Patent ID: 9389398
Filing Date: 2016-07-12
CPC Classification: G02B

Claim Text:
1. An imaging lens, substantially consisting of in the recited order from an object side: a negative first lens group consisting of only a first lens, which is a single biconcave lens; and a positive second lens group consisting of, in the recited order from the object side, a cemented lens that is formed by bonding a second lens, which is a positive lens, and a third lens, which is a negative lens, in this order from the object side and that has a positive refractive power as a whole; an aperture stop; a fourth lens, which is a positive lens; and a fifth lens which is a negative lens, the imaging lens having no lens elements other than the lens elements in the negative first lens group and the positive second lens group, wherein the imaging lens is a fixed focal length lens system and satisfies conditional expressions (1a) and (2a) given below at the same time: where: f23: the combined focal length of the second lens and the third lens; f45: the combined focal length of the fourth lens and the fifth lens; and f: the focal length of the entire lens system.