Imaging lens and imaging apparatus
AssigneeFUJIFILM Corporation
InventorKenichi Sato
Life of this patent
Estimating the term…
Abstract
An imaging lens is substantially constituted by: a negative first lens group; a positive second lens group; an aperture stop; a positive third lens group; and a negative fourth lens group; provided in this order from an object side. The first lens group is constituted only by two or more negative lenses. The second lens group has a positive lens at the most object side thereof. The third lens group has a negative lens having a concave surface toward the object side at the most object side thereof. The fourth lens group is constituted by a single negative lens. The fourth lens group moves from the object side to an image side when changing focus from an object at infinity to an object at an extremely close distance. Only the fourth lens group moves during focusing operations.
Claims20
An imaging lens consisting of, in order from the object side to the image side:
- a first lens group having a negative refractive power as a whole;
- a second lens group having a positive refractive power as a whole;
- an aperture stop;
- a third lens group having a positive refractive power as a whole;
- and
- a fourth lens group having a negative refractive power as a whole;
- the first lens group consisting only of two or more negative lenses;
- the second lens group having a positive lens at the most object side thereof;
- the third lens group having three positive lenses and a negative lens having a concave surface toward the object side at the most object side thereof;
- the fourth lens group consisting only of a single negative lens, the fourth lens group moving from the object side to an image side when changing focus from an object at infinity to an object at an extremely close distance;
- and
- only the fourth lens group moving during focusing operations.
An imaging lens consisting of, in order from the object side to the image side:
- a first lens group having a negative refractive power as a whole;
- a second lens group having a positive refractive power as a whole;
- an aperture stop;
- a third lens group having a positive refractive power as a whole;
- and
- a fourth lens group having a negative refractive power as a whole;
- the first lens group consisting only of two or more negative lenses and the lens surface most toward the object side within the first lens group being convex;
- the second lens group having a positive lens at the most object side thereof, and the number of positive lenses within the second lens group being two;
- the third lens group having a negative lens with a concave surface toward the object side at the most object side thereof;
- the fourth lens group consisting only of a single negative lens, the fourth lens group moving from the object side to an image side when changing focus from an object at infinity to an object at an extremely close distance;
- and
- only the fourth lens group moving during focusing operations.
An imaging lens consisting of, in order from the object side to the image side:
- a first lens group having a negative refractive power as a whole;
- a second lens group having a positive refractive power as a whole;
- an aperture stop;
- a third lens group having a positive refractive power as a whole;
- and
- a fourth lens group having a negative refractive power as a whole;
- the first lens group consisting only of two or more negative lenses;
- the second lens group having a positive lens at the most object side thereof, and the number of positive lenses within the second lens group being two;
- the third lens group having a negative lens with a concave surface toward the object side at the most object side thereof;
- the fourth lens group consisting only of a single negative lens, the fourth lens group moving from the object side to an image side when changing focus from an object at infinity to an object at an extremely close distance;
- only the fourth lens group moving during focusing operations;
- and the imaging lens satisfying Conditional Formula (1) below:
- −90<vdG2P1−vdG2P2<−15 (1)
- wherein vdG2Pl is the Abbe's number of the positive lens most toward the object side within the second lens group with respect to the d line, and vdG2P2 is the Abbe's number of the second positive lens from the object side within the second lens group with respect to the d line.
Dependencies are inferred from the claim text.