where (W) indicates a wide-angle end state, (M) indicates an intermediate focal length state, and (T) indicates a telephoto end. Indicates the state. FIG. 6 is a cross-sectional view showing a lens configuration of an infinitely focused state of a variable magnification optical system according to a third example, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T ) Indicates the telephoto end state. FIG. 10 is a diagram illustrating various aberrations of the zoom optical system according to the third embodiment in an infinitely focused state, where (W) indicates a wide-angle end state, (M) indicates an intermediate focal length state, and (T) indicates telephoto. Indicates the end state. FIG. 10 is a diagram illustrating various aberrations in the close-up focus state of the variable magnification optical system according to the third embodiment, where (W) indicates a wide-angle end state, (M) indicates an intermediate focal length state, and (T) indicates a telephoto end. Indicates the state. FIG. 6 is a cross-sectional view showing a lens configuration of an infinitely focused state of a variable magnification optical system according to a fourth example, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T ) Indicates the telephoto end state. FIG. 11 is a diagram illustrating various aberrations of the zoom optical system according to the fourth embodiment in an infinitely focused state, where (W) indicates a wide-angle end state, (M) indicates an intermediate focal length state, and (T) indicates telephoto. Indicates the end state. FIG. 10 is a diagram illustrating various aberrations in the close-up focus state of the variable magnification optical system according to the fourth embodiment, in which (W) represents a wide-angle end state, (M) represents an intermediate focal length state, and (T) represents a telephoto end. Indicates the state. FIG. 9 is a cross-sectional view showing a lens configuration of an infinitely focused state of a variable magnification optical system according to a fifth example, where (W) shows a wide-angle end state, (M) shows an intermediate focal length state, and (T ) Indicates the telephoto end state. FIG. 11 is a diagram illustrating various aberrations of the variable magnification optical system according to the fifth embodiment in an infinitely focused state, where (W) represents a wide-angle end state, (M) represents an intermediate focal length state, and (T) represents telephoto. Indicates the end state. FIG. 10 is a diagram illustrating various aberrations in the close-up focus state of the variable magnification optical system according to the fifth embodiment, where (W) represents a wide-angle end state, (M) represents an intermediate focal length state, and (T) represents a telephoto end. Indicates the state. It is sectional drawing of the camera carrying the said variable magnification optical system. It is a flowchart for demonstrating the manufacturing method of the said variable magnification optical system.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the zoom optical system ZL according to the present embodiment has a plurality of lens groups, and is configured such that the distance between the lens groups changes during zooming. The variable magnification optical system ZL includes an aperture stop S, at least one object-side focusing group GfF that is disposed on the object side of the aperture stop S and moves in the optical axis direction during focusing, and an image side of the aperture stop S. And at least one image-side focusing group GfR that moves in the optical axis direction during focusing. Further, the object-side focusing group GfF and the image-side focusing group GfR are configured to have different movement trajectories during focusing. Thus, by performing focusing with a plurality of focusing groups arranged before and after the aperture stop S, off-axis performance, particularly field curvature, at the time of short-distance focusing can be corrected well.

  Here, in the zoom optical system ZL according to the present embodiment, one of the object-side focusing group GfF and one of the image-side focusing group GfR is set as the first focusing group Gf1, and the other is set as the second focusing group Gf1. When the focusing group is Gf2, the following conditional expression (1) is satisfied.

| Ff1 / ff2 | <1.000 (1)
However,
ff1: focal length of the first focusing group Gf1 ff2: focal length of the second focusing group Gf2

  Conditional expression (1) indicates that one of the object-side focusing group GfF and one of the image-side focusing group GfR has the stronger refractive power as the first focusing group Gf1 and the one with the lower refractive power as the first focusing group GfR. This is defined as a two-focus group Gf2. In the zoom optical system ZL according to the present embodiment, the first focusing group Gf1 has a function of forming an image on the image plane when the object moves, and the second focusing group Gf2 It has a function of correcting the peripheral aberration (off-axis aberration) due to the movement of the focusing group Gf1. When the upper limit of conditional expression (1) is exceeded, the refractive power of the first focusing group Gf1 becomes weak, the amount of movement during focusing increases, and off-axis aberrations, field curvature, coma that occur during focusing are increased. A lot of aberrations occur. Also, if the refractive power of the second focusing group Gf2 becomes too strong, spherical aberration will be deteriorated when performing field curvature correction. In order to secure the effect of conditional expression (1), it is desirable to set the upper limit value of conditional expression (1) to 0.900. In order to further secure the effect of conditional expression (1), it is desirable to set the upper limit value of conditional expression (1) to 0.800. In order to further secure the effect of the conditional expression (1), it is desirable to set the upper limit value of the conditional expression (1) to 0.700. In order to further secure the effect of the conditional expression (1), it is desirable to set the upper limit value of the conditional expression (1) to 0.600. In order to further secure the effect of conditional expression (1), it is desirable to set the upper limit value of conditional expression (1) to 0.500.

  Also, in the vicinity of the lower limit value of conditional expression (1), the refractive power of the second focusing group Gf2 becomes too weak, so that field curvature correction cannot be performed satisfactorily. Therefore, in order to ensure the effect of the conditional expression (1), it is desirable to set the lower limit value of the conditional expression (1) to 0.020. In order to further secure the effect of the conditional expression (1), it is desirable to set the lower limit value of the conditional expression (1) to 0.040. In order to further secure the effect of the conditional expression (1), it is desirable to set the lower limit value of the conditional expression (1) to 0.060. In order to further secure the effect of the conditional expression (1), it is desirable that the lower limit value of the conditional expression (1) is 0.080. In order to further secure the effect of conditional expression (1), it is desirable to set the lower limit value of conditional expression (1) to 0.100.

  In addition, it is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (2).

0.010 <| FZ2T / FZ1T | <1.000 (2)
However,
FZ1T: On-axis focal position fluctuation amount [mm] when the first focusing group Gf1 moves 1 [mm] in the optical axis direction in the telephoto end state and infinitely focused state
FZ2T: A variation amount [mm] of the on-axis focusing position when the second focusing group Gf2 moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state

  Conditional expression (2) defines the focus position sensitivity of the first focus group Gf1 and the second focus group Gf2 in the wide-angle end state in order to obtain good close-up performance. By satisfying this conditional expression (2), the axial focusing position fluctuation amount is smaller in the second focusing group Gf2 than in the first focusing group Gf1. As described above, since the second focusing group Gf2 performs off-axis aberration correction, the focus position fluctuation amount on the axis needs to be smaller than that of the first focusing group G1f, and the difference between the fluctuation amounts is large. The correction becomes easier. If the upper limit value of conditional expression (2) is exceeded, the amount of on-axis focus position fluctuation of the second focus group Gf2 increases, and the first focus group Gf1 moves to align the on-axis and off-axis focus positions. This increases the amount of spherical aberration and coma when focusing at close distance. In order to secure the effect of the conditional expression (2), it is desirable to set the upper limit value of the conditional expression (2) to 0.900. In order to further secure the effect of the conditional expression (2), it is desirable to set the upper limit value of the conditional expression (2) to 0.800. In order to further secure the effect of conditional expression (2), it is desirable to set the upper limit value of conditional expression (2) to 0.750. In order to further secure the effect of conditional expression (2), it is desirable to set the upper limit value of conditional expression (2) to 0.700. On the other hand, if the lower limit value of conditional expression (2) is not reached, the refractive power of the second focusing group Gf2 becomes weak, making it difficult to correct off-axis aberrations. In order to secure the effect of the conditional expression (2), it is desirable that the lower limit value of the conditional expression (2) is 0.015. In order to further secure the effect of the conditional expression (2), it is desirable that the lower limit value of the conditional expression (2) is 0.020. In order to further secure the effect of the conditional expression (2), it is desirable to set the lower limit value of the conditional expression (2) to 0.025. In order to further secure the effect of the conditional expression (2), it is desirable to set the lower limit value of the conditional expression (2) to 0.030.

  In addition, it is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (3).

0.050 <| FZ2W / FZ2T | <0.950 (3)
However,
FZ2W: On-axis focusing position variation [mm] when the second focusing group Gf2 moves 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focusing state
FZ2T: A variation amount [mm] of the on-axis focusing position when the second focusing group Gf2 moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state

  Conditional expression (3) defines the focus position sensitivity of the wide-angle end state and the telephoto end state in the second focus group Gf2 in order to obtain good close-up performance. By satisfying conditional expression (3), the focus position fluctuation amount of the second focus group Gf2 becomes larger in the telephoto end state than in the wide-angle end state. Although the second focusing group Gf2 performs off-axis aberration correction, it is desirable that the curvature of field is likely to occur in the wide-angle end state and that the change in the focusing position on the axis is small. If the upper limit value of conditional expression (3) is exceeded, the off-axis focusing position on the axis in the wide-angle end state cannot be satisfactorily adjusted. In order to secure the effect of conditional expression (3), it is desirable to set the upper limit value of conditional expression (3) to 0.900. In order to further secure the effect of conditional expression (3), it is desirable to set the upper limit value of conditional expression (3) to 0.850. On the other hand, if the lower limit of conditional expression (3) is not reached, the off-axis focusing position on the axis in the telephoto end state cannot be satisfactorily adjusted. In order to secure the effect of the conditional expression (3), it is desirable to set the lower limit value of the conditional expression (3) to 0.250. In order to further secure the effect of conditional expression (3), it is desirable to set the lower limit of conditional expression (3) to 0.350. In order to further secure the effect of conditional expression (3), it is desirable to set the lower limit value of conditional expression (3) to 0.500. In order to further secure the effect of conditional expression (3), it is desirable to set the lower limit value of conditional expression (3) to 0.600.

  In the zoom optical system ZL according to the present embodiment, one of the image-side focusing groups GfR is a first focusing group Gf1, and one of the object-side focusing groups GfF is a second focusing group. Is desirable. When the object-side focusing group GfF is the first focusing group Gf1, there is a concern about an increase in the front lens diameter and the occurrence of field curvature aberration. Therefore, the image-side focusing group GfR is changed to the first focusing group Gf1. It is desirable to do.

  In addition, it is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (4), that is, the first focusing group Gf1 has a positive refractive power.

ff1> 0 (4)
However,
ff1: Focal length of the first focusing group Gf1

  Further, it is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (5), that is, the second focusing group Gf2 has a negative refractive power.

ff2 <0 (5)
However,
ff2: Focal length of the second focusing group Gf2

  In addition, when the variable magnification optical system ZL according to the present embodiment satisfies the conditional expression (5), it is preferable that the following conditional expression (3 ′) is satisfied instead of the above-described conditional expression (3). .

0.400 <| FZ2W / FZ2T | <0.950 (3 ')
However,
FZ2W: On-axis focusing position variation [mm] when the second focusing group Gf2 moves 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focusing state
FZ2T: A variation amount [mm] of the on-axis focusing position when the second focusing group Gf2 moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state

  In addition, it is desirable that the variable magnification optical system ZL according to the present embodiment satisfies the following conditional expression (6).

0.010 <| FZ1W / FZ1T | <1.500 (6)
However,
FZ1W: On-axis focusing position variation [mm] when the first focusing group Gf1 moves 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focusing state
FZ1T: On-axis focal position fluctuation amount [mm] when the first focusing group Gf1 moves 1 [mm] in the optical axis direction in the telephoto end state and infinitely focused state

  Conditional expression (6) defines the focus position sensitivity of the wide-angle end state and the telephoto end state in the first focus group Gf1 in order to obtain good close-up performance. Exceeding the upper limit value of conditional expression (6) increases the on-axis sensitivity of the first focusing group Gf1 in the wide-angle end state and increases the fluctuations of spherical aberration and coma aberration, thereby obtaining good close-up performance. I can't. In order to secure the effect of the conditional expression (6), it is desirable to set the upper limit value of the conditional expression (6) to 0.700. In order to further secure the effect of conditional expression (6), it is desirable to set the upper limit of conditional expression (6) to 0.350. On the other hand, if the lower limit value of conditional expression (6) is not reached, the on-axis sensitivity of the first focusing group G1f in the telephoto end state increases, and fluctuations in spherical aberration and coma aberration increase, resulting in good close-up performance. Can't get. In order to secure the effect of the conditional expression (6), it is desirable that the lower limit value of the conditional expression (6) is 0.050. In order to further secure the effect of conditional expression (6), it is desirable to set the lower limit value of conditional expression (6) to 0.100.

  In addition, the zoom optical system ZL according to the present embodiment includes at least one object side lens group (for example, the second lens group G2 in FIG. 1) on the object side of the object side focusing group GfF. It is sometimes desirable that the distance between the object side lens group (second lens group G2) and the object side focusing group GfF is changed. By disposing the object-side lens group closer to the object side than the object-side focusing group GfF, the object-side lens group can condense the light beam to the object-side focusing group GfF or multiply the magnification. The object side lens group GfF can be a relatively simple lens group having a small diameter.

  Further, the variable magnification optical system ZL according to the present embodiment has at least one negative lens group having negative refractive power on the object side from the object side focusing group GfF (for example, the second lens group G2 in FIG. 1). It is desirable that the distance between the negative lens group (second lens group G2) and the object-side focusing group GfF changes during zooming. By disposing the negative lens group closer to the object side than the object-side focusing group GfF, it becomes easy to suppress the light incident angle to the object-side focusing group GfF, and thus the amount of field curvature generated in the object-side focusing group GfF Can be made relatively small, and correction in the image-side focusing group GfR can be facilitated.

  In addition, the variable magnification optical system ZL according to the present embodiment has a positive lens group (for example, the first lens group G1 in FIG. 1) having a positive refractive power and a negative refraction, closer to the object side than the object side focusing group GfF. At least one negative lens group (for example, the second lens group G2 in FIG. 1) having power is provided, and at the time of zooming, the positive lens group (first lens group G1) and the negative lens group (second lens group G2) ) And the distance between the negative lens group (second lens group G2) and the object-side focusing group GfF is preferably changed. By disposing the positive lens group further on the object side than the negative lens group described above, the object side and image side focusing groups GfF and GfR can be made relatively small while increasing the zoom ratio, and the focusing speed can be increased. can do.

  In the variable magnification optical system ZL according to the present embodiment, one of the object side focusing groups GfF is preferably composed of a negative lens (for example, a negative meniscus lens L31 in FIG. 1) having a concave surface directed toward the object side. . With this configuration, it is possible to suppress spherical aberration and field curvature aberration fluctuation during zooming. In addition, the magnification can be changed efficiently, leading to a reduction in size of the lens.

  In the zoom optical system ZL according to the present embodiment, it is desirable that each of the object-side focusing group GfF and the image-side focusing group GfR is one. By comprising in this way, the short distance performance of an off-axis ray can be exhibited with a simple structure.

  In the zoom optical system ZL according to the present embodiment, it is desirable that the first focusing group Gf1 has a lens that satisfies the following conditional expression (7) (for example, the negative meniscus lens L31 in FIG. 1). .

νd1> 45.0 (7)
However,
νd1: Abbe number for the d-line of the lens medium included in the first focusing group Gf1

  By disposing a lens that satisfies the conditional expression (7) in the first focusing group Gf1, chromatic aberration generated in the first focusing group Gf1 can be reduced. If the lens is made of a medium having a lower Abbe number than the conditional expression (7), that is, a medium having a small Abbe number, the number of lenses in the first focusing group Gf1 increases in order to perform color correction. In order to secure the effect of conditional expression (7), it is desirable to set the lower limit value of conditional expression (7) to 48.0. In order to further secure the effect of conditional expression (7), it is desirable to set the lower limit value of conditional expression (7) to 50.0. In order to further secure the effect of conditional expression (7), it is desirable to set the lower limit value of conditional expression (7) to 52.0.

  In the variable magnification optical system ZL according to the present embodiment, there is one object-side focusing group GfF, which is composed of one negative lens, and at a position facing the object side of the object-side focusing group GfF. Has a negative lens group having a negative refractive power (for example, the second lens group G2 in FIG. 1), and further has a positive refractive power at a position facing the image side of the object side focusing group GfF. It is desirable to have a lens group (for example, the fourth lens group G4 in FIG. 1). With this configuration, the change in image magnification of the object-side focusing group GfF can be reduced.

  In the zoom optical system ZL according to the present embodiment, the second focusing group Gf2 and a lens group (for example, FIG. 1) disposed at a position facing the object side of the second focusing group Gf2 at the time of zooming. In the second lens group G4), and the second focusing group Gf2 and a lens group (for example, the sixth lens in FIG. 1) disposed at a position facing the image side of the second focusing group Gf2. It is desirable that the distance from the group G6) be changed. With this configuration, it is possible to suppress spherical aberration and field curvature aberration fluctuations during zooming.

  Note that the conditions and configurations described above each exhibit the above-described effects, and are not limited to satisfying all the conditions and configurations. Even if the above conditions or combinations of configurations are satisfied, the above-described effects can be obtained.

  Next, a camera that is an optical apparatus including the variable magnification optical system ZL according to the present embodiment will be described with reference to FIG. This camera 1 is a so-called mirrorless camera of interchangeable lens provided with a variable magnification optical system ZL according to the present embodiment as a photographing lens 2. In the camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and is on the imaging surface of the imaging unit 3 via an OLPF (Optical low pass filter) (not shown). A subject image is formed on the screen. Then, the subject image is photoelectrically converted by the photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. Thus, the photographer can observe the subject via the EVF 4.

  Further, when a release button (not shown) is pressed by the photographer, an image photoelectrically converted by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can shoot the subject with the camera 1. In the present embodiment, an example of a mirrorless camera has been described. However, a variable power optical system ZL according to the present embodiment is applied to a single-lens reflex camera that has a quick return mirror in the camera body and observes a subject with a finder optical system. Even when the camera is mounted, the same effect as the camera 1 can be obtained.

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

  In the present embodiment, the variable magnification optical system ZL having the 5-group, 6-group, and 7-group configurations is shown, but the above-described configuration conditions and the like can also be applied to other group configurations such as the 4-group and 8-group. Further, a configuration in which a lens or a lens group is added closest to the object side, or a configuration in which a lens or a lens group is added closest to the image plane side may be used. Specifically, a configuration in which a lens group whose position relative to the image plane is fixed at the time of zooming or focusing is added to the most image plane side. Further, the group may indicate a portion having at least one lens that is separated by an air interval that changes at least one of when zooming, focusing, and contraction. Further, the variable magnification optical system ZL of the present embodiment has the first lens group G1 to the fifth lens group G5 (or the sixth lens group G6 and the seventh lens) so that the air spacing between the groups changes at the time of zooming. Each group G7) may be configured to move along the optical axis. The lens component refers to a single lens or a cemented lens in which a plurality of lenses are cemented.

  Further, it may be a focusing group that performs focusing from an object at infinity to a short-distance object point by moving two or more lens groups, two or more partial lens groups, or the entire optical system in the optical axis direction. In this case, the focusing group can also be applied to autofocusing, and is also suitable for motor driving for autofocusing (the type of motor is not limited, such as a DC motor, a stepping motor, or a voice coil motor). For example, in the case of the 6-group configuration described above, the third lens group G3 (object-side focusing group GfF) and the fifth lens group G5 (image-side focusing group GfR) are set as the focusing group, and the other lenses are focused. Sometimes it is preferable to fix the position relative to the image plane. In consideration of the load applied to the motor, the focusing lens group is preferably composed of one or two lens components. In addition, it is preferable to dispose at least one lens whose position in the optical axis direction is fixed during focusing between the object-side focusing group GfF and the image-side focusing group GfR.

  In addition, the lens group or partial lens group is moved so as to have a displacement component perpendicular to the optical axis, or rotated (swinged) in the in-plane direction including the optical axis to correct image blur caused by camera shake. It is good also as an anti-vibration group. In particular, at least a part of the lens group disposed on the image side of the aperture stop S and at a position facing the object side or the image side of the image side focusing group GfR may be used as the vibration proof lens group. The anti-vibration lens group is not particularly limited in the number of lenses, and may be composed of a single lens or a plurality of lens components.

  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.

  The aperture stop S is preferably disposed between the object-side focusing group GfF and the image-side focusing group GfR. However, instead of providing a member as an aperture stop, a role of a lens frame is used instead. Also good. When the first focusing group Gf1 is disposed on the image side from the aperture stop S, a lens that fixes the position in the optical axis direction during focusing is provided between the aperture stop S and the first focusing group Gf1. It is preferable to arrange at least one.

  Further, each lens surface may be provided with an antireflection film in order to reduce flare and ghost and achieve high optical performance. The antireflection film can be selected as appropriate, and the type of film is not limited, such as a single layer coating, a multilayer coating, or an antireflection film having an ultra-low refractive index layer made of fine crystal particles. The number of surfaces on which the antireflection film is applied is not particularly limited.

  Hereinafter, an outline of a method for manufacturing the variable magnification optical system ZL according to the present embodiment will be described with reference to FIG. Here, description will be made based on the variable magnification optical system ZL1 having the 6-group configuration shown in FIG. 1, but the same applies to the case of the 5-group or 7-group configuration. First, the first lens group G1 to the sixth lens group G6 are prepared by arranging each lens (step S100). The first lens group G1 to the sixth lens group G6 are arranged on the object side from the aperture stop S and the aperture stop S. At least one object-side focusing group GfF that moves and at least one image-side focusing group GfR that is arranged on the image side from the aperture stop S and moves in the optical axis direction during focusing are arranged (step S200). At the time of focusing, the object side focusing group GfF and the image side focusing group GfR are arranged so as to have different movement trajectories (step S300), and one of the object side focusing group GfF and one of the image side focusing group GfR are arranged. When one is set as the first focusing group Gf1 and the other is set as the second focusing group Gf2, one is arranged so as to satisfy the above-described condition (step S400).

  Specifically, in this embodiment, for example, as illustrated in FIG. 1, in order from the object side, a cemented positive lens in which a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12 are cemented, and the object side A positive meniscus lens L13 having a convex surface is disposed in the first lens group G1, and a negative meniscus lens L21 having a convex surface on the object side, an object side lens surface, and an image side lens surface are formed in an aspheric shape. An aspherical negative lens L22 having a biconcave lens shape and a biconvex lens L23 are arranged as the second lens group G2, and a negative meniscus lens L31 having a concave surface facing the object side is arranged as the third lens group G3. -Side positive lens L41 having a biconvex lens shape in which the lens surface on the side and the lens surface on the image side are formed in an aspheric shape, and a cemented negative lens in which the biconvex lens L42 and the biconcave lens L43 are cemented together The fourth lens group G4 is arranged, and a cemented negative lens in which a biconcave lens L51 and a positive meniscus lens L52 having a convex surface facing the object side are cemented is arranged as a fifth lens group G5, and the object side lens surface A positive meniscus aspherical lens L61 having a concave surface facing the object side, an aspherical positive lens L62 having a biconvex lens shape having an aspheric lens surface on the object side, A cemented positive lens in which a negative meniscus lens L63 having a concave surface directed toward the object side and a negative meniscus lens L64 having a concave surface directed toward the object side are disposed to form a sixth lens group G6. The aperture stop S is disposed on the most object side of the fourth lens group G4. The third lens group G3 is an object-side focusing group GfF (first focusing group Gf1), and the fifth lens group G5 is an image-side focusing group GfR (second focusing group Gf2). The lens groups thus prepared are arranged in the above-described procedure to manufacture the variable magnification optical system ZL.

  Hereinafter, each example of the present application will be described with reference to the drawings. 1, FIG. 4, FIG. 7, FIG. 10, and FIG. 13 are cross-sectional views showing the configuration and refractive power distribution of the variable magnification optical system ZL (ZL1 to ZL5) according to each example. In addition, in the lower part of the sectional views of these variable magnification optical systems ZL1 to ZL5, each lens for zooming from the wide angle end state (W) to the telephoto end state (T) through the intermediate focal length state (M) is shown. The movement direction along the optical axis of the groups G1 to G5 (or G6, G7) and the object-side focusing group GfF and image-side focusing when focusing from the infinitely focused state (∞) to the closest focused state The moving direction of the focal group GfR along the optical axis is indicated by an arrow.

In each embodiment, the height of the aspheric surface in the direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangential plane of the apex of each aspheric surface to each aspheric surface at height y. Is S (y), r is the radius of curvature of the reference sphere (paraxial radius of curvature), K is the conic constant, and An is the nth-order aspherical coefficient, it is expressed by the following equation (a). . In the following examples, “en” represents “× 10 ⁻ⁿ ”.

S (y) = (y ² / r) / {1+ (1−K × y ² / r ² ) ^1/2 }
+ A4 × y ⁴ + A6 × y ⁶ + A8 × y ⁸ + A10 × y ¹⁰ (a)

  In each embodiment, the secondary aspheric coefficient A2 is zero. In the table of each example, an aspherical surface is marked with * on the left side of the surface number.

[First embodiment]
FIG. 1 is a diagram showing a configuration of a variable magnification optical system ZL1 according to the first example. The zoom optical system ZL1 shown in FIG. 1 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a negative refractive power. The third lens group G3 includes a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. .

  In the variable magnification optical system ZL1, the first lens group G1 includes, in order from the object side, a cemented positive lens in which a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12 are cemented, and a convex surface on the object side. The positive meniscus lens L13 is directed. In addition, the second lens group G2, in order from the object side, is a negative meniscus lens L21 having a convex surface directed toward the object side, a lens surface on the object side, and a lens surface on the image side and a biconcave lens shape in which the image side lens surface is formed in an aspheric shape. It has a spherical negative lens L22 and a biconvex lens L23. The third lens group G3 includes a negative meniscus lens L31 having a concave surface directed toward the object side. The fourth lens group G4 includes, in order from the object side, an aspheric positive lens L41 having a biconvex lens shape in which an object-side lens surface and an image-side lens surface are formed in an aspheric shape, and a biconvex lens L42 and both It has a cemented negative lens in which a concave lens L43 is cemented. The fifth lens group G5 includes a negative cemented lens in which, in order from the object side, a biconcave lens L51 and a positive meniscus lens L52 having a convex surface directed toward the object side are cemented. The sixth lens group G6 includes, in order from the object side, an aspheric positive lens L61 having a positive meniscus lens shape with a concave surface facing the object side, and a lens on the object side. A cemented positive lens in which an aspherical positive lens L62 having a biconvex lens shape whose surface is formed in an aspherical shape and a negative meniscus lens L63 having a concave surface facing the object side, and a negative meniscus lens having a concave surface facing the object side L64 is configured. The aperture stop S is disposed on the object side of the most object side lens surface (fifteenth surface) of the fourth lens group G4.

  In the variable magnification optical system ZL1, the air gap between the first lens group G1 and the second lens group G2 increases during the magnification change from the wide-angle end state to the telephoto end state, and the second lens group G2 and the third lens group. The air gap between G3 increases, the air gap between the third lens group G3 and the fourth lens group G4 decreases, the air gap between the fourth lens group G4 and the fifth lens group G5 increases, and the fifth lens. The lens groups of the first lens group G1 to the sixth lens group G6 so that the air gap between the group G5 and the sixth lens group G6 decreases and the air gap between the sixth lens group G6 and the image plane I increases. Moves on the optical axis. The aperture stop S moves together with the fourth lens group G4 during zooming.

  In this variable magnification optical system ZL1, the object-side focusing group GfF is the third lens group G3, the image-side focusing group GfR is the fifth lens group G5, and focusing from an infinite object to a short-distance object is performed. The first lens group G1, the second lens group G2, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image plane I, and the third lens group G3 that is the object-side focusing group GfF is the optical axis. Is moved from the image side to the object side, and the fifth lens group G5 which is the image side focusing group GfR is moved from the image side to the object side along the optical axis. In this focusing, the movement trajectories of the object-side focusing group GfF and the image-side focusing group GfR are configured to be different.

  The values of the specifications of the variable magnification optical system ZL1 according to the first example are listed below. Here, the focal length f, the radius of curvature r, the surface interval d, and other length units listed in all the following specification values are generally “mm”, but the optical system is proportionally enlarged or proportional. Since the same optical performance can be obtained even if the image is reduced, the present invention is not limited to this. The description of these symbols and the description of the specification table are the same in the following embodiments.

  First, Table 1 shows the overall specifications. In this overall specification, f is the focal length of the entire system, FNO is the F number, ω is the half field angle [°], Y is the maximum image height, TL is the total length, and BF is the back focus value. The values in the wide-angle end state (W), the intermediate focal length state (M), and the telephoto end state (T) are shown. Here, the total length TL indicates the distance on the optical axis from the most object side lens surface (first surface in FIG. 1) to the image plane I at the time of infinite focusing. Further, the back focus BF indicates the distance on the optical axis from the most image side lens surface (the 29th surface in FIG. 1) to the image surface I when focusing on infinity. Note that BF (air) indicates the air equivalent length of the back focus.

  Table 2 shows lens data. In the lens data, the first column m indicates the order (surface number) of the lens surfaces from the object side along the direction in which the light beam travels, the second column r indicates the curvature radius of each lens surface, and the third column d. Is the distance (surface spacing) on the optical axis from each optical surface to the next optical surface, the fourth column nd and the fifth column νd are the refractive index and Abbe number for the d-line (λ = 587.6 nm). Show. Further, the radius of curvature of 0.00000 indicates a plane, and the refractive index of air of 1.0000 is omitted.

  Table 3 shows the lens group focal length. In this lens group focal length, g represents the sign of each lens group, m represents the starting surface of each lens group (surface number of the lens surface closest to the object side), and fg represents the focal length of each lens group.

  In the zoom optical system ZL1, the eighth surface, the ninth surface, the fifteenth surface, the sixteenth surface, the twenty-third surface, and the twenty-fifth surface are formed in an aspherical shape. Table 4 below shows aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

  In the variable magnification optical system ZL1, the axial air distance D5 between the first lens group G1 and the second lens group G2, the axial air distance D11 between the second lens group and the third lens group G3, and the third lens. On-axis air gap D13 between group G3 and fourth lens group G4, on-axis air gap D19 between fourth lens group G4 and fifth lens group G5, on-axis between fifth lens group G5 and sixth lens group G6 The air gap D22 and the on-axis air gap D29 (corresponding to the back focus BF) between the sixth lens group G6 and the image plane I change during zooming and focusing. Table 5 below shows the variable intervals in the infinitely focused object state and the closest focused state. In Table 5, Infinite indicates the infinitely focused state, and Closest indicates the closest focused state. W represents the wide-angle end state, M represents the intermediate focal length state, and T represents the telephoto end state. D0 represents the distance from the most object side surface (first surface) of the variable magnification optical system ZL1 to the object, β represents the photographing magnification, and f represents the focal length of the entire system.

  Table 6 below shows values corresponding to the conditional expressions in the variable magnification optical system ZL1. In this conditional expression corresponding value, ff1 is the focal length of the first focusing group Gf1, ff2 is the focal length of the second focusing group Gf2, and FZ1W is the first focusing group in the wide-angle end state and infinite focusing state. The fluctuation amount [mm] of the on-axis focusing position when Gf1 moves 1 [mm] in the optical axis direction, and FZ1T indicates that the first focusing group Gf1 is in the optical axis direction in the telephoto end state and infinite focusing state. FZ2W moves the second focusing group Gf2 by 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focusing state when the movement amount is 1 [mm]. FZ2T is the on-axis alignment when the second focusing group Gf2 moves 1 [mm] in the optical axis direction in the telephoto end state and infinite focus state. The focal position variation [mm], νd1 is the lens medium included in the first focusing group Gf1 Represent respectively the Abbe number for the line. In the first embodiment, the first focusing group Gf1 corresponds to the third lens group G3 that is the object-side focusing group GfF, and the second focusing group Gf2 is the image-side focusing group GfR. This corresponds to the fifth lens group G5. Further, νd1 is a value of the negative meniscus lens L31 of the third lens group G3 that is the first focusing group Gf1.

  Thus, the variable magnification optical system ZL1 according to the first example satisfies the conditional expressions (1) to (3), (5), (3 '), (6), and (7).

  The variable magnification optical system ZL1 has a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram in a wide-angle end state, an intermediate focal length state, and a telephoto end state in an infinitely focused state and a close-in-focus state. Transverse aberration diagrams are shown in FIGS. In each aberration diagram, FNO represents an F number, NA represents a numerical aperture, and Y represents an image height. The spherical aberration diagram shows the F-number or numerical aperture corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram show the maximum image height, and the lateral aberration diagram shows the value of each image height. ing. D represents the d-line (λ = 587.6 nm), and g represents the g-line (λ = 435.8 nm). In the astigmatism diagrams, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. Further, the distortion diagram shows the value of the d-line. Also, the same reference numerals as in this example are used in the aberration diagrams of the examples shown below. From these aberration diagrams, the variable magnification optical system ZL1 corrects various aberrations well from the infinitely focused object state to the closest focused state in focusing and from the wide-angle end state to the telephoto end state in zooming. You can see that

[Second Embodiment]
FIG. 4 is a diagram showing a configuration of the variable magnification optical system ZL2 according to the second example. The zoom optical system ZL2 shown in FIG. 4 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a negative refractive power. The third lens group G3 includes a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a negative refractive power, and a sixth lens group G6 having a positive refractive power. .

  In the variable magnification optical system ZL2, the first lens group G1 includes, in order from the object side, a cemented positive lens in which a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12 are cemented, and a convex surface on the object side. The positive meniscus lens L13 is directed. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface directed toward the object side, a biconcave aspherical negative lens L22 in which the object-side lens surface is formed in an aspheric shape, and The lens has a biconvex lens L23. The third lens group G3 includes a cemented negative lens in which a biconcave lens L31 and a biconvex lens L32 are cemented in order from the object side. The fourth lens group G4 includes, in order from the object side, an aspheric positive lens L41 having a biconvex lens shape in which an object-side lens surface and an image-side lens surface are formed in an aspheric shape, and a biconvex lens L42 and both It has a cemented positive lens that is cemented with the concave lens L43. The fifth lens group G5 includes a negative cemented lens in which, in order from the object side, a biconcave lens L51 and a positive meniscus lens L52 having a convex surface directed toward the object side are cemented. Further, in the sixth lens group G6, in order from the object side, the aspheric lens surface on the object side is formed in an aspheric shape, the aspherical positive lens L61 in the shape of a positive meniscus lens with the concave surface facing the object side, and the concave surface on the object side are formed. A cemented positive lens in which the negative meniscus lens L62 directed toward the object is cemented, a cemented positive lens in which the biconvex lens L63 is bonded to the negative meniscus lens L64 in which the concave surface is directed toward the object side, a positive meniscus lens L65 having a concave surface directed toward the object side, and The lens has a biconcave lens L66. The aperture stop S is disposed on the object side of the lens surface (16th surface) closest to the object side of the fourth lens group G4.

  In the zoom optical system ZL2, the air gap between the first lens group G1 and the second lens group G2 increases during zooming from the wide-angle end state to the telephoto end state, and the second lens group G2 and the third lens group. The air gap between G3 increases, the air gap between the third lens group G3 and the fourth lens group G4 decreases, the air gap between the fourth lens group G4 and the fifth lens group G5 increases, and the fifth lens. The lens groups of the first lens group G1 to the sixth lens group G6 so that the air gap between the group G5 and the sixth lens group G6 decreases and the air gap between the sixth lens group G6 and the image plane I increases. Moves on the optical axis. The aperture stop S moves together with the fourth lens group G4 during zooming.

  In the zoom optical system ZL2, the object-side focusing group GfF is the third lens group G3, the image-side focusing group GfR is the fifth lens group G5, and focusing from an object at infinity to a short-distance object is The first lens group G1, the second lens group G2, the fourth lens group G4, and the sixth lens group G6 are fixed with respect to the image plane I, and the third lens group G3 that is the object-side focusing group GfF is the optical axis. Is moved from the image side to the object side, and the fifth lens group G5 which is the image side focusing group GfR is moved from the image side to the object side along the optical axis. In this focusing, the movement trajectories of the object-side focusing group GfF and the image-side focusing group GfR are configured to be different.

  The values of the specifications of the variable magnification optical system ZL2 according to the second example are listed below. First, Table 7 shows the overall specifications.

  Table 8 shows lens data in the second example.

  Table 9 shows lens group focal lengths in the second example.

  In the variable magnification optical system ZL2, the eighth surface, the sixteenth surface, the seventeenth surface, and the twenty-fourth surface are formed in an aspherical shape. Table 10 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

  In the variable magnification optical system ZL2, the axial air distance D5 between the first lens group G1 and the second lens group G2, the axial air distance D11 between the second lens group and the third lens group G3, and the third lens. On-axis air gap D14 between group G3 and fourth lens group G4, on-axis air gap D20 between fourth lens group G4 and fifth lens group G5, on-axis between fifth lens group G5 and sixth lens group G6 The air space D23 and the on-axis air space D33 (corresponding to the back focus BF) between the sixth lens group G6 and the image plane I change during zooming and focusing. Table 11 below shows variable intervals in an infinitely focused object state and a close-in focused state.

  Table 12 below shows values corresponding to the conditional expressions in the variable magnification optical system ZL2. In the second embodiment, the first focusing group Gf1 corresponds to the third lens group G3 that is the object-side focusing group GfF, and the second focusing group Gf2 is the image-side focusing group GfR. This corresponds to the fifth lens group G5. Further, νd1 is a value of the biconcave lens L31 of the third lens group G3 which is the first focusing group Gf1.

  Thus, the variable magnification optical system ZL2 according to the second example satisfies the conditional expressions (1) to (3), (5), (3 '), (6), and (7).

  This variable magnification optical system ZL2 has a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram in a wide-angle end state, an intermediate focal length state, and a telephoto end state in an infinitely focused state and a close-in-focus state. Transverse aberration diagrams are shown in FIGS. From these aberration diagrams, this variable magnification optical system ZL2 corrects various aberrations well from the infinite object focusing state to the closest focusing state in focusing and from the wide-angle end state to the telephoto end state in zooming. You can see that

[Third embodiment]
FIG. 7 is a diagram showing a configuration of the variable magnification optical system ZL3 according to the third example. The zoom optical system ZL3 shown in FIG. 7 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power. The third lens group G3 includes a third lens group G3, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power.

  In the variable magnification optical system ZL3, the first lens group G1 includes, in order from the object side, a cemented positive lens in which a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side are cemented. It is comprised. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface directed toward the object side, a negative meniscus lens shape in which the lens surface on the object side is formed in an aspherical shape, and the convex surface is directed toward the object side. The aspherical negative lens L22, the biconvex lens L23, and the aspherical negative lens L24 having a biconcave shape in which the image-side lens surface is formed in an aspherical shape. The third lens group G3 includes, in order from the object side, an aspheric positive lens L31 having a biconvex lens shape in which the lens surface on the object side and the lens surface on the image side are formed in an aspheric shape, and a biconvex lens L32 on the object side. A cemented positive lens in which a negative meniscus lens L33 having a concave surface is cemented, a cemented positive lens in which a biconcave lens L34 and a positive meniscus lens L35 having a convex surface on the object side are cemented, and a lens surface on the object side and an image side It has a biconvex lens-shaped aspherical positive lens L36 having a lens surface formed in an aspherical shape. Further, the fourth lens group G4 includes an aspheric negative lens L41 having a negative meniscus lens shape in which an image side lens surface is formed in an aspheric shape and a convex surface is directed toward the object side. The fifth lens group G5 includes an aspheric positive lens L51 having a biconvex lens shape in which the lens surface on the object side is formed in an aspheric shape. The aperture stop S is disposed between the aspheric positive lens L31 and the biconvex lens L32 in the third lens group G3. A filter FL is disposed between the fifth lens group G5 and the image plane I.

  In the variable magnification optical system ZL3, when changing the magnification from the wide-angle end state to the telephoto end state, the air gap between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group. The air gap between G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 increases, the air gap between the fourth lens group G4 and the fifth lens group G5 increases, and the fifth lens. Each lens group from the first lens group G1 to the fifth lens group G5 moves on the optical axis so that the air gap between the group G5 and the filter FL decreases. The aperture stop S moves together with the third lens group G3 during zooming.

  In the zoom optical system ZL3, the object-side focusing group GfF is the second lens group G2, the image-side focusing group GfR is the fourth lens group G4, and focusing from an object at infinity to a short-distance object is performed. The first lens group G1, the third lens group G3, and the fifth lens group G5 are fixed with respect to the image plane I, and the second lens group G2, which is the object side focusing group GfF, is viewed from the image side along the optical axis. The fourth lens group G4, which is the image side focusing group GfR, is moved to the object side and moved from the object side to the image side along the optical axis. In this focusing, the movement trajectories of the object-side focusing group GfF and the image-side focusing group GfR are configured to be different.

  The values of the specifications of the variable magnification optical system ZL3 according to the third example are listed below. First, Table 13 shows the overall specifications.

  Next, Table 14 shows lens data in the third example.

  Table 15 shows lens group focal lengths in the third example.

  In the zoom optical system ZL3, the sixth surface, the eleventh surface, the twelfth surface, the thirteenth surface, the twenty-first surface, the twenty-second surface, the twenty-fourth surface, and the twenty-fifth surface are formed in an aspherical shape. Table 16 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

  In the variable magnification optical system ZL3, the axial air distance D3 between the first lens group G1 and the second lens group G2, the axial air distance D11 between the second lens group and the third lens group G3, the third lens On-axis air gap D22 between group G3 and fourth lens group G4, on-axis air gap D24 between fourth lens group G4 and fifth lens group G5, and on-axis air between fifth lens group G5 and filter FLI The interval D26 changes upon zooming and focusing. Table 17 below shows the variable intervals in the infinitely focused object state and the close-up focused state.

  Table 18 below shows values corresponding to the conditional expressions in the variable magnification optical system ZL3. In the third embodiment, the first focusing group Gf1 corresponds to the second lens group G2 that is the object-side focusing group GfF, and the second focusing group Gf2 is the image-side focusing group GfR. This corresponds to the fourth lens group G4. Further, νd1 is a value of the negative meniscus lens L21 of the second lens group G2 that is the first focusing group Gf1.

  Thus, the variable magnification optical system ZL3 according to the third example satisfies the conditional expressions (1) to (3), (5), (3 '), (6), and (7).

  This variable magnification optical system ZL3 has a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a magnification chromatic aberration diagram in a wide-angle end state, an intermediate focal length state, and a telephoto end state in an infinitely focused state and a close-in-focus state. Transverse aberration diagrams are shown in FIGS. From these aberration diagrams, the variable magnification optical system ZL3 corrects various aberrations well from the infinite object focusing state to the closest focusing state in focusing and from the wide-angle end state to the telephoto end state in zooming. You can see that

[Fourth embodiment]
FIG. 10 is a diagram illustrating a configuration of the variable magnification optical system ZL4 according to the fourth example. The zoom optical system ZL4 shown in FIG. 10 includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power. The third lens group G3 includes a third lens group G3, a fourth lens group G4 having a negative refractive power, and a fifth lens group G5 having a positive refractive power.

  In the variable magnification optical system ZL4, the first lens group G1 includes, in order from the object side, a negative meniscus lens L11 having a convex surface directed toward the object side, a lens surface on the object side formed in an aspherical shape, and a convex surface on the object side. A negative meniscus lens-shaped aspherical negative lens L12 and a biconvex lens L13 are provided. Further, in the second lens group G2, in order from the object side, the lens surface on the object side is formed in an aspheric shape, and the aspheric negative lens L21 having a negative meniscus shape with the concave surface facing the object side and the concave surface on the object side are formed. It has a cemented negative lens in which a positive meniscus lens L22 directed to it is cemented. In the third lens group G3, in order from the object side, the lens surface on the object side and the lens surface on the image side are formed in an aspherical shape, and an aspherical positive lens L31 in the shape of a positive meniscus lens having a convex surface directed toward the object side. And a positive cemented lens in which a biconvex lens L32 and a biconcave lens L33 are cemented. The fourth lens group G4 includes, in order from the object side, a cemented negative lens in which a biconcave lens L41 and a positive meniscus lens L42 having a convex surface facing the object side are cemented. The fifth lens group G5 includes a negative meniscus negative lens L51 having a negative meniscus lens shape having an aspheric lens surface on the object side and a convex surface facing the object side, and a positive meniscus lens having a convex surface facing the object side. The lens includes a cemented negative lens in which L52 is cemented, a cemented positive lens in which a biconvex lens L53 and a negative meniscus lens L54 having a concave surface facing the object side are cemented, a biconvex lens L55, and a biconcave lens L56. The aperture stop S is disposed on the object side of the most object side lens surface (11th surface) of the third lens group G3.

  In the variable magnification optical system ZL4, when changing the magnification from the wide-angle end state to the telephoto end state, the air gap between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group G3. The air gap between the third lens group G3 and the fourth lens group G4 increases, the air gap between the fourth lens group G4 and the fifth lens group G5 decreases, and the fifth lens group G5 and the image are separated. Each lens group from the first lens group G1 to the fifth lens group G5 moves on the optical axis so that the air spacing of the surface I increases. The aperture stop S moves together with the third lens group G3 during zooming.

  In the zoom optical system ZL4, the object-side focusing group GfF is the second lens group G2, the image-side focusing group GfR is the fourth lens group G4, and focusing from an infinite object to a short-distance object is performed. The first lens group G1, the third lens group G3, and the fifth lens group G5 are fixed with respect to the image plane I, and the second lens group G2, which is the object side focusing group GfF, is viewed from the image side along the optical axis. The fourth lens group G4, which is the image side focusing group GfR, is moved to the object side and moved from the image side to the object side along the optical axis. In this focusing, the movement trajectories of the object-side focusing group GfF and the image-side focusing group GfR are configured to be different.

  The values of the specifications of the variable magnification optical system ZL4 according to the fourth example are listed below. First, Table 19 shows the overall specifications.

  Table 20 shows lens data in the fourth example.

  Table 21 shows the focal length of the lens group in the fourth example.

  In the variable magnification optical system ZL4, the third surface, the seventh surface, the eleventh surface, the twelfth surface, and the nineteenth surface are formed in an aspherical shape. Table 22 below shows the aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

  In the zoom optical system ZL4, the axial air distance D6 between the first lens group G1 and the second lens group G2, the axial air distance D9 between the second lens group and the third lens group G3, and the third lens. On-axis air gap D15 between group G3 and fourth lens group G4, on-axis air gap D18 between fourth lens group G4 and fifth lens group G5, and on-axis between fifth lens group G5 and image plane I The air gap D28 (corresponding to the back focus BF) changes during zooming and focusing. Table 23 below shows variable intervals in an infinitely focused object state and a close-in focused state.

  Table 24 below shows values corresponding to the conditional expressions in the variable magnification optical system ZL4. In the fourth embodiment, the first focusing group Gf1 corresponds to the second lens group G2 that is the object-side focusing group GfF, and the second focusing group Gf2 is the image-side focusing group GfR. This corresponds to the fourth lens group G4. Further, νd1 is a value of the aspheric negative lens L21 of the second lens group G2 which is the first focusing group Gf1.

  Thus, the zoom optical system ZL4 according to the fourth example satisfies the conditional expressions (1) to (3), (5), (3 '), (6), and (7).

  This variable magnification optical system ZL4 has a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, a chromatic aberration diagram of magnification, and a wide-angle end state, an intermediate focal length state, and a telephoto end state in an infinitely focused state and a close-in-focus state. Transverse aberration diagrams are shown in FIGS. From these aberration diagrams, this variable magnification optical system ZL4 corrects various aberrations well from the infinitely far object focused state to the closest focused state in focusing and from the wide-angle end state to the telephoto end state in zooming. You can see that

[Fifth embodiment]
FIG. 13 is a diagram showing a configuration of a variable magnification optical system ZL5 according to the fifth example. The zoom optical system ZL5 shown in FIG. 13 includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a negative refractive power. A third lens group G3, a fourth lens group G4 having a positive refractive power, a fifth lens group G5 having a positive refractive power, a sixth lens group G6 having a negative refractive power, and a negative refractive power. And a seventh lens group G7.

  In the zoom optical system ZL5, the first lens group G1 includes, in order from the object side, a cemented positive lens in which a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12 are cemented, and a convex surface on the object side. The positive meniscus lens L13 is directed. In the second lens group G2, in order from the object side, a cemented positive lens in which the biconvex lens L21 and the biconcave lens L22 are cemented, and a positive meniscus lens L24 in which the convex surface is directed to the object side are cemented. It has a cemented negative lens. The third lens group G3 includes a negative meniscus lens L31 having a concave surface directed toward the object side. The fourth lens group G4 includes, in order from the object side, a biconvex lens L41, a cemented positive lens in which the biconcave lens L42 and the biconvex lens L43 are cemented, and a positive meniscus lens L44 having a concave surface facing the object side and the object side. It has a cemented negative lens in which a negative meniscus lens L45 having a concave surface is cemented. In the fifth lens group G5, in order from the object side, a cemented negative lens obtained by cementing the biconvex lens L51 and the biconcave lens L52, and the object-side lens surface and the image-side lens surface are formed in an aspherical shape. It has a biconvex lens-shaped aspherical positive lens L53. Further, in the sixth lens group G6, in order from the object side, the lens surface on the object side is formed in an aspheric shape, and the aspheric negative lens L61 in the shape of a negative meniscus lens having a convex surface directed toward the object side is provided with a convex surface on the object side. It has a cemented negative lens cemented with a directed positive meniscus lens L62, and a biconvex lens L63. The seventh lens group G7 includes, in order from the object side, a cemented negative lens in which a positive meniscus lens L71 having a convex surface facing the object side and a negative meniscus lens L72 having a convex surface facing the object side are cemented. ing. The aperture stop S is disposed on the object side of the most object side lens surface (fifteenth surface) of the fourth lens group G4. A filter FL is disposed between the seventh lens group G7 and the image plane I.

  In the zoom optical system ZL5, when zooming from the wide-angle end state to the telephoto end state, the air gap between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group. The air gap between G3 decreases, the air gap between the third lens group G3 and the fourth lens group G4 decreases, the air gap between the fourth lens group G4 and the fifth lens group G5 changes, and the fifth lens. Each of the first lens group G1 to the sixth lens group G6 is changed so that the air gap between the group G5 and the sixth lens group G6 changes and the air gap between the sixth lens group G6 and the seventh lens group G7 changes. The lens group moves on the optical axis. At this time, the seventh lens group G7 is fixed with respect to the image plane I. The aperture stop S moves together with the fourth lens group G4 during zooming.

  In this variable magnification optical system ZL5, the object-side focusing group GfF is the third lens group G3, the image-side focusing group GfR is the fifth lens group G5, and focusing from an infinite object to a short-distance object is performed. The first lens group G1, the second lens group G2, the fourth lens group G4, the sixth lens group G6, and the seventh lens group G7 are fixed with respect to the image plane I, and are a third object group focusing group GfF. The lens group G3 is moved from the image side to the object side along the optical axis, and the fifth lens group G5 that is the image side focusing group GfR is moved from the image side to the object side along the optical axis. It is configured. In this focusing, the movement trajectories of the object-side focusing group GfF and the image-side focusing group GfR are configured to be different.

  The values of the specifications of the variable magnification optical system ZL5 according to the fifth example are listed below. First, Table 25 shows the overall specifications.

  Table 26 shows lens data in the fifth example.

  Table 27 shows lens group focal lengths in the fifth example.

  In the variable magnification optical system ZL5, the 26th surface, the 27th surface and the 28th surface are formed in an aspherical shape. Table 28 below shows aspheric data, that is, the values of the conic constant K and the aspheric constants A4 to A10.

  In the zoom optical system ZL5, the axial air distance D5 between the first lens group G1 and the second lens group G2, the axial air distance D11 between the second lens group and the third lens group G3, and the third lens. On-axis air gap D13 between group G3 and fourth lens group G4, on-axis air gap D22 between fourth lens group G4 and fifth lens group G5, on-axis between fifth lens group G5 and sixth lens group G6 The air space 27 and the axial air space D32 between the sixth lens group G6 and the seventh lens group G7 change during zooming and focusing. Table 29 below shows the variable intervals in the infinitely focused object state and the closest focused state.

  Table 30 below shows values corresponding to the conditional expressions in the variable magnification optical system ZL5. In the fifth embodiment, the first focusing group Gf1 corresponds to the fifth lens group G5 which is the image side focusing group GfR, and the second focusing group Gf2 is the object side focusing group GfF. This corresponds to the third lens group G3. Further, νd1 is a value of the aspheric positive lens L53 of the fifth lens group G5 which is the first focusing group Gf1.

  Thus, the zoom optical system ZL5 according to Example 5 satisfies the conditional expressions (1), (2), and (4) to (7).

  The variable magnification optical system ZL5 has spherical aberration diagrams, astigmatism diagrams, distortion aberration diagrams, magnification chromatic aberration diagrams in the wide-angle end state, the intermediate focal length state, and the telephoto end state in the infinitely focused state and the closest focused state. Transverse aberration diagrams are shown in FIGS. From these aberration diagrams, the variable magnification optical system ZL5 corrects various aberrations well from the infinite object focusing state to the closest focusing state in focusing and from the wide-angle end state to the telephoto end state in zooming. You can see that

DESCRIPTION OF SYMBOLS 1 Camera (optical apparatus) ZL (ZL1-ZL5) Variable magnification optical system GfF Object side focusing group S Aperture stop GfR Image side focusing group Gf1 1st focusing group Gf2 2nd focusing group

Claims (12)

A variable magnification optical system having a plurality of lens groups, wherein the distance between the lens groups changes at the time of zooming,
An aperture stop,
At least one object-side focusing group that is disposed on the object side of the aperture stop and moves in the optical axis direction during focusing;
And at least one image-side focusing group that is disposed on the image side from the aperture stop and moves in the optical axis direction during focusing,
At the time of focusing, the movement trajectory of the object side focusing group and the image side focusing group is different,
Of one of the object-side focusing groups and one of the image-side focusing groups, when one is a first focusing group and the other is a second focusing group, the following condition is satisfied: A variable power optical system.
| Ff1 / ff2 | <1.00
0.010 <| FZ2T / FZ1T | <1.00
0.050 <| FZ2W / FZ2T | <0.950
However,
ff1: focal length of the first focusing group ff2: focal length of the second focusing group FZ1T: the first focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state Amount of change in focus position on the axis [mm]
FZ2W: On-axis focusing position variation [mm] when the second focusing group moves 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focusing state
FZ2T: A variation amount [mm] of the on-axis focusing position when the second focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state A variable magnification optical system having a plurality of lens groups, wherein the distance between the lens groups changes at the time of zooming,
An aperture stop,
At least one object-side focusing group that is disposed on the object side of the aperture stop and moves in the optical axis direction during focusing;
And at least one image-side focusing group that is disposed on the image side from the aperture stop and moves in the optical axis direction during focusing,
At the time of focusing, the movement trajectory of the object side focusing group and the image side focusing group is different,
A zooming function characterized in that when one of the image-side focusing groups is a first focusing group and one of the object-side focusing groups is a second focusing group, the following condition is satisfied: Optical system.
| Ff1 / ff2 | <1.00
However,
ff1: focal length of the first focusing group ff2: focal length of the second focusing group 3. The variable magnification optical system according to claim 1, wherein a condition of the following formula is satisfied.
0.010 <| FZ1W / FZ1T | <1.500
However,
FZ1W: On-axis focusing position variation [mm] when the first focusing group moves 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focusing state
FZ1T: On-axis focusing position variation [mm] when the first focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state Having at least one object side lens group closer to the object side than the object side focusing group;
4. The zoom optical system according to claim 1, wherein an interval between the object-side lens group and the object-side focusing group changes during zooming. 5. Having at least one negative lens group having negative refractive power closer to the object side than the object side focusing group;
5. The zoom optical system according to claim 1, wherein an interval between the negative lens group and the object-side focusing group changes during zooming. At least one positive lens group having positive refractive power and one negative lens group having negative refractive power on the object side from the object side focusing group,
The distance between the positive lens group and the negative lens group and the distance between the negative lens group and the object-side focusing group change during zooming. The zoom optical system according to item.   The variable power optical system according to claim 1, wherein one of the object-side focusing groups includes a negative lens having a concave surface facing the object side.   The variable power optical system according to claim 1, wherein the object-side focusing group and the image-side focusing group are each one. The variable power optical system according to claim 1, wherein the first focusing group includes a lens that satisfies a condition of the following expression.
νd1> 45.0
However,
νd1: Abbe number of the lens medium included in the first focusing group with respect to the d-line The object side focusing group is one and consists of one negative lens,
A negative lens group having a negative refractive power at a position facing the object side of the object side focusing group;
The variable power optical system according to any one of claims 1 to 9, further comprising a positive lens group having a positive refractive power at a position facing the image side of the object side focusing group.   At the time of zooming, an interval between the second focusing group and the lens group arranged at a position facing the object side of the second focusing group changes, and the second focusing group and the second focusing group are changed. The variable power optical system according to claim 1, wherein an interval between the lens unit and the lens unit disposed at a position facing the image side of the zoom lens is changed. A method of manufacturing a variable magnification optical system having a plurality of lens groups, wherein the distance between the lens groups changes at the time of zooming,
An aperture stop,
At least one object-side focusing group that is disposed on the object side of the aperture stop and moves in the optical axis direction during focusing;
And at least one image side focusing group that is arranged on the image side from the aperture stop and moves in the optical axis direction at the time of focusing, and
At the time of focusing, the object side focusing group and the image side focusing group are arranged so that the movement trajectories are different,
Of one of the object-side focusing groups and one of the image-side focusing groups, when one is a first focusing group and the other is a second focusing group, the condition of the following equation is satisfied: A method of manufacturing a variable magnification optical system, characterized in that it is arranged.
| Ff1 / ff2 | <1.0
0.010 <| FZ2T / FZ1T | <1.00
0.050 <| FZ2W / FZ2T | <0.950
However,
ff1: focal length of the first focusing group ff2: focal length of the second focusing group FZ1T: the first focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state Amount of change in focus position on the axis [mm]
FZ2W: On-axis focusing position variation [mm] when the second focusing group moves 1 [mm] in the optical axis direction in the wide-angle end state and the infinity focusing state
FZ2T: A variation amount [mm] of the on-axis focusing position when the second focusing group moves 1 [mm] in the optical axis direction in the telephoto end state and the infinity focusing state