Patent ID: 8587880

Claim:
A small-size wide angle lens substantially consisting of: a first lens group having positive refractive power; a stop; a second lens group having positive refractive power; and a third lens group having negative refractive power, which are arranged in this order from the object side of the small-size wide angle lens, wherein the first lens group includes a negative lens and a positive lens, and wherein the second lens group includes a negative lens and a positive lens, and wherein the third lens group includes a negative lens and a positive lens, and wherein at least one of the second lens group and the third lens group includes an aspheric surface, and wherein the following formulas (1) through (3) are satisfied: 1< f/Y< 2 (1); 0.7<( SS +BF)/( DD +BF)<0.95 (2); and 3.4< Fno ×( DD +BF)/ Y< 8 (3), where f is the focal length of the entire system of the small-size wide angle lens, Y is a maximum image height at an image plane, SS is a distance on an optical axis from the stop to a most-image-side surface in the small-size wide angle lens, BF is a back focus in air, DD is a distance on the optical axis from a most-object-side surface in the small-size wide angle lens to the most-image-side surface in the small-size wide angle lens, and Fno is a maximum aperture.