The viewfinder on a camera is a simple but immensely useful accessory to picture taking, and an accurate viewfinder can help greatly in securing good composition. In particular, with color slides where the final frame is determined by the outline of the camera image and no cropping or masking is possible, careful use of the viewfinder becomes imperative. A precise viewfinder is also essential when taking motion pictures with a long-focus or telephoto lens; indeed, with a 6-inch lens on a 16mm camera, the best viewfinder would be a small telescope laid along and fastened to the camera body.
Most viewfinder masks are made slightly smaller than the full field recorded on the film to ensure that nothing of value in the picture will be cut off. For this reason it is generally desirable, and quite safe, to fill the viewfinder field with the desired subject matter in order that the picture should occupy as much of the film area as possible. In some so-called âsports findersâ the actual picture area is marked by a rectangular line or other indication, the whole displayed scene being somewhat larger to give the user a better idea of how much of the scene will be photographed, especially with a moving subject as in sports events.
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