Sound image viewfinder for camera - uses multiple lenses of plastics materials to compensate for optical aberrations

摘要

At least two lens elements are cemented together, and at least one is of synthetic/plastics material. Pref. at least one is transparent and one opaque for ultraviolet light. An adjustable lens group is included for zooming and focussing. USE/ADVANTAGE - Video cameras and between-the-lens shutter cameras (non SLRs). Cheap and compact with optical axes of lens elements precision aligned.