Patent ID: 8149514

Claim:
A zoom lens system having a plurality of lens units each composed of at least one lens element and, in order from an object side to an image side, comprising: a first lens unit having negative optical power and composed of two lens elements; a second lens unit having positive optical power; and a third lens unit having positive optical power, wherein in zooming from a wide-angle limit to a telephoto limit during image taking, at least the first lens unit and the second lens unit move along an optical axis, wherein on the image side relative to the second lens unit, an aperture diaphragm is arranged that moves along the optical axis integrally with the second lens unit during zooming, wherein the second lens unit moves in a direction perpendicular to the optical axis, and wherein the following condition (32) is satisfied: 1.00<(1 −m 2W )× m 3W <1.50 (32) here, Z=f T /f W >4.0 and ω W >35 where, m 2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition, m 3W is a lateral magnification of the third lens unit at a wide-angle limit in an infinity in-focus condition, f T is a focal length of the entire system at a telephoto limit, f W is a focal length of the entire system at a wide-angle limit, and ω W is a half value (°) of the maximum view angle at a wide-angle limit.