A Digital Camera Fisheye

Although no one knows how fish see, the prominent shape of there eyes suggested the name for these lenses with a angle of vision above 150 º. For this angle of vision, it's impossible to make a flat undistorted

projection (7.2.3); the projection forgets about what the human vision considers normal and the aspect of the field is curved or directly circular in the image. The straight lines, except for the ones that pass through the center of the field, appear reproduced as curves.