Patent ID: 7948684
Filing Date: 2011-05-24
Classification: G02B

Abstract:
1. A zoom lens system, in order from the object side to the image side, comprising a first lens unit having negative optical power, a second lens unit having positive optical power and a third lens unit having positive optical power, wherein the first lens unit comprises at least two lens elements, the second lens unit, in order from the object side to the image side, comprises a first cemented lens element fabricated by cementing two lens elements having optical power of mutually different signs and a second cemented lens element fabricated by cementing two lens elements having optical power of mutually different signs, in zooming from a wide-angle limit to a telephoto limit, all of the first lens unit, the second lens unit and the third lens unit move along an optical axis, and the following conditions (1), (I-2) and (6) are satisfied: (here, 3.2<f where, αi n n r r d is an optical axial distance between the image side surface of a most object side lens element in the first lens unit and the object side surface of a most image lens element in the first lens unit, ω f f