Patent ID: 7369324

Claim:
A zoom lens system comprising, in order from an object: a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group having negative refractive power; and a fourth lens group having positive refractive power; when a state of lens group positions varies from a wide-angle end state to a telephoto end state, the second lens group, the third lens group and the fourth lens group being moved to the object such that a distance between the first lens group and the second lens group decreases, a distance between the second lens group and the third lens group increases, and a distance between the third lens group and the fourth lens group decreases, the first lens group being composed of at least one positive lens and at least one negative lens, the second lens group being composed of at least one positive lens and at least one negative lens, the third lens group being composed of a single lens, the fourth lens group being composed of at least one positive lens and at least one negative lens, and the following conditional expressions being satisfied: 3.00<f3/f4<−0.60 1.0<mf4/fw<3.00 where f 3 denotes a focal length of the third lens group, f 4 denotes a focal length of the fourth lens group, mv 4 denotes a moving amount of the fourth lens group upon zooming from the wide-angle end state to the telephoto end state, and fw denotes a focal length of the zoom lens system in the wide-angle end state.