Patent ID: 7075733

Claim:
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 consisting of a first lens element having negative optical power and a second lens element having positive optical power, the second lens element being an aspherical lens; a second lens unit having positive optical power; and a third lens unit having positive optical power, wherein during zooming from a wide-angle end to a telephoto end, an interval between the first lens unit and the second lens unit reduces and an interval between the second lens unit and the third lens unit changes, and wherein the following conditions are satisfied, 0.1< r 2/ r 3<0.35, âˆ’2.0<( r 3+ r 4)/( r 3âˆ’ r 4)<0.5, 0.38< d 2/ d 1 t< 0.55, where r 2 represents a curvature radius of an image side surface of the first lens element, r 3 represents a curvature radius of an object side surface of the second lens element, r 4 represents a curvature radius of an image side surface of the second lens element, d 2 represents an axial interval between the first lens element and the second lens element, and d 1 t represents an optical axial thickness of the first lens unit.