Single-lens reflex camera

Single lens reflex camera is a type of camera, more commonly known by the acronym SLR, which utilises a mirror placed between the lens and film shutter to reflect the image seen through the lens (via a pentaprism in modern versions) to the eyepiece. Since the SLR technology became mature in the 1970s, such cameras have been the main type of camera used by dedicated amateur photographers, and, for most applications, by professionals.

The major advantage of single lens reflex cameras is the ability to determine what parts of the image are in focus simply by looking through the lens. Most modern SLRs offer additional focussing aids, including rangefinder devices and automatic focussing methods. The SLR cameras also offer the ability for the photographer to quickly and simply change the lens, thus making them versatile. The same camera can be used for portrait, landscape, action, and close-up photography. Whilst some earlier cameras offered this ability, the SLR immediately allows the photographer to see what the different lenses will capture.

SLR cameras also avoid the difficulty of parallax in close-up photography. Cameras with a seperate optical viewfinder system show the scene from a different viewpoint from that of the camera lens. For photography at normal distances, this difference is not significant, but where the gap between the viewfinder and lens is a significant fraction of the distance to the objects in the scene to be photgraphed, this difference in viewpoint may mean that the image recorded is quite different from that seen through the viewfinder.

The overwhelming majority of SLR cameras have historically used 35mm film, as the format offered a good compromise between image quality, size, and cost for most amateur and many professional applications. Professional photographers often use larger-format cameras for indoor work where the absolute highest image quality is important, such as 2 1/4" x 2 1/4". Digital SLR's have also appeared on the market and are now the camera of choice for most newspaper photographers.

The pros of SLR camera are :

Absence of parallax Ability to check the depth of field (this feature is often ommited on low-end SLR) Interchangeable lenses (this feature is generally implemented on high end rangefinder cameras but the SLR concept is perfect for it)

The cons of view camera are :

Due to Mechanical complexity the SLR camera is lager than rangefinder camera for a given film size. Latency the mirror need time to move before the film is exposed on modern SLR latency is generally incresead by autofocus. Noise mainly due to the mirror movement.

A popular SLR camera of the 1970s