The preview window on a camera that is used to frame, focus and take the picture. On analog cameras, the viewfinder is an eye-sized window that must be pressed against the face. Point-and-shoot digital cameras use small LCD screens that are viewed several inches from the eyes.
Professional photographers generally prefer a viewfinder because it lets them focus on framing the picture. In addition, the LCD screen can become very washed out in bright sunlight, making it almost impossible to frame the picture.
Digital SLRs and Prosumer Cameras
Using optical lenses or a tiny microdisplay, digital SLR (DSLR) cameras employ the eye-sized viewfinder for taking pictures and an LCD screen for viewing the results. Increasingly, DSLRs provide the option of using the LCD screen for taking pictures, known as "live preview" or "live view." See DSLR
Prosumer cameras have fixed lenses like point-and-shoot cameras, but they also have manual focus, aperture and shutter speed settings like DSLRs. Prosumer cameras generally offer both viewfinder and LCD screen for taking the picture. See prosumer
and parallax error
Viewfinder and LCD
This prosumer camera has both viewfinder and live preview screen. The viewfinder has two advantages. Since it is held against the face, it helps steady the camera, and it uses less battery than the LCD screen.