SUNNY 16 RULE

WHAT IS THE SUNNY 16 RULE?

The Sunny 16 Rule is a way to meter for correct exposure during daylight without using

the camera’s meter. 

The basic rule of thumb states that if you have a clear, sunny day and your aperture is at

f/16, whatever ISO you are using, your shutter speed will be the reciprocal value of that

ISO value (ISO X = 1/X seconds shutter speed)

So, for example, if your ISO is 200 at f/16, then your shutter speed will be 1/200 second.

If your ISO is 100, then your shutter speed will be 1/100 second.

WHAT ABOUT APERTURE VALUES?

Ok, so now that we have f/16 out of the way, how can we use the Sunny 16 Rule to

calculate shutter speed values with other aperture values?

So, the way this works is that if you increase/decrease one variable, you have to

increase/decrease at one of the other variables in order to keep the exposure the same. If

one factor goes up by one stop, another factor should go down by one stop, and vice

versa.

So, let’s say that your aperture is f/16, your ISO is 200 and your shutter speed is 1/200. If

you want to open up your aperture by a stop by going from f/16 to f/11, then you have to

go down a stop in either your shutter speed to 1/400 sec or ISO to ISO100.