Patent ID: 8665532
Filing Date: 2014-03-04
Classification: G02B

Abstract:
1. A zoom lens system, in order from an object side to an image side, 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 a fourth lens unit having positive optical power, wherein the first lens unit is composed of a cemented lens element obtained by cementing one object side negative lens element and one image side positive lens element, wherein the fourth lens unit is composed of one lens element, wherein in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit, and the fourth lens unit are individually moved along an optical axis so that air spaces between the respective lens units vary, thereby performing magnification change, and wherein the following conditions (1) and (a) are satisfied: where, vd f f