Patent ID: 7365913

Claim:
A zoom lens system comprising, in order from an object side to an image side: a 1st lens unit with positive optical power, the first lens unit consisting of one lens element; a 2nd lens unit with negative optical power; a 3rd lens unit with positive optical power; and a 4th lens unit with positive optical power, wherein the 1st lens unit and the 3rd lens unit move so as to be located closer to the object side at the telephoto end than the wide-angle end, and the following conditions are satisfied: 3.09 ≦|M 1 /M 2|<7.0 2.0<| M 3 /M 2|<8.0 where M 1 , M 2 and M 3 are the maximum amounts of movement of the 1st lens unit, 2nd lens unit and 3rd lens unit in the direction of the optical axis during zooming from the wide-angle end to the telephoto end, respectively.