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 21 the album had spent ten weeks on the top twenty, while "If You Had My Love" had been in the top ten of the Hot 100 for twelve weeks. By October, "On the 6" had sold 1.6 million copies in the United States. After a one-year run on the chart the album fell off by the week of June 3, 2000 after charting at number 173. It re-entered two weeks later at number 179, before dropping to number 186 and falling off the chart the following week. Overall, "On the 6" experienced a 53-week run on the "Billboard" 200.