Today there is a wide range of compact cameras with automatic exposure controls and fully automatic focusing.
Light enters the viewfinder directly to allow the photographer to frame and compose the picture.
The photograph is taken through the main lens however the view from the lens and the viewfinder is slightly different, this difference is called parallax error. Some compact cameras have a zoom lens, these models are often fitted with zoom viewfinders that mimic the lens. Parallax error increases as the subject gets nearer to the camera therefore some viewfinders have 'close up' frames marked on the viewing screen to enable the subject to be reframed. Before the widespread use of autofocus the coupled rangefinder was an important camera design. The rangefinder camera has two windows on the front, instead of the usual one, this enables two overlapping views to be seen on the focusing screen.