Sunlight vs. Moonlight

Position mouse cursor over image to see moonlight view. Move mouse cursor off image to see sunlight view.

Mt. Whitney, California, July 3, 1993

How much brighter is the sun than the full moon? Most people would probably guess a hundred times, or maybe a thousand. But actually, the sun is about 400,000 times as bright as the full moon!

These two photos illustrate that dramatic difference. They show the same scene illuminated by sunlight (the first photo) and moonlight (the second photo), taken with the same lens at the same aperture. The daylight photo required an exposure of only 1/1000 second. But to get the equivalent exposure at night by the light of a full moon, I had to keep the shutter open for 2 1/2 hours! *

As bright as the light of the full moon may seem, it pales beside the awesome brilliance of the sun!

* If you do the math, that's actually a factor of 9 million -- because the film itself loses sensitivity at low light levels.