| 摘要 |
PURPOSE:To obtain a miniature and high variable power lens system by providing first and second zoom parts before and behind a diaphragm, and providing an element whose radius of curvature can be varied, on the second zoom part. CONSTITUTION:A zoom lens system is constituted of a lens group F1 fixed at the time of zooming, lens groups F2, F3 for forming the first zoom part in front of an iris diaphragm R15 and used as a variable power system and a correction system by moving in the optical axis direction, a telephoto type constituting lens group B1 for forming the second zoom part in the rear of the diaphragm R15 and miniaturizing the overall length and the aperture,a correction system lens group B2 for moving on the optical axis, and a variable power system lens group B3. In such a state, zooming extending from a wide angle end to an intermediate distance range is executed by the first zoom part, the variable power is executed by an element V1 which is provided on the fixed lens group B3 and whose radius of curvature can be varied, and zooming extending from the intermediate point to the telephoto end is executed by the second zoom part. In such a way, the lens constitution is simplified, and a miniature and high variable power zoom lens system is obtained.
|
