Get a good exposure without a lightmeter –The Sunny 16 rule

Sometimes when you don’t have a lightmeter at the hand ( handheld lightmeter or a old film camera without through-the-lens light meter), then you may wonder how to set manually aperture and shutter speed of your film camera for correct exposure. Luckily, there is a very usefull rule called “Sunny 16” to help you with a exposure on a sunny day.
The Sunny 16 Rule
The basic guide to photography exposure is very simple. If you have a bright, sunny day, then use f-stop 16 for your camera lens aperture. The shutter speed should then be set to the equivalent of your ISO film speed – or the next number over. For example, if you are using an ISO film speed of 100, your shutter speed should be set to 1/125. More than often, your shutter speed number will be higher than the ISO film speed, but it is much easier to remember that film speed equals shutter speed.
The Sunny 16 rule can also help to determine aperture and shutter speed settings when conditions are not typical sunny days. For example, super bright areas like snow or sand will require you to open one f-stop to f/22 and a hazy sun will require you to close one stop to f/11. This will, of course, require you to change the shutter speed settings. Remember, when opening your aperture you are doubling the amount of light and halving the shutter speed and when closing the aperture you are halving the amount of light and doubling your shutter speed.
Here is a quick table to help you understand the Sunny 16 rule, how it applies to different film speeds, and how different amounts of sun will affect the f-stop and shutter speed.