Patent ID: 11899278
Assignee: SONY GROUP CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 4:
5. An imaging lens comprising:
a first lens group always fixed and having positive refractive power, and a first focus lens group that moves in an optical axis direction at a time of focusing from an object at infinity to an object at close range, in order from an object side to an image side;
a last lens group always fixed and having negative refractive power, and a second focus lens group that moves in an optical axis direction at a time of focusing from an object at infinity to an object at close range, in order from the image side to the object side,
at least one of the first focus lens group or the second focus lens group having negative refractive power; and
an aperture stop disposed between the first focus lens group and the second focus lens group,
the imaging lens satisfying Conditional Expression (1) below:

0.4<f/ff<1.0  (1)

where
f: a focal length of a whole system
ff: a combined focal length of the first lens group and the first focus lens group, wherein
the first lens group includes at least one meniscus lens having negative refractive power, and
the first lens group satisfies Conditional Expression (4) below:

1.0<(r1+r2)/(r1−r2)<10  (4)

where
r1: an object-side surface of a meniscus lens having negative refractive power located closest to the object side in the first lens group
r2: an image-side surface of the meniscus lens having the negative refractive power located closest to the object side in the first lens group.