发明名称 Lens system of variable magnification range and having a supplementary lens unit
摘要 A zoom lens comprising, from front to rear, a first lens unit of negative refractive power and a second lens unit of positive refractive power, in which either by moving the second lens unit forward to vary the magnification from the wide angle side to the telephoto side, a supplementary lens system is attached on the image side of the second lens unit in the middle of the course of varying the magnification or in the zooming position of the telephoto end side, or by moving at least the second lens unit forward, the supplementary lens system is attached, to change the focal length of the entire system.
申请公布号 US4807982(A) 申请公布日期 1989.02.28
申请号 US19870042024 申请日期 1987.04.24
申请人 CANON KABUSHIKI KAISHA 发明人 TSUJI, SADAHIKO
分类号 G02B15/177;(IPC1-7):G02B15/02 主分类号 G02B15/177
代理机构 代理人
主权项
地址