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US 12,498,549 B2Granted
Zoom lens and imaging apparatus
AssigneeFUJIFILM Corporation
InventorsTakuya Tanaka, Masanao Kawana, Motoari Ota, Daiki Komatsu
Life of this patent
Estimating the term…
Abstract
A zoom lens consists of, in order from the object side, a first lens group that has a positive refractive power, a middle group that includes a plurality of lens groups in which the spacings between adjacent lens groups change during zooming, and the final lens group. The focusing group that moves during focusing is disposed in the middle group. The zoom lens satisfies predetermined conditional expressions.
Claims20
A zoom lens consisting of, in order from an object side to an image side:
- a first lens group that has a positive refractive power;
- a middle group that consists of three or four lens groups in which a spacing between adjacent lens groups changes during zooming;
- and a final lens group,
- wherein a spacing between the first lens group and the middle group changes, and a spacing between the middle group and the final lens group changes during zooming,
- wherein a focusing group that moves during focusing is disposed in the middle group, and
- a difference in an optical axis direction between a position of the focusing group in a state in which an infinite distance object is in focus at a telephoto end and a position of the focusing group in a state in which a lateral magnification of the zoom lens at the telephoto end is-0.1 times is DF,
- a focal length of the zoom lens in a state in which the infinite distance object is in focus at the telephoto end is ft,
- Conditional Expression (1) is satisfied, which is represented by
- 0.04<DF/ft<0.4 (1),
- a difference in the optical axis direction between a position of each lens group in the middle group in a state in which the infinite distance object is in focus at a wide angle end and a position thereof in a state in which the infinite distance object is in focus at the telephoto end is set as an amount of zooming movement,
- the amount of zooming movement of a lens group, of which the amount of zooming movement is maximum, among the lens groups in the middle group is DV,
- a focal length of the zoom lens in a state in which the infinite distance object is in focus at the wide angle end is fw,
- Conditional Expression (2a) is satisfied, which is represented by
- 5.409≤DV/fw<18 (2a),
- a lateral magnification of the focusing group in a state in which the infinite distance object is in focus at the telephoto end is βFt,
- a combined lateral magnification of all lenses closer to the image side than the focusing group in a state in which the infinite distance object is in focus at the telephoto end is βRt,
- Conditional Expression (3a) is satisfied, which is represented by
- 1.075≤(1−βFt2)×βRt2<5 (3a),
- a focal length of the focusing group is fF,
- a focal length of the final lens group is fE, and
- Conditional Expression (7) is satisfied, which is represented by
- 0.04<|fF/fE|<0.4 (7).
19 more elements
A zoom lens consisting of, in order from an object side to an image side:
- a first lens group that has a positive refractive power;
- a middle group that consists of three or four lens groups in which a spacing between adjacent lens groups changes during zooming;
- and a final lens group,
- wherein a spacing between the first lens group and the middle group changes, and a spacing between the middle group and the final lens group changes during zooming,
- wherein a focusing group that moves during focusing is disposed in the middle group, and
- a difference in an optical axis direction between a position of the focusing group in a state in which an infinite distance object is in focus at a telephoto end and a position of the focusing group in a state in which a lateral magnification of the zoom lens at the telephoto end is −0.1 times is DF,
- a focal length of the zoom lens in a state in which the infinite distance object is in focus at the telephoto end is ft,
- Conditional Expression (1) is satisfied, which is represented by
- 0.04<DF/ft<0.4 (1),
- wherein a difference in the optical axis direction between a position of each lens group in the middle group in a state in which the infinite distance object is in focus at a wide angle end and a position thereof in a state in which the infinite distance object is in focus at the telephoto end is set as an amount of zooming movement,
- the amount of zooming movement of a lens group, of which the amount of zooming movement is maximum, among the lens groups in the middle group is DV,
- a focal length of the zoom lens in a state in which the infinite distance object is in focus at the wide angle end is fw,
- Conditional Expression (2b) is satisfied, which is represented by
- 7.374≤DV/fw<18 (2b),
- a lateral magnification of the focusing group in a state in which the infinite distance object is in focus at the telephoto end is βFt,
- a combined lateral magnification of all lenses closer to the image side than the focusing group in a state in which the infinite distance object is in focus at the telephoto end is βRt, and
- Conditional Expression (3a) is satisfied, which is represented by
- 1.075≤(1−βFt2)×βRt2<5 (3a).
15 more elements
Dependencies are inferred from the claim text.