Patent ID: 8488251

Claim:
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 rear lens group including one or more lens units, wherein during zooming, the first lens unit moves along a locus convex towards the image side, and the second lens unit and the third lens unit move such that an interval between the first lens unit and the second lens unit becomes larger at a telephoto end than at a wide-angle end and an interval between the second lens unit and the third lens unit becomes smaller at the telephoto end than at the wide-angle end, wherein the third lens unit includes a positive lens and a negative lens, and wherein, when β2W and β2T are image forming magnifications of the second lens unit at the wide-angle end and at the telephoto end, respectively, β3W and β3T are image forming magnifications of the third lens unit at the wide-angle end and at the telephoto end, respectively, f2 is a focal length of the second lens unit, fT is a focal length of the entire zoom lens at the telephoto end, f3 is a focal length of the third lens unit and fW is a focal length of the entire zoom lens at the wide-angle end, the following conditions are satisfied: 0.10<(β2 T/ β2 W )/(β3 T/ β3 W )<1.65 0.01 <|f 2| /fT< 0.15, 0.5 <f 3/√( fW×fT )≦0.809.