Patent ID: 7864444
Filing Date: 2011-01-04
Classification: G02B

Abstract:
1. A zoom lens, comprising, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a positive refractive power; and a fourth lens unit having a positive refractive power, the zoom lens performing zooming while the first lens unit, the second lens unit, the third lens unit, and the fourth lens unit are moved, wherein during zooming from a wide-angle end to a telephoto end, the first lens unit moves to be located closer to the object side at the telephoto end than at the wide-angle end and the fourth lens unit moves along a locus convex to the object side; and wherein the following conditions are satisfied: where f 2 is a focal length of the second lens unit, fw is a focal length of the zoom lens at the wide-angle end, and β4t is an imaging magnification of the fourth lens unit at the telephoto end.