Vario-Objectiv

摘要

1392224 Zoom lens CANON K K 8 May 1972 [8 May 1971 18 Nov 1971] 21451/72 Heading G2J A zoom lens has a positive focusing lens group, a negative lens group movable to vary the focal length and a compensating lens group moving in dependence upon movement of the negative lens group. The arrangement is such that at one end of the negative lens group travel it may be assisted and the compensating lens group moved independently to produce a focusing movement for microphotography. Suitable cam profiles and optical data are given.