Imaging lens and imaging apparatus
AssigneeFUJIFILM Corporation
InventorHiromitsu Yamakawa
Life of this patent
Estimating the term…
Abstract
The imaging lens consists essentially of a front group that consist essentially of a negative first lens having a meniscus shape with a convex surface toward the object side, a negative second lens and a positive third lens; a stop; a positive rear group that includes a positive lens and a negative lens. When the focal length of the entire system is f, a half angle of view is ω, and the distance from the object-side surface of the first lens to the imaging plane along the optical axis is L, conditional formula (1) below is satisfied: 0.25<2*f*tan(ω/2)/L<1.00 (1).
Claims11
An imaging lens, consisting of:
- a front group which consists of a negative first lens having a meniscus shape with a convex surface toward the object side, a negative second lens, a point along the optical axis at the image-side surface of which is more toward the object side than points on both ends of the effective diameter of the image-side surface, and a positive third lens;
- an aperture stop;
- and
- a rear group which is positive as a whole in this order from the object side, wherein
- the rear group consists of one positive lens and one negative lens;
- and
- conditional formula (1) below is satisfied:
- 0.25<2*f*tan(ω/2)/L<1.00 (1),
- where
- f:
- the focal length of the entire system
- ω:
- a half angle of view
- L:
- the distance from the object-side surface of the first lens to the imaging plane along the optical axis (back focus corresponds to an air converted length), and
- the conditional formula (2) below is satisfied:
- −2.0<f2/f<−0.5 (2),
- where
- f2:
- the focal length of the second lens, and
- f:
- the focal length of the entire system.
An imaging lens, consisting of:
- a front group which consists of a negative first lens having a meniscus shape with a convex surface toward the object side, a negative second lens, a point along the optical axis at the image-side surface of which is more toward the object side than points on both ends of the effective diameter of the image-side surface, and a positive third lens;
- an aperture stop;
- and
- a rear group which is positive as a whole in this order from the object side, wherein
- the rear group consists of one positive lens and one negative lens;
- and
- conditional formula (1) below is satisfied:
- 0.25<2*f*tan(ω/2)/L<1.00 (1),
- where
- f:
- the focal length of the entire system
- ω:
- a half angle of view
- L:
- the distance from the object-side surface of the first lens to the imaging plane along the optical axis (back focus corresponds to an air converted length), and
- the conditional formula (4) below is satisified:
- d4/L<0.07 (4),
- where
- d4:
- the distance from the second lens to the third lens along the optical axis, and
- L:
- the distance from the object-side surface of the first lens to the imaging plane along the optical axis (the back focus corresponds to an air converted length).
Dependencies are inferred from the claim text.