Photographing the Moon
Since I recently addressed photographing the sun, I thought it was an appropriate time to take a look at the moon.
The moon appears in the sky at about the same size as the sun does. At first thought, this may seem counterintuitive since we all know the sun is in fact much larger, but the moon is a lot closer. After all, a solar eclipse wouldn't be possible if they didn't end up appearing the same size once you factor in both their true size and distance. At any rate, the bottom line on this is that the same rule of thumb applies for determining the size of the moon in a 35mm frame. For each 100mm of focal length, the moon will end up roughly 1mm in the frame. Get a big lens if you want a big moon.
Exposure for the moon is not too complicated. Simply spot meter and shoot as appropriate. Generally, the moon should be metered as being one stop over medium-toned.
Often, however, the problem is that at night the moon is a lot brighter than anything else — you either end up with an overexposed moon, or everything else ends up underexposed. The trick is to photograph the moon when it's visible in early twilight so the subject brightness range isn't so much. Generally, this means the moon will be near the horizon, directly opposite the sun, an area that frequently turns a beautiful shade of pink at twilight. So, you get a moon whose brightness is within the range that can be captured on film with the surrounding landscape, often with a very photogenic sky to accompany it. Not a bad deal, if you ask me.