ZOOM LENS SYSTEM FOR EXTREME CLOSEUP PHOTOGRAPHY

摘要

1321060 Zoom lens systems CANON K K 24 July 1970 [26 July 1969] 36114/70 Heading G2J A zoom lens system comprises a positive power focusing lens group F, a negative power variator lens group A, a negative power compensator lens C and a positive power relay lens system L, in the order named, front to rear, wherein the relay system comprises a front (L) and a rear (L 2 ) lens group, the front lens group L 1 being movable relative to the rear lens group, the arrangement being such that an object from infinity to a predetermined focal length is focussed by shifting forward the focussing lens system whilst an object closer than this focal length is brought into focus by moving the front element of the relay lens system towards the image plane. The term "lens group" is used to mean one or more lenses. Optical data are given for one example.