Photography help: What is aperture, shutter speed and focal length?
Apeture: the opening within the lens. The word literally means “hole.” The smaller the number, the larger the hole – and the shorter the depth of field (that which appears in focus.) If you are doing a portrait and want only the person in focus, use a small number like 2.8 ; if you want everything in focus use a large number like 22. These relate to focal length, see below. Each number in sequence indicates a doubling/halving of the amount of light between it and the next number: 2.8 lets in TWICE as much light as 4, which lets in twice as much as 5.6, et cetera. (I emphasize twice as Fraud has it wrong: nothing is 3x in photography. It is either double, or if you back the other way, ƒ4 lets in 1/2 the light of ƒ2.8). Shutter speed: the amount of time the shutter is open allowing light to pass through the lens and hit the film plane (or sensor.) The numbers expressed are fractions: the larger the number the less time the shutter is open. A very short shutter speed is 4000 – you can fre
