Patent ID: 8654450
Filing Date: 2014-02-18
Classification: G02B

Abstract:
1. A zoom lens system comprising: a first lens group comprising one or more lenses, and an optical member for changing a path of light, and having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a positive refractive power, wherein the first lens group, the second lens group, the third lens group, and the fourth lens group are sequentially arranged from an object side to an image side, wherein zooming is performed by varying air gaps between the first through fourth lens groups, and wherein the zoom lens system satisfies the following expressions: where f w indicates an overall focal length at a wide angle end, f T indicates an overall focal length at a telephoto end, f I indicates a focal length of the first lens group, and f II indicates a focal length of the second lens group, wherein the fourth lens group performs focusing, and wherein an F-number at the wide angle end is equal to or less than 1.8.