Patent ID: 7126760

Claim:
A zoom lens comprising, in the following order from an object side: a first lens unit that has a positive refractive power as a whole and that is fixed with respect to an image plane; a second lens unit that has a negative refractive power as a whole and that causes a variable power action when moved along an optical axis; an aperture stop that is fixed with respect to the image plane; a third lens unit that has a positive refractive power as a whole and that is fixed with respect to the optical axis direction when zooming and when focusing; a fourth lens unit that has a negative refractive power as a whole and that is fixed with respect to the image plane; and a fifth lens unit that has a positive refractive power as a whole and that is movable along the optical axis such that the image plane, which is displaced by a movement of the second lens unit along the optical axis and by a movement of the object, is maintained at a constant position from a reference plane, wherein the entire third lens unit is movable in a direction perpendicular to the optical axis in order to stabilize an image, the fifth lens unit is moved to the object side as the object point approaches, and the following conditional expressions (1) and (2) are satisfied 0.035 <|βw·βt/Z|< 0.075 (1) βw: magnification ratio of the second lens unit at the wide-angle end βt: magnification ratio of the second lens unit at the telephoto end Z: zoom ratio 0<( d 45 T−d 45 N )/( IM·Z )<0.04 (2) d 45 T: interval between the fourth lens unit and the fifth lens unit in a telephoto position d 45 N: interval between the fourth lens unit and the fifth lens unit when the second lens unit is in an equal magnification position IM: image size Z: zoom ratio.