Patent ID: 8405906

Claim:
A zoom lens system comprising, in order from an object: a first lens group having positive refractive power; a second lens group; a third lens group; and an N-th lens group disposed nearer to an image than the third lens group, and including, in order from the object, a front lens group having positive refractive power, a middle lens group having negative refractive power, and a rear lens group, and the middle lens group being movable in the direction perpendicular to the optical axis; upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group varying, and a distance between the second lens group and the third lens group varying, upon focusing from an infinity object to a close object, the third lens group moving, and wherein the following conditional expression is satisfied: 1.39 <f 1 /fw≦ 1.838 where f1 denotes a focal length of the first lens group, and fw denotes a focal length of the zoom lens system in the wide-angle end state.