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US 11,353,682 B2Granted
Imaging lens and imaging apparatus
AssigneeFUJIFILM Corporation
InventorsDaiki Kawamura, Michio Cho
Life of this patent
Estimating the term…
Abstract
The imaging lens comprises, successively in order from the object side, a positive first lens group that does not move during focusing, a second lens group that moves during focusing, a stop, and a positive third lens group that consists of all lenses moving integrally with the second lens group during focusing. The composite focal length of the second lens group and the third lens group is positive. The first lens group includes four or more positive lenses and three or more negative lenses. The imaging lens satisfies predetermined conditional expressions.
Claims20
An imaging lens comprising, successively in order from a position closest to an object side to an image side:
- a first lens group that remains stationary with respect to an image plane during focusing and that has a positive refractive power;
- a second lens group that moves during focusing;
- a stop;
- and
- a third lens group that moves during focusing and that has a positive refractive power,
- wherein all lenses in the second lens group move integrally during focusing,
- wherein the third lens group consists of all lenses that move integrally with the second lens group during focusing,
- wherein a composite focal length of the second lens group and the third lens group is positive,
- wherein the first lens group includes at least four positive lenses and at least three negative lenses,
- wherein, assuming that a maximum value of a height of a paraxial ray from an optical axis in the first lens group is H1 max, in a case in which paraxial ray tracing is performed by causing the paraxial ray, whose height from the optical axis on a lens surface closest to the object is H1f and which is parallel to the optical axis, to be incident from the object side, Conditional Expression (1) is satisfied, which is represented by
- 1.1<H1 max/H1f<2 (1),
- and
- wherein assuming that
- an average of Abbe numbers of all the positive lenses in the first lens group based on a d line is ν1p,
- an average of Abbe numbers of all the negative lenses in the first lens group based on the d line is ν1n,
- an average of partial dispersion ratios of all the positive lenses in the first lens group between a g line and an F line is θ1p, and
- an average of partial dispersion ratios of all the negative lenses in the first lens group between the g line and the F line is θ1n,
- Conditional Expressions (7) and (8) are satisfied, which are represented by
- 5<ν1p−ν1n<35 (7),
- and
- 0<θ1n−θ1p<0.05 (8).
18 more elements
An imaging lens comprising, successively in order from a position closest to an object side to an image side:
- a first lens group that remains stationary with respect to an image plane during focusing and that has a positive refractive power;
- a second lens group that moves during focusing;
- a stop;
- and
- a third lens group that moves during focusing and that has a positive refractive power,
- wherein all lenses in the second lens group move integrally during focusing,
- wherein the third lens group consists of all lenses that move integrally with the second lens group during focusing,
- wherein a composite focal length of the second lens group and the third lens group is positive,
- wherein the first lens group includes at least four positive lenses and at least three negative lenses,
- wherein, assuming that a maximum value of a height of a paraxial ray from an optical axis in the first lens group is H1 max, in a case in which paraxial ray tracing is performed by causing the paraxial ray, whose height from the optical axis on a lens surface closest to the object is H1f and which is parallel to the optical axis, to be incident from the object side, Conditional Expression (1) is satisfied, which is represented by
- 1.1<H1 max/H1f<2 (1), and
- wherein assuming that a combined lateral magnification of the second lens group and the third lens group in a state in which an object at infinity is in focus is β23, Conditional Expression (5-1) is satisfied, which is represented by
- 0.3<β23<0.6 (5-1).
10 more elements
An imaging lens comprising, successively in order from a position closest to an object side to an image side:
- a first lens group that remains stationary with respect to an image plane during focusing and that has a positive refractive power;
- a second lens group that moves during focusing;
- a stop;
- and
- a third lens group that moves during focusing and that has a positive refractive power,
- wherein all lenses in the second lens group move integrally during focusing,
- wherein the third lens group consists of all lenses that move integrally with the second lens group during focusing,
- wherein a composite focal length of the second lens group and the third lens group is positive,
- wherein the first lens group includes at least four positive lenses and at least three negative lenses,
- wherein, assuming that a maximum value of a height of a paraxial ray from an optical axis in the first lens group is H1 max, in a case in which paraxial ray tracing is performed by causing the paraxial ray, whose height from the optical axis on a lens surface closest to the object is H1f and which is parallel to the optical axis, to be incident from the object side, Conditional Expression (1) is satisfied, which is represented by
- 1.1<H1 max/H1f<2 (1), and
- wherein, assuming that a focal length of the third lens group is f3 and a focal length of the second lens group is f2, Conditional Expression (14) is satisfied, which is represented by
- −0.3<f3/f2<0.4 (14).
10 more elements
Dependencies are inferred from the claim text.