Patent ID: 7126759

Claim:
A zoom lens system comprising at least, in order from an object: a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group; and a fourth lens group, when the state of lens group positions varies from a wide-angle end state to a telephoto end state; each lens group being moved such that; a distance between the first lens group and the second lens group varies; the first lens group comprising at least one negative lens element; wherein a glass material constructing at least one of the negative lens element among the at least one negative lens element in the first lens group satisfies all of the following three conditional expressions: 67.0<ν 1.40<N 0< N+ 0.0032×ν−1.734 where ν denotes Abbe number of the glass material at d-line (λ=587.6 nm), and N denotes refractive index of the glass material at d-line (λ=587.6 nm).