Patent ID: 9739976
Date: 2017-08-22
CPC Classifications: G02B

Claim:
1. An imaging lens consisting of, in order from the object side to the image side: a first lens group having a positive refractive power; a stop; a second lens group having a positive refractive power; and a third lens group having a negative refractive power; the first lens group consisting of, in order from the object side to the image side, one or more positive single lenses, one or more cemented lenses, one or more negative single lenses, and a negative meniscus single lens having a concave surface toward the image side; the second lens group consisting of, in order from the object side to the image side, a cemented lens formed by cementing a negative lens and a biconvex lens, provided in this order from the object side to the image side, together, and a biconvex lens; the third lens group consisting of, in order from the object side to the image side, a negative meniscus lens having a concave surface toward the image side, one or more negative lenses, and one or more positive lenses; and focusing operations to change focus from an object at infinity to an object at a close distance being performed by moving the first lens group, the stop, and the second lens group toward the object side while the third lens group is fixed with respect to an imaging surface.