Patent ID: 7446956

Claim:
A zoom lens system comprising, in order from an object along an optical axis: a first lens group having negative refractive power; a second lens group having positive refractive power; and a third lens group having positive refractive power; upon zooming from a wide-angle end state to a telephoto end state, at least the first lens group and the second lens group being moved such that a distance between the first lens group and the second lens group decreases, and a distance between the second lens group and the third lens group increases; the first lens group consisting of, in order from the object along the optical axis, a negative meniscus lens having a convex surface facing the object, and a positive lens; at least one surface of the negative meniscus lens being an aspherical surface; the second lens group consisting of, in order from the object along the optical axis, a first positive lens, a second positive lens, a negative lens, and a third positive lens; at least one surface of the first positive lens being an aspherical surface; the third lens group consisting of a single positive lens; and the following conditional expressions being satisfied: 0.50 <ft×Y max/{ fw ×( fw+ft )}<0.70 1.14 <|f 1|/( fw×ft ) 1/2 <1.35 where Ymax denotes the maximum image height of the zoom lens system, fw denotes a focal length of the zoom lens system in the wideangle end state, ft denotes a focal length of the zoom lens system in the telephoto end state, and f 1 denotes a focal length of the first lens group.