The same image projected onto the LCD is also projected onto a tiny LCD within the viewfinder
Electronic viewfinders show you the same view that the lens sees. In fact, what you see when you look through an electronic viewfinder is identical to what you see on the camera's LCD screen.
If it shows the same thing as the LCD, what's the purpose? On a bright day when you can't see the LCD, you can use the electronic viewfinder instead to compose your photo. Since the viewfinder is shaded, it is easier to see the image you are going to photograph.
Some cameras make you turn the electronic viewfinder on and off. You have to switch between the LCD or the viewfinder. Other cameras are smart enough to know that you are looking in the viewfinder, and they activate it automatically.
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
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 (2009):
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 comparable to the main
Electronic viewfinders have been in use with bridge cameras for some years, and later entered the field of compact cameras (with the Ricoh GX100) and of
DSLR "alikes" (Panasonic DMC-G1, a micro four thirds camera, which is not a single lens reflex, but has interchangeable lenses and an electronic viewfinder in place of an optical one).
Many professional photographers and advanced amateurs prefer digital single-lens reflex cameras which have an optical through-the-lens viewfinder (OVF). From 2006 some digital SLR camera models provide both through-the-lens viewing and a permanent "live preview" on the LCD display (as distinct from an electronic viewfinder). 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, Nikon D3X,
Nikon D90 and the