Patent ID: 7599124
Filing Date: 2009-10-06
Classification: G02B

Abstract:
1. In a large-aperture-ratio inner-focusing telephoto zoom lens that has four groups of lens pieces, namely, the 1st lens group of positive refractive power, the 2nd lens group of negative refractive power, the 3rd lens group of positive refractive power, and, the 4th lens group of positive refractive power arranged in series on the basis of “closer to a subject first,” and that has the 2nd and 3rd lens groups moved along the optical axis to vary a magnification power, the 1st lens group includes the leading subgroup of lens pieces or foremost lens subgroup G the rear lens subgroup G where f 1 is a focal length of the 1st lens group, and fw is a focal length of the telephoto zoom lens in the wide-angle view mode.