Aurora photography - a case study in capturing an image
I'd thought some of you might appreciate a bit of insight as to how I photograph and process my aurora shots. Each one is different depending on the brightness and intensity of the display. But I've picked one photo I took earlier this week at Portmuck, Co Antrim.
It was a very modest aurora - and there was quite a lot of cloud and a fair amount of ambient light pollution (including quite a lot coming across the Irish Sea from Troon).
Composing the photo
One of the keys to any decent photo is the composition. The same holds true for aurora photography. Portmuck has many good options in this regard, and I took up position on the sea wall as the waves crashed in around me (and over the sea wall just behind me too!). This allowed me to get the rocks in for foreground interest and I knew with the long exposure that I would get some cool effects with the waves. In the far distance was a lighthouse. And on the horizon, between the cloud, the aurora started to shine through. All was set!
I had set my focus manually on a far off house light. I use an 11 mm lens typically for my aurora shots, so this meant I could go for a 30 second exposure without worrying about star trails. I opened my lens right up to f/2.8. That just left me with the ISO setting. Given the amount of ambient light, I didn't feel the need to push it too high, so I set it at ISO 1000. Then I started snapping away, checking the histogram to ensure I was getting the exposure right. And, of course, I was shooting in RAW to allow me to extract the best shot in post production.
I could have pushed the ISO up higher to make the image appear brighter when I initially imported it into Lightroom, but it would add more noise. And I knew from experience that I had enough to work with in the image to pull up the darks and shadows in post production. That way, I was more in control of just how much noise would appear in the final version.
It really is vital that you get the shot right in-camera. If you do, the post production will simply enhance an already sound shot. Get it wrong, however, and even the post production will not be able to save you without seriously degrading the quality of the final product!
My post production is done in two stages:
This is the equivalent of the old processing of negatives in the dark room and the vital first step in getting the shot right. Below are the main adjustments I made, and the before/after comparison. Shooting in RAW means that the camera collects and keeps a lot more information than it would if you shot a jpg. This means that the image as presented initially in Lightroom is just one version of it. It's possible to make quite significant adjustments which - in the early stages anyway - use actual data the camera has collected rather than extrapolating as it would have to if you were processing a jpg.
The main adjustments I made are shown in the screen grab and include:
- boosting Shadows and Blacks
- boosting the Whites
- reducing Highlights that were blown out by boosting the Whites.
These adjustments increase the amount of noise in the image, so I boosted the Luminance button in the Detail section a bit to reduce this (but not too much, or the image takes on a false plastic look). While in the Detail section, I added a bit of Sharpening to the image too.
Finally, I used a local adjustments brush to bring out some more whites in the breaking waves.
I try to make the vast majority of my adjustments in Lightroom as it uses the data stored in the RAW file. As you can see from the screen grab above, you really can push and batter your RAW file quite considerably!
Once I've made all the Lightroom developments I want to, I export the shot to Photoshop. The Layers and Layer Masks in Photoshop allow for some very fine adjustments.
The first thing I did was to add a Curves Layer to the sky, giving it a gentle S-curve to boost contrasts a little. This also tends to cause the image to become a bit more saturated too, and I liked the way it enhanced all the varied colours in the sky.
Next, I added a Curves Layer for the sea, again giving it a very gentle S-curve.
The only thing that remained was to do a bit of dodging to the water. I added a Dodge Layer and made some adjustments to pull out the whites of the misty waves.
I hope that gives you a bit of insight into my work flow and how I produce my images. Happy shooting to you all!