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
360 Degrees of Billy Paul was similarly enthusiastic in discussing how Paul's sound developed over the years from the early club jazz of "Feelin' Good at the Cadillac Club" (1968) to the merging of jazz and soul on "Going East" (1971): "and then we did Billy's "360 Degrees" album and it all came together with "Me & Mrs. Jones." During his appearance on "Soul Train" in October 1972, Paul was asked by host Don Cornelius whether he had a jazz background. Paul used the opportunity to promote his new album and highlight its diverse styles: “That's very correct. I've been singing since I was 11.