Patent ID: 7450318

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 a negative lens and a positive lens; a second lens unit of positive optical power, said second lens unit including two cemented lenses, each of them consisting of two lens elements cemented together; and a third lens unit of positive optical power, said third lens unit consisting of one positive lens, 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, wherein said zoom lens satisfies the following conditions: ndp3<1.5 νdp3>70.0 where ndp3 and νdp3 are a refractive index and Abbe number, respectively, of material of said positive lens in said third lens unit, wherein, during the variation of magnification, said third lens unit moves so that its position is closer to the image side at the telephoto end than at the wide-angle end, and wherein said zoom lens satisfies the following conditions: ndn1>1.70 vdn1>35.0 where ndn1 and νdn1 are a refractive index and Abbe number, respectively, of material of said negative lens included in said first lens unit.