A system camera is a camera

Camera

A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...

 with interchangeable components that constitutes the core of a system. Early representatives include Leica I Schraubgewinde

Leica

Leica Camera AG, a German optics company, produces Leica cameras. The predecessor of the company, formerly known as Ernst Leitz GmbH, is now three companies: Leica Camera AG, Leica Geosystems AG, and Leica Microsystems AG, producing cameras, geosurvey equipment, and microscopes, respectively...

 (1930), Exakta

Exakta

The Exakta is a pioneer brand camera produced by the Ihagee Kamerawerk in Dresden, Germany, founded as the Industrie und Handels-Gesellschaft mbH, in 1912.- Characteristics :Highlights of Exakta cameras include:...

 (1936) and the Nikon F

Nikon F

The Nikon F camera, introduced in 1959, was Nikon's first SLR camera. It was one of the most advanced cameras of its day. Although most of its concepts had already been introduced elsewhere, it was the first camera to combine them all in one camera. It was produced until October 1973 and was...

(1959). System cameras are often single-lens reflex

Single-lens reflex camera

A single-lens reflex camera is a camera that typically uses a semi-automatic moving mirror system that permits the photographer to see exactly what will be captured by the film or digital imaging system, as opposed to pre-SLR cameras where the view through the viewfinder could be significantly...

 (SLR) or twin-lens reflex

Twin-lens reflex camera

A twin-lens reflex camera is a type of camera with two objective lenses of the same focal length. One of the lenses is the photographic objective or "taking lens" , while the other is used for the viewfinder system, which is usually viewed from above at waist level...

 (TLR) but can also be rangefinder camera

Rangefinder camera

A rangefinder camera is a camera fitted with a rangefinder: a range-finding focusing mechanism allowing the photographer to measure the subject distance and take photographs that are in sharp focus...

s or, more recently, mirrorless interchangeable lens camera

Mirrorless interchangeable lens camera

A mirrorless interchangeable-lens camera is an emerging class of digital system cameras, intermediate between compact digital cameras and digital single-lens reflex cameras . They are characterized by a no-mirror design and an interchangeable lens mount...

s.

Even point-and-shoot cameras often include a tripod

Tripod

A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the...

 socket. A system camera includes at the very least a camera body and separate, interchangeable lenses. In addition it often includes:

• Electronic flash
  Flash (photography)
  A flash is a device used in photography producing a flash of artificial light at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a dark scene. Other uses are capturing quickly moving objects or changing the quality of light...
  
   units matching the camera's capabilities.
• PC socket or tripod-adapter mounts for external flash units, rather than just a hot shoe
• Mechanical
  Bulb (photography)
  Bulb, abbreviated B, is a shutter speed setting on an adjustable camera that allows for long exposure times under the direct control of the photographer. With this setting, the shutter simply stays open as long as the shutter release button remains depressed...
  
  , electric, or IR
  IRDA
  IRDA may refer to:* Infrared Data Association, in information and communications technology , a standard for communication between devices over short distances using infrared signals...
  
  /RF
  Radio frequency
  Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
  
   remote shutter release.
• Extensive supplementary equipment for macro photography
  Macro photography
  Macrophotography is close-up photography, usually of very small subjects. Classically a macrophotograph is one in which the size of the subject on the negative is greater than life size. However in modern use it refers to a finished photograph of a subject at greater than life size...
  
   and photomicrography.
• Adapters for third-party or legacy lenses, including tilt-shift
  Tilt-shift photography
  "Tilt-shift photography" refers to the use of camera movements on small- and medium-format cameras, and sometimes specifically refers to the use of tilt for selective focus, often for simulating a miniature scene...
  
   adapters
• For film cameras, a motor drive
  Motor drive
  A motor drive, in the field of photography, is a powered film transport mechanism. Historically, film loading, advancing, and rewinding were all manually driven functions...
  
   to advance the film automatically.
• For film cameras, different camera backs, e.g. large capacity for bulk film, or data back or datebacks for recording exposure and date information.
• Add on correction or magnifying lenses to help focusing or composition through the viewfinder.
• Interchangeable viewfinder
  Viewfinder
  In photography, a viewfinder is what the photographer looks through to compose, and in many cases to focus, the picture. Most viewfinders are separate, and suffer parallax, while the single-lens reflex camera lets the viewfinder use the main optical system. Viewfinders are used in many cameras of...
  
  s, including interchangeable focusing screen
  Focusing screen
  A focusing screen is a flat translucent material, usually ground glass, found in a system camera that allows the user of the camera to preview the framed image in a viewfinder. Often, focusing screens are available in variants with different etched markings for various purposes...
  
  s in the case of SLR
  SLR
  The initialism SLR can refer to:* Satellite laser ranging* Scalable Linear Recording Tape Drive Backup* Self-Loading Rifle, see semi-automatic rifle.** The UK version of the Belgian FN FAL select fire battle rifle, the L1A1 SLR.* Semi-linear resolution...
  
  s. Viewfinders and focusing screens could give different metering options.
• Extra-capacity battery packs, often in the form of a "battery grip" (a second, portrait
  Page orientation
  Page orientation is the way in which a rectangular page is oriented for normal viewing. The two most common types of orientation are portrait and landscape...
  
  -oriented handgrip), but also including fully external packs with cable interface
• AC adapters with dummy-battery interfaces for studio or other stationary work
• Sockets and matching cables for direct output, e.g., to a television
  HDMI
  HDMI is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA...
  
  
• Depth-of-field preview
• Global navigation satellite system
  Global Navigation Satellite System
  A satellite navigation or SAT NAV system is a system of satellites that provide autonomous geo-spatial positioning with global coverage. It allows small electronic receivers to determine their location to within a few metres using time signals transmitted along a line-of-sight by radio from...
  
   receivers, e.g. (GPS) for geotagging
  GeoTagging
  Geotagging is the process of adding geographical identification metadata to various media such as a geotagged photograph or video, websites, SMS messages, QR Codes or RSS feeds and is a form of geospatial metadata...
  
  
• Bluetooth
  Bluetooth
  Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
  
   or Wifi
  WIFI
  WIFI is a radio station broadcasting a brokered format. Licensed to Florence, New Jersey, USA, the station is currently operated by Florence Broadcasting Partners, LLC.This station was previously owned by Real Life Broadcasting...
  
   networking modules

While some early mechanical interfaces are standardized across brands, optical and electronic interfaces are often proprietary. Hot shoe

Hot shoe

A hot shoe is a mounting point on the top of a camera to attach a flash unit.- Design :The hot shoe is shaped somewhat like an inverted, squared-off "U" of metal. The matching adapter on the bottom of the flash unit slides in from the back of the camera and is sometimes secured by a clamping screw...

s have a common interface for basic flash functions, but often contain proprietary contacts inside for advanced flashes and data modules.