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
Allied Masonic Degrees with the presiding officer being denominated 'Sovereign Master." The Councils are given wide discretion as to choose how frequently they meet and what programs to pursue. Generally speaking, Councils study or discuss Freemasonry in some way at each meeting. The Grand Council has created some internal honors, the most notable being "Knight Grand Cross". The degrees conferred in the United States are: In Canada, the degrees conferred are: Optional degrees are: Royal Order of the Red Branch of Eri: "Fun" degrees: (given at the Annual Assembly) Allied Masonic Degrees The Allied Masonic Degrees (AMD) are a series of Masonic degrees