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
Opposite Day that it is an opposite day. Opposite Day "'Opposite Day" Opposite Day is sometimes declared retroactively to indicate that something which has just been said now has the opposite of its original meaning (similar to the practice of crossed fingers to automatically nullify promises). The game has also been compared to a children's "philosophy course." Opposite day causes a self referential paradox. On opposite day, it could be said that "Today is opposite day." Therefore, it is not opposite day, but if you say it is a normal day it would be considered a normal day, which contradicts the fact