Patent ID: 7280286

Claim:
A zoom lens system comprising, in order from an object: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having negative refractive power; and a fifth 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, a distance between the first lens group and the second lens group increasing, a distance between the second lens group and the third lens group decreasing, a distance between the third lens group and the fourth lens group increasing, a distance between the fourth lens group and the fifth lens group decreasing; and the following conditional expression being satisfied: −0.37 <f 12 W/X 1<−0.20 where f 12 W denotes a combined focal length of the first lens group and the second lens group in the wide-angle end state upon focusing on infinity, and X 1 denotes a moving amount of the first lens group upon zooming from the wide-angle end state to the telephoto end state.