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
Mickey Mouse degrees of a B.A. degree in Education Studies. One thing these courses share is that they are "vocational", which are perceived to be less intellectually rigorous than the traditional academic degrees. Defenders of these courses object that the derogatory comments made in the media rely on the low symbolic capital of new subjects and rarely discuss course contents beyond the titles. Another factor is the correct or incorrect perception that the take up of these subjects, and the decline of more traditional academic subjects like science, engineering, mathematics, is causing annual grade rise in the United Kingdom. The A-level in General