Imaging lens and imaging apparatus
AssigneeFUJIFILM Corporation
InventorYuya Hirakawa
Life of this patent
Estimating the term…
Abstract
The imaging lens includes, in order from a position closest to an object side to an image side: a front lens group that has a positive refractive power and is immovable during focusing; a stop that is disposed subsequent to the front lens group; a first focus lens group that has a positive refractive power; a second focus lens group that has a negative refractive power; and a final lens group that has a positive refractive power, is disposed closest to the image side, and is immovable during focusing. During focusing from an infinite distance object to a short range object, the first focus lens group and the second focus lens group move to increase a mutual distance therebetween.
Claims19
An imaging lens comprising, in order from a position closest to an object side to an image side:
- a front lens group that has a positive refractive power and remains stationary with respect to an image plane during focusing;
- a stop that is disposed subsequent to the front lens group;
- a first focus lens group that has a positive refractive power;
- a second focus lens group that has a negative refractive power;
- and
- a final lens group that has a positive refractive power, is disposed closest to the image side, and remains stationary with respect to the image plane during focusing,
- wherein during focusing from an infinite distance object to a short range object, the first focus lens group and the second focus lens group move to increase a mutual distance therebetween,
- a lens surface closest to the image side in the front lens group is a concave surface,
- a lens surface closest to the object side in the first focus lens group is a concave surface, and
- assuming that
- a curvature radius of the lens surface closest to the image side in the front lens group is RAr, and
- a curvature radius of the lens surface closest to the object side in the first focus lens group is RF1f,
- Conditional Expression (3) is satisfied, which is represented by
- −0.2<(RAr−RF1f)/(RAr+RF1f)<0 (3).
An imaging lens comprising, in order from a position closest to an object side to an image side:
- a front lens group that has a positive refractive power and remains stationary with respect to an image plane during focusing;
- a stop that is disposed subsequent to the front lens group;
- a first focus lens group that has a positive refractive power;
- a second focus lens group that has a negative refractive power;
- and
- a final lens group that has a positive refractive power, is disposed closest to the image side, and remains stationary with respect to the image plane during focusing,
- wherein during focusing from an infinite distance object to a short range object, the first focus lens group and the second focus lens group move to increase a mutual distance therebetween,
- a lens surface closest to the image side in the front lens group is a concave surface,
- a lens surface closest to the object side in the first focus lens group is a concave surface, and
- assuming that
- a focal length of the imaging lens in a state where the infinite distance object is in focus is f, and
- a focal length of the first focus lens group is fF1,
- Conditional Expression (11) is satisfied, which is represented by
- 1.8<f/fF1<4 (11).
An imaging lens comprising, in order from a position closest to an object side to an image side:
- a front lens group that has a positive refractive power and remains stationary with respect to an image plane during focusing;
- a stop that is disposed subsequent to the front lens group;
- a first focus lens group that has a positive refractive power;
- a second focus lens group that has a negative refractive power;
- and
- a final lens group that has a positive refractive power, is disposed closest to the image side, and remains stationary with respect to the image plane during focusing,
- wherein during focusing from an infinite distance object to a short range object, the first focus lens group and the second focus lens group move to increase a mutual distance therebetween,
- a lens surface closest to the image side in the front lens group is a concave surface,
- a lens surface closest to the object side in the first focus lens group is a concave surface, and
- assuming that
- a focal length of the imaging lens in a state where the infinite distance object is in focus is f, and
- a focal length of the second focus lens group is fF2,
- Conditional Expression (12) is satisfied, which is represented by
- −5<f/fF2<−1.4 (12).
Dependencies are inferred from the claim text.