Photography is the process of recording pictures by means of capturing light on a light-sensitive medium, such as a film or sensor. Light patterns reflected or emitted from objects expose a sensitive chemical or electronic medium during a timed exposure, usually through a photographic lens in a device known as a camera that also stores the resulting information chemically or electronically. The word comes from the Greek words phos ("light"),and graphis ("stylus", "paintbrush") or graphĂȘ ("representation by means of lines" or "drawing"), together meaning "drawing with light." Traditionally, the product of photography has been called a photograph, commonly shortened to photo.