Patent ID: 7023625

Claim:
A zoom lens, comprising, in order from an object side to an image side: a first lens unit of negative optical power, said first lens unit consisting of, in order from the object side to the image side, a negative lens and a positive lens; a second lens unit of positive optical power; and a third lens unit of positive optical power, focusing being effected by moving said third lens unit, 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 to effect variation of magnification, and wherein, during the variation of magnification from a wide-angle end to a telephoto end with an infinitely distant object focused on, 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 conditions: 0.08 <M 3/ fw <0.4 0.7 <|f 1/ ft |<1.0 1.45 <f 3/ ft <2.0 0.63 <f 2/ ft <0.8 where M3 is an amount of movement of said third lens unit toward the image side during the variation of magnification from the wide-angle end to the telephoto end with an infinitely distant object focused on, fw and ft are focal lengths of said zoom lens at the wide-angle end and the telephoto end, respectively, and f1, f2 and f3 are focal lengths of said first lens unit, said second lens unit and said third lens unit, respectively.