High-aperture projection lens

摘要

A six-element cinema projection lens is described in front of which an aspherized plane-parallel plate is positioned on the screen side. This arrangement permits the cost-effective design of a cinema projection lens with a relative aperture of 1:1.7 having very good image-forming properties. The high relative aperture increases the light utilization and therefore leads to savings in energy and costs. Furthermore, the projection lens can be used both for cinemascope format and for widescreen format, the differences in brightness being compensated by a variable diaphragm.