> > Sunny 16 works fine when the full moon is high in the sky but can lead to > > *serious* underexposure at other times. You need to allow for phase and > > altitude. > > Don't think I understand that. You mean that somehow the moon low in the > sky isn't in bright sunlight? > > I thought the more basic point was that although the moon is made of > darkish rock, we expect it to look "overexposed" (for darkish rock, that > is). > Brian When the moon is low in the sky it receives just as much light as when it is directly above. The difference though is that the light reflected from it then has to travel all the way through the atmosphere making it *appear* dimmer. Just as the sun does towards sunset!!!! The point about it's albedo is indeed true as well. Left to itself it's dark and grey: the way astronomers expect to see it. The point about us expecting it to look like cream cheese: that's preception. It's easy to look bright when all else is dim. ;o) [it's also why I use the Loony 11 rule when the moon is high and add more when it's low. Jeff Conrad is well respected. Read his take on "Sunny 16" in a page entitled "Getting the Right Exposure When Photographing the Moon " http://www.calphoto.com/moon.htm The moon does not behave like a pure lambertian reflector. At full moon it has a comparitively high reflectance - quite different from that a day before or a day after. The explanation is debatable: and way beyond the scope here, but it's enough to know it is. "Sunny 16" always crops up as the answer - the only answer - the one that MUST be obeyed.. It's a neat (very plausible) explanation that tends to lead to slight to huge underexposures. Unless the moon is both full and very high in the sky. Bob Bob
