Patent ID: 7623306

Claim:
A zoom lens, comprising, in order from an object side thereof, a front lens group having negative refracting power at a wide-angle end, and a rear lens group having positive refracting power at the wide-angle end, wherein: said front lens group comprises, in order from the object side, a first lens group of positive refracting power and a second lens group of negative refracting power, and said rear lens group comprises, in order from the object side, a third lens group of positive refracting power and a fourth lens group of positive refracting power, and wherein: said zoom lens comprises an aperture stop between a lens surface located in, and nearest to an image side of, the second lens group and a lens surface located in, and nearest to an image side of, the third lens group, upon zooming from the wide-angle end to a telephoto end, a spacing between the first lens group and the second lens group grows wide, a spacing between the second lens group and the third lens group becomes narrow, and a spacing between the third lens group and the fourth lens group changes, and positions of said respective lens groups and said aperture stop are adjusted such that an F-number grows greatest when the aperture stop is open in the course of zooming from the wide-angle end to the telephoto end.