A beginner’s guide to astrophotography
Want to snap a pic of the Milky Way or get a cool-looking star-trail photo? Read our beginner’s guide to astrophotography for some top tips and tricks.
Words and Images by Matt Williams: There’s nothing better than getting away from the city for a couple of nights, or longer. Fresh air, dirt roads and sitting around a campfire at the end of the day. Then there’s the dark, dark skies – but just because the sun’s gone down, doesn’t mean you have to put your camera away.
What will you need?
Show me an off-roader who doesn’t take a camera out with them. The great thing is, the majority of these cameras are more than capable of bagging a great photo of the starry skies above. So, your camera’s sorted. What else do you need for astrophotography?
Let’s talk lenses
Firstly, you’ll want a lens with a large aperture to allow as much light as possible, ideally in the f2.8 to f4 range. The Milky Way is pretty huge, so a lens with a wide field of view will make it easier to capture as much of it as possible. A 14mm to 16mm lens is ideal. The wider field of view will also allow you to use longer shutter speeds to gather more light.
Keep it steady
A sturdy tripod is essential as most exposures will be between 15 and 30 seconds. Don’t skimp here, a good tripod will last a lifetime. Just make sure it’s not so heavy that you don’t want to carry it.
See what you’re doing
It’s dark out there, so you’re going to need a torch. Better still, get a head torch, that way you will have both hands to work your camera and controls.
Remote trigger…you’ll need one of these
An intervalometer will allow you to trigger your camera remotely, which prevents vibrations. An intervalometer will also allow you to make time-lapse sequences and star trails. These days, some cameras can even be controlled by your smartphone or may have an in-built intervalometer.
When it comes to astrophotography, planning is one of the most vital factors, which will lead to a successful image being captured. If you haven’t been to a location before, try to visit it in the daytime first, as this saves a lot of time stumbling around in the dark. Knowing where the stars will be, at any given time, will also help you when planning your composition. This is where your trusty smartphone comes in handy. Apps like PhotoPills provide you with sunrise/sunset times, along with moon phase and the position of the Milky Way.
Once you find your location, plan on venturing there sometime between the last quarter and first quarter of the moon, or ideally during the new moon. The closer you are to the new moon, gives you more time during the night with dark, moonless skies.
Another point to consider is the time of the year. The Milky Way (or the best part of it, called the ‘core’) isn’t always visible. In the Southern Hemisphere, the best times to view the core of the Milky Way is from March through to October. Stargazing is also better in the cooler months, as the air is cleaner due to lower humidity.
What settings will you need to use?
Put everything in MANUAL. Focus, exposure, ISO and white balance. Make sure you are shooting in RAW too. Raw image files contain more data than JPG files, which will allow for greater flexibility during post-processing.
Finding focus is critical in any form of photography. In astrophotography, this process is made harder due to the lack of light to auto focus with. Therefore you must use manual focus. If your camera has it, switch to ‘live view’, then zoom in on a bright star and focus manually until it is a sharp point of light. If you can’t focus on a star, you may need to set-up a torch at least 100 metres away and focus on that. After you have got your focus ‘locked in’, you can then compose your shot. Always make a test shot of the stars to check your focus. Zoom the LCD all the way into the image review to make sure that the stars look like pinpoints. If they are out of focus, re-focus and check again. Once happy, you can use some gaffer tape over the focus ring to avoid any accidental bumps.
Long shutter speeds allow you to collect light over time. The longer you go, the brighter the stars will be. There is a slight hitch however – the earth is rotating! If you leave the shutter open for too long, you will create star trails, which is not desirable for a Milky Way shot. So it’s important to know how long you can leave your shutter open before you get star trails. This will vary depending on what focal length you use. The longer the focal length, the shorter the exposure, and vice versa. To avoid this, follow the 500 Rule. Basically, you divide 500 by your focal length which gives you your shutter speed. Say you are shooting with a 16mm lens – divide 500 by 16 to get your shutter speed. 500/16 = 31.25 seconds. You would round this number down to a shutter speed of 30 seconds. Never round up.
In astrophotography, we need as much light to pass through the lens and hit the sensor as possible, so we generally shoot wide open. Set your aperture to the smallest number possible (f2.8, f4); this will depend on the lens you’re using.
High ISOs are the key to capturing a bright Milky Way, so don’t be afraid to push the limits (without compromising quality) of your camera. Start with ISO 3200 and go up or down from there to get the correct exposure. Check and re-check your image review, zoom in on the LCD to check focus and review the histogram for exposure information (check your manual on how to display your camera’s histogram). Once you find an exposure you like, you can usually maintain this throughout the night.
Let’s frame the perfect shot
Taking a photo of the night sky is one thing. Being able to tie it to the surrounding landscape in an appealing way is a must if you want your shots to stand out. There are many compositional rules in photography, but I find one stands out above all others … your image must have a ‘point of interest’. An image without one will not hold your viewer’s attention for long. It could be something as simple as a tree silhouetted against the starry night sky, or you and a group of friends sitting around the campfire.
There’s an app for that
There seems to be an app for everything these days and for working out where and when to take that perfect shot of the night sky, well, you guessed it, there’s an app for that too. So, if you’re wanting to know what the night sky will look like at any place on earth at just about any time, then an app like Sky Safari will be your go to. And if you want to track the Aurora Australis (Southern Lights) then this Solar Monitor is best.
So, the next time you head bush, remember these pointers and you’ll be well on your way to nailing your own image of the Milky Way.