| 摘要 |
PURPOSE:To obtain a compact zoom lens which extends to a smaller extent and is satisfactorily corrected of aberrations by consisting the same, successively from an object side, of a positive lens group moving in the stage of zooming, likewise a variable power lens group and a stationary image-forming lens group, and satisfying prescribed conditions. CONSTITUTION:A lens system consisting, successively from an object side, of a positive lens group moving in the stage of zooming, a variable power lens group having likewise at least one movable lens group, and a stationary image-forming lens group is so formed as to satisfy 0.5<fF/fR<6. Here, fR is the focal length of the image-forming lens group, fF is the focal length of a part of the positive lens group F in the image-forming lens group to be moved in the stage of focusing. If said conditions are satisfied, focusing is made easy with a less number of lenses, whereby the overall length of the lens is reduced and aberrations are satisfactorily corrected. |
