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
Erdős–Bacon number of 6. Firth's Bacon number of 1 is due to his appearance in "Where the Truth Lies". Kristen Stewart has an Erdős–Bacon number of 7; she is credited as a co-author on an artificial intelligence paper that was written after a technique was used for her short film "Come Swim", giving her an Erdős number of 5, and she co-starred with Michael Sheen in "Twilight", who co-starred with Bacon in "Frost/Nixon", giving her a Bacon number of 2. American scholar and actor Michael M. Chemers has an Erdös-Bacon number of 6. He co-authored a 2018 paper about "Game of Thrones"