Electronic viewfinder

An electronic viewfinder (EVF) is a camera 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.

Old video camera viewfinder cutway, note the miniature CRT

Electronic viewfinders in still photography

Advantages

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 approximately how the scene will look under the chosen exposure.
• 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, white balance and color saturation that will appear in the final image.
• EVFs can provide the focus peaking feature that highlights areas of the frame that are in focus.

Limitations

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.
• A very few EVFs do not have automatic gain control and become virtually blank in low-light conditions.
• An EVF has high power consumption, usually comparable to the main LCD screen. For saving battery, Panasonic Lumix G1 and G2 both have automatic eye sensors which switch the display from the rear LCD to the EVF when we put the EVF to our eye. Whereas Panasonic Lumix G10 has a button to switch the display.

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 cameras such as the micro four thirds camera Panasonic DMC-G1 or the newer Nikon 1 V1, which are not actually DSLR, but have interchangeable lenses, and electronic viewfinder in place of an optical one.

Many professional photographers and advanced amateurs prefer digital single-lens reflex cameras which have a true optical through-the-lens viewfinder (OVF). From 2006 some digital SLR camera models provide both through-the-lens viewing and a "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, EOS 50D, EOS 60D, EOS 7D and EOS-1D Mark III, and the Nikon D3, D300 and D90.

Hybrid Viewfinder

To get the advantage of both optical and electronic viewfinders some cameras have hybrid viewfinders. These display the image in an optical eyepiece viewfinder, or electronically on an LCD screen. Examples include the Fujifilm FinePix X100 and X-Pro1.

See also

• Digital photography
• Zoom-lens reflex camera