Patent ID: 6735020
Filing Date: 2004-05-11
Classification: G02B

Abstract:
A zoom lens system comprising, in order from an object side to an image side;a first lens unit having negative optical power, the first lens unit including at least one positive lens element and at least one negative lens element; a second lens unit having positive optical power, the second lens unit including at least one positive lens element and at least one negative lens element, wherein the lens element of the second lens unit disposed on the closest-to-object side is a plastic lens element having positive optical power; and a third lens unit having positive optical power; wherein each lens unit moves in the direction of an optical axis for zooming, and further the following condition is satisfied: 0.5<f2s/f2<0.9 where f2s is a focal length of said plastic lens element of positive optical power, and f2 is a focal length of said second lens unit.