Removable prism viewfinder unit for reflex camera with reflecting means for viewing exposure meter

Claim 1

IN A REFLEX CAMERA HAVING A FIRST HOUSING, A WINDOW IN SAID FIRST HOUSING, AN EXPOSURE METER LOCATED BENEATH SAID WINDOW IN SAID FIRST HOUSING, SAID EXPOSURE METER HAVING A MOVABLE POINTER AND A SCALE THEREON; THE COMBINATION WITH AN INVERTING PENTA-ROOF-PRISM VIEWFINDER HAVING AN EYEPIECE ENCOMPASSING THE VIEWFIELD THEREOF, SAID PRISM VIEWFINDER BEING ENCLOSED IN A SECOND HOUSING LOCATED IN SAID FIRST HOUSING, SAID SECOND HOUSING AND SAID PRISM VIEWFINDER CONSTITUTING A REMOVABLE UNIT STRUCTURE BEING ARRANGED TO BE INTERCHANGED WITH A CONVENTIONAL, OPEN LIGHT-CONDUCTING SHAFT FORMING A VIEWING HOOD, OF FIRST REFLECTING MEANS DISPOSED IN SAID SECOND HOUSING LATERALLY ADJACENT SAID VIEWFINDER BETWEEN THE REAR FACE OF SAID PENTA-ROOF-PRISM AND THE APERTURE OF SAID EYEPIECE, SAID FIRST REFLECTING MEANS OPTICALLY REPRESENTING AN INDEPENDENT NARROW ELONGATED IMAGE AREA LATERALLY ADJACENT SAID VIEWFIELD IN SAID EYEPIECE, SAID FIRST MEANS HAVING A REFLECTING SURFACE ARRANGED AT AN ANGLE OF APPROXIMATELY 45* TO SAID VIEWFINDER EYEPIECE AXIS, THE