Patent ID: 7035023

Claim:
A lens system, comprising in order from an object side to an image side: a aperture stop; a first lens element which has a convex-shaped image side surface and a positive optical power; and a second lens element which has a concave-shaped object side surface and a negative optical power; wherein the following conditions are satisfied: 1.0<( R 12 + R 11 )/( R 12 − R 11 )<−0.1 1.0<( R 22 + R 21 )/( R 22 − R 21 )<3.0 −0.013ν 2 +2.05< N 2 <−0.013ν 2 +2.30 N 2 >1.65 where R 11 and R 12 represent respective radii of curvature of an object side surface and the image side surface of the first lens element, R 21 and R 22 represent the respective radii of curvature of the object side surface and an image side of the second lens element, and N 2 and ν 2 represent a refractive index and an Abbe's number of the material forming the second lens element, respectively.