It’s the time for many of us to see and photograph the auroras. Sadly, that generates a lot of invalid arguments about how the images should or should not look. But here's how you can capture them in all their glory.
An interesting discussion developed in the comments section of a previous article I wrote. I was about whether my use of in-camera and post-production digital effects could still be called photography. It’s an old argument, but it got me wondering where we draw the line, especially when photographing the aurora.
I’ve spoken before about the rift that lies between reality and a photograph; our eyes only pick up a fraction of all the information that makes up reality. Some physicists are struggling with the nature of reality and claim that our universe is just a “product of quantum machinations in a lower dimensional setting.” In plain English, they are theorizing that reality is an illusion.
However, if, as The Beatles’ song Strawberry Fields Forever suggests, nothing is real, and the world around us is an illusion, does anything matter? That idea doesn’t help us in our day-to-day lives. We must rely on naïve realism and believe that the world we see around us is real and as it is, otherwise we can neither function in our daily lives nor in society.
Nevertheless, a photograph is one more step away from actuality. So, although we adopt a naïve realistic approach to what we see about us, with photos it still isn’t as simple as some would have you believe. This is illustrated best when we come to photographing the aurora. Why? Because our cameras reveal what our eyes cannot see.
What Is the Aurora?
We are fast approaching Solar Maximum. It’s the time when the 11-year cycle of the sun’s magnetic poles' flipping occurs. Large numbers of sunspots appear, and the sun’s irradiance increases by 0.07%. There are solar storms with Coronal Mass Ejections (CMEs) spewing enormous amounts of plasma and extending magnetic fields far into space, including at the Earth.
CMEs take 15-18 hours to reach us. They vary in speed from 250 kilometers per second (km/s) to nearly 3,000 km/s. In comparison, the fastest manmade object was the Parker Solar Probe, which reached speeds of a sluggish 147.5 km/s. Putting that into context, the maximum speed limit on an Interstate Highway in the USA is 0.033 km/s.
When these high-speed energized particles slam into our planet’s upper atmosphere, they are deflected by our magnetic poles. They then interact with the molecules of mainly oxygen in our upper atmosphere. Consequently, those impacted molecules produce energy that they release as photons, i.e. light.
What Causes the Different Colors in an Aurora?
When hitting the oxygen molecules at altitudes of around 60 to 190 miles (100 to 300 km) up, the aurora produces green light. Less frequent are red auroras as those are associated with more intense solar activity. They happen when scarcer oxygen molecules at higher altitudes, 180 to 250 miles (300 to 400 km), are excited by the solar radiation.
You may get blue and purple auroras if there is even more intense solar activity. Even more rare, they happen when the solar radiation penetrates to 60 miles or less. Sometimes, all those colors may mix and you will see pink and yellow auroras.
Don’t worry about that talk of radiation and high-energy particles. You are quite safe, protected by our atmosphere. However, solar storms can play havoc with artificial satellites. If you lose your GPS signal or your satellite TV at night, take a look at the sky. There may be an aurora.
How Do We Predict an Aurora?
Like on Earth, solar weather is somewhat unpredictable. The 11-year cycle was supposed to peak in 2025. Scientists are now predicting it to reach its zenith next year. However, we are getting some great displays already.
Astronomers are constantly monitoring the sun and know if there is a solar flare sending plasma our way. Consequently, news sites often mention beforehand that it is going to happen. However, I rely on an app called AuroraWatch UK. There are plenty more that you will find if you search your Play Store or App Store.
Often, if you see an aurora, there will be another seven days later. I have no idea why.
Where Can You See the Auroras and What Do They Look Like?
The nearer you are to the Earth’s poles, the more likely you are to see the aurora.
Here, in the North of England, above the 55-degree parallel, we occasionally see them. I live just about on the same latitude as Pikwitonei in Manitoba – a place so remote that the Google Street View car hasn’t been there, but it looks like a fantastic place to avoid light pollution and see them even better. The aurora isn’t very bright, so escaping from the city will help you see it. Even moonlight can hide it from view.
The Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights) are impressive to observe. However, you won’t necessarily see the colors. Our eyes’ retinas detect light and comprise rods and cones. Cones detect color and don’t work well in low light. Therefore, the aurora is likely to appear as white light in the sky.
If you can see color, it is most likely going to be green. That’s because of the three primary colors: red, green, and blue. We have as many green-detecting cones as red and blue added together. That’s why those color proportions are used in the Bayer pattern of camera sensors; they mimic our retinas.
Our camera sensors can collect more light if the shutter is left open. Also, the objective lenses of our cameras are far larger than our eyes’ pupils. Therefore, they gather a greater amount of light too. This is why astronomers favor telescopes with large objective lenses over more powerful magnifications.
How to Set Your Camera to Photograph the Aurora
You will need a tripod to keep the camera steady. If your camera or lens has in-built image stabilization, the usual advice is to turn that off when on a tripod, although on my camera, I never find it necessary and leave it on auto. It's also a good idea to use a remote trigger or set the self-timer and use the camera in silent mode (the electronic shutter) to prevent any camera movement.
Choosing and Setting the Lens
Ideally, you want a fast lens set with its widest aperture. It should have the biggest objective lens possible. I used the OM System M.Zuiko 12-40mm F2.8 PRO lens, shooting wide open at 12mm. My M.Zuiko 7-14mm F/2.8 PRO lens would have sufficed equally well. A short f/1.4 prime lens would have been even better.
Where to Focus
As with everything in photography, there is a compromise to be made. That wide aperture means a shallower depth of field. Therefore, the closest hyperfocal distance, the point at which you get the maximum field of sharpness is further away than it would be with a small aperture. So, if you want to combine foreground interest with the aurora, your focus point mustn’t be too close to your camera or the aurora and the stars will be unsharp, unless you employ focus stacking, that is.
Conversely, if you are using a wide angle lens, that gives you more depth of field, which works to your benefit.
An app like PhotoPills will help you to calculate the hyperfocal distance. You can, of course, focus beyond that distance, and even on the aurora or stars, but more of the foreground will be blurred as a result.
I generally use manual focus, relying on the focus assistance that highlights the in-focus area. When it's very dark, I use a torch to illuminate something at or beyond the hyperfocal distance.
Setting the Shutter Speed and ISO
The aurora moves. Fortunately, it does not appear to be moving that quickly where I am because I am farther south. So, a shutter speed of 8-10 seconds using a wide angle lens gives me a good resolution of it. If you are closer to the aurora, i.e. closer to one of the Earth’s poles, it will appear to be moving faster. Therefore, you may need a faster shutter. Fortunately, it will also be brighter too.
Either way, the shutter and aperture combination may not be enough to expose the image correctly, so increasing the ISO may be necessary.
This highlights the importance of reducing ambient light, which can overexpose all or parts of your picture. As I mentioned, a moonless night and shooting well away from streetlights is ideal.
Also, it’s worth noting that if your shutter is open for too long then stars in your picture will start to elongate because of the rotation of the earth, although you probably won’t have to worry about it.
As a rule of thumb, you can apply the 500 rule to ensure stars remain as points and not lines in your photo. For a 35mm sensor camera, divide 500 by the focal length of the lens. So, for a 25mm lens, you would have a maximum exposure of 20 seconds. That may be too long for shooting the aurora anyway and you will want a shorter shutter speed to stop movement blur.
With a Micro Four Thirds camera using a 25mm lens, you would halve that time to 10 seconds. That would be about the right shutter length for me to capture the aurora, anyway, although I used a 12mm focal length, so in theory, I can have the shutter open for over 20 seconds without elongating the stars. But, that is far longer than I would want for the aurora because it would show movement blur.
Of course, increasing the ISO will increase noise, especially with longer exposures. Fortunately, newer sensor technology in contemporary digital cameras helps keep noise levels to a minimum, and modern noise reduction such as those found in DxO PhotoLab, ON1, Topaz AI, and Lightroom is incredible for giving clean sharp images.
How About Developing the Images?
This comes back to where I started. The sensor has collected a lot of raw data, that is, if you are shooting raw, and I advise that you do. That data, when it is turned into a picture you can view in your camera, has been processed. The clever technicians behind your camera’s software decide what your picture should look like. However, the technicians who work for your camera company are not the same as the people who work for Adobe, nor are they the same people who work for DxO, Capture One, ON1, and so forth. They will all interpret your photo differently.
Which of them is right?
All of them and none of them are. Similarly, if you want to adjust the photo to appear how you want it to be, it’s entirely up to you. If you want to increase the saturation of the colors or turn it to black and white, or if you want to rely on those camera technicians’ interpretation of reality, it’s entirely up to you. Any variation of how the raw data is displayed is equally valid. Develop it how you like. Anyone who criticizes your choice – and I have seen some ill-natured criticisms about others' photos on Facebook – then they are just showing their own lack of understanding.
If someone else likes it, great. If they don’t, then that’s only their subjective viewpoint being different from yours. What is invalid is saying that your interpretation of the raw data is wrong, unless they accept that every other photo is equally wrong.
Personally, I find the nighttime landscape and aurora images straight out of all cameras look too flat for my taste. Therefore, some adjustments, especially to the tonal contrasts, are needed. I also increase the brightness of shadows in the foreground and reduce the brightness of the highlights. Then, I like to increase the brightness (not the saturation) of the aurora’s colors to make them stand out. Nighttime photos can also stand a lot more mid-tone contrast than daytime shots.