Single lens reflex motion picture camera

Claim 1

A SINGLE LENS REFLEX MOTION PICTURE CAMERA COMPRISING AN OBJECTIVE LENS INCLUDING A MAIN OBJECTIVE LENS AND PROVISIONS FOR MOUNTING INTERCHANGEABLE SUPPLEMENTARY LENSES IN FRONT OF SAID MAIN OBJECTIVE LENS, A SEMITRANSPARENT MIRROR POSITIONED TOWARD THE OBJECT IN FRONT OF SAID MAIN OBJECTIVE LENS WHICH TRANSMITS PART OF SAID LIGHT FROM SAID OBJECT ALONG THE OPTICAL AXIS OF SAID CAMERA, A ROTARY SHUTTER MOUNTED BETWEEN SAID SEMITRANSPARENT MIRROR AND SAID MAIN OBJECTIVE LENS, THE SURFACE OF SAID ROTARY SHUTTER FACING SAID OBJECT BEING REFLECTIVE, SAID SEMI-TRANSPARENT MIRROR REFLECTING AN OTHER PART OF THE LIGHT RAYS ORIGINATING FROM SAID OBJECT IN A DIRECTION WHICH IS ANGULARLY DISPLACED FROM SAID OPTICAL AXIS OF SAID CAMERA AND REFLECTING PART OF THE LIGHT RAYS FROM SAID REFLECTIVE SURFACE OF SAID REFLECTIVE SHUTTER IN A DIRECTION WHICH IS 180* OPPOSITE TO SAID REFLECTED DIRECTION OF SAID LIGHT RAYS FROM SAID OBJECT, A VIEWFINDER DISPOSED IN THE PATH OF SAID OTHER PART OF THE LIGHT RAYS REFLECTED BY THE SAID SEMI-TRANSPARENT MIRROR FROM SAID OBJECT, AND LIGHT-MEASURING MEANS DISPOSED IN THE PATH OF SAID LIGHT RAYS REFLECTED BY SAID SEMI-TRANSPARENT MIRROR FROM SAID ROTARY SHUTTER WHEREBY THE AMOUNT OF LIGHT IMPINGING UPON SAID LIGHT-MEASURING MEANS IS MAINTAINED IN CORRESPONDENCE WITH THE LIGHT PASSING THROUGH SAID OBJECTIVE LENS REGARDLESS OF ANY CHANGE IN OVERALL FOCAL LENGTH.