Photography is the process of making pictures by means of the action of light. Light patterns reflected or emitted from objects are recorded onto a sensitive medium or storage chip through a timed exposure. The process is done through mechanical shutters or electronically timed exposure of photons into a chemical processing or digitizing devices known as cameras.
The word comes from the Greek words φως phos ("light"), and γραφις graphis ("stylus", "paintbrush") or γραφη graphê, together meaning "drawing with light" or "representation by means of lines" or "drawing." Traditionally, the product of photography has been called a photograph. The term photo is an abbreviation; many people also call them pictures. In digital photography, the term image has begun to replace photograph. (The term image is traditional in geometric optics.)