Patent ID: 9405094
Filing Date: 2016-08-02
CPC Classification: G02B,G03B

Claim Text:
1. A photographing lens comprising, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; and a third lens group having positive refractive power, the photographing lens being configured such that the second lens group moves along an optical axis upon focusing from an object at infinity to an object at a finite distance, the first lens group including, in order from the object, a front lens group and a rear lens group, an air interval between the front lens group and the rear lens group being a longest air interval in the first lens group, the second lens group including, in order from the object, a negative lens and a cemented lens in which a positive lens and a negative lens are cemented in order from the object, and the following conditional expressions being satisfied: where f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, f1an denotes a focal length of a negative lens of which focal length is shortest in the front lens group, ν1bp denotes an Abbe number of a positive lens of which Abbe number is largest in the rear lens group, ν1bn denotes an Abbe number of a negative lens of which Abbe number is smallest in the rear lens group, Rm denotes a radius of curvature of a cemented surface of the cemented lens of the second lens group, ν2p denotes an Abbe number of a positive lens of which Abbe number is smallest in the second lens group, and ν2n denotes an Abbe number of a negative lens of which Abbe number is largest in the second lens group.