Ask Dave, March 30th

'Ask Dave' week seven... I get tons of questions each week, and I respond as quickly as possible, and this is week number seven of answering them here too. If you have questions you can email me at Learn@DaveShumway.com.

Question:
From Nannie...
How do I photograph the Northern Lights?

Answer:
Well first you need a relatively clear night in a place where you can see the Northern Lights; but I assume you knew that :) With digital cameras allowing quality captures at ISO400-800, and beyond, shooting Northern Light displays are easier now than ever before. The common problem with shooting the Northern Lights is streaking stars in the shot, and the higher ISO availability of digital comes to the rescue. To avoid streaking stars the general rule is take 600 and divide by your lenses focal length (camera crop taken into account). Some used to say that 800-1000 would work; but I have had that fail me, and 600 never has. Let us look at a few examples. You are in northern Montana using a Canon 7D and a 70-200/2.8L IS II you are shooting at 200mm (you need to zoom in as the Northern Lights are low in the sky). Your 200mm lens is acting like a 320mm lens with the cameras 1.6FOVC, so 600/320=1.9 seconds not much time to make a night exposure, so your lens will likely need to be wide open and your ISO up. Next situation you are in Alaska and the Northern Lights fill the sky, so you take out your 5DII and 17-40/4.0L and are shooting at 24mm. 600/24=25 seconds and that affords you the luxury of a lower ISO and a smaller aperture opening (bigger Av # = smaller opening = more Depth of field).

Another issue in photographing the Northern Lights is dealing with focus in the dark. NO, you should not just turn your camera to infinity, that is a very common thought; but not a correct one (most of the time). What you really want to do is focus your lens at its hyperfocal point for the aperture value you are going to be shooting at. Wide angles are much easier, for example, my 17mm on a full frame camera at f/4.0 focused at 8 feet will, for a normal print size, make everything from 4 feet through infinity appear to be in focus. Alternatively at 300mm and f/22 I would need to focus at 450 feet to have everything from 225 feet through infinity appear to be in focus, for a normal print. (You can always focus further away than the lenses hyperfocal setting and everything from half of that distance through infinity will appear in focus, for a normal print).

Remember…

• Late night sky is normally supposed to be black, not grey as your camera will try to make it.
• RAW is the only way to go.
• The further away from town (light pollution) the better the Northern Lights will look.
• Looking away from town towards the Northern Lights is normally a good idea.

Things you need/should have…

• A tripod is almost a must.
• A Remote Shutter Release. (I am a fan of Intervalometer remotes)
• A bubble level will make your life much easier.
• Live view on your camera will help you get the focus and exposure set properly.
• If you want solid images mirror lockup or live view both paired with a cable release is a must.
• A headlamp, hat, gloves, warm boots/coat/pants, snacks, basically all the things you need to stand outside in the cold.
• I am assuming you have a camera and lens that you can control, and know how to use. If you do not know how to use your camera in the warm, well light, indoors, then you will not be able to use it in the cold, dark, outdoors.

Quality predictions can be found for the state of Alaska here.

If you have more questions just ask. Oh and one confession I need to make… I have not photographed the Northern Lights digitally; but I still know plenty about it from the days gone by, and the advice here can all be corroborated across the internet.

Much of this is a great base for next weeks 'Ask Dave' which is all about shoot star trails.