Patent ID: 7675689
Filing Date: 2010-03-09
Classification: G02B

Abstract:
1. A zoom lens system, in order from an object side to an image side, comprising: a first lens unit having negative optical power and 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 and a positive lens element with a convex surface facing the object side; a second lens unit having positive optical power and moving along an optical axis during zooming; and a third lens unit having positive optical power and moving along an optical axis during zooming, wherein the second lens unit has four lens elements, the negative lens element of the first lens unit has an aspheric surface, and the following condition (1) is satisfied: where, n12 is a refractive index of the positive lens element of the first lens unit, and 2ω