How to photograph a lunar eclipse

Tonight the moon will be eclipsed by the Earth which will turn it red for a few hours from about 10:44pm. I’ll be outside with my 20D and a Canon 75-300mm zoom hoping to grab a few shots, but first it’s important to know a few things:

• The moon shines by reflecting light from the Sun and the Earth, it’s bright.
• The night sky is dark which will fool camera sensors.
• All celestial bodies are in motion. You won’t see it from moment to moment with your eyes of course but even a 1 second exposure of the night sky will produce an image that captures that movement.

What can you do? When photographing the moon normally, you expose as if you were shooting at midday on a bright sunlit day. The eclipsed moon isn’t as bright though. If you can, shoot in manual mode. Open your aperture as wide as possible on your lens (smaller f numbers), and take a few shots with different speeds. That’s called bracketing and is really easy and inexpensive with digital. Use the LCD screen on your camera and most importantly the histogram function – that will tell you if your image is exposed properly.

With my lens zoomed in it opens to f5.6, and I found that an exposure of 1/125sec gives a slightly underexposed shot of the moon. Start around there and work your way up and down the exposure times. If you’re using a digital camera it’s costing you nothing.

As you’ll be using a zoom lens, make sure that you have a tripod handy. It also helps to have a cable release too, but if not, use your camera’s timer function to reduce shake.

Here’s an excellent guide to shooting the moon. That guide recommends the “sunny 16” rule. Shoot at f/16 and bracket from there, but the eclipsed moon is much dimmer than a full moon. If you search around there’s a wealth of information online about photographing the moon. Good luck!

The picture above was shot on November 19th, 2005, colour corrected and sharpened but not resized. That’s about as big as a 300mm lens on a Canon 20D will do without extra magnification. It’s getting foggy outside. I hope it clears in the next hour!