If you live in a high or a low latitude, you’ll have a greater chance of seeing an aurora, that shimmering curtain of light that sometimes appears in the night sky. It’s is caused by high-energy particles from the Sun impacting on our atmosphere and being funneled by the Earth’s magnetic field towards the north and south poles. Photos of these are always striking and combining one with a landscape gives a very appealing image and provides a sense of scale for the aurora itself.

Here are a few hints to get you started taking your own aurora photos. Don’t be afraid to experiment with different exposures because night photography pretty experimental. There are no hard and fast rules and your camera’s metering won’t be of much help in determining an exposure. This is trial-and-error photography and experience will help you gauge what exposures will work and which won’t.

 

© Giuseppe Menardi, 2003. Canon EOS 60, 16mm f/2.8 Sigma lens. To see more photos, click here

 

When the aurora is extremely bright (it can actually cast a shadow!) it is usually moving too fast for ISO 100 films or digital sensors. A nice glow that stands out and moves reasonably slowly will be recorded better. Try lots of different exposures when shooting at night; occasionally you will get some pleasant surprises.

On those rare occasions I get to see the aurora and point a camera at it, I start out with an exposure of 15 seconds and increase the exposure time in 30% increments.

Reciprocity Failure

I need to mention something here that applies to films but not digital sensors. It’s called reciprocity failure. To cut a long story short, what it means is that film responds differently outside the standard shutter time ranges of 1 sec to 1/4000 sec. How the film responds depends on the emulsion (where the image is recorded) which, in turn, depends on the manufacturer. The upshot, though, is that the greater the shutter speed, the slower the film reacts to light. So, as an example, if you want a 1 minute exposure, you expect to leave the shutter open for 1 minute. But reciprocity failure means that the film doesn’t respond in a linear fashion and you actually need to leave the shutter open for longer in order for the film to collect the amount of light you expect it to in that 1 minute period. That might mean leaving the shutter open for a minute and a half. The color balance of some films is also affected by very long exposures. Again, which color cast predominates or which colors respond less with increasing exposure time depends on the film and manufacturer. If you want a more technical explanation of what happens to film and why it doesn’t respond the way you might expect during long exposures, then visit this page.

Digital sensors respond to light linearly and do not suffer from reciprocity failure. So, if you leave the shutter open for 1 minute, you do get one minute’s worth of light falling on the sensor. There’s also no color shift or loss of response with certain colors during a long exposure. This is one advantage digital sensors have over film.

Taking The Photos

Film and digital sensors record a lot more than the eye can see. The longer the exposure, the more detail is recorded. Leave the shutter open for too long though and parts of the image will start to burn out. Figuring out the right exposure under aurora conditions is more art than science, but the table below will give you a good idea of at least where to start:

You’re unlikely to have an f/1.4 lens so instead, use faster films with f/2.8 lenses. Depending on its intensity, leave the shutter open for 25 to 40 seconds with f/2.8 lenses and use ISO 400 film of a digital sensor set to ISO 400. If you only have f/3.5 or f/4 lenses use an ISO 1000 film and expose for 20 to 40 seconds. If you use a digital camera, set your ISO rating to 800 or 1600.

Whatever settings you do use, remember that an overexposed image is better than an underexposed one. When using faster films, try using negative film rather than slides as they seem to have a finer grain. However, the way films are being improved all means you should select a film that suits you personally.

Processing

If you shoot auroras using a digital camera, then all your processing will be carried out using an image manipulation package such as Adobe PhotoShop or Paint Shop Pro and you will have fill control over the final result.

It’s not that simple where film is concerned. To get the “what you see is what you get” (WYSIWYG) result, you need to use slide film as all that’s involved is the chemical processing that goes on with any slide film. With negatives, the photo labs will have problems trying to balance the print, both in terms of how bright the image is printed and the colors in the print. Don’t expect a WYSIWYG result or you will be disappointed. If you have a photo lab you can talk to, explain to them what you want – maybe they can accommodate you.

One of the best things you can do is shoot a couple of frames of normal scenes on a new film. This will let the machines in the lab know where the frames are and will prevent your images from being cut in two if the machine can’t determine the start point on the film. You could also ask your lab to use the first or second frame as the master for all the other exposures on the roll rather than have the machine auto-expose each print.

The best thing to do though is have your negatives scanned and then do any manipulations to the image in the likes of PhotoShop.

Aurora Resource

The aurora is always there. Sometimes it’s stronger and more visible. Sometimes it’s very active and extends down to more southerly latitudes so folks who don’t live in the arctic circle get a chance to see it. Below are some resources that will help you find out if seeing one is likely in your neck of the woods. The image in the table below shows the current position of the northern aurora. Click it for more info.

 

Aurora Information Sites

Worldwide Aurora Forecast
The forecast map will show the approximate Universal Time (UT) of greatest activity for your longitude.

Aurora Monitor
Real-time notification of activity & updates of conditions during significant solar, geophysical and auroral activity events.

Aurora WebCam
Live aurora webcast from Mt. Aurora in Alaska.

 

Other Weather Pages:

 

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Aurora Videos: