Patent ID: 9423596
Filing Date: 2016-08-23
CPC Classification: G02B

Claim Text:
1. A retrofocus-type wide angle lens consisting of: a first lens group having negative refractive power as a whole; a second lens group having positive refractive power as a whole; and a third lens group having positive refractive power as a whole in this order from an object side, wherein the first lens group consists of a positive meniscus lens with its convex surface facing the object side and three negative meniscus lenses with their convex surfaces facing the object side in this order from the object side, wherein the second lens group includes at least two cemented lenses, and a lens closest to an image side in the second lens group is one of the at least two cemented lenses, and wherein the third lens group consists of a 3a-th lens group, which consists of a positive meniscus lens with its convex surface facing the object side and a negative meniscus lens with its convex surface facing the object side, and a 3b-th lens group, which includes at least two cemented lenses and has positive refractive power as a whole, in this order from the object side.