Patent ID: 8400553

Claim:
An image pickup lens comprising, in order from an object side to an image surface side: a first lens that is a biconvex lens having positive power; a second lens that has negative power and whose lens surface facing the image surface side is concave; a third lens that is a meniscus lens having positive power and whose lens surface facing the image surface side is convex; and a fourth lens that has negative power, whose lens surfaces are both aspherical and whose lens surface facing the image surface side is concave near an optical axis, wherein the image pickup lens satisfies the following conditional expressions (1) to (3), where f is a focal length of an overall optical system, Y′ is a maximum image height, TL is an overall length of the optical system, R11 is a radius of curvature of a lens surface of the first lens facing the object side, and R12 is a radius of curvature of a lens surface of the first lens facing the image surface side: 1.20 <f/Y′ <1.35 (1) TL/Y′< 2.0 (2) 1.05 <|R 11 /R 12|<3.0 (3).