Patent ID: 8144403

Claim:
A zoom lens system comprising, in order from an object side: a first lens group having negative refractive power; a second lens group having positive refractive power; and a third lens group having negative refractive power, each distance between adjacent lens groups being variable for zooming from a wide-angle end state to a telephoto end state, the first lens group including, in order from the object side, a front group having negative refractive power, and a rear group having negative refractive power, and the rear group being movable along an optical axis of the zoom lens system for focusing on the object, wherein the following conditional expressions are satisfied; 1.20< f 2 /fw< 2.50 −2.15< f 3 /fw<− 0.80 where f 2 denotes a focal length of the second lens group, f 3 denotes a focal length of the third lens group, and fw denotes a focal length of the zoom lens system in a wide-angle end state.