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.
Professional photographers generally prefer a viewfinder because it lets them hold the camera steady against their face and focus on framing the picture without distraction. In addition, the LCD screen can be hard to see in bright sunlight.
Digital SLRs and Prosumer Cameras
Using optical lenses or a tiny microdisplay, digital SLR (DSLR) cameras employ an eye-sized viewfinder for taking pictures and an LCD screen to display the results. A "live preview" or "live view" on a DSLR means the LCD screen can also be used as the viewfinder. 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. Such 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.