Patent ID: 8837055

Claim:
A zoom lens system comprising: a plurality of lens units, each lens unit comprising at least one lens element; wherein the plurality of lens units include a plurality of movable lens units which individually move along an optical axis at a time of zooming from a wide-angle limit to a telephoto limit during image taking, a lens unit located closest to an object side is fixed relative to an image surface at the time of zooming, at least two of the movable lens units are focusing lens units which move along the optical axis at a time of focusing from an infinity in-focus condition to a close-object in-focus condition in at least one zooming position from a wide-angle limit to a telephoto limit, an aperture diaphragm, either located between lens elements constituting a lens unit that is located having two air spaces toward an image side from the lens unit located closest to the object side, or located on an image side relative to the lens unit that is located having two air spaces toward the image side from the lens unit located closest to the object side, one focusing lens unit among the focusing lens units has negative optical power, and is located on an image side relative to the aperture diaphragm, a lens unit located closest to the image side does not move along the optical axis at the time of focusing, and the following condition (1) is satisfied: 0.1 <T 1 / f W <1.5 (1) where T 1 is an axial thickness of the lens unit located closest to the object side, and f W is a focal length of the zoom lens system at a wide-angle limit.