|This article does not cite any references or sources. (September 2009)|
A candid photograph is a photograph that is captured without creating a posed appearance. This is achieved by avoiding prior preparation of the subject and by either surprising the subject or by not distracting the subject during the process of taking photos. Thus, the candid character of a photo is regardless of the subject's knowledge or consent as to the fact that photos are being taken, and regardless of the subject's permission for subsequent usage such as distribution, but related to the apparent absence of posing. It is distinguished from making secret photography by the photographer usually remaining discernible to the public and not wearing cover.
As an art form 
Some professional photographers develop candid photography into an art form. Henri Cartier-Bresson might be considered the master of the art of candid photography, capturing the "decisive moment" in everyday life over a span of several decades. Arthur Fellig, better known as Weegee, was one of the great photographers to document life in the streets of New York to often capture life — and death — at their rawest edges.
Almost all successful photographers in the field of candid photography master the art of making people relax and feel at ease around the camera, they master the art of blending in at parties, of finding acceptance despite an obvious intrusive element - the camera. This is certainly true for most celebrity photographers, such as René Burri, or Raeburn Flerlage.
It could be argued that candid photography is the purest form of photojournalism. There is a fine line between photojournalism and candid photography, a line that was blurred by photographers such as Bresson and Weegee. Photojournalism often sets out to tell a story in images, whereas candid photography simply captures people living an event.
Camera equipment 
Equipment for candid photography is typically lightweight, small and unobtrusive rather than big and intimidating. Lomo rule photography describes using an old Russian point-and shoot-camera for candid photography. The larger the equipment, the more difficult to master the art of making the equipment appear to be unobtrusive to achieve candid photography.
Candid photography typically requires high film speeds or ISOs as strobe flashes can interrupt interactions, causing people to stage their photo appearance rather than behaving naturally. For this reason, candid photography has traditionally taken place outdoors, where the sun provides ample light. Due to higher film speeds (ISO) being required for indoor ambient light photography, candid photography can feature grainy, high contrast images. However, several recent full-frame DSLR cameras have brought high-ISO noise to historically low levels, allowing for clean, saturated images at speeds up to and beyond ISO 6400.
As small point and shoot cameras with affordable lenses are used widely for candid photography, photographs may feature vignetting, distortion and over saturation of colors. Due to short reaction times, exposure or focus may be slightly off. Due to strobe flashes being obstructive to candid photography and incompatible with many compacts, pictures may show blurring or other technical faults. All these are usually accepted as features of candid photography, and often, part of what makes candid photography an art.
Rangefinders and small, early film SLRs have long been preferred equipment for candid photographers. Candid photographers also seem to prefer the use of black and white film, which has an inherently artistic appearance and roughly 3 stops more dynamic range compared to digital cameras. However, as the dynamic range of digital cameras improves, smaller cameras are developed, and lens speed and sharpness improves, candid photographers are given many new tools to capture high quality candid images.
See also 
- Celebrity photography
- Documentary photography
- Secret photography
- Street photography
- Snapshot (photography)
- Photojournalism Ethics: Chapter 5, "The Right to Privacy"
- 11 Tips for Better Candid Photography by Darren Rowse. Digital Photography School.