Patent ID: 8531786

Claim:
An optical system for imaging pickup, sequentially arranged from an object side to an image side, comprising: a first lens element with positive refractive power, having a convex image-side surface; a second lens element with refractive power, having a concave image-side surface; a third lens element with refractive power; a fourth lens element with refractive power, having both object-side surface and image-side surface being aspheric; and a fifth lens element with negative refractive power, having a concave image-side surface, both object-side surface and image-side surface being aspheric, and at least one of the object-side surface and the image-side surface having at least one inflection point; wherein, R 1 is a curvature radius of the object-side surface of the first lens element, R 2 is a curvature radius of the image-side surface of the first lens element, f is a focal length of the optical system for imaging pickup, f 1 is a focal length of the first lens element, f 5 is a focal length of the fifth lens element, and the following relations are satisfied: | R 1 |/R 2 <−1.0; 0.5 <f 1 /f< 1.4; and −1.5 <f 5 /f<− 0.3.