Transform Your Aurora Photos

Hello. In this week’s Coffee Break photography, I will talk about the settings I use to take these fantastic photographs of the Aurora Borealis. Last Thursday, we had alerts to say there would be a massive storm across Scotland where we could see the northern lights. I headed out around about eight o’clock and found it to be one of the best displays of the Northern Lights I’ve ever seen.

I’m not going to share the exact same settings that I used to take these pictures, but instead, I’m going to tell you about the process that I use to get aurora pictures that look as good as this. My process has three elements: exposure settings, focusing techniques, and editing.

Before we look at exposure, let’s first understand how the Northern Lights can be seen. They’ll usually be visible in two ways. The first is what I think is the preferred one for me, where we see lots of shafts of lights spiking into the sky. Alternatively, there can be a relatively slow-moving type of Aurora, which provides more of a blanket of colour across the sky. As there are two different ways the lights are visible, we must use two different ways of exposing the lights.

Let’s start with the slow-moving one. We want to get as much light as possible into the camera, as there is very little movement. We will use a shutter speed between eight to fifteen seconds to do that. That shutter speed will give us lots of light coming onto the sensor. To get even more light in, we will use a wide-open aperture, so somewhere around f2.8 to F4, depending upon the lens you use; the balancing item we will use to correct the exposure is our ISO. I set my ISO to be about one stop below what the correct exposure is when the camera is making a reading.

I use this technique of one-stop underexposed because of how a camera exposure meter works. At a very high level, the sensor looks for neutral grey in a scene and then compares what it knows neutral grey should look like with the photographer’s exposure. When it’s dark, it is often the case that there is no grey in the exposure. When the sensor can’t “see” grey, it says, ‘If I can’t find grey, I’ll choose the closet thing in the scene to grey, and I’m going to call it grey’. The closest thing to grey in the night sky is black. So, we need to counteract what the camera’s doing and correct the grey sky back to black, which is to underexpose by one stop. This will give us a proper black sky, and everything around it will be correctly exposed. If we use these settings, it should provide us with a really nice flood of green in these exposures.

When we’ve got the conditions we had last Thursday, we need to be more thoughtful in setting our exposure, as the movement is relatively quick. We’re going to change our shutter speed to start around two seconds. Again, set your aperture so it is wide open, and again, use your ISO to get an exposure at minus one on your exposure meter. We will then need to review the images to see how we’re capturing the movement. If the movement is really, really fast, you might need to make your shutter speed faster; take it to 1.5 or 1.3 seconds. If the movement is slower, you can extend the shutter speed, add more light to the pictures, and bring the exposure back to minus one. There is a little bit of trial and error here, but with a little bit of movement either way, from two seconds, you should get to see some nice pillars in your photographs, which now leads us to one of the issues I saw in a lot of the pictures that were coming out on Friday morning, and that’s the focus.

So, there are two ways to focus. Most of the time, your camera will not do a good job of focusing in dark conditions at night. It’s hunting for some kind of straight line, and it can’t find it.

Method one focuses on infinity, which can work well if there isn’t anything close to us. If you look at some of your lenses, you’ll see a little figure of eight, the symbol for infinity, on the lens’s focus ring. If you set the focus ring to the Infinity position, it’s going to, as it says, focus at infinity. If you’re quite a distance away from any foreground interest, this will work well; it will give you a pretty good focus on far-away subjects.

What happens if you’ve got things quite close up, as I did at Portobello Beach just outside Edinburgh? To do this, we’re going to use a slightly different technique. You’ve got the tool you need in your pocket. Switch on the light on your mobile phone and shine it on the thing you want to focus on, maybe three or four meters away. The focus system on your camera should now be able to latch on to the subject and focus on it. Now, if you use the half button press to take your photographs, where you press the shutter button halfway down to allow it to focus and then press the rest of the way down to take the shot, you’re going to need the light to continue shining on the focus point, which will impact the photo.

There are two ways to stop having to have the light on so we can capture the natural scene. Way number one is, once you’ve focused using the light and using the half button press, switch your lens to manual focus. Now, the lens isn’t going to hunt for focus, and you should be able to press the shutter button, and it’ll take the picture focused on where it was initially focused. The second way, and in my opinion, the best way to do it, is to use a technique I would highly recommend. You use a process called back button focus. You can read about it here on this old written blog. I’ll probably do a video about this at some stage in the future.  This means that one button becomes the focus button, and the shutter button does exactly what it says: operate the shutter without focusing. When you take the photograph, it’ll be focused where you were when the light was shining on the subject, and every picture after that will be focused in the same position.

Let’s now come to the final element. Every photograph taken with a camera, particularly when you shoot RAW, is actually quite flat. We need an editing process to enhance the photographs.

Everything will need slightly different editing, and I’m not going to give you a magic bullet for the editing process, as it will be a very personal decision. But the key thing I will talk about is what you do after you’ve edited, and that’s noise reduction. There are various tools for reducing noise in images. As we will be shooting at higher ISO values, the photos will have a degree of noise. My preferred tool choice is DxO PureRaw 4.

Once you’ve edited your images, run them through DxO PureRAW, and most of the noise will be removed. I’ve been so impressed by how well this works at high noise values, even up to 10,000 ISO, and it does a great job of making it look like it’s almost been taken at a native ISO level.

As I said, there are other software options, but I’ve found PureRaw 4 to be an impressive performer. One little tip when using PureRAW4 is that it uses the data inside the raw file. If you make edits where you’re using a spot healing brush, for instance, those aren’t contained in the raw file, so always leave any kind of spot removal until after you finish the PureRaw editing.

This is a very quick overview of how I approach photographing the Northern Lights. We are currently at the height of Northern Lights activity. So, hopefully, in the next few days and weeks, we might see some more really nice, strong storms. If we do, you’re now armed with the process, tools, and technique to get some really excellent Northern Light photographs.