Patent ID: 7636207

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, the third lens being a meniscus-shaped lens with a convex surface facing the object side of the lens system, wherein the lens system satisfies the following conditions: 0.25 <R 1 F/F< 0.5 (1); R2F<R2R<0 (2); 0<R1F<R1R (3); R3F>O (4); 0.7<F1/F<1.5 (5); and 45<v2<60, wherein, R 1 R is the radius of curvature of a surface of the first lens facing the image side of the lens system, R 1 F is the radius of curvature of the surface of the first lens facing the object side of the lens system, R 2 R is the radius of curvature of a surface of the second lens facing the image side of the lens system, R 2 F is the radius of curvature of the surface of the second lens facing the object side of the lens system, R 3 F is the radius of curvature of the surface of the third lens facing the object side of the lens system, F1 is a focal length of the first lens, F the focal length of the lens system, and v 2 is the Abbe constant of the second lens.