Photographic camera accessory

Claim 1

IN A PHOTOGRAPHIC CAMERA HAVING AN OBJECTIVE LENS SYSTEM WITH A FIRST FOCUSING RANGE AND AN OPTIONALLY USABLE, AUXILIARY LENS SYSTEM, WITH A SECOND FOCUSING RANGE, THE COMBINATION COMPRISING: (A) A VIEWFINDER SYSTEM HAVING A NEGATIVE OBJECTIVE AND A POSITIVE EYEPIECE LENS FOCUSED AT INFINITY; (B) MEANS WITHIN SAID VIEWFINDER SYSTEM DEFINING A FIXED FRAME OF THE ALBADA TYPE WHICH APPEARS TO AN OPERATOR VIEWING THROUGH SAID EYEPIECE TO BE PROJECTED A FIRST, PREDETERMINED DISTANCE FORWARDLY OF SAID CAMERA; (C) SAID VIEWFINDER SYSTEM BEING SO CONSTRUCTED AND ARRANGED RELATIVE TO SAID CAMERA OBJECTIVE LENS SYSTEM THAT THE OPTICAL AXES OF THE TWO SYSTEMS CROSS SUBSTANTIALLY AT THE PLANE FOCUSED BY SAID CAMERA OBJECTIVE AT THE CAMERA FILM PLANE THROUGHOUT SAID FIRST FOCUSING RANGE, AND SAID FIXED FRAME ACCURATELY DEFINES THE FIELD OF SAID CAMERA OBJECTIVE AT A FIRST, PREDETERMINED PLANE FORWARDLY OF SAID CAMERA; (D) A DE-CENTERED POSITIVE LENS; (E) A NEGATIVE LENS OF WEAK POWER RELATIVE TO SAID NEGATIVE OBJECTIVE OF SAID VIEWFINDER SYSTEM; (F) A HOLDER FOR SAID DE-CENTERED POSITIVE AND WEAK NEGATIVE LENSES HOLDING THE TWO IN SPACED RELATION; (G) MEANS FOR REMOVABLY POSITIONING SAID HOLDER RELATIVE TO SAID VIEWFINDER SYSTEM WITH SAID DE-CENTERED POSITIVE LENS FORWARD OF SAID NEGATIVE OBJECTIVE AND SAID WEAK NEGATIVE LENS REARWARDLY OF SAID POSITIVE EYEPIECE LENS; (H) SAID DE-CENTERED POSITIVE LENS BEING CONSTRUCTED AND ARRANGED TO SHIFT THE OPTICAL AXIS OF SAID VIEWFINDER SYSTEM TO CROSS THAT OF SAID CAMERA OBJECTIVE SUBSTANTIALLY AT THE PLANE FOCUSED THEREBY AT SAID FILM PLANE THROUGHOUT SAID SECOND FOCUSING RANGE, AND TO SO MAGNIFY THE FIELD SEEN THROUGH SAID VIEWFINDER SYSTEM THAT SAID FRAME ACCURATELY DEFINES THE FIELD OF SAID CAMERA OBJECTIVE AT A SECOND, PREDETERMINED PLANE, CLOSER TO SAID CAMERA THAN SAID FIRST PLANE; AND (I) SAID WEAK NEGATIVE LENS BEING CONSTRUCTED AND ARRANGED TO FOCUS SAID VIEWFINDER SYSTEM AT A PLANE CLOSER THAN INFINITY AND TO CAUSE SAID FRAME TO APPEAR TO BE PROJECTED A SECOND DISTANCE, CLOSER THAN SAID FIRST DISTANCE, FORWARDLY OF SAID CAMERA.