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An example of the use of f-numbers in photography is the sunny 16 rule: an approximately correct exposure will be obtained on a sunny day by using an aperture of f /16 and the shutter speed closest to the reciprocal of the ISO speed of the film; for example, using ISO 200 film, an aperture of f /16 and a shutter speed of 1 ⁄ 200 second. The f ...
Illuminance is measured using a flat sensor; if the common value of C = 250 (unit: lux s ISO=lm s/m 2 ISO) is used, an EV of zero (e.g., an aperture of f /1 and a shutter time of 1 sec) for ISO = 100 corresponds to an illuminance of 2.5 lux (0.23 fc). At EV = 15 (the "sunny sixteen" amount of light) the illuminance is 82,000 lux (7600 fc). For ...
On a sunny day at ISO 100 ("100 speed film"), the aperture is set to f /16 and the shutter speed (i.e. exposure time) to 1 / 100 or 1 / 125 [2] seconds (on some cameras 1 / 125 second is the closest available setting to 1 / 100 second). On a sunny day at ISO 200 and aperture at f /16, set shutter speed to 1 / ...
For example, the photographer may prefer to make his sunny-16 shot at an aperture of f /5.6 (to obtain a shallow depth of field). As f /5.6 is 3 stops "faster" than f /16, with each stop meaning double the amount of light, a new shutter speed of (1/125)/(2·2·2) = 1/1000 s is needed. Once the photographer has determined the exposure, aperture ...
The ISO arithmetic speed has a useful property for photographers without the equipment for taking a metered light reading. Correct exposure will usually be achieved for a frontlighted scene in bright sun if the aperture of the lens is set to f/16 and the shutter speed is the reciprocal of the ISO film speed (e.g. 1/100 second for 100 ISO film).
For example, f /8 lets four times more light into the camera as f /16 does. A shutter speed of 1 ⁄ 50 s with an f /4 aperture gives the same exposure value as a 1 ⁄ 100 s shutter speed with an f /2.8 aperture, and also the same exposure value as a 1 ⁄ 200 s shutter speed with an f /2 aperture, or 1 ⁄ 25 s at f /5.6. [citation needed]
For example, an EV of 10 may be achieved with an aperture of f / 2.8 and a shutter speed of 1/125 s. The same exposure is achieved by doubling the aperture area to f / 2 and halving the exposure time to 1/250 s, or by halving the aperture area to f / 4 and doubling the exposure time to 1/60 s; in each case the response of the film is expected ...
Many digital cameras have a display setting and possibly a physical dial whereby the photographer can set the camera to either over or under expose the subject by up to three f-stops in 1/3 stop intervals. Each number on the scale (1,2,3) represents one f-stop, decreasing the exposure by one f-stop will halve the amount of light reaching the ...