Setting out to shoot amazing astrophotography is a bit like cooking. You mix in all of the ingredients, then click the camera shutter, opening it again a full 20 or so seconds later to see what kind of dish you’ve created. So, here are six steps, which I field tested in the Starlight Reserve of La Palma, for your to shoot your own stunning images of the night sky…
Compared to many kinds of photography, the camera bag you’ll need to pack for astrophotography can be fairly compact. This proved to be to my advantage when hiking out from the trail head, across the black fields of lava sand and between the pines of La Palm’s Llano de Jable viewpoint, 1200m above El Paso.
a) Camera with full manual control and bulb mode (for multi-second exposures). A wide angle, fast lens – prime lenses usually perform better. I used a Zeiss Batis 18mm 2.8 paired with a Sony Alpha A7R series, but you don’t have to use an autofocusing lens, because you will be using manual focus.
b) Stable tripod. You’ve got two options here – the first is a heavyweight tripod (super-stable, harder to carry on a hike), or a lightweight, yet strong travel tripod (I use a Three-Legged Thing Billy carbon fibre). You can clip a weight (your bag, for example) to the bottom of a lighter tripod, with a carabiner and climber’s cord. Personally, I always travel light where I can.
c) A couple of headtorches, at least one with a red light setting (which you will use when setting up your shot, to avoid killing your night vision).
d) Your smartphone, loaded with an app such as Photopills (to find out when the moon sets, and other astrological data) and enabled with GPS + maps, or another GPS navigation device, because no one likes getting lost in the dark.
e) A remote trigger for taking an exposure – these can be wireless, or wired, or if you are in a pinch, you can use the self-timer on your camera to press the shutter, and then allow camera shake to subside before the exposure starts.
Cameras often have boatloads of settings and confusing menus, so to avoid fumbling with controls in the dark, I pre-set my camera for astrophotography before I go out:
a) Shoot In RAW You need to have the maximum amount of data in your exposures.
b) Full Manual And Bulb Exposure Enable your manual focus magnifier if you have one.
c) Crank The ISO Don’t be afraid of a high ISO setting because this will raise the light sensitivity of your camera’s sensor, often boosting its night-time performance.
Remember, you’re shooting in RAW so you can control the appearance of noise later on, with software – some RAW processing programs, such as Capture One Pro (which I use) have in-built noise reduction sliders. You may need to experiment to find your camera’s optimal balance of sensor sensitivity and noise.
a) Find A Star Usually you want to wait until the moon sets, then set off for your location and set up your tripod. When you first look through the viewfinder you will see very little, because so little light is making it into the camera.
So, switch to full manual control, open up your lens’ aperture (try wide open) pick a bright star in the sky, point your camera at it, then use manual focus (it helps to use your camera’s manual focus magnifier) to try to bring the point of light into sharper definition.
b) Go Hyperfocal Once you have done this with a big, bright star, shift the focus point to a close-by, fainter star and repeat the process. The focus will now be finer, and closer to being hyper-focal, which is your lens’ best possible field of view for this kind of astrophotography.
c) Kill The Lights Once you’re happy with the focus, turn off your headtorch. At this point, there’s a bunch of maths you can get stuck into, OR you can just use a rule of thumb to decide on an exposure time. Because the earth is spinning, anything over about a 20-30 second exposure (depending on the focal length of your lens) will start to turn those points of starlight into streaks (commonly referred to as tadpoles).
And your window gets shorter the narrower your lens goes. At 18mm the Zeiss Batis is wide but not the widest, and I know from experience that 30 seconds is really borderline, so I start at 20 or 25 secs and go from there. You can use more time for more light, less time for sharper definition.
d) Review Your Image It’s easy to get intoxicated by the starscape above you, and the temptation is to keep swinging your camera around for new compositions and areas of the sky. Resist this and really evaluate your astrophotography exposure. This is one occasion where pixel peeping really is worth it – how defined are the points of light? Is there any hint of movement? Are your stars looking like tadpoles?
Twenty to thirty seconds is a long time. During that span, wind could have shaken the tripod, you could have missed the focus slightly, your ISO could be too low/ high, or the exposure could be too long for your focal length, creating those star tadpoles. This is the time to fix it, in order to refine your technique and improve your eventual success rate.
The night sky over La Palma is bewitching, but unless you include the landscape in some of your images, even if it’s just silhouetted, your astrophotography images could have been taken from any other bit of rock in the hemisphere. So, to give your images some context, consider shooting at a lower angle, while being conscious to avoid pockets of light pollution from distant settlements, or roads.
In the image below, I’ve combined both context and drama in the sight of the moon setting behind the imposingly recognisable silhouette of La Palma’s 2,349m Pared De Roberto mountain. You can also make out a sign by the side of the road, which reveals part of the story of this shot – I jumped out of the car and took it in a hurry before some storm clouds blew in!
The image further below shows a more subtle use of the landscape, which actually takes advantage of some light pollution to illuminate the break between two ridges.
Imagine for a moment that you could take those pieces of silhouetted landscape and, within a single exposure of your camera, somehow ‘colour them in’ with a soft, otherworldly light, reveal their textures and bring them to life, while simultaneously capturing the outlandish beauty overhead.
a) Get Creative Well, now you can. During your multi-second astrophotography exposure, take your headtorch, on a low white light setting, and make passes with it over the landscape features you want to illuminate, just as you would with a gigantic paint brush. Less is more with this technique, so don’t do it for the whole exposure, or you’ll blow out the image – start small, making slower passes over areas you really want to bring out, and work up from there with trial and error.
b) Adjust Depth Of Field You may find that the depth of field with your lens wide open doesn’t allow you to convincingly capture detail in the landscape, so you may need to dial that in slightly.
My ethos as a photographer is to capture my images in a single exposure. I just find the process far more satisfying than aggressively lighting a scenes, then taking a separate starfield image, then merging the exposures later on, which you may prefer to do. But all of my images you see here were shot in a single exposure – I find it frees up time to capture more scenes!
a) Contrast Is Your Friend: Once you get back to base and import your RAW image files to your post-processing software, you may not realise that the best way to bring the detail out of your starscape is to bump up the contrast slider, which will make the stars really pop and bring more definition into the Milky Way, for instance.
b) Get Dynamic You can also play with dynamic range, by bringing up the shadows and reducing the highlights, but be careful not to blow out the brighter areas with this technique.
c) Address Noise: You’ll have used a high ISO number in order to increase your camera sensor’s sensitivity to light, so you will probably benefit from the noise reduction tools embedded in your software.
d) Crop Creatively: Chances are that you have shot as wide as possible on a fixed focal length prime lens, which can sometimes compromise composition. Take the time to add to the drama of the night sky with careful and creative cropping of the image.
Whatever your astrophotography goals, follow these simple steps and you’ll be well on the way to capturing some amazing night sky images!
Photos © Matt Ray, all rights reserved. Shot with a Sony A7R and mostly a Zeiss Batis 18mm 2.8 lens.