Variable power optical system

Abstract

To provide a variable power optical system that can be miniaturized and made light and has a high optical performance.SOLUTION: A variable power optical system ZL used for an optical device, such as a camera 1, comprises a first lens group G1 that is disposed in the most object side and has positive refractive power, a second lens group G2, and a rear group GL. An interval between the respective lens groups is changed at the time of variable magnification. The first lens group G1 has a positive lens L11 on the most object side. The rear group GL has a positive lens group, a positive lens group, and a negative lens group in this order from the object side. An aperture diaphragm S is provided in the rear group GL. At least one portion of an image surface side relative to the aperture diaphragm S is a focusing group Gf that travels in a light axis direction at the time of focusing. The focusing group Gf comprises a positive lens and a negative lens in this order from the object side, and satisfies a predetermined condition.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a variable magnification optical system. [Background technology]

[0002] In recent years, there has been a demand for smaller and lighter lens barrels in variable magnification telephoto optical systems (see Patent Document 1). However, there is a demand for further improvement in the optical performance of the optical system described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-080824 Summary of the Invention

[0004] A variable magnification optical system according to a first aspect of the present invention comprises a first lens group having positive refractive power and arranged closest to the object, a second lens group, and a rear group, wherein the spacing between each lens group changes during magnification variation, the first lens group has a positive lens closest to the object, the rear group has, in order from the object side, a positive lens group, a positive lens group, and a negative lens group, and an aperture is provided within the rear group, and at least a portion of the lens group closer to the image plane than the aperture is a focusing group that moves in the optical axis direction during focusing, and the focusing group is composed of, in order from the object side, a positive lens and a negative lens, and satisfies the following condition: 0.30 < D1MAX / G1d < 0.70 0.064 < D1MAX / f1 < 0.140 0.005 < Gfd / TLt < 0.015 however, D1MAX: the maximum air gap on the optical axis within the first lens group G1d: the thickness of the first lens group on the optical axis f1: focal length of the first lens group Gfd: the thickness of the focusing group on the optical axis TLt: total optical length of the variable magnification optical system in the telephoto end state [Brief explanation of the drawings]

[0005] [Figure 1] 1 is a cross-sectional view showing the lens configuration of a variable magnification optical system according to Example 1 in a wide-angle end state and in a state focused on infinity. [Figure 2] 1A and 1B are diagrams showing various aberrations of the variable magnification optical system according to Example 1 when focused at infinity, where FIG. 1A shows the wide-angle end state and FIG. 1B shows the telephoto end state. [Figure 3] FIG. 10 is a cross-sectional view showing the lens configuration of a variable magnification optical system according to Example 2 in a wide-angle end state and in a state focused on infinity. [Figure 4] 10A and 10B are diagrams showing various aberrations in the infinity-focused state of the variable-magnification optical system according to Example 2, where FIG. 10A shows the wide-angle end state and FIG. [Figure 5] FIG. 11 is a cross-sectional view showing the lens configuration of a variable magnification optical system according to Example 3 in a wide-angle end state and focused on infinity. [Figure 6] 10A and 10B are diagrams showing various aberrations in the infinity-focused state of the variable-magnification optical system according to Example 3, where FIG. 10A shows the wide-angle end state and FIG. [Figure 7] FIG. 10 is a cross-sectional view showing the lens configuration of a variable magnification optical system according to Example 4 in the wide-angle end state and in a state focused on infinity. [Figure 8] 10A and 10B are diagrams showing various aberrations of the variable magnification optical system according to Example 4 when focused at infinity, where FIG. 10A shows the wide-angle end state and FIG. [Figure 9] FIG. 11 is a cross-sectional view showing the lens configuration of a variable magnification optical system according to Example 5 in the wide-angle end state and in a state focused on infinity. [Figure 10] 10A and 10B are diagrams showing various aberrations of the variable magnification optical system according to Example 5 in a state focused at infinity, where FIG. 10A shows the wide-angle end state and FIG. [Figure 11] FIG. 13 is a cross-sectional view showing the lens configuration of a variable magnification optical system according to Example 6 in the wide-angle end state and in a state focused on infinity. [Figure 12] 10A and 10B are diagrams showing various aberrations in the infinity-focused state of the variable-magnification optical system according to Example 6, where FIG. 10A shows the wide-angle end state and FIG. [Figure 13] FIG. 13 is a cross-sectional view showing the lens configuration of a variable magnification optical system according to Example 7 in the wide-angle end state and in a state focused on infinity. [Figure 14] 10A and 10B are diagrams showing various aberrations in the infinity-focused state of the variable-magnification optical system according to Example 7, where FIG. 10A shows the wide-angle end state and FIG. [Figure 15] FIG. 13 is a cross-sectional view showing the lens configuration of a variable magnification optical system according to Example 8 in the wide-angle end state and in a state focused on infinity. [Figure 16] 13A and 13B are diagrams showing various aberrations in the infinity-focused state of the variable magnification optical system according to Example 8, where FIG. 13A shows the wide-angle end state and FIG. [Figure 17] FIG. 2 is a cross-sectional view of a camera equipped with the variable magnification optical system. [Figure 18] 10 is a flowchart illustrating a method for manufacturing the variable magnification optical system. DETAILED DESCRIPTION OF THE INVENTION

[0006] Preferred embodiments will now be described with reference to the drawings.

[0007] (First embodiment) As shown in Fig. 1, the variable magnification optical system ZL according to the first embodiment has a first lens group G1 having positive refractive power and arranged closest to the object, a second lens group G2, and a rear group GL, and the spacing between each lens group changes during magnification. In addition, in this variable magnification optical system ZL, the first lens group G1 has a positive lens (for example, a biconvex positive lens L11 in the example of Fig. 1) closest to the object. This configuration allows the variable magnification optical system ZL to be made smaller and lighter while maintaining optical performance.

[0008] Furthermore, it is desirable that the variable magnification optical system ZL according to the first embodiment satisfy the following conditional expression (1).

[0009] 0.30 < D1MAX / G1d < 0.70 (1) however, D1MAX: Maximum air gap on the optical axis within the first lens group G1 G1d: Thickness of the first lens group G1 on the optical axis

[0010] Conditional formula (1) defines the ratio of the maximum air gap within the first lens group G1 to the axial thickness of the first lens group G1. Exceeding the upper limit of conditional formula (1) undesirably makes the axial thickness of the first lens group G1 too thick, making it difficult to correct spherical aberration, axial chromatic aberration, lateral chromatic aberration, and other aberrations. To ensure the effectiveness of conditional formula (1), the upper limit of conditional formula (1) should preferably be set to 0.68, 0.65, 0.63, 0.60, 0.58, or even 0.55. Falling below the lower limit of conditional formula (1) is undesirable because it is disadvantageous for compactness and weight reduction, making it difficult to correct spherical aberration, coma, field curvature, and other aberrations. To ensure the effectiveness of conditional formula (1), the lower limit of conditional formula (1) should preferably be set to 0.33, or even 0.35.

[0011] Furthermore, it is desirable that the variable magnification optical system ZL according to the first embodiment satisfy the following conditional expression (2).

[0012] 0.064 < D1MAX / f1 < 0.140 (2) however, D1MAX: Maximum air gap on the optical axis within the first lens group G1 f1: focal length of the first lens group G1

[0013] Conditional expression (2) defines the ratio between the maximum air gap within the first lens group G1 and the focal length of the first lens group G1. Exceeding the upper limit of conditional expression (2) undesirably makes the axial thickness of the first lens group G1 too thick, making it difficult to correct spherical aberration, axial chromatic aberration, lateral chromatic aberration, and other aberrations. To ensure the effectiveness of conditional expression (2), it is preferable to set the upper limit of conditional expression (2) to 0.138, 0.135, 0.133, or even 0.130. Falling below the lower limit of conditional expression (2) is undesirable because it is disadvantageous for achieving compactness and weight reduction, making it difficult to correct spherical aberration, coma, field curvature, and other aberrations. To ensure the effectiveness of conditional expression (2), it is preferable to set the lower limit of conditional expression (2) to 0.065, 0.068, or even 0.070.

[0014] (Second embodiment) As shown in Fig. 1, the variable magnification optical system ZL according to the second embodiment has a first lens group G1 having positive refractive power and arranged closest to the object, a second lens group G2, and a rear group GL, and the spacing between each lens group changes during magnification. In addition, in this variable magnification optical system ZL, the first lens group G1 has a positive lens (for example, a biconvex positive lens L11 in the example of Fig. 1) closest to the object. This configuration allows the variable magnification optical system ZL to be made smaller and lighter.

[0015] Furthermore, it is desirable that the variable magnification optical system ZL according to the second embodiment satisfy the following conditional expression (2).

[0016] 0.064 < D1MAX / f1 < 0.140 (2) however, D1MAX: Maximum air gap on the optical axis within the first lens group G1 f1: focal length of the first lens group G1

[0017] Conditional expression (2) defines the ratio between the maximum air gap within the first lens group G1 and the focal length of the first lens group G1. Exceeding the upper limit of conditional expression (2) undesirably makes the axial thickness of the first lens group G1 too thick, making it difficult to correct spherical aberration, axial chromatic aberration, lateral chromatic aberration, and other aberrations. To ensure the effectiveness of conditional expression (2), it is preferable to set the upper limit of conditional expression (2) to 0.138, 0.135, 0.133, or even 0.130. Falling below the lower limit of conditional expression (2) is undesirable because it is disadvantageous for achieving compactness and weight reduction, making it difficult to correct spherical aberration, coma, field curvature, and other aberrations. To ensure the effectiveness of conditional expression (2), it is preferable to set the lower limit of conditional expression (2) to 0.065, 0.068, or even 0.070.

[0018] (Regarding the first and second embodiments) Furthermore, it is desirable that the variable magnification optical system ZL according to the first and second embodiments (hereinafter referred to as "the present embodiment") satisfy the following conditional expression (3).

[0019] 0.20 < f1 / ft < 0.50 (3) however, f1: focal length of the first lens group G1 ft: focal length of the entire system at the telephoto end of the variable magnification optical system ZL

[0020] Conditional expression (3) defines the ratio between the focal length of the first lens group G1 and the focal length of the entire system at the telephoto end. By satisfying the range of conditional expression (3), fluctuations in various aberrations, such as spherical aberration, curvature of field, and coma, during zooming can be effectively corrected. Exceeding the range of conditional expression (3) is undesirable because fluctuations in aberrations, such as spherical aberration, curvature of field, and coma, during zooming become significant. To ensure the effectiveness of conditional expression (3), it is preferable to set the upper limit of conditional expression (3) to 0.48, 0.46, 0.45, or even 0.44. To ensure the effectiveness of conditional expression (3), it is preferable to set the lower limit of conditional expression (3) to 0.23, 0.25, 0.28, or even 0.30.

[0021] Furthermore, the variable magnification optical system ZL according to this embodiment has a stop (for example, the aperture stop S shown in FIG. 1) in the rear group GL, and it is desirable that at least a portion of the image plane side of this stop is an image-stabilizing group Gv that moves so as to have a component in a direction perpendicular to the optical axis.

[0022] Furthermore, it is desirable that the variable magnification optical system ZL according to this embodiment satisfy the following conditional expression (4).

[0023] 1.50 < (1-βtv)×βtvb < 3.00 (4) however, βtv: Lateral magnification of the vibration control group Gv at the telephoto end βtvb: Lateral magnification of the group on the image plane side of the image stabilization group Gv at the telephoto end

[0024] Conditional expression (4) defines the conditions for vibration reduction by the vibration reduction group Gv. By satisfying conditional expression (4), fluctuations in various aberrations, such as coma, curvature of field, and astigmatism, can be effectively corrected during vibration reduction. Furthermore, exceeding the range of conditional expression (4) is undesirable because it becomes difficult to balance the correction of various aberrations during normal operation while correcting coma, curvature of field, and astigmatism during vibration reduction. To ensure the effectiveness of conditional expression (4), it is preferable to set the upper limit of conditional expression (4) to 2.90, 2.80, 2.70, 2.60, or even 2.50. To ensure the effectiveness of conditional expression (4), it is preferable to set the lower limit of conditional expression (4) to 1.60, 1.70, 1.80, 1.90, 2.00, 2.10, or even 2.20.

[0025] In the variable magnification optical system ZL according to this embodiment, it is desirable that the vibration reduction group Gv has, in order from the object side, a positive lens, a positive lens, and a negative lens. By configuring it in this manner, it is possible to correct fluctuations in various aberrations such as coma during vibration reduction.

[0026] Furthermore, it is desirable that the variable magnification optical system ZL according to this embodiment satisfy the following conditional expression (5).

[0027] 0.020 < Gvd / TLt < 0.040 (5) however, Gvd: Thickness of the vibration isolation group Gv on the optical axis TLt: Total optical length of the variable magnification optical system ZL in the telephoto end state

[0028] Conditional expression (5) defines the ratio between the axial thickness of the image stabilization group and the total optical length of this variable magnification optical system ZL in the telephoto end state. Satisfying conditional expression (5) enables favorable correction of fluctuations in aberrations such as coma and astigmatism during image stabilization. Furthermore, exceeding the range of conditional expression (5) is undesirable because it becomes difficult to correct aberrations such as coma and astigmatism during image stabilization while achieving compactness and weight reduction. To ensure the effectiveness of conditional expression (5), it is preferable to set the upper limit of conditional expression (5) to 0.038, 0.036, or even 0.035. To ensure the effectiveness of conditional expression (5), it is preferable to set the lower limit of conditional expression (5) to 0.022, 0.024, 0.025, or even 0.027.

[0029] Furthermore, the variable magnification optical system ZL according to this embodiment has a stop in the rear group GL, and it is desirable that at least a portion on the image plane side of this stop is a focusing group Gf that moves in the optical axis direction during focusing.

[0030] Furthermore, it is desirable that the variable magnification optical system ZL according to this embodiment satisfy the following conditional expression (6).

[0031] -8.00 < (1-βtf 2 )×βtfb 2 < -4.00 (6) however, βtf: Lateral magnification of the focusing group Gf at the telephoto end βtfb: Lateral magnification of the group on the image plane side of the focusing group Gf at the telephoto end

[0032] Conditional expression (6) defines the condition for focusing by the focusing group Gf. Satisfying conditional expression (6) enables favorable correction of fluctuations in various aberrations, such as spherical aberration, coma, curvature of field, and astigmatism, during focusing. Furthermore, exceeding the range of conditional expression (6) is undesirable because it becomes difficult to balance the correction of spherical aberration, coma, curvature of field, and astigmatism during focusing while correcting various aberrations during normal operation. To ensure the effectiveness of conditional expression (6), it is preferable to set the upper limit of conditional expression (6) to -4.25, -4.50, -4.75, or -5.00. To ensure the effectiveness of conditional expression (6), it is preferable to set the lower limit of conditional expression (6) to -7.50, -7.00, -6.50, -6.00, -5.80, or -5.50.

[0033] In the variable magnification optical system ZL according to this embodiment, it is desirable that the focusing group Gf include, in order from the object side, a positive lens and a negative lens, which makes it possible to correct fluctuations in axial chromatic aberration and lateral chromatic aberration during focusing.

[0034] Furthermore, it is desirable that the variable magnification optical system ZL according to this embodiment satisfy the following conditional expression (7).

[0035] 0.005 < Gfd / TLt < 0.015 (7) however, Gfd: The thickness of the focusing group Gf on the optical axis TLt: Total optical length of the variable magnification optical system ZL in the telephoto end state

[0036] Condition (7) defines the ratio of the axial thickness of the focusing group Gf to the total optical length of the variable-magnification optical system ZL in the telephoto end state. Satisfying condition (7) enables favorable correction of fluctuations in aberrations, such as coma and astigmatism, during focusing. Exceeding the range of condition (7) is undesirable because it becomes difficult to correct aberrations, such as coma and astigmatism, during focusing while achieving compactness and weight reduction. To ensure the effectiveness of condition (7), it is preferable to set the upper limit of condition (7) to 0.014, 0.013, or even 0.012. To ensure the effectiveness of condition (7), it is preferable to set the lower limit of condition (7) to 0.006, 0.007, or even 0.008.

[0037] In the variable magnification optical system ZL according to this embodiment, it is desirable that the first lens group G1 has a negative lens closest to the image plane. As described above, by arranging a positive lens closest to the object in the first lens group G1 and further arranging a negative lens closest to the image plane, the variable magnification optical system ZL can be made smaller and lighter.

[0038] Furthermore, it is desirable that the variable magnification optical system ZL according to this embodiment satisfy the following conditional expression (8).

[0039] 0.04 < G1d / ft < 0.15 (8) however, G1d: Thickness of the first lens group G1 on the optical axis ft: focal length of the entire system at the telephoto end of the variable magnification optical system ZL

[0040] Conditional expression (8) defines the ratio between the axial thickness of the first lens group G1 and the focal length of the entire variable magnification optical system ZL at the telephoto end. Satisfying conditional expression (8) enables favorable correction of various aberrations. Exceeding the upper limit of conditional expression (8) undesirably makes it difficult to correct various aberrations, such as spherical aberration, axial chromatic aberration, and lateral chromatic aberration, because the axial thickness of the first lens group G1 becomes too large. To ensure the effect of conditional expression (8), it is preferable to set the upper limit of conditional expression (8) to 0.14, 0.13, or even 0.12. Exceeding the lower limit of conditional expression (8) is undesirable because it is disadvantageous for achieving compactness and weight reduction, making it difficult to correct various aberrations, such as spherical aberration, coma, and curvature of field. In order to ensure the effect of conditional expression (8), it is more desirable to set the lower limit of conditional expression (8) to 0.05, and more preferably 0.055.

[0041] In the variable magnification optical system ZL according to this embodiment, the rear group GL has a lens group including a diaphragm (for example, the third lens group G3 in FIG. 1), and it is desirable that the following conditional expression (9) be satisfied.

[0042] 0.05 < Gsd / TLt < 0.30 (9) however, Gsd: Thickness of the lens group including the aperture on the optical axis TLt: Total optical length of the variable magnification optical system ZL in the telephoto end state

[0043] Condition (9) defines the ratio of the axial thickness of the lens group including the aperture stop to the total optical length of this variable-magnification optical system ZL in the telephoto end state. By satisfying condition (9), it is possible to effectively correct various aberrations, such as spherical aberration, curvature of field, and astigmatism. Furthermore, exceeding the range of condition (9) is undesirable because it becomes difficult to correct various aberrations, such as spherical aberration, curvature of field, and astigmatism, while achieving compactness and weight reduction. To ensure the effectiveness of condition (9), it is preferable to set the upper limit of condition (9) to 0.28, 0.25, 0.23, or even 0.20. To ensure the effectiveness of condition (9), it is preferable to set the lower limit of condition (9) to 0.06, 0.08, 0.10, 0.12, or even 0.13.

[0044] In the variable magnification optical system ZL according to this embodiment, it is desirable that the first lens group G1 have a negative lens arranged closest to the image plane and a positive lens arranged adjacent to the object side of this negative lens. As described above, by arranging a positive lens closest to the object side of the first lens group G1, and further arranging a negative lens closest to the image plane and a positive lens adjacent to the object side of this negative lens, it is possible to reduce the size and weight of the variable magnification optical system ZL.

[0045] Furthermore, it is desirable that the variable magnification optical system ZL according to this embodiment satisfy the following conditional expression (10).

[0046] 0.015 < D1MAX / ft < 0.080 (10) however, D1MAX: Maximum air gap on the optical axis within the first lens group G1 ft: focal length of the entire system at the telephoto end of the variable magnification optical system ZL

[0047] Conditional expression (10) defines the ratio between the maximum air gap on the optical axis within the first lens group G1 and the focal length of the entire variable-magnification optical system ZL at the telephoto end. By satisfying conditional expression (10), various aberrations can be effectively corrected. Exceeding the upper limit of conditional expression (10) is undesirable because it makes it difficult to correct various aberrations, such as spherical aberration, axial chromatic aberration, and lateral chromatic aberration. To ensure the effectiveness of conditional expression (10), the upper limit of conditional expression (10) should preferably be set to 0.075, 0.070, 0.065, 0.060, 0.058, or even 0.055. Exceeding the lower limit of conditional expression (10) is undesirable because it is disadvantageous for achieving compactness and weight reduction, making it difficult to correct various aberrations, such as spherical aberration, coma, and curvature of field. In order to ensure the effect of conditional expression (10), it is more desirable to set the lower limit of conditional expression (10) to 0.016, 0.018, or even 0.020.

[0048] Furthermore, it is desirable that the variable magnification optical system ZL according to this embodiment satisfy the following conditional expression (11).

[0049] 0.15 < Bfw / fw < 0.50 (11) however, Bfw: Back focus at the wide-angle end of the variable magnification optical system ZL fw: focal length of the entire variable magnification optical system ZL at the wide-angle end

[0050] Conditional expression (11) defines the ratio between the back focal length of the variable magnification optical system ZL in the wide-angle end state and the focal length of the entire system. To ensure the effect of conditional expression (11), it is preferable to set the upper limit of conditional expression (11) to 0.48, 0.45, 0.43, or even 0.40. To ensure the effect of conditional expression (11), it is preferable to set the lower limit of conditional expression (11) to 0.18, 0.20, 0.23, 0.25, or even 0.28.

[0051] Furthermore, it is desirable that the variable magnification optical system ZL according to this embodiment satisfy the following conditional expression (12).

[0052] 4.00° < ωw < 10.00° (12) however, ωw: Half angle of view at the wide-angle end of the variable magnification optical system ZL

[0053] Conditional expression (12) defines the range of the half angle of view of this variable magnification optical system ZL in the wide-angle end state. To ensure the effect of conditional expression (12), it is more desirable to set the upper limit of conditional expression (12) to 9.50°, 9.00°, 8.80°, 8.50°, 8.30°, or even 8.00°. To ensure the effect of conditional expression (12), it is more desirable to set the lower limit of conditional expression (12) to 4.30°, 4.50°, 4.80°, 5.00°, 5.30°, or even 5.50°.

[0054] In the variable magnification optical system ZL according to this embodiment, it is desirable that the rear group GL have, in order from the object side, a positive lens group, a positive lens group, and a negative lens group. It is also desirable that at least a portion of at least one of the positive lens group, positive lens group, and negative lens group included in this rear group GL is a vibration reduction group Gv that moves so as to have a component in a direction perpendicular to the optical axis, and that at least a portion of at least one of the positive lens group, positive lens group, and negative lens group is a focusing group Gf that moves in the optical axis direction during focusing. This configuration makes it possible to reduce the size and weight of the variable magnification optical system ZL while suppressing aberration fluctuations during vibration reduction and focusing.

[0055] Furthermore, in the variable magnification optical system ZL according to this embodiment, the rear group GL has an image stabilization group Gv that moves so as to have a component in a direction perpendicular to the optical axis, and this image stabilization group Gv is preferably a positive lens group.

[0056] In the variable magnification optical system ZL according to this embodiment, the rear group GL has a focusing group Gf that moves in the optical axis direction during focusing, and this focusing group Gf is preferably a negative lens group.

[0057] In the variable magnification optical system ZL according to this embodiment, it is desirable that the lens group arranged closest to the image plane in the rear group GL has positive refractive power.

[0058] Furthermore, in the variable magnification optical system ZL according to this embodiment, it is desirable that the first lens group G1 be fixed relative to the image plane during magnification. This configuration reduces the number of components used in the mechanism that moves the lens groups during magnification, making it possible to reduce the size and weight of this variable magnification optical system ZL. This also makes it possible to prevent variations in optical performance during magnification. This is also advantageous for suppressing variations in optical performance during manufacturing.

[0059] It should be noted that the conditions and configurations described above each exert the effects described above, and are not limited to those that satisfy all of the conditions and configurations; the effects described above can be obtained by satisfying any one of the conditions or configurations, or any combination of the conditions or configurations.

[0060] Next, a camera, which is an optical device equipped with the variable magnification optical system ZL according to this embodiment, will be described with reference to FIG. 17. This camera 1 is a so-called mirrorless camera with interchangeable lenses that uses the variable magnification optical system ZL according to this embodiment as a photographing lens 2. In this camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and forms a subject image on the imaging plane of the imaging unit 3 via an OLPF (Optical low pass filter) (not shown). The subject image is then photoelectrically converted by a photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic Viewfinder) 4 provided in the camera 1. This allows the photographer to observe the subject through the EVF 4.

[0061] Furthermore, when the photographer presses a release button (not shown), the image photoelectrically converted by the imaging unit 3 is stored in a memory (not shown). In this way, the photographer can photograph a subject using this camera 1. Note that although an example of a mirrorless camera has been described in this embodiment, the same effects as those of the camera 1 can be achieved even when the variable magnification optical system ZL according to this embodiment is installed in a single-lens reflex camera that has a quick-return mirror in the camera body and observes a subject through a viewfinder optical system.

[0062] The following contents can be appropriately adopted within the scope that does not impair the optical performance.

[0063] In this embodiment, as will be described later, a variable magnification optical system ZL having a six-group or seven-group configuration is shown. However, the above configurations, conditions, etc., can also be applied to other group configurations, such as eight groups or nine groups. Furthermore, a configuration in which a lens or lens group is added closest to the object, or a configuration in which a lens or lens group is added closest to the image plane, may also be used. Specifically, a configuration in which a lens group whose position relative to the image plane is fixed during zooming or focusing is added closest to the image plane, may be considered. Furthermore, a lens group (also simply referred to as a "group") refers to a portion having at least one lens separated by an air gap that changes during zooming or focusing. Furthermore, a lens component refers to a single lens or a cemented lens in which multiple lenses are cemented together.

[0064] Alternatively, a single or multiple lens groups, or a partial lens group, may be moved in the optical axis direction to function as a focusing group that focuses from an object at infinity to a close-up object. In this case, the focusing group can be used for autofocusing and is suitable for driving a motor (such as an ultrasonic motor) for autofocusing. In particular, it is preferable to use at least a portion of the fifth lens group G5 (sixth lens group G6 in the seventh embodiment) as a focusing group. It is also preferable that the positions of lenses other than the focusing group be fixed relative to the image plane during focusing. Considering the load on the motor, it is preferable that the focusing group be composed of a single lens or one lens component.

[0065] Alternatively, a lens group or a partial lens group may be moved so as to have a displacement component perpendicular to the optical axis, or rotated (oscillated) in a plane including the optical axis, to serve as an image stabilization group that corrects image blur caused by camera shake. In particular, it is preferable to use at least a portion of the fourth lens group G4 (fifth lens group G5 in the seventh embodiment) as an image stabilization group.

[0066] The lens surface may be spherical, flat, or aspherical. A spherical or flat lens surface is preferable because it facilitates lens processing and assembly adjustment and prevents degradation of optical performance due to errors in processing and assembly adjustment. It is also preferable because degradation of imaging performance is minimal even when the image plane is misaligned. If the lens surface is aspherical, the aspherical surface may be any of the following aspherical surfaces: a ground aspherical surface, a glass-molded aspherical surface in which glass is molded into an aspherical shape, or a hybrid aspherical surface in which a resin is molded into an aspherical shape on the surface of glass. The lens surface may also be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

[0067] It is preferable that the aperture stop S be located within the third lens group G3 of the rear group GL (within the fourth lens group G4 in the seventh embodiment), but it is also possible to use the lens frame to fulfill that role without providing a component serving as an aperture stop.

[0068] Furthermore, each lens surface may be coated with an anti-reflection coating that has high transmittance over a wide wavelength range in order to reduce flare and ghosting and achieve high contrast and high optical performance.

[0069] A manufacturing method for a variable magnification optical system ZL according to this embodiment will be outlined below with reference to FIG. 18. First, a first lens group G1, a second lens group G2, and a rear group GL, all having positive refractive power, are prepared (Step S100). Next, the lens groups are arranged so that the spacing between them changes during magnification (Step S200), and further, a positive lens L11 is arranged closest to the object side of the first lens group G1 (Step S300). Then, the lens groups are arranged so that a predetermined condition (for example, the above-mentioned conditional formula (1)) is satisfied (Step S400).

[0070] With the above-described configuration, it is possible to provide a variable magnification optical system, an optical device, and a method for manufacturing a variable magnification optical system that can be made compact and lightweight and has high optical performance. [Example]

[0071] Each embodiment will be described below with reference to the drawings. Figures 1, 3, 5, 7, 9, 11, 13, and 15 are cross-sectional views showing the configuration and refractive power distribution of a variable magnification optical system ZL (ZL1 to ZL8) according to each embodiment. The bottom of each figure also shows the movement locus of each lens group of the variable magnification optical system ZL as it changes magnification from the wide-angle end state (W) to the telephoto end state (T).

[0072] In each embodiment, the aspherical surface is expressed by the following formula (a), where y is the height in the direction perpendicular to the optical axis, S(y) is the distance (amount of sag) along the optical axis from the tangent plane of the vertex of each aspherical surface at the height y to each aspherical surface, r is the radius of curvature (paraxial radius of curvature) of the reference spherical surface, K is the conic constant, and An is the n-th order aspherical coefficient. Note that in the following embodiments, "En" is expressed as "×10 -n " indicates.

[0073] 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)

[0074] In each example, the second-order aspherical coefficient A2 is zero.

[0075] Furthermore, the following examples show specific examples of the present invention, and the present invention is not limited to these examples.

[0076] [First Example] 1 shows the configuration of a variable magnification optical system ZL1 according to Example 1. This variable magnification optical system ZL1 is composed of, from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear group GL. The rear group GL is composed of, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.

[0077] The first lens group G1 is composed of, from the object side, a biconvex positive lens L11 and a cemented positive lens formed by cementing a biconvex positive lens L12 and a biconcave negative lens L13. The second lens group G2 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L21 and a biconcave negative lens L22, a cemented negative lens formed by cementing a biconvex positive lens L23 and a biconcave negative lens L24, and a biconcave negative lens L25. The third lens group G3 is composed of, from the object side, a biconvex positive lens L31, a biconvex positive lens L32, a cemented negative lens formed by cementing a biconvex positive lens L33 and a biconcave negative lens L34, and a cemented negative lens formed by cementing a positive meniscus lens L35 with its concave surface facing the object side and a biconcave negative lens L36. The fourth lens group G4 is composed of, from the object side, a biconvex positive lens L41 and a cemented negative lens formed by cementing a biconvex positive lens L42 and a biconcave negative lens L43. The fifth lens group G5 is composed of, from the object side, a cemented lens formed by cementing a biconvex positive lens L51 and a biconcave negative lens L52. The sixth lens group G6 is composed of, from the object side, a cemented positive lens formed by cementing a biconcave aspherical negative lens L61 having an aspherical surface formed on the object side and a biconvex positive lens L62.

[0078] An aperture stop S is disposed between the biconcave negative lens L34 and the positive meniscus lens L35 of the third lens group G3. A filter group FL is disposed between the rear group GL and the image plane I.

[0079] In this variable magnification optical system ZL1, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move along the optical axis so that the spacing between the lens groups changes during magnification. Furthermore, during magnification, the first lens group G1 is fixed with respect to the image plane I.

[0080] In addition, in this variable magnification optical system ZL1, correction of the image position (vibration prevention) when camera shake occurs is performed by using the fourth lens group G4 as a vibration prevention group Gv and moving this vibration prevention group Gv so that it has a displacement component in a direction perpendicular to the optical axis.

[0081] In this variable magnification optical system ZL1, focusing from infinity to a close object point is performed by using the fifth lens group G5 as the focusing group Gf and moving this focusing group Gf toward the image side along the optical axis.

[0082] Table 1 below lists the specifications of the variable magnification optical system ZL1. In Table 1, the overall specifications include f, the focal length of the entire system, Fno, the F-number, ω, the half angle of view (maximum angle of incidence, measured in degrees), Y, the maximum image height, BF, the back focus when focused at infinity, and TL, the total optical length when focused at infinity, expressed as values ​​for the wide-angle end state, the mid-focal length state, and the telephoto end state. Here, the back focus BF indicates the distance on the optical axis from the lens surface closest to the image plane (surface No. 36) to the image plane I. The total optical length TL indicates the distance on the optical axis from the lens surface closest to the object plane (surface No. 1) to the image plane I. In the lens data, the first column m indicates the order of the lens surfaces (surface number) from the object side along the direction of light travel, the second column r indicates the radius of curvature of each lens surface, the third column d indicates the distance on the optical axis from each optical surface to the next optical surface (surface spacing), and the fourth column nd and fifth column vd indicate the refractive index and Abbe number for the d-line (λ=587.6 nm). A radius of curvature of ∞ indicates a flat surface, and the refractive index of air, 1.000000, is omitted. If the lens surface is aspherical, an asterisk (*) is added to the right of the surface number, and the column for the radius of curvature r indicates the paraxial radius of curvature. The lens group focal lengths indicate the number and focal length of the first surface of each of the first through sixth lens groups G1 through G6.

[0083] Here, the focal length f, radius of curvature r, surface spacing d, and other length units listed in the following specifications are generally in millimeters, but this is not limiting, as the same optical performance can be obtained even when the optical system is proportionally enlarged or reduced.

[0084] The explanations of these symbols and the specifications tables also apply to the following examples.

[0085] (Table 1) First Example [Overall specifications] Wide-angle end Mid-range focal length Telephoto end f 185.000 305.000 581.999 Fno 5.151 5.259 6.480 ω 6.53 3.93 2.08 Y 21.630 21.630 21.630 BF 56.619 58.421 54.491 BF (air equivalent) 56.074 57.876 53.946 TL 330.000 329.999 330.000 TL (air equivalent) 329.455 329.454 329.455 [Lens data] mrd nd νd object surface ∞ 1 114.53279 11.500 1.518600 69.89 2 -3061.17760 25.000 3 105.69467 9.500 1.496997 81.61 4 -577.89907 2.000 1.795040 28.69 5 187.41793 d1 6 231.95439 5.100 1.892860 20.36 7 -143.36563 1.200 1.603000 65.44 8 60.53698 4.000 9 79.45471 5.200 1.808090 22.74 10 -278.51621 1.200 1.903658 31.32 11 87.26332 12.973 12 -63.24454 1.200 1.902000 25.26 13 547.46152 d2 14 128.87267 5.600 1.437001 95.10 15 -80.05371 0.200 16 124.19685 4.700 1.496997 81.61 17 -127.34752 0.200 18 76.12573 6.000 1.487489 70.44 19 -74.22322 1.200 1.903658 31.32 20 350.93166 24.378 21 ∞ 10.000 Aperture S 22 -240.73230 4.400 1.854779 24.80 23 -46.89217 1.000 1.618000 63.34 24 54.46304 d3 25 56.46175 4.000 1.720467 34.71 26 -143.84626 0.200 27 37.26021 4.400 1.672700 32.19 28 -77.53975 1.000 1.860740 23.08 29 38.85225 d4 30 84.46824 2.000 1.688930 31.16 31 -117.74138 1.000 1.834810 42.73 32 36.08530 d5 33* -484.81263 0.100 1.560930 36.64 34 -3406.43640 1.000 1.816000 46.59 35 36.92132 7.000 1.647690 33.72 36 -85.19724 d6 37 ∞ 1.600 1.516800 63.88 Image plane ∞ [Lens group focal length] Lens group First surface Focal length First lens group G1 1 202.200 Second lens group G2 6 -48.201 Third lens group G3 14 78.109 4th lens group G4 25 71.573 Fifth lens group G5 30 -62.915 6th lens group G6 33 499.711

[0086] In this variable magnification optical system ZL1, surface No. 33 is an aspherical surface. Table 2 below shows the aspherical surface data for surface number m, that is, the values ​​of the conic constant K and each of the aspherical surface constants A4 to A10.

[0087] (Table 2) [Aspherical data] m K A4 A6 A8 A10 33 1.00 1.75163E-06 8.31126E-10 1.77225E-12 -4.35522E-15

[0088] In this variable magnification optical system ZL1, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, the axial air distance d3 between the third lens group G3 and the fourth lens group G4, the axial air distance d4 between the fourth lens group G4 and the fifth lens group G5, the axial air distance d5 between the fifth lens group G5 and the sixth lens group G6, and the axial air distance d6 between the sixth lens group G6 and the filter group FL change during magnification. Table 3 below shows the variable distances in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0089] (Table 3) [Variable Interval Data] Wide-angle end Mid-range focal length Telephoto end d1 18.150 43.488 51.449 d2 64.299 38.961 1.000 d3 5.237 4.200 3.822 d4 2.500 5.233 17.594 d5 25.944 22.446 44.393 d6 54.519 56.322 52.391

[0090] FIG. 2 shows diagrams of spherical aberration, astigmatism, distortion, lateral chromatic aberration, and coma for this variable magnification optical system ZL1 when focused at infinity in the wide-angle end state and the telephoto end state. In each aberration diagram, FNO indicates the F-number, and A indicates the half angle of view (unit: °) for each image height. Note that the spherical aberration diagram indicates the F-number value for the maximum aperture, the astigmatism and distortion diagrams indicate the half angle of view, and the coma diagrams indicate the values ​​for each half angle of view. In the spherical aberration diagram, lateral chromatic aberration diagram, and coma diagram, d indicates the d-line (λ=587.6 nm), and g indicates the g-line (λ=435.8 nm). In the astigmatism diagram, the solid line indicates the sagittal image plane, and the dashed line indicates the meridional image plane. The same symbols as in this embodiment are used in the aberration diagrams of each embodiment shown below. From these aberration diagrams, it can be seen that this variable magnification optical system ZL1 has excellent correction for various aberrations and has excellent imaging performance.

[0091] [Second Example] 3 shows the configuration of a variable magnification optical system ZL2 according to Example 2. This variable magnification optical system ZL2 is composed of, from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear group GL. The rear group GL is composed of, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.

[0092] The first lens group G1 is composed of, from the object side, a positive meniscus lens L11 with a convex surface facing the object side, a positive meniscus lens L12 with a convex surface facing the object side, and a cemented negative lens formed by cementing a biconvex positive lens L13 and a biconcave negative lens L14. The second lens group G2 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L21 and a biconcave negative lens L22, a cemented positive lens formed by cementing a biconvex positive lens L23 and a biconcave negative lens L24, and a biconcave negative lens L25. The third lens group G3 is composed of, from the object side, a biconvex positive lens L31, a biconvex positive lens L32, a cemented negative lens formed by cementing a biconvex positive lens L33 and a biconcave negative lens L34, and a cemented negative lens formed by cementing a positive meniscus lens L35 with a concave surface facing the object side and a biconcave negative lens L36. The fourth lens group G4 is composed of, from the object side, a biconvex positive lens L41 and a cemented positive lens formed by cementing a biconvex positive lens L42 and a biconcave negative lens L43. The fifth lens group G5 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L51 and a biconcave negative lens L52. The sixth lens group G6 is composed of, from the object side, a cemented positive lens formed by cementing a biconcave aspherical negative lens L61 having an aspherical surface formed on the object side and a biconvex positive lens L62.

[0093] An aperture stop S is disposed between the biconcave negative lens L34 and the positive meniscus lens L35 of the third lens group G3. A filter group FL is disposed between the rear group GL and the image plane I.

[0094] In this variable magnification optical system ZL2, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move along the optical axis so that the spacing between the lens groups changes during magnification. Furthermore, during magnification, the first lens group G1 is fixed with respect to the image plane I.

[0095] In addition, in this variable magnification optical system ZL2, correction of the image position (vibration prevention) when camera shake occurs is performed by using the fourth lens group G4 as the vibration prevention group Gv and moving this vibration prevention group Gv so that it has a displacement component in a direction perpendicular to the optical axis.

[0096] In this variable magnification optical system ZL2, focusing from infinity to a close object point is performed by using the fifth lens group G5 as the focusing group Gf and moving this focusing group Gf toward the image side along the optical axis.

[0097] Table 4 below lists the specifications of the variable magnification optical system ZL2.

[0098] (Table 4) Second Example [Overall specifications] Wide-angle end Mid-range focal length Telephoto end f 185.000 304.999 582.000 Fno 5.152 5.287 6.500 ω 6.52 3.93 2.08 Y 21.630 21.630 21.630 BF 60.191 59.296 55.101 BF (air equivalent) 59.646 58.751 54.555 TL 330.000 329.999 330.000 TL (air equivalent) 329.455 329.454 329.455 [Lens data] mrd nd νd object surface ∞ 1 199.65699 5.500 1.487490 70.32 2 870.00053 0.200 3 118.86881 10.000 1.496997 81.61 4 4884.78510 25.000 5 128.05963 7.100 1.496997 81.61 6 -1061.59360 2.000 1.806099 33.27 7 140.31227 d1 8 288.68406 6.000 1.846660 23.80 9 -104.05044 1.500 1.603000 65.44 10 58.46334 1.524 11 65.13069 4.800 1.808090 22.74 12 -156.61651 1.200 1.850260 32.35 13 72.27751 8.511 14 -65.76029 1.200 1.921189 23.96 15 674.80181 d2 16 125.15648 5.800 1.496997 81.61 17 -86.49181 0.200 18 109.52756 4.200 1.496997 81.61 19 -168.55272 0.200 20 71.85821 6.000 1.487489 70.44 21 -77.90815 1.500 1.903658 31.32 22 225.53679 21.564 23 ∞ 10.000 Aperture S 24 -1129.22470 4.400 1.854779 24.80 25 -46.62310 1.000 1.658440 50.84 26 49.39481 d3 27 158.31945 4.000 1.719990 50.27 28 -92.73310 0.200 29 32.14452 4.400 1.688930 31.16 30 -142.66139 1.000 1.860740 23.08 31 43.08702 d4 32 83.33868 2.000 1.688930 31.16 33 -121.29117 1.000 1.834810 42.73 34 36.82441 d5 35* -248.87152 0.100 1.560930 36.64 36 -444.63279 1.000 1.816000 46.59 37 41.36088 6.500 1.647690 33.72 38 -77.63179 d6 39 ∞ 1.600 1.516800 63.88 Image plane ∞ [Lens group focal length] Lens group First surface Focal length First lens group G1 1 221.343 Second lens group G2 8 -50.723 Third lens group G3 16 80.366 4th lens group G4 27 68.183 Fifth lens group G5 32 -65.424 6th lens group G6 35 595.006

[0099] In this variable magnification optical system ZL2, surface No. 35 is an aspherical surface. Table 5 below shows the aspherical surface data for surface number m, that is, the values ​​of the conic constant K and each of the aspherical surface constants A4 to A10.

[0100] (Table 5) [Aspherical data] m K A4 A6 A8 A10 35 1.00 1.59390E-06 4.38735E-10 2.13630E-12 -4.90176E-15

[0101] In this variable magnification optical system ZL2, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, the axial air distance d3 between the third lens group G3 and the fourth lens group G4, the axial air distance d4 between the fourth lens group G4 and the fifth lens group G5, the axial air distance d5 between the fifth lens group G5 and the sixth lens group G6, and the axial air distance d6 between the sixth lens group G6 and the filter group FL change during magnification. Table 6 below shows the variable distances in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0102] (Table 6) [Variable Interval Data] Wide-angle end Mid-range focal length Telephoto end d1 22.997 49.485 58.457 d2 66.604 40.116 1.000 d3 6.423 4.200 4.129 d4 2.500 5.237 15.161 d5 21.686 22.066 46.555 d6 58.091 57.197 53.000

[0103] Figure 4 shows diagrams of spherical aberration, astigmatism, distortion, lateral chromatic aberration, and coma when this variable magnification optical system ZL2 is focused at infinity in the wide-angle end state and the telephoto end state. These aberration diagrams show that this variable magnification optical system ZL2 has excellent correction for various aberrations and has excellent imaging performance.

[0104] [Third Example] 5 shows the configuration of a variable magnification optical system ZL3 according to Example 3. This variable magnification optical system ZL3 is composed of, from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear group GL. The rear group GL is composed of, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.

[0105] The first lens group G1 is composed of, from the object side, a biconvex positive lens L11 and a cemented negative lens formed by cementing a biconvex positive lens L12 and a biconcave negative lens L13. The second lens group G2 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L21 and a biconcave negative lens L22, a cemented positive lens formed by cementing a positive meniscus lens L23 with a convex surface facing the object side and a negative meniscus lens L24 with a convex surface facing the object side, and a biconcave negative lens L25. The third lens group G3 is composed of, from the object side, a biconvex positive lens L31, a biconvex positive lens L32, a cemented negative lens formed by cementing a biconvex positive lens L33 and a biconcave negative lens L34, and a cemented negative lens formed by cementing a positive meniscus lens L35 with a concave surface facing the object side and a biconcave negative lens L36. The fourth lens group G4 is composed of, from the object side, a biconvex positive lens L41 and a cemented negative lens formed by cementing a biconvex positive lens L42 and a biconcave negative lens L43. The fifth lens group G5 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L51 and a biconcave negative lens L52. The sixth lens group G6 is composed of, from the object side, a cemented positive lens formed by cementing an aspherical negative lens L61 having a negative meniscus shape with its convex surface facing the object side and an aspherical surface formed on its object side, and a biconvex positive lens L62.

[0106] An aperture stop S is disposed between the biconcave negative lens L34 and the positive meniscus lens L35 of the third lens group G3. A filter group FL is disposed between the rear group GL and the image plane I.

[0107] In this variable magnification optical system ZL3, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move along the optical axis so that the spacing between the lens groups changes during magnification. Furthermore, during magnification, the first lens group G1 is fixed with respect to the image plane I.

[0108] In addition, in this variable magnification optical system ZL3, correction of the image position (vibration prevention) when camera shake occurs is performed by using the fourth lens group G4 as a vibration prevention group Gv and moving this vibration prevention group Gv so that it has a displacement component in a direction perpendicular to the optical axis.

[0109] In this variable magnification optical system ZL3, focusing from infinity to a close object point is performed by using the fifth lens group G5 as the focusing group Gf and moving this focusing group Gf toward the image side along the optical axis.

[0110] Table 7 below lists the specifications of the variable magnification optical system ZL3.

[0111] (Table 7) Third Example [Overall specifications] Wide-angle end Mid-range focal length Telephoto end f 154.500 296.173 485.000 Fno 5.150 5.334 6.480 ω 7.84 4.05 2.50 Y 21.630 21.630 21.630 BF 59.400 56.396 53.563 BF (air equivalent) 58.855 55.851 53.017 TL 320.000 320.000 319.999 TL (air equivalent) 319.455 319.455 319.454 [Lens data] mrd nd νd object surface ∞ 1 109.89168 11.500 1.518600 69.89 2 -11921.75300 25.000 3 105.30936 9.500 1.496997 81.61 4 -639.14794 2.000 1.795040 28.69 5 177.31407 d1 6 250.72773 5.100 1.892860 20.36 7 -136.09656 1.200 1.603000 65.44 8 61.04872 4.000 9 71.28310 5.200 1.808090 22.74 10 2721.85150 1.200 1.903658 31.32 11 83.32156 11.209 12 -70.17775 1.200 1.902000 25.26 13 270.80287 d2 14 117.97908 5.600 1.437001 95.10 15 -84.42046 0.200 16 113.92037 4.700 1.496997 81.61 17 -137.32141 0.200 18 75.33153 6.000 1.487489 70.44 19 -75.26863 1.200 1.903658 31.32 20 311.74750 21.696 21 ∞ 10.000 Aperture S 22 -199.17073 4.400 1.854779 24.80 23 -45.66609 1.000 1.618000 63.34 24 56.74499 d3 25 56.79693 4.000 1.720467 34.71 26 -133.19871 0.200 27 38.05662 4.400 1.672700 32.19 28 -71.06035 1.000 1.860740 23.08 29 40.65342 d4 30 96.07316 2.000 1.688930 31.16 31 -122.75615 1.000 1.834810 42.73 32 34.74212 d5 33* 786.75543 0.100 1.560930 36.64 34 328.93291 1.000 1.816000 46.59 35 37.30304 7.000 1.647690 33.72 36 -101.89055 d6 37 ∞ 1.600 1.516800 63.88 Image plane ∞ [Lens group focal length] Lens group First surface Focal length First lens group G1 1 204.797 Second lens group G2 6 -50.756 Third lens group G3 14 81.290 4th lens group G4 25 68.673 Fifth lens group G5 30 -56.327 6th lens group G6 33 292.990

[0112] In this variable magnification optical system ZL3, surface No. 33 is an aspherical surface. Table 8 below shows the aspherical surface data for surface number m, that is, the values ​​of the conic constant K and each of the aspherical surface constants A4 to A10.

[0113] (Table 8) [Aspherical data] m K A4 A6 A8 A10 33 1.00 1.60977E-06 2.71250E-09 -7.68774E-12 1.08551E-14

[0114] In this variable magnification optical system ZL3, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, the axial air distance d3 between the third lens group G3 and the fourth lens group G4, the axial air distance d4 between the fourth lens group G4 and the fifth lens group G5, the axial air distance d5 between the fifth lens group G5 and the sixth lens group G6, and the axial air distance d6 between the sixth lens group G6 and the filter group FL change during magnification. Table 9 below shows the variable distances in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0115] (Table 9) [Variable Interval Data] Wide-angle end Mid-range focal length Telephoto end d1 3.971 39.264 43.927 d2 71.924 35.631 5.891 d3 3.831 5.723 4.200 d4 2.500 8.071 18.632 d5 25.569 22.110 40.982 d6 57.300 54.296 51.463

[0116] Figure 6 shows diagrams of spherical aberration, astigmatism, distortion, lateral chromatic aberration, and coma for this variable magnification optical system ZL3 when focused at infinity in the wide-angle end state and the telephoto end state. These aberration diagrams show that this variable magnification optical system ZL3 has excellent correction for various aberrations and has excellent imaging performance.

[0117] [Fourth Example] 7 shows the configuration of a variable magnification optical system ZL4 according to Example 4. This variable magnification optical system ZL4 is composed of, from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear group GL. The rear group GL is composed of, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.

[0118] The first lens group G1 is composed of, from the object side, a positive meniscus lens L11 with a convex surface facing the object side, a biconvex positive lens L12, and a cemented negative lens formed by cementing a biconvex positive lens L13 and a biconcave negative lens L14. The second lens group G2 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L21 and a biconcave negative lens L22, a cemented positive lens formed by cementing a biconvex positive lens L23 and a biconcave negative lens L24, and a biconcave negative lens L25. The third lens group G3 is composed of, from the object side, a biconvex positive lens L31, a biconvex positive lens L32, a cemented negative lens formed by cementing a biconvex positive lens L33 and a biconcave negative lens L34, and a cemented negative lens formed by cementing a biconvex positive lens L35 and a biconcave negative lens L36. The fourth lens group G4 is composed of, from the object side, a biconvex positive lens L41 and a cemented positive lens formed by cementing a biconvex positive lens L42 and a biconcave negative lens L43. The fifth lens group G5 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L51 and a biconcave negative lens L52. The sixth lens group G6 is composed of, from the object side, a cemented positive lens formed by cementing a biconcave aspherical negative lens L61 having an aspherical surface formed on the object side and a biconvex positive lens L62.

[0119] An aperture stop S is disposed between the biconcave negative lens L34 and the biconvex positive lens L35 of the third lens group G3. A filter group FL is disposed between the rear group GL and the image plane I.

[0120] In this variable magnification optical system ZL4, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move along the optical axis so that the spacing between the lens groups changes during magnification. Furthermore, during magnification, the first lens group G1 is fixed relative to the image plane I.

[0121] In addition, in this variable magnification optical system ZL4, correction of the image position (vibration prevention) when camera shake occurs is performed by using the fourth lens group G4 as a vibration prevention group Gv and moving this vibration prevention group Gv so that it has a displacement component in a direction perpendicular to the optical axis.

[0122] In this variable magnification optical system ZL4, focusing from infinity to a close object point is performed by using the fifth lens group G5 as the focusing group Gf and moving this focusing group Gf toward the image side along the optical axis.

[0123] Table 10 below lists the specifications of the variable magnification optical system ZL4.

[0124] (Table 10) Fourth Example [Overall specifications] Wide-angle end Mid-range focal length Telephoto end f 206.000 338.504 679.001 Fno 5.768 5.779 8.061 ω 5.85 3.55 1.78 Y 21.630 21.630 21.630 BF 69.874 66.556 56.349 BF (air equivalent) 69.329 66.011 55.804 TL 350.000 350.000 350.000 TL (air equivalent) 349.455 349.455 349.455 [Lens data] mrd nd νd object surface ∞ 1 199.65699 5.500 1.487490 70.32 2 870.00053 0.200 3 125.74649 10.000 1.496997 81.61 4 -6240.68890 25.000 5 135.83992 7.100 1.496997 81.61 6 -597.25343 2.000 1.806099 33.27 7 158.15411 d1 8 228.55470 6.000 1.846660 23.80 9 -109.51878 1.500 1.603000 65.44 10 57.52324 1.524 11 64.67604 4.800 1.808090 22.74 12 -169.80932 1.200 1.850260 32.35 13 67.79568 8.638 14 -66.20801 1.200 1.921189 23.96 15 663.39753 d2 16 107.04018 5.800 1.496997 81.61 17 -94.60917 0.200 18 114.97574 4.200 1.496997 81.61 19 -182.21043 0.200 20 69.47396 6.000 1.487489 70.44 21 -79.09053 1.500 1.903658 31.32 22 192.62875 20.496 23 ∞ 10.000 Aperture S 24 9683.25180 4.400 1.854779 24.80 25 -49.09864 1.000 1.658440 50.84 26 47.84612 d3 27 402.72567 4.000 1.719990 50.27 28 -87.36308 2.024 29 34.01137 4.400 1.688930 31.16 30 -127.94458 1.000 1.860740 23.08 31 49.12405 d4 32 94.39480 2.000 1.688930 31.16 33 -147.35376 1.000 1.834810 42.73 34 42.71705 d5 35* -180.66760 0.100 1.560930 36.64 36 -265.53822 1.000 1.816000 46.59 37 35.91344 6.500 1.647690 33.72 38 -73.75303 d6 39 ∞ 1.600 1.516800 63.88 Image plane ∞ [Lens group focal length] Lens group First surface Focal length First lens group G1 1 218.072 Second lens group G2 8 -50.806 Third lens group G3 16 85.529 4th lens group G4 27 76.432 Fifth lens group G5 32 -76.984 6th lens group G6 35 2912.201

[0125] In this variable magnification optical system ZL4, surface No. 35 is an aspherical surface. Table 11 below shows the aspherical surface data for surface number m, that is, the values ​​of the conic constant K and each of the aspherical surface constants A4 to A10.

[0126] (Table 11) [Aspherical data] m K A4 A6 A8 A10 35 1.00 1.44736E-06 7.44821E-10 6.68958E-13 -1.03489E-15

[0127] In this variable magnification optical system ZL4, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, the axial air distance d3 between the third lens group G3 and the fourth lens group G4, the axial air distance d4 between the fourth lens group G4 and the fifth lens group G5, the axial air distance d5 between the fifth lens group G5 and the sixth lens group G6, and the axial air distance d6 between the sixth lens group G6 and the filter group FL change during magnification. Table 12 below shows the variable distances in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0128] (Table 12) [Variable Interval Data] Wide-angle end Mid-range focal length Telephoto end d1 26.753 52.931 60.680 d2 73.789 47.610 1.000 d3 4.200 5.635 9.746 d4 2.500 3.988 16.199 d5 22.402 22.797 55.544 d6 67.774 64.456 54.249

[0129] Fig. 8 shows diagrams of spherical aberration, astigmatism, distortion, lateral chromatic aberration, and coma of this variable magnification optical system ZL4 when focused at infinity in the wide-angle end state and the telephoto end state. These aberration diagrams show that this variable magnification optical system ZL4 has excellent correction for various aberrations and has excellent imaging performance.

[0130] [Fifth Example] 9 shows the configuration of a variable magnification optical system ZL5 according to Example 5. This variable magnification optical system ZL5 is composed of, from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear group GL. The rear group GL is composed of, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.

[0131] The first lens group G1 is composed of, from the object side, a biconvex positive lens L11 and a cemented positive lens formed by cementing a biconvex positive lens L12 and a biconcave negative lens L13. The second lens group G2 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L21 and a biconcave negative lens L22, a cemented positive lens formed by cementing a positive meniscus lens L23 with a convex surface facing the object side and a negative meniscus lens L24 with a convex surface facing the object side, and a biconcave negative lens L25. The third lens group G3 is composed of, from the object side, a biconvex positive lens L31, a biconvex positive lens L32, a cemented negative lens formed by cementing a biconvex positive lens L33 and a biconcave negative lens L34, and a cemented negative lens formed by cementing a positive meniscus lens L35 with a concave surface facing the object side and a biconcave negative lens L36. The fourth lens group G4 is composed of, from the object side, a biconvex positive lens L41 and a cemented negative lens formed by cementing a biconvex positive lens L42 and a biconcave negative lens L43. The fifth lens group G5 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L51 and a biconcave negative lens L52. The sixth lens group G6 is composed of, from the object side, a cemented positive lens formed by cementing an aspherical negative lens L61 having a negative meniscus shape with its convex surface facing the object side and an aspherical surface formed on its object side, and a biconvex positive lens L62.

[0132] An aperture stop S is disposed between the biconcave negative lens L34 and the positive meniscus lens L35 of the third lens group G3. A filter group FL is disposed between the rear group GL and the image plane I.

[0133] In this variable magnification optical system ZL5, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move along the optical axis so that the spacing between the lens groups changes during magnification. Furthermore, during magnification, the first lens group G1 is fixed with respect to the image plane I.

[0134] In addition, in this variable magnification optical system ZL5, correction of the image position (vibration prevention) when camera shake occurs is performed by using the fourth lens group G4 as a vibration prevention group Gv and moving this vibration prevention group Gv so that it has a displacement component in a direction perpendicular to the optical axis.

[0135] In this variable magnification optical system ZL5, focusing from infinity to a close object point is performed by using the fifth lens group G5 as the focusing group Gf and moving this focusing group Gf toward the image side along the optical axis.

[0136] Table 13 below lists the specifications of the variable magnification optical system ZL5.

[0137] (Table 13) Fifth Example [Overall specifications] Wide-angle end Mid-range focal length Telephoto end f 206.000 295.398 484.999 Fno 5.150 5.364 6.482 ω 5.84 4.06 2.50 Y 21.630 21.630 21.630 BF 62.638 58.331 54.193 BF (air equivalent) 62.093 57.786 53.648 TL 306.000 306.000 306.000 TL (air equivalent) 305.455 305.455 305.455 [Lens data] mrd nd νd object surface ∞ 1 112.63116 11.500 1.518600 69.89 2 -6427.39710 25.000 3 94.39021 9.500 1.496997 81.61 4 -2714.42750 2.000 1.795040 28.69 5 157.60583 d1 6 245.33581 5.100 1.892860 20.36 7 -133.77042 1.200 1.603000 65.44 8 59.07330 4.000 9 68.83954 5.200 1.808090 22.74 10 656.79367 1.200 1.903658 31.32 11 81.34842 6.418 12 -78.39816 1.200 1.902000 25.26 13 196.81417 d2 14 159.87776 5.600 1.437001 95.10 15 -83.33381 0.200 16 84.94804 4.700 1.496997 81.61 17 -137.07495 0.200 18 75.59916 6.000 1.487489 70.44 19 -84.50304 1.200 1.903658 31.32 20 250.83493 23.715 21 ∞ 10.000 Aperture S 22 -166.06414 4.400 1.854779 24.80 23 -45.80045 1.000 1.618000 63.34 24 55.58065 d3 25 54.57757 4.000 1.720467 34.71 26 -130.35013 0.200 27 37.07653 4.400 1.672700 32.19 28 -68.45113 1.000 1.860740 23.08 29 39.45171 d4 30 100.87591 2.000 1.688930 31.16 31 -136.99706 1.000 1.834810 42.73 32 35.15552 d5 33* 602.89640 0.100 1.560930 36.64 34 291.73653 1.000 1.816000 46.59 35 37.17378 7.000 1.647690 33.72 36 -105.27614 d6 37 ∞ 1.600 1.516800 63.88 Image plane ∞ [Lens group focal length] Lens group First surface Focal length First lens group G1 1 195.061 Second lens group G2 6 -51.823 Third lens group G3 14 76.696 4th lens group G4 25 66.294 Fifth lens group G5 30 -56.477 6th lens group G6 33 285.826

[0138] In this variable magnification optical system ZL5, surface No. 33 is an aspherical surface. Table 14 below shows the aspherical surface data for surface number m, that is, the values ​​of the conic constant K and each of the aspherical surface constants A4 to A10.

[0139] (Table 14) [Aspherical data] m K A4 A6 A8 A10 33 1.00 1.59106E-06 3.27161E-09 -1.06659E-11 1.58785E-14

[0140] In this variable magnification optical system ZL5, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, the axial air distance d3 between the third lens group G3 and the fourth lens group G4, the axial air distance d4 between the fourth lens group G4 and the fifth lens group G5, the axial air distance d5 between the fifth lens group G5 and the sixth lens group G6, and the axial air distance d6 between the sixth lens group G6 and the filter group FL change during magnification. Table 15 below shows the variable distances in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0141] (Table 15) [Variable Interval Data] Wide-angle end Mid-range focal length Telephoto end d1 17.823 33.918 39.217 d2 50.844 30.221 1.000 d3 4.209 7.333 4.200 d4 2.500 5.537 16.148 d5 17.952 20.626 41.209 d6 60.539 56.231 52.093

[0142] Fig. 10 shows diagrams of spherical aberration, astigmatism, distortion, lateral chromatic aberration, and coma of this variable magnification optical system ZL5 when focused at infinity in the wide-angle end state and the telephoto end state. These aberration diagrams show that this variable magnification optical system ZL5 has excellent correction for various aberrations and has excellent imaging performance.

[0143] [Sixth Example] 11 shows the configuration of a variable magnification optical system ZL6 according to Example 6. This variable magnification optical system ZL6 is composed of, from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear group GL. The rear group GL is composed of, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having negative refractive power.

[0144] The first lens group G1 is composed of, from the object side, a positive meniscus lens L11 with a convex surface facing the object side, a biconvex positive lens L12, and a cemented negative lens formed by cementing a biconvex positive lens L13 with a biconcave negative lens L14. The second lens group G2 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L21 with a biconcave negative lens L22, a cemented positive lens formed by cementing a biconvex positive lens L23 with a biconcave negative lens L24, and a biconcave negative lens L25. The third lens group G3 is composed of, from the object side, a biconvex positive lens L31, a biconvex positive lens L32, a cemented negative lens formed by cementing a biconvex positive lens L33 with a biconcave negative lens L34, and a cemented negative lens formed by cementing a positive meniscus lens L35 with a concave surface facing the object side with a biconcave negative lens L36. The fourth lens group G4 is composed of, from the object side, a biconvex positive lens L41 and a cemented positive lens formed by cementing a biconvex positive lens L42 and a biconcave negative lens L43. The fifth lens group G5 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L51 and a biconcave negative lens L52. The sixth lens group G6 is composed of, from the object side, a cemented negative lens formed by cementing a biconcave aspherical negative lens L61 having an aspherical surface formed on the object side of the lens L61 and a biconvex positive lens L62.

[0145] An aperture stop S is disposed between the biconcave negative lens L34 and the positive meniscus lens L35 of the third lens group G3. A filter group FL is disposed between the rear group GL and the image plane I.

[0146] In this variable magnification optical system ZL6, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move along the optical axis so that the spacing between the lens groups changes during magnification. Furthermore, during magnification, the first lens group G1 is fixed with respect to the image plane I.

[0147] In addition, in this variable magnification optical system ZL6, correction of the image position (vibration prevention) when camera shake occurs is performed by using the fourth lens group G4 as the optical axis and the vibration prevention group Gv, and moving this vibration prevention group Gv so that it has a displacement component in a direction perpendicular to the optical axis.

[0148] In this variable magnification optical system ZL6, focusing from infinity to a close object point is performed by using the fifth lens group G5 as the focusing group Gf and moving this focusing group Gf toward the image side along the optical axis.

[0149] Table 16 below lists the specifications of the variable magnification optical system ZL6.

[0150] (Table 16) Sixth Example [Overall specifications] Wide-angle end Mid-range focal length Telephoto end f 206.000 332.574 679.001 Fno 5.598 5.596 7.702 ω 5.87 3.62 1.79 Y 21.630 21.630 21.630 BF 65.838 64.252 122.246 BF (air equivalent) 65.293 63.707 121.701 TL 350.000 350.000 350.000 TL (air equivalent) 349.455 349.455 349.455 [Lens data] mrd nd νd object surface ∞ 1 199.65699 5.500 1.487490 70.30 2 870.00053 0.200 3 120.83520 10.000 1.496997 81.60 4 -6077.90170 15.000 5 140.33059 7.100 1.496997 81.60 6 -774.66098 2.000 1.806099 33.20 7 163.61217 d1 8 225.41580 6.000 1.846660 23.80 9 -110.15488 1.500 1.603000 65.40 10 55.84766 1.524 11 58.57424 4.800 1.808090 22.70 12 -1240.16080 1.200 1.850260 32.30 13 62.43379 12.645 14 -61.79699 1.200 1.921189 23.90 15 1297.67340 d2 16 106.91200 5.800 1.496997 81.60 17 -93.68419 0.200 18 126.09374 4.200 1.496997 81.60 19 -181.31294 0.200 20 70.57798 6.000 1.487489 70.40 21 -78.01209 1.500 1.903658 31.30 22 234.36861 20.531 23 ∞ 10.000 Aperture S 24 -1703.35100 4.400 1.854779 24.80 25 -46.72121 1.000 1.658440 50.80 26 45.47166 d3 27 742.39834 4.000 1.719990 50.20 28 -80.64699 1.007 29 34.04211 4.400 1.688930 31.10 30 -118.58376 1.000 1.860740 23.00 31 51.10412 d4 32 90.09316 2.000 1.688930 31.10 33 -165.28520 1.000 1.834810 42.70 34 43.10143 d5 35* -222.28646 0.100 1.560930 36.60 36 -366.35285 1.000 1.816000 46.50 37 33.88278 6.500 1.647690 33.70 38 -81.90306 d6 39 ∞ 1.600 1.516800 63.80 Image plane ∞ [Lens group focal length] Lens group First surface Focal length First lens group G1 1 209.167 Second lens group G2 8 -50.184 Third lens group G3 16 86.564 4th lens group G4 27 74.177 Fifth lens group G5 32 -80.976 6th lens group G6 35 -56114.006

[0151] In this variable magnification optical system ZL6, surface No. 35 is an aspherical surface. Table 17 below shows the aspherical surface data for surface number m, that is, the values ​​of the conic constant K and each of the aspherical surface constants A4 to A10.

[0152] (Table 17) [Aspherical data] m K A4 A6 A8 A10 35 1.00 1.81575E-06 -3.86294E-10 7.26574E-12 -1.32629E-14

[0153] In this variable magnification optical system ZL6, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, the axial air distance d3 between the third lens group G3 and the fourth lens group G4, the axial air distance d4 between the fourth lens group G4 and the fifth lens group G5, the axial air distance d5 between the fifth lens group G5 and the sixth lens group G6, and the axial air distance d6 between the sixth lens group G6 and the filter group FL change during magnification. Table 18 below shows the variable distances in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0154] (Table 18) [Variable Interval Data] Wide-angle end Mid-range focal length Telephoto end d1 32.126 56.552 65.499 d2 74.374 49.804 1.000 d3 4.200 4.932 11.029 d4 2.500 3.043 12.974 d5 27.455 27.827 55.943 d6 63.738 62.235 57.946

[0155] Fig. 12 shows diagrams of spherical aberration, astigmatism, distortion, lateral chromatic aberration, and coma of this variable magnification optical system ZL6 when focused at infinity in the wide-angle end state and the telephoto end state. These aberration diagrams show that this variable magnification optical system ZL6 has excellent correction for various aberrations and has excellent imaging performance.

[0156] [Seventh Example] 13 shows the configuration of a variable magnification optical system ZL7 according to Example 7. This variable magnification optical system ZL7 is composed of, from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear group GL. The rear group GL is composed of, from the object side, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having positive refractive power, a sixth lens group G6 having negative refractive power, and a seventh lens group G7 having negative refractive power.

[0157] The first lens group G1 is composed of, from the object side, a positive meniscus lens L11 with a convex surface facing the object side, a biconvex positive lens L12, and a cemented negative lens formed by cementing a biconvex positive lens L13 with a biconcave negative lens L14. The second lens group G2 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L21 with a biconcave negative lens L22, and a cemented positive lens formed by cementing a biconvex positive lens L23 with a biconcave negative lens L24. The third lens group G3 is composed of a biconcave negative lens L31. The fourth lens group G4 is composed of, from the object side, a biconvex positive lens L41, a biconvex positive lens L42, a cemented negative lens formed by cementing a biconvex positive lens L43 with a biconcave negative lens L44, and a cemented negative lens formed by cementing a positive meniscus lens L45 with a concave surface facing the object side with a biconcave negative lens L46. The fifth lens group G5 is composed of, from the object side, a biconvex positive lens L51 and a cemented positive lens formed by cementing a biconvex positive lens L52 and a biconcave negative lens L53. The sixth lens group G6 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L61 and a biconcave negative lens L62. The seventh lens group G7 is composed of, from the object side, a cemented negative lens formed by cementing a biconcave aspherical negative lens L71 having an aspherical surface formed on the object side and a biconvex positive lens L72.

[0158] An aperture stop S is disposed between the biconcave negative lens L44 and the positive meniscus lens L45 of the fourth lens group G4. A filter group FL is disposed between the rear group GL and the image plane I.

[0159] In this variable magnification optical system ZL7, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 move along the optical axis so that the spacing between the lens groups changes during magnification. Furthermore, during magnification, the first lens group G1 is fixed with respect to the image plane I.

[0160] In addition, in this variable magnification optical system ZL7, correction of the image position (vibration prevention) when camera shake occurs is performed by using the fifth lens group G5 as the vibration prevention group Gv and moving this vibration prevention group Gv so that it has a displacement component in a direction perpendicular to the optical axis.

[0161] In this variable magnification optical system ZL7, focusing from infinity to a close object point is performed by using the sixth lens group G6 as the focusing group Gf and moving this focusing group Gf toward the image side along the optical axis.

[0162] Table 19 below lists the specifications of the variable magnification optical system ZL7.

[0163] (Table 19) Seventh Example [Overall specifications] Wide-angle end Mid-range focal length Telephoto end f 190.685 360.000 679.000 Fno 5.601 5.661 7.702 ω 6.35 3.35 1.79 Y 21.630 21.630 21.630 BF 74.877 71.456 63.873 BF (air equivalent) 74.332 70.911 63.328 TL 350.000 350.000 350.000 TL (air equivalent) 349.455 349.455 349.455 [Lens data] mrd nd νd object surface ∞ 1 199.65699 5.500 1.487490 70.32 2 870.00053 0.200 3 128.66663 10.000 1.496997 81.61 4 -1459.51630 21.000 5 166.51797 7.100 1.496997 81.61 6 -319.20777 2.000 1.806099 33.27 7 191.60966 d1 8 215.83903 6.000 1.846660 23.80 9 -100.62825 1.500 1.603000 65.44 10 55.76061 1.524 11 66.99117 4.800 1.808090 22.74 12 -148.83089 1.200 1.850260 32.35 13 71.74054 d2 14 -66.75644 1.200 1.921189 23.96 15 841.17757 d3 16 99.52613 5.800 1.496997 81.61 17 -105.03727 0.200 18 94.03032 4.200 1.496997 81.61 19 -218.92401 0.200 20 68.84351 6.000 1.487489 70.44 21 -84.71142 1.500 1.903658 31.32 22 165.88652 15.062 23 ∞ 10.000 Aperture S 24 -2175.75670 4.400 1.854779 24.80 25 -53.97324 1.000 1.658440 50.84 26 48.43659 d4 27 189.43215 4.000 1.719990 50.27 28 -102.22848 1.071 29 35.90682 4.400 1.688930 31.16 30 -157.04433 1.000 1.860740 23.08 31 49.37418 d5 32 85.45977 2.000 1.688930 31.16 33 -175.34295 1.000 1.834810 42.73 34 42.18567 d6 35* -160.31480 0.100 1.560930 36.64 36 -223.78190 1.000 1.816000 46.59 37 37.74525 6.500 1.647690 33.72 38 -74.00964 d7 39 ∞ 1.600 1.516800 63.88 Image plane ∞ [Lens group focal length] Lens group First surface Focal length First lens group G1 1 223.563 Second lens group G2 8 -245.757 Third lens group G3 14 -67.097 4th lens group G4 16 92.816 Fifth lens group G5 27 76.202 6th lens group G6 32 -81.403 7th lens group G7 35 -49458.500

[0164] In this variable magnification optical system ZL7, surface No. 35 is an aspheric surface. Table 20 below shows the aspheric surface data for surface number m, that is, the values ​​of the conic constant K and each of the aspheric surface constants A4 to A10.

[0165] (Table 20) [Aspherical data] m K A4 A6 A8 A10 35 1.00 1.51773E-06 5.81173E-10 9.41588E-13 -1.64693E-15

[0166] In this variable magnification optical system ZL7, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, the axial air distance d3 between the third lens group G3 and the fourth lens group G4, the axial air distance d4 between the fourth lens group G4 and the fifth lens group G5, the axial air distance d5 between the fifth lens group G5 and the sixth lens group G6, the axial air distance d6 between the sixth lens group G6 and the seventh lens group G7, and the axial air distance d7 between the seventh lens group G7 and the filter group FL change during magnification variation. Table 21 below shows the variable distances in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0167] (Table 21) [Variable Interval Data] Wide-angle end Mid-range focal length Telephoto end d1 31.704 63.236 68.135 d2 6.000 9.000 10.000 d3 80.911 45.287 1.000 d4 4.200 5.392 8.803 d5 4.109 5.252 13.884 d6 16.742 18.919 52.847 d7 72.777 69.356 61.773

[0168] Fig. 14 shows diagrams of spherical aberration, astigmatism, distortion, lateral chromatic aberration, and coma when this variable magnification optical system ZL7 is focused at infinity in the wide-angle end state and the telephoto end state. These aberration diagrams show that this variable magnification optical system ZL7 has excellent correction for various aberrations and has excellent imaging performance.

[0169] [Eighth Example] 15 is a diagram showing the configuration of a variable magnification optical system ZL8 according to Example 8. This variable magnification optical system ZL8 is composed of, from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a rear group GL. The rear group GL is composed of, from the object side, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, a sixth lens group G6 having positive refractive power, and a seventh lens group G7 having negative refractive power.

[0170] The first lens group G1 is composed of, from the object side, a positive meniscus lens L11 with a convex surface facing the object side, a positive meniscus lens L12 with a convex surface facing the object side, and a cemented negative lens formed by cementing a biconvex positive lens L13 and a biconcave negative lens L14. The second lens group G2 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L21 and a biconcave negative lens L22, a cemented positive lens formed by cementing a biconvex positive lens L23 and a biconcave negative lens L24, and a biconcave negative lens L25. The third lens group G3 is composed of, from the object side, a biconvex positive lens L31, a biconvex positive lens L32, a cemented negative lens formed by cementing a biconvex positive lens L33 and a biconcave negative lens L34, and a cemented negative lens formed by cementing a positive meniscus lens L35 with a concave surface facing the object side and a biconcave negative lens L36. The fourth lens group G4 is composed of, from the object side, a biconvex positive lens L41 and a cemented positive lens formed by cementing a biconvex positive lens L42 and a biconcave negative lens L43. The fifth lens group G5 is composed of, from the object side, a cemented negative lens formed by cementing a biconvex positive lens L51 and a biconcave negative lens L52. The sixth lens group G6 is composed of, from the object side, a cemented positive lens formed by cementing an aspherical negative lens L61 having a negative meniscus shape with its concave surface facing the object side and an aspherical surface formed on its object side, and a biconvex positive lens L62. The seventh lens group G7 is composed of a plano-concave negative lens L71 with its concave surface facing the image side.

[0171] An aperture stop S is disposed between the biconcave negative lens L34 and the positive meniscus lens L35 of the third lens group G3. A filter group FL is disposed between the rear group GL and the image plane I.

[0172] In this variable magnification optical system ZL7, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 move along the optical axis so that the spacing between the lens groups changes during magnification. Furthermore, during magnification, the first lens group G1 is fixed with respect to the image plane I.

[0173] In addition, in this variable magnification optical system ZL7, correction of the image position (vibration prevention) when camera shake occurs is performed by using the fourth lens group G4 as a vibration prevention group Gv and moving this vibration prevention group Gv so that it has a displacement component in a direction perpendicular to the optical axis.

[0174] In this variable magnification optical system ZL7, focusing from infinity to a close object point is performed by using the fifth lens group G5 as the focusing group Gf and moving this focusing group Gf toward the image side along the optical axis.

[0175] Table 22 below lists the specifications of the variable magnification optical system ZL8.

[0176] (Table 22) Example 8 [Overall specifications] Wide-angle end Mid-range focal length Telephoto end f 206.000 349.178 679.000 Fno 5.600 5.667 7.700 ω 5.87 3.45 1.79 Y 21.630 21.630 21.630 BF 62.645 62.466 62.555 BF (air equivalent) 62.100 61.921 62.010 TL 350.000 350.000 350.000 TL (air equivalent) 349.455 349.455 349.455 [Lens data] mrd nd νd object surface ∞ 1 199.65699 5.500 1.487490 70.32 2 870.00053 0.200 3 120.33194 10.000 1.496997 81.61 4 27574.90200 22.000 5 134.38217 7.100 1.496997 81.61 6 -720.08206 2.000 1.806099 33.27 7 157.03441 d1 8 228.93734 6.000 1.846660 23.80 9 -114.21937 1.500 1.603000 65.44 10 55.94416 1.524 11 65.30486 4.800 1.808090 22.74 12 -205.54332 1.200 1.850260 32.35 13 68.92805 10.429 14 -64.80801 1.200 1.921189 23.96 15 1483.14680 d2 16 104.99405 5.800 1.496997 81.61 17 -89.82110 0.200 18 123.52811 4.200 1.496997 81.61 19 -189.13537 0.200 20 72.70242 6.000 1.487489 70.44 21 -73.20487 1.500 1.903658 31.32 22 192.86458 19.855 23 ∞ 10.000 Aperture S 24 -7500.20550 4.400 1.854779 24.80 25 -47.26357 1.000 1.658440 50.84 26 50.22911 d3 27 682.82542 4.000 1.719990 50.27 28 -84.11431 1.802 29 34.65118 4.400 1.688930 31.16 30 -115.99702 1.000 1.860740 23.08 31 52.01736 d4 32 76.97765 2.000 1.688930 31.16 33 -461.73538 1.000 1.834810 42.73 34 42.19461 d5 35* -201.45277 0.100 1.560930 36.64 36 -313.00355 1.000 1.816000 46.59 37 43.36113 6.500 1.647690 33.72 38 -66.78891 d6 39 ∞ 1.500 1.516800 63.88 40 150.00000 d7 41 ∞ 1.600 1.516800 63.88 Image plane ∞ [Lens group focal length] Lens group First surface Focal length First lens group G1 1 211.895 Second lens group G2 8 -50.789 Third lens group G3 16 91.777 4th lens group G4 27 76.789 Fifth lens group G5 32 -92.210 6th lens group G6 35 397.522 7th lens group G7 39 -290.248

[0177] In this variable magnification optical system ZL8, surface No. 35 is an aspherical surface. Table 23 below shows the aspherical surface data for surface number m, that is, the values ​​of the conic constant K and each of the aspherical surface constants A4 to A10.

[0178] (Table 23) [Aspherical data] m K A4 A6 A8 A10 35 1.00 6.23272E-07 4.57420E-10 -8.07994E-13 1.79217E-15

[0179] In this variable magnification optical system ZL8, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, the axial air distance d3 between the third lens group G3 and the fourth lens group G4, the axial air distance d4 between the fourth lens group G4 and the fifth lens group G5, the axial air distance d5 between the fifth lens group G5 and the sixth lens group G6, the axial air distance d6 between the sixth lens group G6 and the seventh lens group G7, and the axial air distance d7 between the seventh lens group G7 and the filter group FL change during magnification. Table 24 below shows the variable distances in the wide-angle end state, the intermediate focal length state, and the telephoto end state.

[0180] (Table 24) [Variable Interval Data] Wide-angle end Mid-range focal length Telephoto end d1 29.369 54.807 61.392 d2 73.022 45.442 1.000 d3 4.115 5.698 4.200 d4 2.500 2.500 8.850 d5 21.782 25.652 61.893 d6 6.656 3.524 0.200 d7 60.545 60.366 60.455

[0181] Figure 16 shows diagrams of spherical aberration, astigmatism, distortion, lateral chromatic aberration, and coma for this variable magnification optical system ZL8 when focused at infinity in the wide-angle end state and the telephoto end state. These aberration diagrams show that this variable magnification optical system ZL8 has excellent correction for various aberrations and has excellent imaging performance.

[0182] [Conditional expression corresponding value] The values ​​corresponding to the conditional expressions (1) to (12) in the first to eighth examples are shown in Table 25 below.

[0183] (Table 25) (1) D1MAX / G1d (2) D1MAX / f1 (3) f1 / ft (4)(1-βtv)×βtvb (5) Gvd / TLt (6)(1-βtf 2 )×βtfb 2 (7) Gfd / TLt (8) G1d / ft (9) Gsd / TLt (10) D1MAX / ft (11) Bfw / fw (12)ωw First Example Second Example Third Example Fourth Example βtv 0.024 0.027 0.011 0.039 βtvb 2.458 2.465 2.427 2.497 βtf 2.679 2.631 2.921 2.453 βtfb 0.917 0.937 0.831 1.018 (1) 0.521 0.502 0.521 0.502 (2) 0.124 0.113 0.122 0.115 (3) 0.347 0.380 0.422 0.321 (4) 2.400 2.400 2.400 2.400 (5) 0.029 0.029 0.030 0.033 (6) -5.200 -5.200 -5.200 -5.200 (7) 0.009 0.009 0.009 0.009 (8) 0.082 0.086 0.099 0.073 (9) 0.175 0.166 0.172 0.154 (10) 0.043 0.043 0.052 0.037 (11) 0.303 0.322 0.381 0.337 (12) 6.530 6.523 7.844 5.849 5th Example 6th Example 7th Example 8th Example βtv 0.010 0.042 0.042 0.051 βtvb 2.424 2.504 2.506 2.529 βtf 2.946 2.419 2.410 2.314 βtfb 0.823 1.035 1.040 1.093 (1) 0.521 0.377 0.459 0.470 (2) 0.128 0.072 0.094 0.104 (3) 0.402 0.308 0.329 0.312 (4) 2.400 2.400 2.400 2.400 (5) 0.031 0.030 0.030 0.032 (6) -5.200 -5.200 -5.200 -5.200 (7) 0.010 0.009 0.009 0.009 (8) 0.099 0.059 0.067 0.069 (9) 0.186 0.154 0.138 0.152 (10) 0.052 0.022 0.031 0.032 (11) 0.301 0.317 0.393 0.301 (12) 5.843 5.869 6.346 5.873 [Explanation of symbols]

[0184] 1 Camera (Optical Equipment) ZL (ZL1~ZL8) Variable Magnification Optical System G1 First lens group G2 Second lens group GL Rear group Gv vibration-proof group Gf focusing group S aperture diaphragm (stop)

Claims

[Claim 1] a first lens group having positive refractive power and arranged closest to the object; a second lens group; and It consists of a rear group, When changing magnification, the spacing between each lens group changes, the first lens group has a positive lens closest to the object, the rear group includes, in order from the object side, a positive lens group, a positive lens group, and a negative lens group; a stop is provided within the rear group, At least a portion of the lens group on the image plane side of the aperture stop is a focusing group that moves in the optical axis direction during focusing, the focusing group comprises, in order from the object side, a positive lens and a negative lens, The following condition is satisfied: Variable magnification optical system. 0.30 < D1MAX / G1d < 0.70 0.064 < D1MAX / f1 < 0.140 0.005 < Gfd / TLt < 0.015 however, D1MAX: the maximum air gap on the optical axis within the first lens group G1d: the thickness of the first lens group on the optical axis f1: focal length of the first lens group Gfd: the thickness of the focusing group on the optical axis TLt: total optical length of the variable magnification optical system in the telephoto end state

Images