A camera is an optical instrument that captures a visual image. At a basic level, cameras are sealed boxes (the camera body) with a small hole (the aperture) that allows light in to capture an image on a light-sensitive surface (usually photographic film or a digital sensor). Cameras have various mechanisms to control how the light falls onto the light-sensitive surface. Lenses focus the light entering the camera and the size of the aperture can be widened or narrowed. A shutter mechanism determines the amount of time the photosensitive surface is exposed to the light.

The still image camera is the main instrument in the art of photography and captured images may be reproduced later as a part of the process of photography, digital imaging, or photographic printing. Similar artistic fields in the moving image camera domain are film, videography, and cinematography.

The word camera comes from camera obscura, which means "dark chamber." It is the Latin name of the original device for projecting an image of external reality onto a flat surface. The modern photographic camera evolved from the camera obscura. The first permanent photograph was made in 1825 by Joseph Nicéphore Niépce.

 

Note:   The above text is excerpted from the Wikipedia article Camera, which has been released under the GNU Free Documentation License.