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
Less-is-better effect of top-quality candy than a box containing those 24 pieces plus 16 lower-quality pieces. If a manufacturer has developed two versions of a product and wishes to know which will be more popular with consumers and should therefore be put on the market, presenting them jointly to the public will enable consumers to evaluate differences between them, while presenting them separately will better predict the consumer's actual experience of the product when and if it is actually put on sale. Less-is-better effect The less-is-better effect is a type of preference reversal that occurs when the lesser or smaller alternative of