Patent ID: 7545580

Claim:
A zoom lens comprising, in order from an object side to an image side: a first lens unit having positive refractive power; a second lens unit having negative refractive power; a third lens unit having positive refractive power; a fourth lens unit having positive refractive power, wherein the zoom lens performs zooming by moving each of the lens units; the first lens unit and the third lens unit are positioned closer to the object at a telephoto end than at a wide-angle end; and the zoom lens satisfies the following conditions: 0.3<| m 1/ m 2|<1.5 0.3<| m 3/ m 2|<0.8 where m 1 , m 2 , and m 3 are the amounts of movement of the first lens unit, the second lens unit, and the third lens unit, respectively, along an optical axis during zooming from the wide-angle end to the telephoto end, wherein the third lens unit includes, in order from the object side to the image side, a positive lens element, a positive lens element, and a negative lens element.