Patent ID: 9285573
Filing Date: 2016-03-15
CPC Classification: G02B

Claim Text:
1. A zoom lens system comprising a plurality of lens units each composed of at least one lens element, the zoom lens system, in order from an object end to an image end thereof, comprising: a first lens unit having positive optical power; a second lens unit having negative optical power; a third lens unit having positive optical power; and one or more subsequent lens units, as being in an interval from the image end-ward side of the third lens unit to an image surface defining the image end of the zoom lens system; wherein in zooming from a wide-angle limit to a telephoto limit at a time of image taking, the first lens unit, the second lens unit, and the third lens unit are moved along an optical axis to perform magnification change, wherein two air spaces are included within the third lens unit, wherein the third lens unit consists of three lens elements separated from each other by the two air spaces, wherein the three lens elements constituting the third lens unit are, in order from the object end to the image end, a lens element having positive optical power, a cemented lens element having optical power, and a lens element having optical power, wherein a part of the third lens unit is a third-b lens unit that moves in a direction perpendicular to the optical axis to optically compensate image blur, and wherein the following conditions (2) and (3) are satisfied: where, D D D BF is a shortest optical axial distance that is converted with air, between an apex of a most image side lens surface and the image surface, Ir is a value represented by the following equation: f f ω