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
Adler Standard 6 10/45 in the car’s name referred respectively to the Tax horsepower (on which car tax was based till 1928) and actual horsepower in PS (i.e. applying the German standard formula). The car was offered with a standard wheelbase of or a longer wheelbase of . The Shorter wheelbase Standard 6N continued as the entry level model until 1930, but the longer wheel base ceased to be available with the 6N’s engine before the end of 1928. The standard body was made from steel which at this time was a common feature on North American cars but still unusual in Europe.