The massive-format camera, taking sheet film, is a direct successor of the early plate cameras and remained in use for top of the range photography and for technical, architectural and industrial pictures. There are three widespread varieties, the view camera with its monorail and subject camera variants, and the press camera.
About Camera Labs
Twin-lens reflex cameras used a pair of almost similar lenses, one to type the picture and one as a viewfinder. The lenses had been arranged with the viewing lens immediately above the taking lens. The viewing lens projects an image onto a viewing screen which could be seen from above.
They have an extensible bellows with the lens and shutter mounted on a lens plate at the entrance. Backs taking rollfilm, and later digital backs are available in addition to the usual dark slide again. These cameras have a wide range of movements permitting very close control of focus and perspective. Composition and focusing is done on view cameras by viewing a floor-glass display which is replaced by the film to make the exposure; they’re appropriate for static subjects only, and are gradual to make use of.
Some manufacturers similar to Mamiya also offered a reflex head to attach to the viewing display screen to permit the camera to be held to the attention when in use. The benefit of a TLR was that it could be easily focussed utilizing the viewing display screen and that underneath most circumstances the view seen in the viewing display screen was similar to that recorded on movie. At close distances however, parallax errors had been encountered and some cameras also included an indicator to point out what a part of the composition can be excluded.
When vertical traces within the object being photographed meet precisely within the mixed image, the object is in focus. Many rangefinder cameras had interchangeable lenses, each lens requiring its own vary- and viewfinder linkages.