In 1972, the U.S. proclaimed a contiguous zone extending from 3 to 12 miles offshore (Department of State Public Notice 358, 37 Fed. Reg. 11906 (June 15, 1972), consistent with the 1958 UN Convention on the Territorial Sea and Contiguous Zone.
The aperture of a lens is the opening in the diaphragm that controls how much light is allowed to reach your focal plane (film or sensor). The aperture is usually rated as a fraction of the focal length, hence the f/x.y nomenclature. The wider an aperture is, the more light it allows through, and the smaller the number under f/ is.
If youâve ever had a portrait taken in a park or seen a wedding picture and wondered why they looked so much better than the images from your phone, the answer is really a three-parter: 1  A relatively wide aperture is being used, which causes (among other effects) the âfield of focus,â or the bit of the picture that is sharp, to be very narrow.