20mm, f1.8, 6 seconds, ISO 1600
To begin with:
Set your camera on manual mode.
Start with an ISO of at least 400, and go higher if you need to. Obviously, a camera that can handle high ISOs without much noise is a huge advantage. We often shoot with an ISO of 1600 or even higher.
Open the lens to its widest aperture, or close to it--4.5 or under should work fine. Faster lenses give you much more leeway. Our favorite lenses have maximum apertures of 1.8 and 2.8.
Set the shutter speed for around 15 seconds to start with. Make it longer if the aurora is not noticeable, or shorter if the aurora is over exposed. With an ISO of 1600 and a lens at f1.8 we can often use shutter speeds in the 4 to 6 second range. Sometimes the aurora moves a great deal, and a fast shutter speed helps capture the patterns. With a fairly wide lens, the stars will begin to streak if the shutter is open for longer than 25 seconds. And the longer your focal length, the less time before the stars begin to streak.
Pre-focus the lens to almost infinity--don’t go all the way to the infinity mark. After pre-focusing, switch the lens to manual focus so you don’t accidentally re-focus after you have your shot composed.
Use a cable release or self-timer to trip the shutter.
17-35 @ 19mm, f2.8, 6 seconds, ISO 1600
Things to keep in mind:
In most instances, a wide angle lens will give you the best results. If the aurora is wide enough, a fisheye can be fun to try, although it does make the stars even smaller.
Usually you can see well enough by the light of the aurora to compose your images.
Bring a small flashlight, and be sure not to point it at, or in front of your lens (or anyone else’s) while your shutter is open (unless you are painting some of the foreground elements).
If you use mirror lock-up, hesitate a second or two between raising the mirror and tripping the shutter or the camera movement will blur the photo.
The foreground is often what makes or breaks a night photo, although with the aurora, the patterns of light can overwhelm the rest of the composition. Still, if you include elements that are closer than 10 feet, they may be out of focus, and if you focus on them, the stars may be objectionably blurry. You just don’t have much depth of field to work with. Luckily, wide angle lenses offer more depth of field automatically, and the entire scene is usually in focus from 10 or 12 feet to infinity.
The more you know about operating your camera without having to look at all the buttons and dials, the easier it will be to work in the dark. Be sure you know where the button is that lights up the LCD panel, at least.
You probably won’t know exactly what you’ve gotten until you can look at the images more closely on your computer.
17-35 @ 19mm, f2.8, 13 seconds, ISO 1600, taillights used to paint trees in foreground.
EXPERIMENT AND HAVE FUN!!