If you have ever watched photography videos on YouTube you sometimes heard people talk about the “Sunny Sixteen” Rule to determine exposure. This is an old way of determining exposure without the use of an exposure meter or to just verify your meter is working correctly when photography was all done on film.
Now with newer DSLR cameras they have built-in light exposure meters that do the work for you. While this is a great bit of technology it sometimes does not work very well or get it completely correct. This is why you should learn to use this classic rule to help you properly expose your images when you need it.
Here is the rule: In Daylight Your Shutter Speed = 1 / ISO (Read: One over ISO)
On a sunny day, with an exposure of f/16, the correct exposure requires a shutter speed closest to the reciprocal of the ISO. Of course you can use a larger aperture if you adjust your shutter speed accordingly.
To help demonstrate this rule the following exposures are based on using 200 ISO*.
|Sunny day on snow or light sand||1/500 sec @ f/16 or 1/200 @ f/22**|
|Sunny day with distinct shadows||1/200 sec @ f/16|
|Hazy sunlight with soft shadows||1/125 sec @ f/16 or 1/200 sec @ f11|
|Cloudy, bright with no shadows||1/60 sec @ f/16 or 1/200 sec @ f/8|
|Heavy overcast of open shade||1/30 sec @ f/16 or 1/200 sec @ f/5.6***|
*Some cameras do not have a shutter speed of 1/200 sec so use 1/250 sec.
** Snow and Light Sand tend to reflect more light back onto the subject to you need a full stop less to compensate for it.
*** You can even open you Aperture to f/4 if very dark, or even f/2.6 if needed.
Thank for reading