Patent ID: 8441745

Claim:
An optical lens assembly for image taking comprising, in order from an object side to an image side: a front lens group further comprising a first lens element with negative refractive power having a concave object-side surface; a stop; and a rear lens group comprising, in order from the object side to the image side: a second lens element with positive refractive power having a concave object-side surface and a convex image-side surface; a third lens element with positive refractive power; and a fourth lens element with negative refractive power having a concave object-side surface and a convex image-side surface, and at least one of the object side-surface and the image-side surface of the fourth lens element being aspheric; the optical lens assembly for image taking satisfies the following conditions: −3.0 <R 1 /R 2 <0.9; 1.2< f/f 3 <2.0 wherein, R 1 is a radius of curvature of the object-side surface of the first lens element, R 2 is a radius of curvature of the image-side surface of the first lens element, f is a focal length of the optical lens assembly for image taking, and f 3 is a focal length of the third lens element.