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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 ...
On a sunny day at ISO 400 and aperture at f /16, set shutter speed to 1 / 400 or 1 / 500 . Shutter speeds can be changed as long as the f-number is adjusted accordingly, e.g. 1 / 250 second at f /11 gives equivalent exposure to 1 / 125 second at f /16. Exposure adjustments are done in a manner that retains the EV ...
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 ...
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 any given shutter speed, a flash device can only fill shadows to 50% the contribution from the sun out to a certain distance; at a camera's X‑sync shutter speed, no change in ISO sensitivity—and accompanying f‑stop setting—can influence this proportional relationship.
GN = distance × f-number. One needs to specify the film or sensor ISO speed, and it is conventional to quote for ISO 100/21°. The distance can be in feet or in metres, the units to be specified. [4] GND: Graduated neutral density. A type of neutral density filter in which brightness is reduced more on one side of the filter than on the other ...