Patent ID: 9354430
Filing Date: 2016-05-31
CPC Classification: G02B,G03B

Claim Text:
1. A zoom lens comprising, in order from an object side: a front lens group having negative refractive power; and a rear lens group having positive refractive power, the rear lens group including, in order from the object side, a positive lens La, a negative lens Lb having a concave surface facing the object side, a cemented positive lens Lc constructed by a negative lens cemented with a positive lens, and a cemented lens Ld constructed by a positive lens cemented with a negative lens, the rear lens group further including a focusing lens group Gf having positive refractive power, disposed to the object side of the positive lens La for carrying out focusing from an infinitely distant object to a close object by moving from the object side to an image side, a distance between the front lens group and the rear lens group being varied thereby carrying out zooming from a wide-angle end state to a telephoto end state, the following conditional expression being satisfied: where Fw denotes a focal length of the zoom lens in a wide-angle end state upon focusing on an infinitely distant object, and Fb denotes a focal length of the negative lens Lb in the rear lens group.