Photography is the process of making pictures by means of the action of light. It involves recording light patterns, as reflected from objects, onto a sensitive medium through a timed exposure. The process is done through mechanical, chemical or digital devices commonly known as cameras.
Traditional photography was a considerable burden for photographers working at remote locations (such as press correspondents) without access to processing facilities. With increased competition from television, there was pressure to deliver their images to newspapers with greater speed. Photo-journalists at remote locations would carry a miniature photo lab with them, and some means of transmitting their images down the telephone line. In 1981, Sony unveiled the first consumer camera to use a CCD for imaging, and which required no film -- the Sony Mavica. While the Mavica did save images to disk, the images themselves were displayed on television, and therefore the camera could not be considered fully digital. In 1990, Kodak unveiled the DCS 100, the first commercially available digital camera. Its cost precluded any use other than photojournalism and professional applications, but commercial digital photography was born.
Some info above extracted from wikipedia.