Patent ID: 8009366

Claim:
A super wide-angle lens comprising, in order from an object side thereof: a first lens with a negative refractive power, being a meniscus lens comprising a convex surface facing the object side; a second lens with a negative refractive power; a third lens with a positive refractive power; and a fourth lens with a positive refractive power, wherein each of the second lens and the fourth lens comprises at least one rotationally-asymmetric surface, wherein the at least one rotationally-asymmetric surface of the second lens changes an aspect ratio in a horizontal direction and a vertical direction, wherein the at least one rotationally-asymmetric surface of the fourth lens corrects a difference between shifts of focusing positions in the horizontal direction and the vertical direction which are caused on the at least one rotationally-asymmetric surface of the second lens, and wherein the super wide-angle lens satisfies the following expressions: 0.5≦| f 2 x/f 4 x|≦ 2, 0.5≦| f 2 y/f 4 y|≦ 2 where f2 x is a paraxial focal length of the second lens in a XZ section, f2 y is a paraxial focal length of the second lens in a YZ section, f4 x is a paraxial focal length of the fourth lens in the XZ section, and f4 y is a paraxial focal length of the fourth lens in the YZ section.