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
On the 6 country by the Bundesverband Musikindustrie (BVMI) for sales exceeding 250,000 units. The album also peaked at number three (and was certified gold) in Switzerland, where it sold 15,000 copies. In Canada "On the 6" peaked at number five, and was certified five times for shipments of over a half-million copies. In Belgium, the album reached number ten in Flanders and number six in Wallonia. "On the 6" entered the Dutch album chart at number 55 for the week of July 10, 1999. Nearly a month later, on August 7, it peaked at number six. The album spent a total of