Sunday, May 23, 2010

the sunny 16 rule explained

(written by splatou)
when dealing with old cameras like the lomo lubitel 166b there are no fancy functions like light-metering. therefore, the photographer has to manually estimate the light, and choose a combination of aperture and shutter-speed, given the ISO value of the film to get the correct exposure. as this can be quite hard, some genius came up with the so-called "sunny 16 rule".

in short, the sunny 16 rule say that in sunny conditions (broad daylight), when the aperture is set to f/16, the shutter speed should be set to 1/ISO-value seconds. So if you are shooting with ISO 400, the right shutter speed for aperture f/16 is 1/400 seconds. if you take that as a starting point, you can begin adjusting to your preferred aperture or shutter by adjusting in "stop". in the table below are the normal available apertures. each step up or down in the table is one "stop" up or down. the lower the aperture number, the more the light


when it comes to shutter-times, every double or half (approximately) of the shutter speed, is one "stop" down or up. the slower the shutter speed, the more the light

and here comes the method of applying the sunny 16 rule, using an example.
let's say it is sunny, and you are using ISO 100. but instead of shooting f/16, which would have given shutter speed of 1/100, you wish to shoot f/8. this means you are adding two more stops of light compared to f/16 (see table above). this means you need to balance with two stops LESS light using your shutter speed, in this case 1/400. this can be summarized in the following table, combining shutter speeds and aperture (using ISO 100):


so, in sum, if it is sunny, start at f/16 and 1/ISO, and work your way through stops on aperture and shutter speeds. keep the balance, so if one stop brighter aperture, use one stop darker shutter-speed.

there has also been developed several expansions of the sunny 16 rule, so that it can be used in more conditions than just sunlight. here is a table summarizing this:
ApertureLight Condition
f/11Slight Overcast
f/5.6Heavy Overcast
f/4.5Open Shade/Sunset

the way this table work is: you start with the light condition, and choose aperture thereafter. then set the shutter speed to 1/ISO, and start working your way from there upwards/downwards using stops and keeping the balance between light from aperture and light from shutter speeds.

and to finish it off, here are two shots where the sunny-16 rule is used to determine the exposure. i know they are not great picture-wise, but at least they are well exposed. (the pictures in the previous post are also according to the sunny 16 rule, btw).


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