Viewfinder
This article is about the definition, for the short story by Raymond Carver, see Viewfinder (short story)In
photography a
viewfinder is what the photographer looks through to compose, and in many cases to focus, the picture.
Viewfinders are widely used in
cameras of different types: still and movie, film, analog and digital.
Viewfinders can be optical and electronic. An optical viewfinder is simply a reversed
telescope. It has many drawbacks, but one advantage: it consumes no power. An electronic viewfinder is a
CRT,
LCD or
OLED based display device. In addition to its primary purpose, an electronic viewfinder can be used to replay previously captured material and usually has
on-screen display.
It is not uncommon for a camera to have two viewfinders. Here are two examples:
1. A digital still camera may have an optical viewfinder and an electronic (usually LCD or OLED based) one. The latter can be used to replay previously captured material, has on-screen display, and can be switched off to save power.
2. A
camcorder may have two viewfinders, both are electronic. One of them is monochrome, CRT-based and has an ocular. The other viewfinder is color, LCD-based and is much larger. Both can be used to replay previously captured material, have on-screen display, but the second, large viewfinder is more power hungry, so it is made possible to turn it off to save power.
Some special purpose cameras do not have viewfinders at all. These are, for example, web cameras and video surveillance cameras. They use external
monitors as their viewfinders.
