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
Etiquette in Japan from the waist with the back and neck straight, hands at the sides (males) or clasped at the lap (females), and eyes looking down. The body should be composed but not rigid. Generally, the longer and deeper the bow, the stronger the emotion and respect expressed. The three main types of bows are informal, formal, and very formal. Informal bows are made at about a fifteen-degree angle or just tilt over one's head to the front, and more formal bows at about thirty degrees. Very formal bows are deeper. The etiquette surrounding bowing, including the length, depth, and appropriate response,