While astrophotography may be considered a niche area of photography, it is quite extensive with different areas, styles and techniques. So, we’ve got Adobe’s Paul Burnett to take us through the basics of wide field astrophotography.
Moonrise at Pambula
Beach Surf Club
Wide Field Astrophotography is all about wide angle shots of the starry sky and a beautiful landscape below, and it can be done any interchangeable lens camera (ILC) with a wide-angle lens. The holy-grail of wide field astrophotography is the galactic core of the Milky Way – the center of our universe. It’s a spectacular collection of stars, planets, dust, clouds and nebulae, and we are part of it. Getting a great photo is a combination of planning, technical skills, artistic composition and a little bit of luck, but Paul’s here to help.
One enemy of astrophotography is light pollution (the extra light from towns and cities), and Singapore has a lot of that. While it’s not impossible, it’s best to head somewhere that’s far from towns and cities. Another enemy is the full moon – it also drenches the night sky with light, washing out the stars.
Plan your sessions as close to new moon as possible. Although the Milky Way is visible all year round, the galactic core is only visible above the horizon for part of the year. In the northern hemisphere, this is between March and October although the best time is between April and July. In the southern hemisphere, it is visible between February and October with the best time between May and August.
The last enemy of astrophotography is clouds, and this is where a little planning and a lot of luck helps. Cross your fingers for a clear, dark, moon-free night. Paul uses a mobile application called PhotoPills to plan his shots as it lets you plan almost to the meter where you will take your photo. See where the Milky Way and the galactic core will be at a precise time, and much more. Great for planning shots in advance!
The screenshot above is an eample of Paul’s plan to shoot the image of the Green Cape lighthouse in Australia in June.
You’ll be surprised how little you need to start with Astrophotography. Here’s a basic setup:
Tripod – A sturdy tripod is important as you don’t want the camera to move during those long exposure shots. It’s also handy for it to be light, as the good spots often require a hike. If necessary, weigh it down by hanging your camera bag from it. Just make sure it doesn’t swing in the wind.
Camera – Most modern ILCs will work fine but one that deals well with low light is the best. Paul mostly uses a Canon 6D for its low light performance. You can use a full frame or cropped camera but remember to compensate for the focal length of your lens.
Lens –Use a wide angle lens so you can get both the landscape in the foreground and as much of the galactic core as possible. Anything from 12mm to 24mm is fine (remember to account for sensor crop). You’ll also want a lens with a wide aperture (ƒ/2.8 or even wider) to let in as much light as possible.
You don’t have to spend a fortune, in fact Samyang (also known as Rokinon) makes a 14mm ƒ/2.8 lens that’s around US$300 to $400 which is much loved by many wide field. But don’t rush out and buy a lens – Paul recommends you try your widest lens first and see how it performs.
Shutter Release – To avoid moving the camera while you are taking a shot, use a remote shutter release or the timer built into the camera (set it to a few seconds so you can get your hands off the camera before the shot).
THE 500 RULE
Before we look at camera settings, here’s an important rule to learn – the 500 rule. The earth spins at about 360º every 24 hours. If you look at the stars over time, they will appear to move, but in fact we’re the ones moving. Because we’re taking long exposures, the stars will move during that time and we want them to appear as sharp dots – not trails (unless you’re trying to shoot star trails).
So how long can we expose an image before we get noticeable trails? Well, just divide 500 by the focal length of your lens. The result is the maximum number of seconds you should expose for. For example – for a 14mm lens – 500/14 = gives you around 35 seconds. If you shoot for 30 seconds then you are safe.
If you are shooting the Aurora and not the Milky Way though, keep all the settings the same but reduce the shutter speed to around 5 – 10 seconds. You will adjust this depending on the conditions.
Several things will affect the ideal settings on your camera, including the conditions, the camera and lens. Here are some basic settings to get you started, and you can play with them from there.
• First set your camera to the manual setting. If you have never done that before, don’t panic –it’s fun!
• Next, set the image quality to RAW and not JPEG. This is important, not just for astrophotography, but any photography, as it gives you so much more image information to edit in post.
• Set the white balance to around 3200k or select Tungsten. We can adjust this later in post if you are shooting in RAW.
• Set the aperture –as wide as possible go e.g. ƒ/2.8. Once set, you shouldn’t change this.
• Set the shutter speed based on the 500 rule above – for Paul, that’s 30 seconds with a 14mm lens. Once set, you shouldn’t change this either.
• Set ISO to around 3200 to start. This setting we can change depending on our test shots.
• Set the lens to manual focus, and then focus to infinity. Although many lenses have a mark for infinity, it isn’t always correct so test it. To test this during the day, focus the camera on something on the horizon and check where it is on the lens. You can even put a mark on the lens so you can see it later. Some people tape it so it won’t move.
The other way is to do it at night. Temporarily set the ISO to as high as it will go, and use Live View on to zoom into the shot as far as you can. Find the brightest star you can see, then focus on that. Once set, don’t move the lens and set your ISO back to 3200.
Take a test shot using your remote shutter release or timer. You’ll be amazed at how many more stars the camera can see in a long exposure than you can with your eyes. If the shot is too dark, increase the ISO or vice-versa. Once you are happy with the overall exposure, concentrate on your composition.
In summary: Manual mode, RAW, 3200k WB, Manual focus to infinity, ƒ2.8, ISO3200, 30 Seconds.
Out of the camera
EDITING IN ADOBE LIGHTROOM CC
Your photos of the night sky will capture colors and details not visible to the naked eye – the oranges, magentas, purples and reds of the nebulae and galactic dust clouds. While this may not be obvious in your ‘out of the camera’ RAW image, Lightroom can bring out these color and details. We’ll also adjust levels, white balance and reduce noise that comes with high ISO long exposures. (Paul says not to overdo this, so that your end image still looks natural.)
Starting with white balance, Paul says he finds it handy to temporarily turn Vibrance up while working on Temperature and Tint. Adjust Temperature so that the sky is not too blue or yellow. You should hopefully start to get some yellow and orange in the core, and a mostly black sky, but don’t overdo it. Now adjust Tint so that you get a nice balance without having it look green or magenta.
Next, adjust Exposure so that the image has a nice overall level to it – remember that it’s a night shot, so don’t make it too bright. Then hold down the shift key and double click on both the Whites and Blacks to set your white and black points.
Before doing more in the Basic panel, jump to the Effects panel and increase the Dehaze slider. Although this is normally meant to remove fog and haze from an image, it is perfect for astrophotography as it will darken the sky and boost the Milky Way.
Again, don’t be tempted to push it too far. Back to the Basic panel, and adjust Highlights and Shadows a little to bring out the stars and the Milky Way. Add a little Clarity to bring up the stars a little more, and add a touch of Vibrance.
If you like, you can go to the HSL panel and increase Saturation of magenta, orange, purple and even red, to bring out the color in the core.
Last of all, use the Local Adjustment Brush to brush over the Milky Way and increase Exposure just a bit to make it jump out a little from the sky.
All of these settings will depend on your image, and all the changes are non-destructive so you can go back and change any of them in any order.
COMPOSITION AND A CATCH-22
Depending on when you’re shooting, the Milky Way may be more vertical or horizontal. Try capturing as much of the core as you can. You may need to take several shots and stitch them together in Lightroom later.
Try to get a nice object in the foreground to add interest to the shot. Here’s the catch-22. If you shoot at new moon in a dark area, the foreground will be too dark but the stars will be at their brightest. If you shoot during a full moon, then the foreground will be lit but the stars will be a bit washed out.
Finding a happy medium is part of the challenge. Sometimes you can light up parts of the foreground with a torch, but be careful. A little bit of light makes a huge difference over 30 seconds. Try flashing light for just a second or two to “paint” the foreground.
This photo of Devil’s Golf Course in Death Valley was lit by a torch for a split second. The glow on the horizon is from a small town about 30km away. In the photo of Moonrise at Pambula Beach Surf Club, the beach, surf and headland was lit by the surf club’s toilet lights behind Paul and from the moon rising.
Text & Photos By Paul Burnett, Principal APAC Evangelist, Adobe Systems.
Edited by Marcus Wong.