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.
2) Size of Aperture â Large vs Small Aperture. The iris of the lens that controls the size (diameter) of the aperture is called âdiaphragmâ in optics. The sole purpose of the diaphragm is to block or stop all light, with the exception of the light that goes through the aperture. In photography, aperture is expressed in f-numbers (for example f/5.6).