Variable magnification optical system, optical apparatus, and method for manufacturing variable magnification optical system

A method for manufacturing a variable magnification optical system, comprising:

• disposing, in a lens barrel:
• a first lens group having a negative refractive power;
• at least one positive lens disposed closer to an image side than the first lens group, an aperture, the at least one positive lens being disposed between the first lens group and the aperture;
• an intermediate group having a plurality of lenses disposed closer to the image side than the aperture and being constituted by three lenses;
• and a vibration-reduction lens group disposed closer to the image side than the intermediate group and movable so as to have a movement component in a direction orthogonal to an optical axis;
• arranging the plurality of lenses of the intermediate group so as to integrally move upon varying magnification;
• and
• satisfying the following conditional expression:
• 1.500<f(1˜Gn)t/ft<100.000
• where
• f(1˜Gn)t:
• a composite focal length from the first lens group to the intermediate group in a telephoto end state
• ft:
• a focal length of the entire system in the telephoto end state.

A variable magnification optical system, comprising:

• a first lens group having a negative refractive power;
• at least one positive lens disposed closer to an image side than the first lens group;
• an aperture, the at least one positive lens being disposed between the first lens group and the aperture;
• an intermediate group having a plurality of lenses disposed closer to the image side than the aperture;
• and
• a vibration-reduction lens group disposed closer to the image side than the intermediate group and movable so as to have a movement component in a direction orthogonal to an optical axis, wherein
• the plurality of lenses of the intermediate group integrally move upon varying magnification,
• the system is constituted by, in order from an object:
• the first lens group, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power,
• the first lens group is constituted by, in order from the object, a negative lens, a negative lens and a positive lens, and
• the system satisfies the following conditional expression:
• 1.500<f(1˜Gn)t/ft<100.000
• where
• f(1˜Gn)t:
• a composite focal length from the first lens group to the intermediate group in a telephoto end state
• ft:
• a focal length of the entire system in the telephoto end state.

A variable magnification optical system, comprising:

• a first lens group having a negative refractive power;
• at least one positive lens disposed closer to an image side than the first lens group;
• an aperture, the at least one positive lens being disposed between the first lens group and the aperture;
• an intermediate group having a plurality of lenses disposed closer to the image side than the aperture;
• and
• a vibration-reduction lens group disposed closer to the image side than the intermediate group and movable so as to have a movement component in a direction orthogonal to an optical axis, wherein
• the plurality of lenses of the intermediate group integrally move upon varying magnification, and
• the system satisfies the following conditional expressions:
• 1.500<f(1˜Gn)t/ft<100.000
• 1.360<−f(Gn˜G(VR))w/fw<5.000
• where
• f(1˜Gn)t:
• a composite focal length from the first lens group to the intermediate group in a telephoto end state
• ft:
• a focal length of the entire system in the telephoto end state
• f(Gn˜G(VR))w:
• a composite focal length from the intermediate group to the vibration-reduction lens group in a wide-angle end state
• fw:
• a focal length of the entire system in the wide-angle end state.

A variable magnification optical system, comprising:

• a first lens group having a negative refractive power;
• at least one positive lens disposed closer to an image side than the first lens group;
• an aperture, the at least one positive lens being disposed between the first lens group and the aperture;
• an intermediate group having a plurality of lenses disposed closer to the image side than the aperture;
• and
• a vibration-reduction lens group disposed closer to the image side than the intermediate group and movable so as to have a movement component in a direction orthogonal to an optical axis, wherein
• the plurality of lenses of the intermediate group integrally move upon varying magnification,
• the system includes an image-side lens group having a strongest positive refractive power among lens groups having positive refractive power which are disposed closer to the image side than the vibration-reduction lens group,
• a distance between the image-side lens group and the vibration-reduction lens group changes upon varying magnification, and
• the system satisfies the following conditional expressions:
• 1.500<f(1˜Gn)t/ft<100.000
• 0.400<f(RP)/f(FP)<2.000
• where
• f(1˜Gn)t:
• a composite focal length from the first lens group to the intermediate group in a telephoto end state
• ft:
• a focal length of the entire system in the telephoto end state
• f(RP):
• a focal length of the image-side lens group
• f(FP):
• a composite focal length in a wide-angle end state, of lenses disposed closer to the image side than the first lens group and disposed closer to an object side than the intermediate group.