Patent ID: 8004585
Filing Date: 2011-08-23
Classification: G02B

Abstract:
1. 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 positive lens unit that is arranged on an object side relative to the aperture diaphragm and that has positive optical power; a negative lens unit that is arranged on an image side relative to the positive lens unit and on an object side relative to the aperture diaphragm and provided with negative optical power having an absolute value greatest in the entire system and that moves in a direction along an optical axis at the time of zooming; and a focusing lens unit that is arranged in an optical path between the negative lens unit and the aperture diaphragm and that moves in a direction along the optical axis at the time of focusing such that an interval relative to the negative lens unit should vary, and wherein the following condition is satisfied: (here, f where, β β f f