Ultra wide angle lens the difference is only whether distortion is present or not. However, the shorter the focal length, the more difficult it is to implement rectilinear correction. In fisheye lenses, the visual angle is close to or more than 180 degrees in at least one direction. For example, a "diagonal fish eye" would have a viewing angle of at least 180 degrees within the diagonals of the frame. A "circular fisheye" would represent the image in the form of a circle. Rectilinear ultra-wide angle lenses are used in photography and cinematography sometimes to achieve three-dimensional perspective distortion instead of simply two-dimensional barrel
How Many Miles to Babylon? How Many Miles to Babylon? "How Many Miles to Babylon" is an English language nursery rhyme. It has a Roud Folk Song Index number of 8148. The accepted modern lyrics are: <poem>How many miles to Babylon? Three score miles and ten. Can I get there by candle-light? Yes, and back again.. If your heels are nimble and your toes are light, You may get there by candle-light.</poem> A longer Scottish version has the lyrics: <poem>King and Queen of Cantelon, How many miles to Babylon? Eight and eight, and other eight. Will I get there by candle-light? If your horse be