Patent ID: 7535659

Claim:
An image pickup lens for forming a subject image on a photo-electric converter of a solid image pickup element, the image pickup lens comprising, in order from an object side thereof: an aperture stop; a first lens having a positive refractive power; a second lens having a negative refractive power; a third lens having a positive refractive power; and a fourth lens having a negative refractive power whose surface facing the object side is a concave surface, the fourth lens comprising at least one optical surface in an aspheric shape, wherein the image pickup lens satisfies 0.40 <f 1/ f< 1.30, and −3.0<( r 7+ r 8)/( r 7− r 8)<0, where f 1 is a focal length of the first lens, f is a focal length of a total system of the image pickup lens, r 7 is a curvature radius of the surface facing the object side on the fourth lens, and r 8 is a curvature radius of the surface facing an image side on the fourth lens.