Patent ID: 7331693

Claim:
A zoom lens comprising, in order from an object side to an image side: a first lens unit with a negative refractive power; a second lens unit with a positive refractive power; and; a third lens unit with a negative refractive power, wherein the second lens unit and the third lens unit move during zooming, wherein the first lens unit includes a negative biconcave lens element, and wherein the following conditions are satisfied: −1.4<φ1 /φw<− 1.0 0.9<φ2/ φw< 1.4 −1.3<φ3/ φw<− 0.9 where φ1 is a refractive power of the first lens unit, φ2 is a refractive power of the second lens unit, φ3 is a refractive power of the third lens unit, and φw is a refractive power of the entire system at a wide-angle end.