Cue sports playing nine-ball. Snooker balls are smaller than American-style pool balls with a diameter of 52.5 mm ( in), and come in sets of 22 (15 reds, 6 "", and a cue ball). English billiard balls are the same size as snooker balls and come in sets of three balls (two cue balls and a red, an object ball). Other games, such as bumper pool, have custom ball sets. Billiard balls have been made from many different materials since the start of the game, including clay, bakelite, celluloid, crystallite, ivory, plastic, steel and wood. The dominant material from 1627 until the
Full-frame digital SLR the lens's image circle is captured. The edges are cropped off, which is equivalent to zooming in on the center section of the imaging area. The ratio of the size of the full-frame 35mm format to the size of the smaller format is known as the "crop factor" or "focal-length multiplier", and is typically in the range 1.3–2.0 for non-full-frame digital SLRs. When used with lenses designed for full frame film or digital cameras, full-frame DSLRs offer a number of advantages compared to their smaller-sensor counterparts. One advantage is that wide-angle lenses designed for full-frame 35mm retain that same wide