Patent ID: 7952812

Claim:
A zoom lens system comprising a plurality of lens units each consisting of at least one lens element, wherein the zoom lens system, in order from the object side to the image side, comprises at least; a first lens unit having positive optical power; a second lens unit having negative optical power; a third lens unit having positive optical power; and a fourth lens unit having positive optical power, wherein in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit move in an optical axis direction, and wherein the second lens unit, in order from the object side to the image side, comprises at least: a most object side lens element 2 a having negative optical power; a lens element 2 b having negative optical power; and a lens element 2 c having positive optical power, and wherein the two surfaces of the most object side lens element 2 a are aspheric.