I have always been fascinated by astrophotography but never found the courage to go in the middle of nowhere for an entire night to take shots. So when the editor asked me for a photography tutorial I thought to myself, “What would I want to read about and learn myself that I could share with my readers?” It was the perfect opportunity to brave the night and, together with my partner, who is also a photography enthusiast, go on the quest for some star trails.
In this tutorial I will be taking you through what I did to get the final shot here as well as what I learned for the many other star trail shots to come. After all, practice makes perfect and this was only a first.
What you need
- Camera (one able to take long exposures);
- A fast (f/2.8 for example) wide-angle lens;
- Remote shutter release;
- Tripod;
- A fully charged battery;
- Clear skies with minimal light pollution;
- Time, and lots of it;
- Thermos flask with coffee, warm clothes, something to sit on and something to keep you entertained (that is, unless you’re not into meditation – if you are, you’re in for a treat).
Preparing for your star trail photography
Your shoot preparation is probably the hardest part of star trail photography. I would almost go so far as to say you need all the planets to be aligned to get the perfect circumstances for a great result. Timing is everything. Location is a key factor. You need dark skies, so stay away from light pollution and schedule your shoot for a day when the moon isn’t around. You also need clear skies and as little wind as possible.
When photographing star trails (or any type of astrophotography really), light pollution is one of the biggest factors that can ruin a potentially amazing shot. To shoot crisp looking star trails without that unwanted night sky glow of artificial light in your shots, make sure you get as far away from light pollution as you can. That’s quite a challenge in Malta, but with a little scouting there are a few spots that are suitable for star trail photography.
Your next step is planning the timing of your shoot. Another form of light pollution that may prevent you from getting good results on your star trail photography adventure is the moon. If it’s around and visible in the sky, it will drown out any visible stars so plan to shoot on the day of the new moon. You can get away shooting a few days before or after new moon as long as you frame your shot well away from where the moon is visible.
The weather also plays an important role in the end result. If any clouds are visible and passing through your composed shot you’ll be photographing cloud trails rather than star trails, while shooting on a windy evening will be challenging (if not impossible) because that will cause camera shake and therefore images that aren’t sharp. Finally, although it’s hard to avoid humid nights in Malta, humidity can cause a hue in your images, making the stars appear less bright than you’d want them to be.
Getting the shot
Your aim is to get a series of 30-second exposures, which you will then blend together in post-processing to create your final star trail shot. One very long exposure (in BULB mode) is possible too, but that will cause the sensor to heat up, which may cause hot spots to show on your final exposure. I went for the former with mine.
Step 1: Select the right settings
- Select manual mode to avoid changes in exposure between shots
- Select a white balance setting
- Check that the battery is fully charged, as well as the batteries of your remote trigger
- Set your shutter speed at 30 seconds and select the maximum aperture of your lens, paired with the ISO needed to get well exposed 30-second shots. Guidelines: f/1.4 and ISO400 = 30s; f/2.8 and ISO1600 = 30s; f/4.0 and ISO3200 = 30s; f/5.6 and ISO6400 = 30s
- Set your camera drive to continuous shooting so that shots are taken with minimal interruption
- Shoot in RAW so you have more options when it comes to post-processing
Step 2: Positioning your camera
For a sharp, long exposure, make sure you use a sturdy tripod on a firm surface. Then, look around to find the Northern star (Polaris), to be able to predict the direction of star trails and help you better position your camera and frame your shot. For this, I used Google Sky Maps (Android app), which uses your phone’s gyroscopic sensor to show you in what part of the sky you can find particular stars, constellations and planets.
Step 3: Setting up your other gear
Lens: You’ll want to use a fast lens, and depending on the environment, a wide focal length such as 16-28mm.
Remote shutter release: Ideally, use a remote shutter release to avoid introducing camera shake (which can affect sharpness) and to make it easier to take successive 30-second shots by being able to keep the shutter button pressed continuously.
Step 4: Start shooting!
First you need to focus. Point at Jupiter or a bright star and use your autofocus to lock focus. Then switch to manual focus carefully. Manually adjusting your focus ring to infinity rarely works.
Frame your shot. Although the star of your shot is the actual star trails, consider adding something of interest on the horizon or in the foreground. You will want to get at least 50–60 photos (which takes 25 minutes in all), though experiment and you’ll learn what number of shots works best for a given situation. Of course, the more shots, the longer your star trails will be.
Take a few test shots to start with, to make sure your composition looks good and the exposure you get is spot on. If you have a remote trigger, press the shutter button and put on the shutter lock and for the next 30 minutes or so you can find a way to entertain yourself.
Post-processing
Here is where the fun starts and where all that time out in the cold in a dark, deserted place pays off. There are a few methods to process your images.
The first is using Adobe Bridge and Adobe Photoshop. Manually editing your shots and blending them together in Photoshop takes time and patience, especially if conditions during the shoot weren’t perfect. Start by editing the first RAW file in the series of shots you took to make your adjustments, then synchronise those adjustments across all images. Load all images as layers in Photoshop, making only the bottom layer visible to start with, setting the layer mode to ‘Lighten’. Go through all other layers, making them visible one by one and switching the mode to ‘Lighten’.
Another method is to use software specifically built for star trail photography, such as StarTrax, which will automatically line up all your images and blend them together. The downside is that any flaws like the streaks of an airplane passing through your shot will show in your final image.
The final photo
I know, it isn’t flawless and there’s room for improvement, but it being a first attempt I’m pretty pleased with this. In fact, I’m already planning my next star trail photography session. Here are some things I’ve learned from this experience:
- Planning and waiting patiently for the perfect circumstances is vital.
- A lens that allows you to shoot at f/2.8 (or wider) will give you far better results.
- Be wary of light disturbances. Going for a series of 30-second exposures paid off as I could remove ruined shots caused by passing cars.
- Bring a thermos with hot coffee — you’re waiting in pitch darkness and the cold for a long time.
I hope this has inspired you. Now go reach for the stars.
Article first published in Tech Sunday, Sunday Times of Malta, April 6, 2014