Patent ID: 7532409

Claim:
A zoom lens system, in order from an object side to an image side, comprising: a first lens unit having negative optical power, moving along an optical axis during zooming, the first lens unit, in order from the object side to the image side, having a negative lens element with a convex surface facing the object side and a positive lens element with a convex surface facing the object side; a second lens unit having positive optical power, moving along an optical axis during zooming, the second lens unit having two sets of positive cemented lens elements; and a third lens unit having positive optical power, moving along an optical axis during zooming, wherein the following conditions (1), (2) and (3) are satisfied: n12>1.88 (1) ν12<26 (2) 3.0<f 3 /f W <5.5 (3) (where, ω w >30) in which, n 12 is a refractive index of the positive lens element of the first lens unit, ν 12 is an Abbe number of the positive lens element of the first lens unit, f 3 is a composite focal length of the third lens unit, f W is a focal length of the entire zoom lens system at a wide-angle limit, and ω W is a half view angle at a wide-angle limit.