Photographing lens system with focus informing means

Claim 1

A photographic lens system for a photographic camera comprising, a photographic lens, a lens system housing which for holding said photographic lens, including a mounting means for detachable mounting on a camera body, said lens system housing comprising at least a means for adjusting focus by movement thereof and a cooperating handle, by which focussing is made, an electrically operated distance measuring means, provided in said lens system housing, for measuring distance to a principal object and generating a measured distance signal corresponding to said measured distance, an electrically operated adjustment indication means, provided in said lens system housing, for generating an adjusted distance signal corresponding to the distance of said principal object at which the lens is adjusted, an electrically operated comparator circuit which compares said measured distance signal and said lens adjustment signal, and generates a focus information signal, at least one electrically operated informing means responsive to said focus information signal, for generating discernable indicia of said focussing, and a switch cooperating with a hand on said lens system housing for selectively applying power from a power source to said distance measuring means, said adjustment indication means, said comparator circuit, and said informing means.