| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens system that is compact in a lens entire system, becomes a thin-type when housed and has excellent optical performance, while attaining a wide-angle and a high variable magnification.SOLUTION: The zoom lens system is composed of, in oder from an object side: a positive first lens group G1; a negative second lens group G2; a positive third lens group G3; and a positive fourth lens group G4. When a magnification is varied from a wide-angle end to a telephoto end, all lens groups from the first lens group to the fourth lens group move, and the zoom lens system satisfies the following conditional expressions (1) and (2). (1) 0.75<ft/f1<1.17 and (2) 1.7<m2t/m2w<3.2, where ft denotes a focal length of an entire system at a long focal length end, f1 denotes a focal length of the first lens group, m2t denotes a lateral magnification of the second lens group when focused on an object at infinity at the long focal length end, and m2w denotes a lateral magnification of the second lens group when focused on the object at the infinity at a short focal length end. |
