Camera Obscura

Camera Obscura (lit. 'a dark chamber'), an instrument described by Giambattista della Porta in his Magia Naturalis (1569). It is known in its simplest form as a familiar toy, consisting of a rectangular box, furnished at one end with a lens whose focal length is equal to the length and depth of the box; at the opposite end of which a plane reflector is placed at an angle of $45^\backslash circ$, which throws the image of any objects to which the lens may be directed on a piece of ground-glass on the top of the box in a non-inverted position, so that they may be viewed or sketched from as in nature. The instrument received a new interest when in the hands of Daguerre it became the main instrument used in photography. For the photographic camera, see PHOTOGRAPHY.