Photography Basics: Exposure by Robert Meeks I had originally written an article on exposure intended to provide a foundation of the basics for novice photographers. Someone had pointed out that it was perhaps a bit too complex for absolute beginners not familiar with some of the terms used in photography; hence, I wrote this simpler introduction to exposure in photography. One of the most common terms someone will encounter when getting into photography is the term ‘stop’. Aside from jokes about paparazzi being told this several times, a stop is actually referring to exposure. A stop originally was a reference to the aperture in a lens. In the early days of lens development, even before photography, a lens was often a single or double element (piece of glass) which did not provide a very sharp image due to the center of the photography basics lens providing a sharper image than the surrounding portion of the lens. Since the lower sharpness of the outer portion of the lens would reduce the sharpness of the image produced by the lens, someone came up with the idea of blocking or ‘stopping’ the light which would pass through the outer portion of the lens by placing a metal disk with a hole in it between the lens elements. This metal disk was called a ‘stop’. Since a ‘stop’ also reduces the amount of light which passes through the lens in a given amount of time, it also requires more time to expose film as the size of the stop decreases. We now use the term ‘stop’ as a reference for exposure differences. Exposure differences can be caused by adjusting the amount of time the film is exposed (shutter speed) or by varying the size of the opening in the lens (aperture).
« Posts under Photography