“Sunny 16″ is the rule that says to set your aperture to 16 (usingAV mode on your camera) in bright sun-lit situations. If you’re in fullmanual mode, remember ISO should be at 100. And for shutter speed, try1/100 or 1/125. For faster shutter speeds, you may find it helpful tobump up the ISO to 200.

A variation of Sunny 16 is to set your shutter speed nearest to thereciprocal of the ISO speed and the aperture accordingly. The followingtable from the Wikipedia Sunny 16 entry should help: