Patent ID: 7920334
Filing Date: 2011-04-05
Classification: G02B,Y10S

Abstract:
1. A zoom lens system comprising, in order from an object along an optical axis: a first lens group having negative refractive power; a second lens group having positive refractive power; and a third lens group having positive refractive power; for zooming from a wide-angle end state to a telephoto end state, each distance between adjacent lens groups is variable , and the following conditional expression being satisfied: where Nnav denotes an average of refractive indices at d-line (wave length λ=587.6 nm) of all negative lenses included in the zoom lens system, ft denotes a focal length of the zoom lens system in the telephoto end state, ωw denotes a half angle of view of the zoom lens system in the wide-angle end state, and TLw denotes a total lens length of the zoom lens system in the wide-angle end state.