Patent ID: 7113348
Filing Date: 2006-09-26
Classification: G02B

Abstract:
1. A zoom lens, comprising, in order from an object side to an image side: a first lens unit of negative optical power; a second lens unit of positive optical power; and a third lens unit of positive optical power, wherein a separation between said first lens unit and said second lens unit and a separation between said second lens unit and said third lens unit are varied during zooming, and wherein, during zooming from a wide-angle end to a telephoto end, said first lens unit moves with a locus convex toward the image side and said third lens unit moves monotonically toward the image side or moves with a locus convex toward the image side, and said zoom lens satisfies the following condition: where M 3 is an amount of movement of said third lens unit toward the image side during zooming from the wide-angle end to the telephoto end with an infinitely distant object focused on, and fw is a focal length of said zoom lens at the wide-angle end, wherein said second lens unit comprises a cemented lens consisting of two lens elements cemented together, wherein the number of lens elements which comprise said second lens unit is three or four, and wherein said third lens unit moves toward the object side during focusing from an infinitely distant object to a closest object.