Patent ID: 8405916

Claim:
A zoom lens comprising: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; an aperture stop; a third lens unit having a positive refractive power; and a rear group including at least one lens unit, wherein the first lens unit, the second lens unit, the aperture stop, the third lens unit, and the rear group are arranged along an optical axis in order from an object side to an image side, wherein, during zooming from a wide angle end to a telephoto end, the first lens unit moves to the object side, the second lens unit moves to the image side, the aperture stop moves to the object side along a convex path, and the third lens unit moves to the object side, and wherein the following conditions are satisfied: 0.90<|( R 21 b+R 21 a )/( R 21 b−R 21 a )|1.10 7.00 <f 1 /fw< 40.00 0.05 <|f 2 /ft|< 0.10 where R 21 a and R 21 b respectively represent radii of curvature of an object-side lens surface and an image-side lens surface of a lens closest to the object side in the second lens unit, fw and ft respectively represent focal lengths of the entire zoom lens at the wide angle end and the telephoto end, and f 1 and f 2 respectively represent focal lengths of the first lens unit and the second lens unit.