Patent ID: 11906715
Assignee: FUJIFILM CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 15:
16. An imaging lens consisting of, in order from an object side to an image side:
a first lens group;
a second lens group that has a positive refractive power; and
a third lens group that has a negative refractive power,
wherein the first lens group includes, successively in order from a position closest to the object side to the image side, two negative lenses and a positive lens,
the second lens group includes a positive lens and a negative lens,
during focusing from an object at infinity to a closest object, the first lens group remains stationary with respect to an image plane, and the second lens group moves along an optical axis,
assuming that a focal length of the first lens group is f1, and
a focal length of the second lens group is f2,
Conditional Expression (1) is satisfied:

−0.5<f2/f1<0.5  (1),

the second lens group includes a stop, and has lenses adjacent to the object side and the image side of the stop, and
assuming that a radius of curvature of an image side surface of the lens adjacent to the object side of the stop is Rstf, and
a radius of curvature of an object side surface of the lens adjacent to the image side of the stop is Rstr,
Conditional Expression (11) is satisfied:

−1<(Rstr−Rstf)/(Rstr+Rstf)<−0.3  (11).