ZOOM LENS SYSTEM, IMAGING DEVICE, AND CAMERA

摘要

A zoom lens system comprises, in order from the object side to the image side, a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, and a fourth lens group having positive power. In zooming, all the first to fourth lens groups move along the optical axis and satisfy conditions (1): 04 .fW .tan?)/LW3/f4=0.97 (16T/fW, ?>35), where?is a half angle of view at the wide-angle end, LW is the total length measured along the optical axis at the wide-angle end of the entire system, f3 is the focal length of the third lens group, f4 is the focal length of the fourth lens group, fT is the focal length of the entire system at the telephoto end, and fW is the focal length of the entire system at the wide-angle end). The zoom lens system is small in size and has a wide angle of view at the wide-angle end, an extremely high zooming ratio, and high performance.