Patent ID: 8054549

Claim:
A zoom lens comprising, in order from an object side to an image side: a first lens unit having a positive refractive power and whose position is fixed; a second lens unit having a negative refractive power and being movable mainly for zooming; a third lens unit having a positive refractive power and whose position is fixed; a fourth lens unit having a positive refractive power and being movable for correction of a focal position and for focusing performed in response to zooming; and a fifth lens unit having a positive refractive power, wherein the fifth lens unit includes, in order from the object side to the image side, a fixed sub-unit having a negative refractive power and whose position is fixed; and a movable sub-unit having a positive refractive power and being movable in a direction substantially perpendicular to an optical axis, wherein an image formed on an image surface is movable in a direction'substantially perpendicular to the optical axis by moving the movable sub-unit of the fifth lens unit in the direction substantially perpendicular to the optical axis, wherein an aperture stop is provided on the object side of the third lens unit, and wherein the third lens unit includes a positive sub-unit having a positive refractive power; and a negative sub-unit having a negative refractive power wherein the third lens unit satisfies the following conditional expressions: 0.4 <|f 31 /f 32|<0.6 0.3 <fw/f 31<0.5 where f 31 denotes a focal length of the positive sub-unit included in the third lens unit, f 32 denotes a focal length of the negative sub-unit included in the third lens unit, and fw denotes an overall focal length of the zoom lens at a wide-angle end.