WO2024095858A1 - 変倍光学系、光学機器および変倍光学系の製造方法 - Google Patents

変倍光学系、光学機器および変倍光学系の製造方法 Download PDF

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Publication number
WO2024095858A1
WO2024095858A1 PCT/JP2023/038488 JP2023038488W WO2024095858A1 WO 2024095858 A1 WO2024095858 A1 WO 2024095858A1 JP 2023038488 W JP2023038488 W JP 2023038488W WO 2024095858 A1 WO2024095858 A1 WO 2024095858A1
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Prior art keywords
lens group
optical system
variable magnification
magnification optical
focusing
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English (en)
French (fr)
Japanese (ja)
Inventor
幸介 町田
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Nikon Corp
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Nikon Corp
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Priority to CN202380076042.0A priority Critical patent/CN120077312A/zh
Priority to JP2024554432A priority patent/JPWO2024095858A1/ja
Publication of WO2024095858A1 publication Critical patent/WO2024095858A1/ja
Priority to US19/194,349 priority patent/US20250314862A1/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/009—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras having zoom function
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/006—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element at least one element being a compound optical element, e.g. cemented elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/144—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only
    • G02B15/1445—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only the first group being negative
    • G02B15/144511—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only the first group being negative arranged -+-+
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/146—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having more than five groups
    • G02B15/1465—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having more than five groups the first group being negative
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G02B15/177—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a negative front lens or group of lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G02B15/20—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having an additional movable lens or lens group for varying the objective focal length
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/025—Mountings, adjusting means, or light-tight connections, for optical elements for lenses using glue

Definitions

  • This disclosure relates to a variable magnification optical system, an optical instrument, and a method for manufacturing a variable magnification optical system.
  • variable magnification optical systems have been proposed for use in optical devices such as photo cameras, electronic still cameras, and video cameras (see, for example, Patent Document 1).
  • variable magnification optical system disclosed herein has, in order from the object side, a first lens group having negative refractive power and a subsequent lens group having a plurality of lens groups, and the subsequent lens group includes, in order from the object side, a second lens group having positive refractive power and a third lens group having positive refractive power, and during magnification change, the first lens group is fixed with respect to the image plane and the spacing between adjacent lens groups changes, and satisfies the following conditional expression: 1.00 ⁇ f2/f3 ⁇ 5.00 however, f2: focal length of the second lens group f3: focal length of the third lens group
  • variable magnification optical system of the present disclosure has, in order from the object side, a first lens group having negative refractive power and a subsequent lens group having a plurality of lens groups, the subsequent lens group including a first focusing lens group having positive refractive power and moving upon focusing, and a second focusing lens group having negative refractive power, positioned closer to the image plane than the first focusing lens group, and moving upon focusing, and during magnification change, the first lens group is fixed with respect to the image plane and the spacing between adjacent lens groups changes, and satisfies the following conditional formula: 0.70 ⁇ fF1/(-fF2) ⁇ 5.00 however, fF1: focal length of the first focusing lens group fF2: focal length of the second focusing lens group
  • a manufacturing method for a variable magnification optical system includes configuring a variable magnification optical system having, in order from the object side, a first lens group having negative refractive power and a subsequent lens group having a plurality of lens groups, the subsequent lens group including, in order from the object side, a second lens group having positive refractive power and a third lens group having positive refractive power, wherein, during magnification change, the first lens group is fixed with respect to the image plane and the spacing between adjacent lens groups changes, so as to satisfy the following conditional expression: 1.00 ⁇ f2/f3 ⁇ 5.00 however, f2: focal length of the second lens group f3: focal length of the third lens group
  • the manufacturing method of a variable magnification optical system disclosed herein includes configuring a variable magnification optical system having, in order from the object side, a first lens group having negative refractive power and a subsequent lens group having a plurality of lens groups, wherein the subsequent lens group includes a first focusing lens group having positive refractive power and moving when focusing, and a second focusing lens group having negative refractive power, positioned closer to the image plane than the first focusing lens group, and moving when focusing, wherein, during magnification change, the first lens group is fixed with respect to the image plane and the spacing between adjacent lens groups changes, so as to satisfy the following conditional formula: 0.70 ⁇ fF1/(-fF2) ⁇ 5.00 however, fF1: focal length of the first focusing lens group fF2: focal length of the second focusing lens group
  • FIG. 2 is a cross-sectional view of the variable magnification optical system of the first embodiment when focused on an object at infinity in the wide-angle end state.
  • 1A is a diagram showing various aberrations when the variable magnification optical system of Example 1 is in the wide-angle end state and focused on an object at infinity
  • FIG. 1B is a diagram showing various aberrations when the variable magnification optical system of Example 1 is in the telephoto end state and focused on an object at infinity
  • FIG. 11 is a cross-sectional view of the variable magnification optical system of the second embodiment when focused on an object at infinity in the wide-angle end state.
  • FIG. 13A is a diagram showing various aberrations when the variable magnification optical system of the second embodiment is in the wide-angle end state and focuses on an object at infinity
  • FIG. 13B is a diagram showing various aberrations when the variable magnification optical system of the second embodiment is in the telephoto end state and focuses on an object at infinity
  • FIG. 13 is a cross-sectional view of the variable magnification optical system of the third embodiment when focused on an object at infinity in the wide-angle end state.
  • 1A is a diagram showing various aberrations when the variable magnification optical system of the third embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 1B is a diagram showing various aberrations when the variable magnification optical system of the third embodiment is focused on an object at infinity in the telephoto end state
  • FIG. 1C is a diagram showing various aberrations when the variable magnification optical system of the third embodiment is focused on an object at close range in the wide-angle end state
  • FIG. 1D is a diagram showing various aberrations when the variable magnification optical system of the third embodiment is focused on an object at close range in the telephoto end state.
  • FIG. 13 is a cross-sectional view of the variable magnification optical system of the fourth embodiment when focused on an object at infinity in the wide-angle end state.
  • FIG. 1A is a diagram showing various aberrations when the variable magnification optical system of the fourth embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 1B is a diagram showing various aberrations when the variable magnification optical system of the fourth embodiment is focused on an object at infinity in the telephoto end state
  • FIG. 1C is a diagram showing various aberrations when the variable magnification optical system of the fourth embodiment is focused on an object at close range in the wide-angle end state
  • FIG. 1D is a diagram showing various aberrations when the variable magnification optical system of the fourth embodiment is focused on an object at close range in the telephoto end state.
  • FIG. 1A is a diagram showing various aberrations when the variable magnification optical system of the fourth embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 1B is a diagram showing various aberrations when the variable magnification optical system of the fourth embodiment is focused on an object at infinity in the telephoto end state
  • FIG. 13 is a cross-sectional view of a variable magnification optical system according to a fifth embodiment when focused on an object at infinity in a wide-angle end state.
  • 1A is a diagram showing various aberrations when the variable magnification optical system of the fifth embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 1B is a diagram showing various aberrations when the variable magnification optical system of the fifth embodiment is focused on an object at infinity in the telephoto end state
  • FIG. 1C is a diagram showing various aberrations when the variable magnification optical system of the fifth embodiment is focused on an object at close range in the wide-angle end state
  • FIG. 1D is a diagram showing various aberrations when the variable magnification optical system of the fifth embodiment is focused on an object at close range in the telephoto end state.
  • FIG. 1 is a schematic diagram of a camera equipped with a variable magnification optical system according to an embodiment of the present invention.
  • 5 is a flowchart outlining a first manufacturing method for the variable magnification optical system of the present embodiment.
  • 10 is a flowchart outlining a second manufacturing method of the variable magnification optical system of the present embodiment.
  • variable magnification optical system optical device, and manufacturing method of the variable magnification optical system according to the embodiments of the present application.
  • the variable magnification optical system of this embodiment has, in order from the object side, a first lens group having negative refractive power and a subsequent lens group having a plurality of lens groups.
  • the subsequent lens group includes, in order from the object side, a second lens group having positive refractive power and a third lens group having positive refractive power.
  • the first lens group is fixed with respect to the image plane and the spacing between adjacent lens groups changes, and the following conditional expression is satisfied: (1) 1.00 ⁇ f2 / f3 ⁇ 5.00 however, f2: focal length of the second lens group f3: focal length of the third lens group
  • the variable magnification optical system of this embodiment has a first lens group with negative refractive power and a subsequent lens group having multiple lens groups.
  • the subsequent lens group includes, in order from the object side, a second lens group with positive refractive power and a third lens group with positive refractive power, thereby making it possible to suppress fluctuations in various aberrations, including spherical aberration, when the magnification is changed.
  • Conditional formula (1) defines the ratio between the focal length of the second lens group and the focal length of the third lens group.
  • variable magnification optical system of this embodiment if the value of conditional expression (1) exceeds the upper limit, the refractive power of the third lens group becomes too strong, making it difficult to suppress fluctuations in various aberrations, including spherical aberration, during magnification.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (1) to 5.00. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (1) to 4.50, 4.00, 3.50, 3.00, 2.50, or even 2.30.
  • variable magnification optical system of this embodiment if the value of conditional formula (1) falls below the lower limit, the refractive power of the second lens group becomes too strong, making it difficult to suppress fluctuations in various aberrations, including spherical aberration, during magnification.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (1) to 1.00. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (1) to 1.20, 1.35, or even 1.50.
  • the variable magnification optical system of this embodiment has, in order from the object side, a first lens group having negative refractive power and a subsequent lens group having multiple lens groups, and the subsequent lens group includes a first focusing lens group having positive refractive power and moving when focusing, and a second focusing lens group having negative refractive power, positioned closer to the image plane than the first focusing lens group, and moving when focusing, and during magnification change, the first lens group is fixed with respect to the image plane and the spacing between adjacent lens groups changes, and the following conditional expression is satisfied.
  • the variable magnification optical system of this embodiment has a first lens group with negative refractive power and a subsequent lens group having multiple lens groups.
  • the subsequent lens group includes a second focusing lens group that has negative refractive power, is positioned closer to the image plane than the first focusing lens group, and moves when focusing, thereby making it possible to suppress fluctuations in various aberrations, including spherical aberration, when focusing.
  • Conditional formula (2) defines the ratio between the focal length of the first focusing lens group and the focal length of the second focusing lens group.
  • variable magnification optical system of this embodiment if the value of conditional expression (2) exceeds the upper limit, the refractive power of the second focusing lens group becomes too strong, making it difficult to suppress fluctuations in various aberrations, including spherical aberration, during focusing.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (2) to 5.00. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (2) to 4.50, 4.00, 3.50, 3.00, 2.60, or even 2.40.
  • variable magnification optical system of this embodiment if the value of conditional expression (2) falls below the lower limit, the refractive power of the third focusing lens group becomes too strong, making it difficult to suppress fluctuations in various aberrations, including spherical aberration, during focusing.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (2) to 0.70. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (2) to 0.85, 1.00, 1.15, or even 1.30.
  • the subsequent lens group further includes a fourth lens group arranged on the image surface side of the third lens group.
  • variable magnification optical system of this embodiment has such a configuration, which makes it possible to suppress fluctuations in various aberrations, including spherical aberration, when changing magnification.
  • the subsequent lens group includes, in order from the object side, a second lens group having positive refractive power, a third lens group having positive refractive power, and a fourth lens group.
  • variable magnification optical system of this embodiment has such a configuration, which makes it possible to suppress fluctuations in various aberrations, including spherical aberration, when changing magnification.
  • the second lens group is the first focusing lens group.
  • variable magnification optical system of this embodiment has such a configuration, which makes it possible to suppress fluctuations in various aberrations, including spherical aberration, during focusing.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (3) 0.12 ⁇ (-f1) / f2 ⁇ 0.95 however, f1: focal length of the first lens group f2: focal length of the second lens group
  • Conditional expression (3) defines the ratio between the focal length of the first lens group and the focal length of the second lens group.
  • variable magnification optical system of this embodiment if the value of conditional expression (3) exceeds the upper limit, the refractive power of the second lens group becomes too strong, making it difficult to suppress fluctuations in various aberrations, including coma, during magnification.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (3) to 0.95. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (3) to 0.85, 0.70, 0.60, 0.50, or even 0.47.
  • variable magnification optical system of this embodiment if the value of conditional expression (3) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to suppress fluctuations in various aberrations, including coma, during magnification.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (3) to 0.12. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (3) to 0.15, 0.18, or even 0.20.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (4) 0.20 ⁇ (-f1) / fw ⁇ 2.40 however, f1: focal length of the first lens group fw: focal length of the variable magnification optical system in the wide-angle end state
  • Conditional expression (4) defines the ratio between the focal length of the first lens group and the focal length of the variable magnification optical system in the wide-angle end state.
  • conditional expression (4) in the variable magnification optical system of this embodiment exceeds the upper limit, the refractive power of the first lens group becomes too weak, and the variable magnification optical system becomes large. In addition, it becomes difficult to suppress fluctuations in various aberrations, including coma, during magnification.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (4) to 2.40. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (4) to 2.35, 2.25, 2.20, or even 2.15.
  • variable magnification optical system of this embodiment if the value of conditional expression (4) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to suppress fluctuations in various aberrations, including coma, during magnification.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (4) to 0.20. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (4) to 0.35, 0.50, 0.60, 0.75, 0.80, or even 0.85.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (5) 0.10 ⁇
  • Conditional expression (5) specifies the ratio between the focal length of the lens group adjacent to the lens group closest to the image side on the object side and the focal length of the lens group closest to the image side.
  • variable magnification optical system of this embodiment if the value of conditional expression (5) exceeds the upper limit, the refractive power of the lens group located closest to the image surface becomes too strong, making it difficult to suppress fluctuations in various aberrations, including coma, when the magnification is changed.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (5) to 1.10. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (5) to 1.00, 0.90, 0.80, or even 0.70.
  • variable magnification optical system of this embodiment if the value of conditional expression (5) falls below the lower limit, the refractive power of the lens group adjacent to the lens group located closest to the image plane on the object side becomes too strong, making it difficult to suppress fluctuations in various aberrations, including coma, when changing magnification.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (5) to 0.10. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (5) to 0.15, and more preferably 0.20.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (6) 0.15 ⁇ BFw/fw ⁇ 1.10 however, BFw: Back focus of the variable magnification optical system when focusing at infinity in the wide-angle end state fw: Focal length of the variable magnification optical system in the wide-angle end state
  • Conditional expression (6) defines the ratio between the back focus of the variable magnification optical system when focusing on infinity in the wide-angle end state and the focal length of the variable magnification optical system in the wide-angle end state.
  • variable magnification optical system of this embodiment if the value of conditional expression (6) exceeds the upper limit, the back focus becomes large relative to the focal length in the wide-angle end state, making it difficult to satisfactorily correct various aberrations, including coma aberration, when focusing on infinity in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (6) to 1.10. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (6) to 1.00, 0.95, or even 0.90.
  • variable magnification optical system of this embodiment if the value of conditional expression (6) falls below the lower limit, the back focus becomes small relative to the focal length in the wide-angle end state, making it difficult to satisfactorily correct various aberrations, including coma aberration, when focusing on infinity in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (6) to 0.15. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (6) to 0.20, 0.25, 0.30, 0.35, or even 0.40.
  • variable magnification optical system of this embodiment it is preferable to have an aperture stop between the third lens group and the fourth lens group.
  • variable magnification optical system of this embodiment has such a configuration that it is possible to effectively correct various aberrations, including coma aberration when focusing at infinity in the wide-angle end state, without increasing the size of the variable magnification optical system.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (7) 0.40 ⁇ Dwa/Dwb ⁇ 2.50 however, Dwa: Distance from the surface of the first lens group closest to the object to the aperture stop in the wide-angle end state Dwb: Distance from the aperture stop to the image plane in the wide-angle end state
  • Conditional expression (7) defines the ratio of the distance from the surface of the first lens group closest to the object to the aperture stop to the distance from the aperture stop to the image plane.
  • variable magnification optical system of this embodiment if the value of conditional expression (7) exceeds the upper limit, the distance from the surface of the first lens group closest to the object to the aperture stop and the distance from the aperture stop to the image plane become too large, making it difficult to satisfactorily correct various aberrations, including spherical aberration, when focusing on infinity in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (7) to 2.50. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (7) to 2.25, 2.10, 2.00, 1.85, or even 1.70.
  • variable magnification optical system of this embodiment if the value of conditional expression (7) falls below the lower limit, the distance from the aperture stop to the image plane becomes too large, making it difficult to satisfactorily correct various aberrations, including spherical aberration, when focusing on infinity in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (7) to 0.40. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (7) to 0.50, 0.65, 0.80, 0.95, 1.10, or even 1.20.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied.
  • fwa composite focal length from the lens closest to the object in the first lens group in the wide-angle end state to the lens adjacent to the object side of the aperture stop
  • fwb composite focal length from the lens adjacent to the image side of the aperture stop to the lens closest to the image side in the wide-angle end state
  • Conditional formula (8) defines the ratio of the composite focal length from the lens in the first lens group closest to the object to the lens adjacent to the object side of the aperture stop to the composite focal length from the lens adjacent to the image side of the aperture stop to the lens closest to the image.
  • variable magnification optical system of this embodiment if the value of conditional expression (8) exceeds the upper limit, the refractive power from the lens adjacent to the image side of the aperture stop to the lens closest to the image side becomes too large, making it difficult to effectively correct various aberrations, including spherical aberration, when focusing on infinity in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (8) to 0.30. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (8) to 0.25, 0.20, 0.17, or even 0.14.
  • variable magnification optical system of this embodiment if the value of conditional expression (8) falls below the lower limit, the refractive power from the lens closest to the object in the first lens group to the lens adjacent to the object side of the aperture stop becomes too large, making it difficult to satisfactorily correct various aberrations, including spherical aberration, when focusing on infinity in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (8) to 0.01. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (8) to 0.02, 0.03, or even 0.04.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (9) 1.00 ⁇ MWF1/MWF2 ⁇ 15.00 however, MWF1: Amount of movement of the first focusing lens group when focusing from an object at infinity to an object at a close distance in the wide-angle end state MWF2: Amount of movement of the second focusing lens group when focusing from an object at infinity to an object at a close distance in the wide-angle end state
  • Conditional formula (9) specifies the ratio between the amount of movement of the first focusing lens group and the amount of movement of the second focusing lens group when focusing from an object at infinity to a close object in the wide-angle end state.
  • close distance refers to the distance at which the shooting magnification is 1/30.
  • variable magnification optical system of this embodiment if the value of conditional expression (9) exceeds the upper limit, the amount of movement of the first focusing lens group becomes too large, making it difficult to suppress fluctuations in various aberrations, including coma, during focusing in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (9) to 15.00. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (9) to 12.50, 11.00, 10.00, 8.50, 7.00, or even 6.50.
  • variable magnification optical system of this embodiment if the value of conditional expression (9) falls below the lower limit, the amount of movement of the second lens group becomes too large, making it difficult to suppress fluctuations in various aberrations, including coma, when focusing in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (9) to 1.00. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (9) to 1.50, 2.00, 2.50, 3.00, 3.50, or even 3.80.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (10) 0.70 ⁇ MTF1/MTF2 ⁇ 10.00 however, MTF1: Amount of movement of the first focusing lens group when focusing from an object at infinity to an object at a close distance in the telephoto end state. MTF2: Amount of movement of the second focusing lens group when focusing from an object at infinity to an object at a close distance in the telephoto end state.
  • Conditional formula (10) specifies the ratio between the amount of movement of the first focusing lens group and the amount of movement of the second focusing lens group when focusing from an object at infinity to a close object in the telephoto end state.
  • conditional formula (10) the variable magnification optical system of this embodiment can suppress fluctuations in various aberrations, including coma, when focusing in the telephoto end state.
  • variable magnification optical system of this embodiment if the value of conditional expression (10) exceeds the upper limit, the amount of movement of the first focusing lens group becomes too large, making it difficult to suppress fluctuations in various aberrations, including coma, during focusing in the telephoto end state.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (10) to 10.00. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (10) to 9.00, 7.50, 5.00, 3.50, or even 2.80.
  • variable magnification optical system of this embodiment if the value of conditional expression (10) falls below the lower limit, the amount of movement of the second lens group becomes too large, making it difficult to suppress fluctuations in various aberrations, including coma, during focusing in the telephoto end state.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (10) to 0.70. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (10) to 0.85, 1.00, 1.25, 1.50, or even 1.80.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (11) 0.60 ⁇ ⁇ WF1/ ⁇ WF2 ⁇ 10.00 however, ⁇ WF1: lateral magnification of the first focusing lens group when focusing on an object at infinity in the wide-angle end state ⁇ WF2: lateral magnification of the second focusing lens group when focusing on an object at infinity in the wide-angle end state
  • Conditional formula (11) specifies the ratio between the lateral magnification of the first focusing lens group and the lateral magnification of the second focusing lens group when focusing on an object at infinity in the wide-angle end state.
  • conditional formula (11) the variable magnification optical system of this embodiment can suppress fluctuations in various aberrations, including coma, when focusing in the wide-angle end state.
  • variable magnification optical system of this embodiment if the value of conditional expression (11) exceeds the upper limit, the lateral magnification of the first focusing lens group when focusing on an object at infinity in the wide-angle end state becomes too large, making it difficult to suppress fluctuations in various aberrations, including coma, when focusing in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (11) to 10.00. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (11) to 8.50, 7.00, 5.00, or even 4.00.
  • variable magnification optical system of this embodiment if the value of conditional expression (11) falls below the lower limit, the lateral magnification of the second focusing lens group when focusing on an object at infinity in the wide-angle end state becomes too large, making it difficult to suppress fluctuations in various aberrations, including coma, when focusing in the wide-angle end state.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (11) to 0.60. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (11) to 0.90, 1.00, 1.25, 1.50, 1.70, or even 1.80.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (12) 0.20 ⁇ ⁇ TF1/ ⁇ TF2 ⁇ 5.00 however, ⁇ WT1: lateral magnification of the first focusing lens group when focusing on an object at infinity in the telephoto end state ⁇ WT2: lateral magnification of the second focusing lens group when focusing on an object at infinity in the telephoto end state
  • Conditional formula (12) specifies the ratio between the lateral magnification of the first focusing lens group and the lateral magnification of the second focusing lens group when focusing on an object at infinity in the telephoto end state.
  • conditional formula (12) the variable magnification optical system of this embodiment can suppress fluctuations in various aberrations, including coma, when focusing in the telephoto end state.
  • variable magnification optical system of this embodiment if the value of conditional expression (12) exceeds the upper limit, the lateral magnification of the first focusing lens group when focusing on an object at infinity in the telephoto end state becomes too large, making it difficult to suppress fluctuations in various aberrations, including coma, when focusing in the telephoto end state.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (12) to 5.00. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (12) to 4.00, 3.00, 2.50, 2.00, or even 1.40.
  • variable magnification optical system of this embodiment if the value of conditional expression (12) falls below the lower limit, the lateral magnification of the second focusing lens group when focusing on an object at infinity in the telephoto end state becomes too large, making it difficult to suppress fluctuations in various aberrations, including coma, when focusing in the telephoto end state.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (12) to 0.20. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (12) to 0.35, 0.50, 0.65, or even 0.80.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (13) 0.50 ⁇ Gw / Gt ⁇ 1.50 however, Gw: Distance from the lens surface closest to the object of the variable magnification optical system in the wide-angle end state to the center of gravity of the variable magnification optical system. Gt: Distance from the lens surface closest to the object of the variable magnification optical system in the telephoto end state to the center of gravity of the variable magnification optical system.
  • Conditional expression (13) defines the ratio between the distance from the lens surface closest to the object of the variable magnification optical system in the wide-angle end state to the position of the center of gravity of the variable magnification optical system, and the distance from the lens surface closest to the object of the variable magnification optical system in the telephoto end state to the position of the center of gravity of the variable magnification optical system.
  • conditional expression (13) is not satisfied in the variable magnification optical system of this embodiment, the change in the center of gravity position during magnification will be large, impairing operability.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (13) to 1.50. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (13) to 1.48, 1.45, or even 1.40.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (13) to 0.50. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (13) to 0.60, 0.75, 0.90, or even 1.00.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (14) 37.00° ⁇ ⁇ however, ⁇ w: Half angle of view of the variable magnification optical system in the wide-angle end state
  • Conditional expression (14) defines the half angle of view of the variable magnification optical system in the wide-angle end state.
  • conditional expression (14) the variable magnification optical system of this embodiment can form an image of a wide range of subjects on the image plane.
  • the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (14) to 37.00°. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (14) to 39.00°, or even 42.00°.
  • variable magnification optical system of this embodiment it is preferable that the following conditional expression be satisfied. (15) ⁇ t ⁇ 44.00° however, ⁇ t: Half angle of view of the variable magnification optical system in the telephoto end state
  • Conditional expression (15) defines the half angle of view of the variable magnification optical system in the telephoto end state.
  • conditional expression (15) defines the half angle of view of the variable magnification optical system in the telephoto end state.
  • the effect of this embodiment can be made more certain by setting the upper limit value of conditional expression (15) to 44.00°. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value of conditional expression (15) to 42.00°, 33.00°, 18.00°, or even 14.00°.
  • the above configuration makes it possible to realize a variable magnification optical system that is compact and has good imaging performance.
  • the optical device of this embodiment has a variable magnification optical system with the above-mentioned configuration. This makes it possible to realize an optical device with good optical performance.
  • the manufacturing method of the variable magnification optical system of the present embodiment includes configuring a variable magnification optical system having, in order from the object side, a first lens group having negative refractive power and a subsequent lens group having a plurality of lens groups, the subsequent lens group including, in order from the object side, a second lens group having positive refractive power and a third lens group having positive refractive power, wherein, during magnification change, the first lens group is fixed with respect to the image plane and the spacing between adjacent lens groups changes, so as to satisfy the following conditional expression: (1) 1.00 ⁇ f2 / f3 ⁇ 5.00 however, f2: focal length of the second lens group f3: focal length of the third lens group
  • the manufacturing method of the variable magnification optical system of this embodiment includes configuring a variable magnification optical system having, in order from the object side, a first lens group having negative refractive power and a subsequent lens group having a plurality of lens groups, wherein the subsequent lens group includes a first focusing lens group having positive refractive power and moving when focusing, and a second focusing lens group having negative refractive power, positioned closer to the image plane than the first focusing lens group, and moving when focusing, wherein, during magnification change, the first lens group is fixed with respect to the image plane and the spacing between adjacent lens groups changes, so as to satisfy the following conditional formula: (2) 0.70 ⁇ fF1/(-fF2) ⁇ 5.00 however, fF1: focal length of the first focusing lens group fF2: focal length of the second focusing lens group
  • This method of manufacturing an optical system makes it possible to manufacture a variable magnification optical system with good optical performance.
  • FIG. 1 is a cross-sectional view of a variable magnification optical system according to a first embodiment when focused on an object at infinity in the wide-angle end state.
  • variable magnification optical system of this embodiment has, from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having negative refractive power.
  • the first lens group G1 consists of, in order from the object side, a meniscus-shaped negative lens L11 with its convex surface facing the object side, and a cemented negative lens consisting of a biconcave negative lens L12 and a meniscus-shaped positive lens L13 with its convex surface facing the object side.
  • the second lens group G2 is made up of a cemented positive lens L21 having a biconvex shape and a biconcave negative lens L22.
  • the third lens group G3 is made up of a cemented positive lens consisting of a negative meniscus lens L31 with its convex surface facing the object side and a biconvex positive lens L32.
  • the fourth lens group G4 consists of, in order from the object side, an aperture stop S, a biconcave negative lens L41, and a meniscus positive lens L42 with its convex surface facing the object side.
  • the fifth lens group G5 consists of, from the object side, a cemented positive lens consisting of a biconvex positive lens L51 and a biconcave negative lens L52, and a meniscus positive lens L53 with its concave surface facing the object side.
  • the sixth lens group G6 consists of, from the object side, a biconcave negative lens L61 and a meniscus positive lens L62 with its concave surface facing the object side.
  • An image sensor (not shown) composed of a CCD or CMOS or the like is disposed on image plane I.
  • variable magnification optical system of this embodiment focuses by moving the fifth lens group G5 along the optical axis.
  • the fifth lens group G5 is moved from the image plane side to the object side.
  • Table 1 below lists the specifications of the variable magnification optical system of this embodiment.
  • TL is the distance from the lens surface closest to the object to the image plane
  • fw is the focal length of the entire system at the wide-angle end
  • ft is the focal length of the entire system at the telephoto end
  • FNOw is the F-number at the wide-angle end
  • FNOt is the F-number at the telephoto end
  • ⁇ w is the half angle of view (degrees) at the wide-angle end
  • ⁇ t is the half angle of view (degrees) at the telephoto end
  • Y is the maximum image height.
  • m is the order of the optical surface counted from the object side
  • r is the radius of curvature
  • d is the surface spacing
  • nd is the refractive index for the d line (wavelength 587.6 nm)
  • ⁇ d is the Abbe number for the d line.
  • optical surfaces marked with an "*" are aspheric.
  • m is the optical surface that corresponds to the aspherical data
  • K is the conic constant
  • A4-A12 are the aspherical coefficients.
  • the aspheric 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 along the optical axis from the tangent plane of the apex of each aspheric surface at height y to each aspheric surface (amount of sag), 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 aspheric coefficient. In each embodiment, the second order aspheric coefficient A2 is 0. Also, "En” represents " ⁇ 10 -n ".
  • the focal lengths fw and ft, the radius of curvature r, and other lengths listed in Table 1 are in units of "mm.” However, this is not limited to this because the optical system can achieve the same optical performance even when proportionally enlarged or reduced.
  • FIG. 2(a) is a diagram showing various aberrations when the variable magnification optical system of the first embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 2(b) is a diagram showing various aberrations when the variable magnification optical system of the first embodiment is focused on an object at infinity in the telephoto end state.
  • FNO indicates the F-number and Y indicates the image height.
  • the spherical aberration diagram indicates the F-number value corresponding to the maximum aperture
  • the astigmatism diagram and distortion diagram indicate the maximum image height
  • the coma diagram indicates the value of each image height.
  • d indicates the d-line
  • g indicates the g-line (wavelength 435.8 nm).
  • the solid line indicates the sagittal image plane and the dashed line indicates the meridional image plane.
  • variable magnification optical system of this embodiment properly corrects various aberrations and has high optical performance.
  • FIG. 3 is a cross-sectional view of the variable magnification optical system of the second embodiment when focused on an object at infinity in the wide-angle end state.
  • variable magnification optical system of this embodiment has, from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having positive refractive power, and a sixth lens group G6 having negative refractive power.
  • the first lens group G1 consists of, in order from the object side, a meniscus-shaped negative lens L11 with its convex surface facing the object side, and a cemented negative lens consisting of a biconcave negative lens L12 and a meniscus-shaped positive lens L13 with its convex surface facing the object side.
  • the second lens group G2 is made up of a cemented positive lens L21 having a biconvex shape and a biconcave negative lens L22.
  • the third lens group G3 is made up of a cemented positive lens consisting of a negative meniscus lens L31 with its convex surface facing the object side and a biconvex positive lens L32.
  • the fourth lens group G4 consists of, in order from the object side, an aperture stop S, a biconcave negative lens L41, and a meniscus positive lens L42 with its convex surface facing the object side.
  • the fifth lens group G5 consists of, in order from the object side, a cemented positive lens consisting of a biconvex positive lens L51 and a meniscus negative lens L52 with its concave surface facing the object side, and a meniscus positive lens L53 with its concave surface facing the object side.
  • the sixth lens group G6 consists of, from the object side, a biconcave negative lens L61 and a biconvex positive lens L62.
  • An image sensor (not shown) composed of a CCD or CMOS or the like is disposed on image plane I.
  • variable magnification optical system of this embodiment focuses by moving the fifth lens group G5 along the optical axis.
  • the fifth lens group G5 is moved from the image plane side to the object side.
  • Table 2 below lists the specifications of the variable magnification optical system of this embodiment.
  • FIG. 4(a) is a diagram showing various aberrations when the variable magnification optical system of the second embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 4(b) is a diagram showing various aberrations when the variable magnification optical system of the second embodiment is focused on an object at infinity in the telephoto end state.
  • variable magnification optical system of this embodiment properly corrects various aberrations and has high optical performance.
  • FIG. 5 is a sectional view of the variable magnification optical system of the third embodiment when focused on an object at infinity in the wide-angle end state.
  • variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, 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.
  • the first lens group G1 consists of, in order from the object side, a meniscus negative lens L11 with its convex surface facing the object side, a biconcave negative lens L12, and a cemented negative lens consisting of a biconcave negative lens L13 and a meniscus positive lens L14 with its convex surface facing the object side.
  • the second lens group G2 consists of a biconvex positive lens L21.
  • the third lens group G3 consists of, in order from the object side, a meniscus-shaped positive lens L31 with its convex surface facing the object side, a meniscus-shaped positive lens L32 with its convex surface facing the object side, and a cemented positive lens consisting of a meniscus-shaped negative lens L33 with its convex surface facing the object side and a biconvex positive lens L34.
  • the fourth lens group G4 consists of, in order from the object side, an aperture stop S, a biconcave negative lens L41, a cemented negative lens consisting of a meniscus positive lens L42 with its concave surface facing the object side and a meniscus negative lens L43 with its concave surface facing the object side, a biconvex positive lens L44, a cemented negative lens consisting of a meniscus negative lens L45 with its convex surface facing the object side and a meniscus positive lens L46 with its convex surface facing the object side, and a biconvex positive lens L47.
  • the fifth lens group G5 is made up of a cemented negative lens consisting of a meniscus-shaped positive lens L51 with its concave surface facing the object side and a biconcave negative lens L52.
  • the sixth lens group G6 consists of a positive meniscus lens L61 with its convex surface facing the object side.
  • An image sensor (not shown) composed of a CCD or CMOS or the like is disposed on image plane I.
  • variable magnification optical system of this embodiment focuses by moving the second lens group G2 and the fifth lens group G5 along the optical axis.
  • the second lens group G2 is moved from the object side to the image plane side
  • the fifth lens group G5 is moved from the image plane side to the object side.
  • the second lens group G2 corresponds to the first focusing lens group
  • the fifth lens group G5 corresponds to the second focusing lens group
  • Table 3 below lists the specifications of the variable magnification optical system of this embodiment.
  • FIG. 6(a) is a diagram of various aberrations when the variable magnification optical system of the third embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 6(b) is a diagram of various aberrations when the variable magnification optical system of the third embodiment is focused on an object at infinity in the telephoto end state
  • FIG. 6(c) is a diagram of various aberrations when the variable magnification optical system of the third embodiment is focused on a close object in the wide-angle end state
  • FIG. 6(d) is a diagram of various aberrations when the variable magnification optical system of the third embodiment is focused on a close object in the telephoto end state.
  • variable magnification optical system of this embodiment properly corrects various aberrations and has high optical performance.
  • FIG. 7 is a sectional view of the variable magnification optical system of the fourth embodiment when focused on an object at infinity in the wide-angle end state.
  • variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, 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.
  • the first lens group G1 consists of, in order from the object side, a meniscus negative lens L11 with its convex surface facing the object side, a biconcave negative lens L12, and a cemented negative lens consisting of a biconcave negative lens L13 and a biconvex positive lens L14.
  • the second lens group G2 consists of a biconvex positive lens L21.
  • the third lens group G3 consists of, in order from the object side, a meniscus-shaped positive lens L31 with its convex surface facing the object side, and a cemented positive lens consisting of a meniscus-shaped negative lens L32 with its convex surface facing the object side and a biconvex positive lens L33.
  • the fourth lens group G4 consists of, in order from the object side, an aperture stop S, a cemented negative lens consisting of a biconcave negative lens L41 and a biconvex positive lens L42, a biconvex positive lens L43, a cemented negative lens consisting of a meniscus negative lens L44 with its convex surface facing the object side and a meniscus positive lens L45 with its convex surface facing the object side, and a biconvex positive lens L46.
  • the fifth lens group G5 is made up of a cemented negative lens consisting of a meniscus-shaped positive lens L51 with its concave surface facing the object side and a biconcave negative lens L52.
  • the sixth lens group G6 consists of a biconvex positive lens L61.
  • An image sensor (not shown) composed of a CCD or CMOS or the like is disposed on image plane I.
  • variable magnification optical system of this embodiment focuses by moving the second lens group G2 and the fifth lens group G5 along the optical axis.
  • the second lens group G2 is moved from the object side to the image plane side
  • the fifth lens group G5 is moved from the image plane side to the object side.
  • the second lens group G2 corresponds to the first focusing lens group
  • the fifth lens group G5 corresponds to the second focusing lens group
  • Table 4 below lists the specifications of the variable magnification optical system of this embodiment.
  • FIG. 8(a) is a diagram of various aberrations when the variable magnification optical system of the fourth embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 8(b) is a diagram of various aberrations when the variable magnification optical system of the fourth embodiment is focused on an object at infinity in the telephoto end state
  • FIG. 8(c) is a diagram of various aberrations when the variable magnification optical system of the fourth embodiment is focused on a close object in the wide-angle end state
  • FIG. 8(d) is a diagram of various aberrations when the variable magnification optical system of the fourth embodiment is focused on a close object in the telephoto end state.
  • variable magnification optical system of this embodiment properly corrects various aberrations and has high optical performance.
  • FIG. 9 is a cross-sectional view of the variable magnification optical system of the fifth embodiment when focused on an object at infinity in the wide-angle end state.
  • variable magnification optical system of this embodiment has, from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power.
  • the first lens group G1 consists of, in order from the object side, a meniscus negative lens L11 with a convex surface facing the object side, a meniscus positive lens L12 with a concave surface facing the object side, and a cemented negative lens consisting of a biconcave negative lens L13 and a meniscus positive lens L14 with a convex surface facing the object side.
  • the second lens group G2 consists of a biconvex positive lens L21.
  • the third lens group G3 consists of, in order from the object side, a meniscus positive lens L31 with a convex surface facing the object side, a cemented positive lens consisting of a meniscus negative lens L32 with a convex surface facing the object side and a biconvex positive lens L33, an aperture stop S, a biconcave negative lens L34, a cemented negative lens consisting of a meniscus positive lens L35 with a concave surface facing the object side and a biconcave negative lens L36, a biconvex positive lens L37, a cemented positive lens consisting of a meniscus negative lens L38 with a convex surface facing the object side and a biconvex positive lens L39, and a biconvex positive lens L310.
  • the fourth lens group G4 is made up of a cemented negative lens consisting of a meniscus-shaped positive lens L41 with its concave surface facing the object side and a biconcave negative lens L42.
  • the fifth lens group G5 consists of a positive meniscus lens L51 with its convex surface facing the object side.
  • An image sensor (not shown) composed of a CCD or CMOS or the like is disposed on image plane I.
  • variable magnification optical system of this embodiment focuses by moving the second lens group G2 and the fourth lens group G4 along the optical axis.
  • the second lens group G2 is moved from the object side to the image surface side
  • the fourth lens group G4 is moved from the image surface side to the object side.
  • the second lens group G2 corresponds to the first focusing lens group
  • the fourth lens group G4 corresponds to the second focusing lens group
  • Table 5 lists the specifications of the variable magnification optical system of this embodiment.
  • FIG. 10(a) is a diagram of various aberrations when the variable magnification optical system of the fifth embodiment is focused on an object at infinity in the wide-angle end state
  • FIG. 10(b) is a diagram of various aberrations when the variable magnification optical system of the fifth embodiment is focused on an object at infinity in the telephoto end state
  • FIG. 10(c) is a diagram of various aberrations when the variable magnification optical system of the fifth embodiment is focused on a close object in the wide-angle end state
  • FIG. 10(d) is a diagram of various aberrations when the variable magnification optical system of the fifth embodiment is focused on a close object in the telephoto end state.
  • variable magnification optical system of this embodiment properly corrects various aberrations and has high optical performance.
  • fw is the focal length of the variable magnification optical system in the wide-angle end state
  • BFw is the back focus of the variable magnification optical system when focused at infinity in the wide-angle end state.
  • f1 is the focal length of the first lens group
  • f2 is the focal length of the second lens group
  • f3 is the focal length of the third lens group
  • fF1 is the focal length of the first focusing lens group
  • fF2 is the focal length of the second focusing lens group
  • fRF is the focal length of the lens group adjacent to the object side of the lens group arranged closest to the image surface
  • fR is the focal length of the lens group arranged closest to the image surface.
  • fwa is the composite focal length from the lens closest to the object side of the first lens group to the lens adjacent to the object side of the aperture stop in the wide-angle end state
  • fwb is the composite focal length from the lens adjacent to the image surface side of the aperture stop to the lens closest to the image surface in the wide-angle end state.
  • Dwa is the distance from the surface of the first lens group closest to the object to the aperture stop in the wide-angle end state
  • Dwb is the distance from the aperture stop to the image plane in the wide-angle end state
  • MWF1 is the amount of movement of the first focusing lens group when focusing from an object at infinity to a close object in the wide-angle end state
  • MWF2 is the amount of movement of the second focusing lens group when focusing from an object at infinity to a close object in the wide-angle end state
  • MTF1 is the amount of movement of the first focusing lens group when focusing from an object at infinity to a close object in the telephoto end state
  • MTF2 is the amount of movement of the second focusing lens group when focusing from an object at infinity to a close object in the telephoto end state.
  • ⁇ WF1 is the lateral magnification of the first focusing lens group when focusing on an object at infinity in the wide-angle end state
  • ⁇ WF2 is the lateral magnification of the second focusing lens group when focusing on an object at infinity in the wide-angle end state
  • ⁇ TF1 is the lateral magnification of the first focusing lens group when focusing on an object at infinity in the telephoto end state
  • ⁇ TF2 is the lateral magnification of the second focusing lens group when focusing on an object at infinity in the telephoto end state.
  • Gw is the distance from the lens surface of the variable magnification optical system closest to the object to the center of gravity of the variable magnification optical system in the wide-angle end state
  • Gt is the distance from the lens surface of the variable magnification optical system closest to the object to the center of gravity of the variable magnification optical system in the telephoto end state
  • ⁇ w is the half angle of view of the variable magnification optical system in the wide-angle end state
  • ⁇ t is the half angle of view of the variable magnification optical system in the telephoto end state.
  • the fourth lens group does not have to have an aperture diaphragm. Furthermore, the position of the aperture diaphragm in the variable magnification optical system of this embodiment is not limited to the position of the aperture diaphragm S in the variable magnification optical system of each of the above examples.
  • variable magnification optical system of this embodiment may have an optical component such as a filter between the lens surface closest to the image surface and the image surface.
  • variable magnification optical system of this embodiment may have an anti-vibration lens group that corrects image blur caused by camera shake by being moved so as to have a component in a direction perpendicular to the optical axis.
  • the anti-vibration lens group may be a lens group, or a partial lens group consisting of one or more lens components included in the lens group.
  • the lens surface may be formed as a spherical or flat surface, or as an aspheric surface. If the lens surface is spherical or flat, this is preferable because it facilitates lens processing and assembly adjustment, and prevents deterioration of optical performance due to errors in processing and assembly adjustment. In addition, if the lens surface is spherical or flat, this is preferable because there is less deterioration in imaging performance when the image plane is shifted.
  • the aspheric surface may be formed by grinding glass or by glass molding using a mold having an aspheric shape, or may be formed on the surface of a resin bonded to the surface of the glass.
  • the lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.
  • FIG. 11 is a schematic diagram of a camera equipped with the variable magnification optical system of this embodiment.
  • Camera 1 is a so-called mirrorless camera with interchangeable lenses that has the optical system according to the first embodiment described above as the photographic lens 2.
  • camera 1 In camera 1, light from an object (subject) (not shown) is collected by photographing lens 2 and reaches image sensor 3. Image sensor 3 converts the light from the subject into image data. When the photographer presses a release button (not shown), the image data is stored in memory (not shown). In this way, the photographer can photograph the subject using camera 1.
  • variable magnification optical system of the first embodiment mounted on the camera 1 as the photographic lens 2 is a variable magnification optical system with good optical performance. Therefore, the camera 1 can achieve good optical performance. Note that the same effects as the camera 1 can be achieved by constructing a camera that mounts the variable magnification optical system of the second to fifth embodiments as the photographic lens 2.
  • FIG. 12 is a flow chart outlining a first manufacturing method for the variable magnification optical system of this embodiment.
  • the first manufacturing method for the variable magnification optical system of this embodiment shown in FIG. 12 includes the following steps S11-S13.
  • Step S11 Prepare a first lens group and a subsequent lens group including a second lens group and a third lens group.
  • Step S12 When changing the magnification, the first lens group is fixed relative to the image plane, and the spacing between adjacent lens groups is changed.
  • Step S13 The variable magnification optical system is made to satisfy the following conditional expression. (1) 1.00 ⁇ f2 / f3 ⁇ 5.00 however, f2: focal length of the second lens group f3: focal length of the third lens group
  • FIG. 13 is a flow chart outlining a second manufacturing method for the variable magnification optical system of this embodiment.
  • the second manufacturing method for the variable magnification optical system of this embodiment shown in FIG. 13 includes the following steps S21-S23.
  • Step S21 Prepare a first lens group and a subsequent lens group including a first focusing lens group and a second focusing lens group.
  • Step S22 When changing the magnification, the first lens group is fixed relative to the image plane, and the spacing between adjacent lens groups is changed.
  • Step S23 The variable magnification optical system is made to satisfy the following conditional expression. (2) 0.70 ⁇ fF1/(-fF2) ⁇ 5.00 however, fF1: focal length of the first focusing lens group fF2: focal length of the second focusing lens group
  • variable magnification optical system of this embodiment make it possible to manufacture an optical system with good imaging performance.

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PCT/JP2023/038488 2022-11-04 2023-10-25 変倍光学系、光学機器および変倍光学系の製造方法 Ceased WO2024095858A1 (ja)

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WO2026053931A1 (ja) * 2024-09-03 2026-03-12 キヤノン株式会社 ズームレンズ及び撮像装置

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JPH03140911A (ja) * 1989-10-27 1991-06-14 Olympus Optical Co Ltd 変倍レンズ
JP2006098961A (ja) * 2004-09-30 2006-04-13 Canon Inc ズームレンズ及びそれを有する撮像装置
JP2006098962A (ja) * 2004-09-30 2006-04-13 Canon Inc ズームレンズ及びそれを有する撮像装置
JP2011059598A (ja) * 2009-09-14 2011-03-24 Olympus Imaging Corp 変倍光学系及びそれを有する撮像装置
JP2017078767A (ja) * 2015-10-20 2017-04-27 キヤノン株式会社 ズームレンズ及びそれを有する撮像装置
JP2017078768A (ja) * 2015-10-20 2017-04-27 キヤノン株式会社 ズームレンズ及びそれを有する撮像装置

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Publication number Priority date Publication date Assignee Title
JPH03140911A (ja) * 1989-10-27 1991-06-14 Olympus Optical Co Ltd 変倍レンズ
JP2006098961A (ja) * 2004-09-30 2006-04-13 Canon Inc ズームレンズ及びそれを有する撮像装置
JP2006098962A (ja) * 2004-09-30 2006-04-13 Canon Inc ズームレンズ及びそれを有する撮像装置
JP2011059598A (ja) * 2009-09-14 2011-03-24 Olympus Imaging Corp 変倍光学系及びそれを有する撮像装置
JP2017078767A (ja) * 2015-10-20 2017-04-27 キヤノン株式会社 ズームレンズ及びそれを有する撮像装置
JP2017078768A (ja) * 2015-10-20 2017-04-27 キヤノン株式会社 ズームレンズ及びそれを有する撮像装置

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Publication number Priority date Publication date Assignee Title
WO2026053931A1 (ja) * 2024-09-03 2026-03-12 キヤノン株式会社 ズームレンズ及び撮像装置

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