Sunny 16 rule and Exposure Calculators
Sunny 16 Rule
The Issues
Don't let complex metering issues get in the way of enjoying your vintage cameras. The 'Sunny 16’ rule is a method of estimating correct daylight exposures without a light meter. The rule is based on incident light rather than reflected light so the intricacies of the 'zone system' and other systems invented to confuse things don't apply. Reflected light meters can lead to a black cat becoming grey and the White Villages of Spain also becoming grey. You have to compensate for the nature of the subject. With incident light systems, this does not happen. The rule works well for negative film which has a lot of latitude, but not so well for colour slide film where more accurate exposure is desirable.
The Solution
On a sunny day set aperture to f/16 and shutter speed to the reciprocal of the ISO film speed - Job done!
So, on a sunny day using ISO 100 film, set the aperture to f/16 and the speed to 1/100s. The assumption is that the sun is at least 30 degrees above the horizon. In the UK that's 10am - 5pm on a summers day from May to August and 11am - 4pm for April and September. A simple and effective way to check if the sunny 16 rule can be applied, at any time in any country, is to ensure that the length of your shadow is less than 3 paces.
From this basic setting, other settings for different weather conditions, different apertures and different shutter speeds can be calculated. The information for working out these settings can be found elsewhere on the web. Simply use the calculators below to be able to enjoy your vintage camera without stress.
The Calculators
These calculators have been designed with vintage cameras in mind. The speed and aperture settings are what you might find on these old cameras. Negative film is very forgiving and can be overexposed by 3 stops or underexposed by 1 stop without much effect on the final image. If the settings don't tally with the camera you are using, err on the side of overexposure. This means choose a lower aperture number or a slower shutter speed.
Remember - The assumption is that the sun is at least 30 degrees above the horizon. In the UK, that's approximately 10am - 5pm on a summers day from May to August and 11am - 4pm for April and September. For any country at any time, the length of your shadow should be less than 3 paces.