Patent ID: 7158315

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; and a third lens group having positive refractive power, when a state of the zoom lens system 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, and a distance between the second lens group and the third lens group decreasing, the first lens group being composed of, in order from the object, a 1 A lens group having positive refractive power, and a 1 B lens group having positive refractive power, focusing from infinity to a close-range object being carried out by moving only the 1 B lens group to the object, and the following conditional expressions being satisfied: 1.55 <f 1 /fw< 2.20 −0.55 <f 2/ fw<− 0.30 2.0 <f 1 A/f 1 B< 4.0 0.16 <DAB/fw< 0.30 where fw denotes the focal length of the zoom lens system in the wide-angle end state, f 1 denotes the focal length of the first lens group, f 2 denotes the focal length of the second lens group, f 1 A denotes the focal length of the 1 A lens group, f 1 B denotes the focal length of the 1 B lens group, and DAB denotes the distance between the 1 A lens group and the 1 B lens group when the zoom lens system is focused infinity.