Patent ID: 7742242

Claim:
A lens system comprising, in order from the object side: a positive refractive power first lens; a positive refractive power second lens; and a negative refractive power third lens, wherein the lens system satisfies the following conditions: (| G 1 R 2| −G 1 R 1)/(| G 1 R 2 |+G 1 R 1)<0.5; (1) 0.2< G 1 R 1 /F< 0.6; (2) 1< F 1 /F< 1.5; (3) 1< F/G 3 R 2<7; (4) and 0.5< h/D 3<0.7, (5) wherein, G 1 R 1 is the radius of curvature of a surface of the first lens facing the object side of the lens system, G 1 R 2 is the radius of curvature of the surface of the first lens facing the image side of the lens system, F is a focal length of the lens system, F 1 is a focal length of the first lens, G 3 R 2 is the radius of curvature of a surface of the third lens facing the image side of the lens system, D 3 is the effective lens radius of the third lens, and h is the distance from the optical axis to a point on the image-side surface of the third lens farthest from the first lens.