David VanKeuren's Photography: September 2011

Last night I went out to take advantage of an extraordinary opportunity to photograph the northern lights over Baker Lake. This was my first time photographing the northern lights and as such I learned a few things from my outing. Hopefully next time I will have more successful images to share with the viewers. But in the meantime, let me share what I learned so that it may be helpful to other photographers.

Use your fastest lens and ONLY your fastest lens! By "fast" I mean your lens with the largest aperture. For me, that is my 50mm prime lens with an aperture of F 1.4 . You want to shoot wide open so that you can catch the patterns visible in the aurora as you shoot. If you use a lens with a smaller aperture you will either have to increase your ISO to freeze the action (which will result in unacceptable levels of 'noise' in your image) or you will have to shoot for a longer exposure time, which will result in your aurora losing all detail and looking like a blur and you won't get all those nicely defined patterns.

2) Focus carefully! My images were out of focus for two reasons. The first was because I used my widest aperture which results in a super shallow depth of field, which I thought wouldn't be much of an issue because I was focusing on infinity, but that turned out not to be the case. The second reason that my image was out of focus is because I relied upon my focusing ring to tell me that I was focused on infinity instead of focusing through the viewfinder. However, that was nearly impossible due to how difficult it was to see my subject (the mountain) well enough to focus on it in the dark.

3) Use a tripod. This, thankfully, I did right.

4) Use your lowest ISO setting. I was able to use an ISO of 100 because of the wide open aperture that my lens could achieve.

So, for my next trip I will do the following:

Arrive right before twilight while theres still some daylight. Set up the camera and tripod and pre-focus on the subject. Be prepared to sit around a while.

Try increasing my ISO to 200 and tightening my lenses aperture 2 stops smaller than its widest aperture. This will allow greater depth of field and also, most lenses are at their sharpest at about that aperture. For my lens, that would have placed me at about F 1.8. Thats probably going to be my starting point next time. However, I feel that I could probably go up to F 2.o. ISO 200 may not even be needed as those apertures will still gather a lot of light and be fairly fast. I certainly wouldn't go higher than ISO 200 as noise artifacts would start to become too noticeable.

Fortunately, we are heading towards an increase in the 11 year solar cycle that will yield more opportunities to photograph the Northern Lights and I will have another chance to refine my technique and bring back some better images!

Here are some links for those of you interested in the Northern Lights:

NOAA/Space Weather Prediction Center

Geophysical Institute

Aurora Borealis Forecast

NOAA POES Auroral Activity Page

Wikipedia article on Auroras

Enjoy!