The "Sunny 16" rule is a very simple method to determine correct exposure without the use of a light meter. I'm sure for many, the idea of taking photos without a light meter is a daunting thought, but the beauty of this "rule" is that it is incredibly simple! The thing that makes it simple is the fact that it effectively works on the basis that you are using incident light as opposed to reflected light. A light meter in a camera takes a reflected reading from what you point the camera at. So if you point it at a white subject the camera will often under-expose and if pointed at black, the camera will often over-expose. (Paul has written an article about this that goes into a lot of detail that we will be publishing in due course) An incident reading would be the light falling on to a subject rather than the light reflected from it! Out in the open, on a sunny day, the light hitting a subject is always going to be the same. Because it is pretty much a constant, the correct exposure for taking a photo is also pretty much a constant! And this is where it gets simple. The correct exposure for taking photos out in the open on a sunny day is: aperture = f/16 ISO = x shutter speed = 1/x Simply set the camera to f/16 and set the shutter speed to the same value as the ISO setting being used, so... aperture = f/16 ISO = 100 shutter speed = 1/100 or aperture = f/16 ISO = 200 shutter speed = 1/200 That's the sunny 16 rule... simple! So what if its not sunny? Well, this principle can be expanded upon quite easily if you know a few simple rules... f/11 = Slightly Overcast f/8 = Overcast f/5.6 = Heavy Overcast f/4 = Dawn and Dusk The sunny 16 rule can also be used as a starting point for more creative use. Maybe you don't want f/16. Maybe you want f/5.6. You just adjust the other settings accordingly... f/5.6 (plus 3 stops) ISO 100 Shutter 1/800 (minus 3 stops) Knowing all this, and with a little understanding of how to use a camera, there is no reason you shouldn't be able to take photos without a light meter! Since the invention of digital cameras, you can now practice without wasting film! And, once you feel you have the hang of it why not go out and take some shots with a meter-less 1950's zone focus film camera? I can guarantee it will be the most satisfying thing you do this year! Winter Sun In addition to the above I should point out that the sunny 16 rule is based on summer time conditions! In the winter the sun is lower in the sky, because of this some adjustments are necessary when shooting outside summer conditions. This will vary depending on where you are in the world... As with anything in photography, practice makes perfect!