Patent ID: 7652826

Claim:
A three-unit zoom lens system comprising in order from an object side thereof: a first lens unit having a negative refracting power; a second lens unit having a positive refracting power; a third lens unit having a negative refracting power; and an aperture stop which is at an image side of the first lens unit, and at the object side of a lens surface nearest to the image side of the second lens unit, and which moves integrally with the second lens unit, wherein at a time of zooming from a wide angle end to a telephoto end, a distance between the first lens unit and the second lens unit is narrowed, and a distance between the second lens unit and the third lens unit changes, and at the time of zooming from the wide angle end to the telephoto end, the first lens unit, after moving toward the image side at first, moves toward the object side, the second lens unit moves toward the object side at the time of zooming from the wide angle end to the telephoto end, and the third lens unit moves to be positioned at the object side at the telephoto end, with respect to the wide angle end, and the three-unit zoom lens system satisfies the following conditional expressions f t /f w >3.8 (1) d G3 /f w <1.0 (2) where, f w denotes a focal length at the wide angle end, of the three-unit zoom lens system, f t denotes a focal length at the telephoto end, of the three-unit zoom lens system, and d G3 denotes an optical axial thickness of the third lens unit.