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
900 Degrees on the Dance Club Songs chart the following year. UK CD Single German CD Single 900 Degrees "900 Degrees" is a song by German DJ and producer Ian Pooley. The song was released as a single from his sixth studio album, "Since Then", released in October 2001. Upon its release, the song peaked within the top 60 on the UK Singles chart and remained Pooley's highest-peaking UK single for more than a year, until his 2002 single "Piha" peaked higher. The song also entered the "Billboard" Hot Dance Breakouts Maxi-Single Sales chart, becoming his first chart entry there. "900 Degrees"