- Jun 27, 2014
Try to shoot a moon illuminated scene at ISO 200 F16 1/200 and you will discover the moon is merely reflective, and not an emitter. If you took a picture of a rock outside on a sunny day, you'd need to stop your camera down and shoot at low ISO to capture the details on the rock. The same is true of the moon, which is washed out by direct sunlight against a black background. The sunny 16 rule applies to things illuminated by direct sunlight, as the moon is. It does not however apply to things illuminated by moonlight. The moon is not so bright as to require the moon to be an emitter as flat-man suggests. It is no brighter than one would expect.Actually, the moon really is "that bright".
From the film days of photograph, many professional photographers used the "sunny 16" rule to determine exposure when we didn't have an exposure meter at hand, or were too lazy to use one. That rule said when shooting a scene in bright sunlight if you used an aperture of f16, then the shutter speed on the camera would be the reciprocal of the film ISO. That means that if your film was ISO 200 then you could shoot at f16 with a shutter speed of 1/200 sec.
This rule applied pretty well to shooting the full moon too. Day or night you could get good detailed shots of the moon at that "sunny 16" or equivalent exposure. Sometimes some photogs liked to open up one stop from that exposure but basically the moon behaves just like any earthbound object when determining exposure in sunlight.