F-number lengths. Therefore, reduced–depth-of-field effects will require smaller f-numbers when using small-format cameras than when using larger-format cameras. Image sharpness is related to f/number through two different optical effects: aberration, due to imperfect lens design, and diffraction which is due to the wave nature of light. The blur optimal f-stop varies with the lens design. For modern standard lenses having 6 or 7 elements, the sharpest image is often obtained around 5.6–8, while for older standard lenses having only 4 elements (Tessar formula) stopping to 11 will give the sharpest image. The larger number of elements in modern lenses allow the
Russ Bray the same event. He has called seven more nine-darters live on TV since then including the first televised nine-darter outside of Europe by Mervyn King in Johannesburg, South Africa. Russ is also a member of Team Unicorn. Russ was a county player for Hertfordshire and subsequently played on the pro circuit. He teamed up with Eric Bristow to win the Norway and Finland pairs. Russ also hit the bullseye on a standard dartboard from 10 feet, outdoors, on Blackpool's North Pier, thus achieving a Guinness World Record in the process. Russ beat the day's previous best of 9' 6" which