Patent ID: 8520322

Claim:
A lens system comprising, in order from an object side to an image side: a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a second lens element with refractive power; a third lens element with positive refractive power having a convex image-side surface; a fourth lens element with negative refractive power having a concave object-side surface, wherein the fourth lens element is connected to the third lens element; and a fifth lens element with negative refractive power; wherein the lens system has a total of five lens elements with refractive power, a focal length of the first lens element is f1, a focal length of the fifth lens element is f5, a focal length of the lens system is f, a focal length of the third lens element is f3, and they satisfy the following relationships: 0 <f 5 /f 1<1.0; and 3.39 ≦f/f 3<4.5.