Patent ID: 7057818

Claim:
A zoom lens comprising, from an object side to an image side: a first lens unit which has a positive optical power; a second lens unit which has a negative optical power; a third lens unit which has a positive optical power; and a fourth lens unit which has a positive optical power; wherein said third lens unit is movable in a direction having a component perpendicular to an optical axis, and during zooming, said first lens unit is moved to be positioned closer to an object at a telephoto end than at a wide angle end, said second lens unit is moved to be positioned closer to an image plane at the telephoto end than at the wide angle end, said third lens unit is moved to be positioned closer to the object at the telephoto end than at the wide angle end, and said fourth lens unit is moved along a convex track toward the object or moved monotonously toward the object side during zooming from the wide angle end to the telephoto end.