MEANS AND METHOD FOR CONVERSION OF A CONVENTIONAL CAMERA FROM FULL-FRAME TO HALF-FRAME FORMAT

摘要

MEANS AND METHOD FOR THE CONVERSION OFA CONVENTIONAL CAMERA FROM FULL-FRAMETO HALF-FRAME FORMATABSTRACT OF THE DISCLOSUREMeans and a method are disclosed by which aconventional camera can be converted from its usualfull-frame format to a half-frame format. Theconversion means comprises a mask removably locatablewithin the camera body directly forward (i.e. facingthe lens rear surface) of the film in the camera, andhaving a window therein centrally located withrespect to that aperture in the camera body definingthe full-frame image format. The mask window isproperly sized to provide a half-frame image format,effecting a 50% reduction in the exposed image area,by blocking quarter frame areas of the camera bodyaperture at either end thereof. The mask is preferablybowed rearwardly against the film's emulsion surface,so as to bias the film against the camera pressureplate. The conversion means may also include meansto apply indicia to a film leader, cooperating withindicia applied to the inside of the camera body, toassure proper indexing of the film through thecamera; means to apply a half-frame reticle to thefocusing screen of a view finder assembly; andaudible or physical means to assist in preventingcomplete rewind of the film leader into the filmcassette. The mask, or the mask and some or all ofthe above identified elements, may be packaged as aconversion kit.In use, the mask is mounted in the camera and aroll of film is loaded, having been properly indexedwith respect to the camera sprocket. The film isthen advanced in a first pass through the camera,exposing a first set of half-frame image areas onthe film, with unexposed half-frame areas locatedtherebetween. The film is thereafter rewound andreloaded, again properly indexed with respect to thecamera sprocket, and advanced in a second passthrough the camera exposing a second set of half-frame image areas constituting those alternateunexposed areas.