Patent ID: 8531778

Claim:
A zoom lens comprising: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a positive refractive power, wherein the first lens group, the second lens group, the third lens group, and the fourth lens group are sequentially arranged from an object side to an image side, wherein zooming is performed by moving the second lens group in an optical axis direction and focusing is performed by moving the fourth lens group in the optical axis direction, and wherein the zoom lens satisfies the following Equations: 1.4 <|f 2 |/f W <2.0, 0.3 <f 1 /f T <0.6, where a combined focal length of the first lens group is f 1 , a combined focal length of the second lens group is f 2 , a focal length of the zoom lens at a wide angle end is f w , and a focal length of the zoom lens at a telephoto end is f T .