Patent ID: 7800831

Claim:
A zoom lens system, in order from the object side to the image side, comprising a first lens unit having negative optical power, a second lens unit having positive optical power and a third lens unit having positive optical power, wherein the first lens unit is composed of two lens elements, in order from the object side to the image side, comprising a first lens element that has a concave surface at least on the image side and that has negative optical power and a second lens element that has a convex surface at least on the object side and that has positive optical power, the second lens unit, in order from the object side to the image side, comprises a first cemented lens element fabricated by cementing a third lens element and a fourth lens element having optical power of mutually different signs and a second cemented lens element fabricated by cementing a fifth lens element and a sixth lens element having optical power of mutually different signs, in zooming from a wide-angle limit to a telephoto limit, all of the first lens unit, the second lens unit and the third lens unit move along an optical axis, and the following condition (I-2) is satisfied: n 11 ≧1.9 (I-2) (here, 3.2<f T /f W and (ω W >35) where, n 11 is a refractive index of the first lens element to the d-line, ω W is a half view angle (°) at a wide-angle limit, f T is a focal length of the entire system at a telephoto limit, and f W is a focal length of the entire system at a wide-angle limit.