An electronic viewfinder or EVF is a viewfinder where the image captured by the lens is projected electronically onto a miniature display. The image on this display is used to assist in aiming the camera at the scene to be photographed.
Operation
The sensor records the view through the lens, the view is processed, and finally projected on a miniature display which is viewable through the eyepiece. Electronic viewfinders in digital still cameras are very similar to those in video cameras.
Electronic viewfinders in still photography
Electronic viewfinders have the following advantages over optical viewfinders:
- Lack of parallax and ability to cope with high zoom-ratio lenses, without the need for a bulky reflex mirror. Cameras with a separate optical viewfinder show the scene from a different viewpoint than that of the camera lens.
- Information about the scene, such as a histogram, can be overlaid with the scene.
- EVFs can show an approximation of the final exposure when they are exposure-priority.
- EVFs can show a low-light scene brighter than it is when they are display-priority.
- Most EVFs show 100% coverage of the final image.
- EVFs provide a more accurate depiction of the contrast and tonal qualities that will appear in the final image.
Electronic viewfinders have the following limitations (2007):
- There may be a noticeable lag between the changes in the scene and the electronic viewfinder display.
- The resolution of the display may be too low to allow for accurate manual focusing. Some cameras assist in this by magnifying the center of the image or by outlining the edges of in-focus objects; even with this adaptation, manual focus using an EVF is more difficult than using a DSLR optical viewfinder.
- In low-light conditions, an EVF display that does not auto-gain can be virtually blank, making it difficult to use. In practice, very few EVF displays do not auto-gain.
- An EVF has high power consumption, usually equivalent to the main LCD screen.
Many professional photographers and advanced amateurs prefer digital single-lens reflex cameras which provide a traditional optical viewfinder (OVF). Beginning in 2006 some new digital SLR camera models provide both traditional through-the-lens viewing and a full-time "live preview" on the LCD display. These include the Olympus E-330, E-410, E-510 and E-3, the Panasonic Lumix DMC-L1 and DMC-L10, the Leica Digilux 3, the Canon EOS 40D and the Canon EOS-1D Mark III. Nikon Cameras that have this feature are the Nikon D3 and the Nikon D300
See also
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