Patent ID: 8437089

Claim:
A zoom lens system comprising, in an order from an object to an image: a first lens group comprising at least one lens and a refraction member for bending an optical axis, and having positive refractive power; a second lens group having negative refractive power; a third lens group; and a fourth lens group, wherein zooming is performed by changing at least one interval between the first through fourth lens groups, and the zoom lens system satisfies expressions below: Fno — w≦ 2.0, 5.5 ≦f T /f W , and 7.5%≦ BFL/OAL, wherein Fno_w denotes an F-number at a wide-mode, f T denotes an overall focal length at a tele-mode, f W denotes an overall focal length at the wide-mode, BFL denotes a back focal length of the zoom lens system, and OAL denotes an overall length of the zoom lens system from a center of a lens surface of a lens closest to the object to an image plane of the image.