Its drawbacks are many, but it also has advantages it consumes no power, it does not wash out in sunlight, and it has "full resolution" (i.e. An optical viewfinder is simply a reversed telescope mounted to see what the camera will see. Viewfinders can be optical or electronic. The live preview feature of digital cameras share this advantage of the SLR, as they also show the image exactly as it will be recorded, with no additional optics or parallax error. The big advantage of the SLR was that any lens, or other optical device, could be used the viewfinder always showed exactly the image that would be projected onto the film. Instead of a waist-level arrangement, a prism was used to allow the camera to be held to the eye. Later SLRs had a mechanism which flipped the mirror out of the way when the shutter button was pressed, followed immediately by the shutter opening. When ready to take the picture, the mirror was pivoted out of the way (without moving the camera). Early SLRs were plate cameras, with a mechanism to insert a mirror between the lens and the film which reflected the light upwards, where it could be seen at waist level on a ground glass screen. Single-lens reflex (SLR) cameras viewed the scene through the taking lens. Cameras with interchangeable lenses had to indicate the field of view of each lens in the viewfinder more usually, interchangeable viewfinders to match the lenses were used. Some sophisticated 20th century cameras with direct viewfinders had coincidence (split-image) rangefinders, initially with separate windows from the viewfinder, later integrated with it they were called rangefinder cameras. Viewfinders often show lines to indicate the edge of the region which would be included in the photograph. The error varies with distance, being negligible for distant scenes, and very large for close-ups. Parallax error results from the viewfinder being offset from the lens axis, to point above and usually to one side of the lens. A declining minority of point and shoot cameras use them. 1.2 Waist-level (reflecting) viewfindersīefore the development of microelectronics and electronic display devices, only optical viewfinders existed.ĭirect viewfinders are essentially miniature Galilean telescopes the viewer's eye was placed at the back, and the scene viewed through the viewfinder optics.
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