Patent ID: 8472123

Claim:
A zoom lens system comprising a plurality of lens units and an aperture diaphragm arranged in the lens units, wherein the plurality of lens units include: a focusing lens unit that is arranged on an object side relative to the aperture diaphragm and that moves in a direction along the optical axis at the time of focusing; and a negative lens unit that is arranged on the object side relative to the focusing lens unit, wherein the focusing lens unit consists of one lens unit, and the following conditions are satisfied: 0.10 <|f F /f T |<1.8 (2) 1.00 <|f F /f NW |<5.00 (3) here, f T /f w >3.0 where, f F is a focal length of the focusing lens unit, f NW is a composite focal length of the focusing lens unit and the negative lens unit in an infinity in-focus condition at a wide-angle limit when the focusing lens unit has negative optical power, or the focal length of the negative lens unit when the focusing lens unit has positive optical power, f T is a focal length of the entire system at a telephoto limit, and f W is focal length of the entire system at a wide-angle limit.