In photography, a view-finder is what the snapper looks through to compose, and in several cases to focus, the picture. Most viewfinders are separate, and suffer parallax, while the more complicated single-lens reflex camera lets the rangefinder use the primary optical system. Rangefinders are employed in many cameras of differing sorts: still and flick, film, digital and analog.

A zoom camera typically zooms its finder in synchronization with its lens, one exception being rangefinder cameras. Rangefinders can be optical or electronic. An optical view-finder is just a reversed telescope mounted to see what the camera will see. It has a lot of drawbacks, nevertheless it has 2 main advantages; it consumes no power, and it has "full resolution" (i.e. the resolution of the photographer's eye). An electronic range-finder is a CRT, LCD or OLED based display machine though CRT is never used today due to weight and size. As well as its major purpose, an electronic range-finder may be used to replay formerly caught material, and as an on-screen display to flick through menus. A still camera's optical range-finder often has one or two tiny extra LED displays surrounding the view of the scene. On a film camera, shooting information such as the shutter speed and aperture is shown in these displays and, for auto-focus cameras, provide a suggestion that the image is properly focused. Digital still cameras will usually also display information like the existing ISO setting and the quantity of remaining shots which can often be taken in a burst. One more display which overlays the view of the scene is frequently provided. It often shows the location and state of the camera's provided automatic focus points. This overlay can also provide lines or a grid which aid in picture composition.
 
Standard film SLR rangefinder: It isn't unusual for a camera to have 2 range-finders. As an example, a digital still camera could have an optical range-finder and an electronic one. The second can replay formerly caught material, has an on-screen display, and can be switched off to save power. A video recorder might have 2 view-finders, both electronic. The first is viewed through a magnifying eyepiece, and because of a rubber eyepiece it can be viewed perfectly even in intense light. The second rangefinder would be bigger, of a higher resolution, and can be mounted on the side of the camera. As it consumes more power, a strategy is frequently provided to switch it off to save energy. Some special purpose cameras don't have view-finders in any way. These are, for instance, web cameras and video cameras. They use external monitors as their viewfinders.