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
Lonely Planet Six Degrees San Francisco, Mexico City, Paris, and Bangkok. The series ran for 3 consecutive seasons and showed on Discovery Networks and dozens of other international channels. Lonely Planet Six Degrees Lonely Planet Six Degrees is Lonely Planet's flagship travel show, hosted by Asha Gill and Toby Amies. The show is centered on unique people living within locations, rather than simply famous tourist attractions, with one of the hosts meeting with one contact in a specific country, who in turn leads them to another contact, and so on, following the idea of six degrees of separation. In the first season Asha travelled