Patent ID: 8446680
Filing Date: 2013-05-21
Classification: G02B

Abstract:
1. A zoom lens comprising: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; and a fourth lens group having positive refractive power, the first lens group, the second lens group, the third lens group, and the fourth lens group being arranged in order from an object side, wherein, when a positional state of a lens is changed from a wide-angle end to a telephoto end, an interval between the first lens group and the second lens group is increased, an interval between the second lens group and the third lens group is decreased, an interval between the third lens group and the fourth lens group is decreased, an aperture stop is arranged between the second lens group and the third lens group, and the second lens group moves in close range focusing, and the zoom lens satisfies conditional expression (1) and conditional expression (2) below, where, in conditional expression (1) and conditional expression (2), fw12 denotes a synthetic focal length of the first lens group and the second lens group at a wide-angle end, fw denotes a focal length of a whole lens system at the wide-angle end, f1 denotes a focal length of the first lens group, and βt234 denotes synthetic magnification of the second lens group, the third lens group, and the fourth lens group at a telephoto end.