I’m going to start posting photography tidbits and links that I find here when I think they could benefit someone else, or when I know I’d like to keep them somewhere safe.
For instance, a good starting point for exposure is the Sunny 16 Rule:
In bright sunlight, according to the sunny f/16 rule, the correct exposure for a front lit 18% medium grey is 1/ISO at f/16, or any equivalent exposure.
So if you’re shooting Illford Delta with an ISO of 100. The sunny f/16 rule says that the correct exposure is 1/125th of a second (125 is the number closest to ISO 100) with an aperture of f/16.
It could be any equivalent. An exposure of 1/250th sec. at f/11 is exactly the same – except for the difference depth of field.
When the day isn’t clear and sunny, you then have to adjust the exposure. Bob Harris was one of the speakers at the NECCC conference at Amherst last year speaking on this very topic. His Harris Photoguide for Xisting Light ($11.95 from Harris Photoguides, 83 Rock Beach Rd., Rochester, NY 14617) shows that with hazy sun you must open up one stop from the sunny 16 exposure, two stops on cloudy bright days, three stops on heavy overcast days, etc.
SUNNY 16 CHART
Aperture Lighting Conditions Shadow Detail f/16 Sunny Distinct f/11 Slight Overcast Soft around edges f/8 Overcast Barely visible f/5.6 Heavy Overcast No shadows
Good to know.