发明名称 Zoom lens system
摘要 A zoom lens system comprising a first lens group of a negative refractive power, a second lens group of a positive refractive power located on the image side of the first lens group with a first variable air space, a third lens group of a negative refractive power located on the image side of the second lens group with a second variable air space and a fourth lens group or unit of a positive refractive power located on the image side of the third lens group with a third variable air space is provided. The first and third variable air spaces are reduced and the second variable air space is increased in accordance with the increase of the focal length of the whole lens system during the zooming. The absolute value of the focal length of the third lens group is greater than that of the second lens group.
申请公布号 US4516839(A) 申请公布日期 1985.05.14
申请号 US19820393492 申请日期 1982.06.29
申请人 MINOLTA CAMERA KABUSHIKI KAISHA 发明人 TOKUMARU, HISASHI
分类号 G02B15/20;G02B15/177;(IPC1-7):G02B9/64;G02B15/18 主分类号 G02B15/20
代理机构 代理人
主权项
地址