Having a viewing angle of 180ï¿1/2, these lenses can provided a very surreal image. Can be divided into diagonal types which provide a frame-filling picture; or circular lenses which project a round image on the frame.
An extreme-wide-angle lens in which all lines appear to curve around the center.
a wide angle lens that captures the scene exactly as it appears, thereby incorporating curves which the human eye does not perceive because the focal length of the human eye is approximately 50mm. Fisheye lens images tend to cause all straight lines to appear curved. See also rectilinear lens. You can use such lenses and use a program like DeFish to make it rectilinear and therefore usable in a simple stitching program like PhotoStitch (Canon.com)