The Camera Obscura is a 19th century optical device often used by artists to make quick sketches in the field. A competing device is the Camera Lucida. Camera Obscura means dark room, and the use of a pinhole in a window blind to form an inverted image of an outside scene on an opposite wall of a dark room has been known since at least the time of the Arab scholar Ibn al Hait[h]em (or Alhazen, ca. 956-1038).