Zoom lens system and photographic device equipped therewith

Abstract

The object of the present invention is to provide a negative-positive, two-group type zoom lens system having a uniquely high zoom ratio of about 3.5, and having relatively small diameter and compactness with small number of lens element. According to one aspect, a zoom lens system includes, in order from an object-side, a first lens group having negative refractive power and a second lens group having positive refractive power. Zooming is carried out by varying the space between the first lens group and the second lens group. The first lens group includes, in order from the object side, a negative lens group G1F composed of one or two negative lens element, and a positive lens group G1R. The following conditional expressions are satisfied: 4.5≦|X2|·ft/fw2≦15  (1) 0.7≦|f1|/(fw·ft)½≦1.3  (2) where X2 denotes the maximum moving amount of the second lens group while zooming, f1 denotes the focal length of the first lens group, fw denotes the focal length of the zoom lens system in a wide-angle end state, and ft denotes the focal length of the zoom lens system in a telephoto end state.

Dependencies are inferred from the claim text.