How To Photograph The Milky Way In 14 Fully Explained Steps
There are 400 billion stars in the Milky Way. How many did you see last time you looked up at the night sky? 20 - 30 maybe? Now remember the last time you went camping, or drove through the middle of nowhere. Remember the hundreds of stars of many colours, stretched out across the big black. That's nothing. With this guide you'll be able to photograph the Milky Way in all its glory.
This is going to be a long guide - so I've included a step by step summary at the end to help you to remember.
How to photograph the Milky Way - 14 steps (short version).
The TL;DR version, for full details I highly recommend reading the full article.
Choose a time of year when the Milky Way’s core is visible.
This is Summer time in the Northern hemisphere - March to October and February to October in the Southern hemisphere.
Find a dark clear sky far away from city lights.
Seek an approved dark sky site - Milky Way-class sites offer easy access and guaranteed darkness. Use the weather forecast to plan when to go, and try to avoid times where the moon is visible above the horizon.
Arrive before dark and set up your shot.
Use a planisphere or mobile star chart app to plan your shot. The milky way rises in the South, so be sure to pick a spot where the southern sky is not facing a city or light source.
Use a tripod and remote shutter release or self timer mode for your shoot.
Use a DSLR with good low light quality.
Use RAW not JPEG.
Use a wide angle lens with a wide aperture.
Pre-focus on a very distant object or a star,
Set your focus onto a very distant object ahead of time and then turn off auto focus.
Fine tune your focus using the live-view screen zoomed in. Then leave it alone.
Lock your focus or tape down your focus ring.
Use High ISO and the widest aperture.
ISO 3200+ will be necessary to capture the fainter stars.
Set the widest aperture you can on your lens without losing image sharpness.
Use the 500 rule to set your shutter speed.
For full frame cameras, use 500 / focal length to know how many seconds to leave your shutter open for without star trails. For APS-C cameras, use 333.
Shoot your photo, and adjust settings as needed.
Shoot a dark frame to reduce sensor noise in Photoshop. (optional / advanced)
Put the lens cap back on after you have your photo and shoot one more with the exact same settings and camera placement. This can be used to remove the noise in your photo when you edit.
Adjust contrast and exposure gradually in Lightroom or Photoshop to bring out the details.
Milky Way Photography - The complete and professional guide
Expanding on the steps above, you'll learn everything you need to shoot a professional Milky Way photo. Just add practice.
Equipment needed to photograph the Milky Way
A sturdy tripod - the more sturdy the better. Don’t go all cheap and plasticy on me here - this makes or breaks your photograph. (Essential)
A DSLR or Mirrorless Interchangeable lens camera with good high ISO capability - needed for a clean, high quality image.
A wide angle lens - as in wide-wide. 14mm for full frame, 8mm for APSC (not full frame), you’ll be able to use longer, like 24mm but you’ll capture less stars. It’ll need a wide aperture too. F2.8 or wider is preferred. I’ll be using a Samyang (also known as Rokinon) 14mm F2.8 manual focus lens - about £280. (Essential)
A camera remote - Ideal but you can use self timer instead.
A torch or head lamp - it’s going to be dark where we’re going. (Essential)
Find a very dark place away from lights
From a busy city location, the light pollution overpowers the weaker star light, blotting out all but the brightest of stars, making the experience far less rewarding. Even in the best locations we want to be taking exposures of up to 20 - 30 seconds to capture the faintest stars. In heavily light polluted areas the light from the street lamps will fill the atmosphere, washing out the photo. So, the answer is to get away from the cities, ideally to a dark sky site to the north of a less populated area.
It can be very difficult to find a suitable location here in the UK, however this excellent resource lists all approved UK dark sky sites:
Try to avoid a full moon or shooting too close to sunset as these will cause the sky to be bright and make it very difficult to bring out the contrast (as seen further down).
Know the best time to observe the Milky Way
The milky way is only visible for part of the year, when the galactic core and the Sun are on opposite sides of the earth.
In the northern hemisphere the Milky way is visible from March to October.
In the southern hemisphere you can see the Milky way from February to October.
Locate the galactic core of the Milky Way
To locate the Milky Way galactic core you'll need to locate the constellation of Sagittarius. Using a planisphere will help you to do this if you are new to astronomy.
Firstly, if you can see the three bright stars of Orion’s belt in front of you, turn around about 180 degrees then locate Scorpio and Sagittarius. The band of the Milky Way runs all the way from orion, over head, through Cygnus to Scorpio and Sagittarius at the core. It’ll take about 15 to 20 minutes for your eyes to adjust to darkness before you will see the Milky Way clearly so avoid all light sources and use these brighter stars and constellations to help you pick your shot.
Alternatively you could use an app to locate your stars and the galactic core. Stellarium tells you where, and when to catch each of the sky’s features which can be very helpful when setting up in advance.
Note: The further north the viewing position, the lower the galactic core will rise from the horizon. Further north than 65 degrees latitude and you’ll be out of luck for the milky way, but more likely to catch the Aurora Borealis (or northern lights).
I highly recommend planning ahead of your visit so that you can set up before it goes dark and know where the Milky Way will rise. This will allow you to compose a pleasing shot with a great foreground.
Arrive before dark to set up
Whenever possible it’s always best to arrive at your location before dark. With some careful planning you should know where to aim your camera and at what time your shot will come into view. Use the daylight to choose an interesting location with some foreground features to add interest to your photograph.
Set up your tripod and camera.
Ensure that have a stable setup, with a well placed tripod and that your camera is securely attached to the mount. Any movement or ‘creep’ due to a loose attachment or too much weight on the mount will ruin your shot.
Attach a remote trigger. This will enable you to trigger the camera without risking any camera shake, or accidentally adjusting any settings.
Compose your shot so that the desired area is in frame and double check against the app. Use a compass or landmarks if possible to ensure you are facing the correct direction.
Set your focus. Do this while it’s still light as it will be much easier.
Use a very distant object to focus on infinity. Often the infinity marking on the lens will not be one hundred percent accurate. To ensure the sharpest stars switch your auto focus off, and using live view on your camera's screen, focus on something far away.
Next, use your camera's live view zoom to see more detail and further refine your focus.
Lastly, leave auto focus turned off and note the position of the focus and zoom rings on your lens. This will ensure your focus stays sharp.
How do I focus in the dark?
Focusing on infinity after sunset can be considerably more difficult, however sometimes it becomes necessary.
Depending on your camera's low light capability, it is possible to choose a very bright star to focus on. You may have to adjust your exposure settings to be able to see the star in your live view. Do not try to use auto focus or the viewfinder, it just won’t work. If even a bright star proves too difficult to use, perhaps a distant street lamp, or a using a torch placed far enough away will help.
Tip: Note the highest distance on your lens focus indicator or ring, infinity is any distance further than away.
Milky Way Camera exposure settings
To capture the most stars and detail you will have to make the most of your camera’s ability to capture light.
We will use a long exposure, wide aperture, and high ISO.
Long exposure (shutter speed)
Taking your photo over a longer period of time will allow plenty of time to gather enough light from even the faintest of stars. There is a limit to the length of time we can expose for however.
Since the Earth is spinning, the stars will appear to move across the sky. Very slowly, but still quick enough to turn into streaks in a long enough exposure.
In order to keep the stars sharp and point-like and use the longest exposure possible we can use the 500 rule. This is a rule created for full frame professional cameras or 35mm film. I’ve also included a modified version of the rule for entry level to mid range crop sensor cameras.
Calculating shutter speed for Full Frame (FX) cameras
Max exposure time (seconds) = 500 / focal length (zoom)
500 / 25mm Zoom = 20 Seconds.
500 / 14mm Zoom = 35 Seconds
Calculating shutter speed for APS-C (DX) cameras
Max exposure time (seconds) = 333 / focal length (zoom)
333 / 18mm Zoom = 18 Seconds
333 / 10mm Zoom = 33 Seconds
By using this rule, we can keep exposure long enough to get the most light before those stars turn into streaks. This also illustrates the importance of using a wide angle lens. The less zoomed your lens, the longer you can capture light for, and the more detailed and vivid your milky way or astrophoto will be.
Use a wide aparture to capture as much detail as possible
The goal of astrophotography is to capture as much light as possible in the limited time available. The wider the aperture of the lens, the more light your camera will capture. So setting your aperture to a low f number will help.
Set the lowest f number possible without losing image sharpness.
For more info on aperture read the exposure guide.
Use an ISO of at least 3200
ISO is the camera’s sensitivity to light. At 100 it’s the least sensitive (too low for stars), but highest quality, and at it’s highest level it’s the most sensitive but at low quality.
We need to find a good compromise. I suggest starting at 3200, take a picture, and then raise the ISO as desired to find the best exposure (more on this below).
High ISO values do produce unwanted noise, however editing software is very good at eliminating the majority of the noise in most photos.
Check the histogram to find the best exposure
One of the biggest challenges in milky way photography or any other form of astrophotography is judging exposure. Since the raw image on the back of your camera is likely to require some post processing to bring out the details, and more so if you are photographing with more than ideal ambient light from light pollution, the image on your camera can be somewhat underwhelming.
In order to judge the quality of your exposure you will need to use the camera’s histogram. While previewing a photograph, your camera will offer the option for different display modes, one will include the histogram; a graph displaying the intensity and amount of light from dark to light. On my Nikon DSLR this can be viewed by pressing the up or down arrow buttons while in image preview until the histogram displays on the right of the image. Other camera’s option controls will vary slightly.
Viewing the histogram, you should see peaks on the graph, if the majority of the peaks are on the left, this means your image is mostly dark, and to the right means mostly bright. Seeing peaks all the way to one side or the other usually means you’ve under or over exposed and some of the light couldn’t be recorded. There is usually some tolerance for this, especially if you are shooting in RAW (you should be), but it’s best to play it safe and keep all of your peaks within the bounds of the graph. Unless of course there is a large bright pure white source of light in the image.
Expose to the right (ETTR)
A method used commonly by astro photographers, and absolutely crucial to anyone photographing without pure complete darkness is ‘Expose to the right’ or ETTR. This simply means exposing for long enough, and using a high enough ISO to have most of the peaks as far to the right side of the histogram as possible without falling off the right (clipping). The reasoning behind this is a little more complex, but well worth understanding.
Skip this bit if you don’t want the technical details.
Most digital camera sensors do not record light and shadow equally. At risk of oversimplifying, due to the way sensors record light linearly then convert the range to a logarithmic scale, about half of the image data effectively occupies the top quarter of the images brightness range. This can lead to poor quality shadows and lost detail when corrected later in post processing if under exposed. You can read the detail about linear and corrected distribution here: https://en.wikipedia.org/wiki/Exposing_to_the_right.
The most important reason. In astrophotography, the majority of the image will be darkness, or shadow. By using the ETTR method, we ensure that we have captured the maximum possible amount of light and data from the scene which later we can manipulate to bring out the range of brightness required without loss of details. In doing so, the noise created by using a high ISO can be at least partially avoided since noise mostly manifests in shadow areas where not enough data was captured to overwhelm the random signal noise.
By giving ourselves headroom to dial down the exposure we’re effectively reducing signal noise instead of amplifying it. At the same time, we’re allowing our camera to capture even the dimmest of stars. Brilliant!
Edit your Milky Way photo to bring out the subtle details
Without going into a full guide on editing techniques, you’ll almost certainly need to process your raw file in an application such as Adobe Lightroom, or Photoshop. For the sake of remaining neutral, here’s some general tips for any application.
Don’t be put off by the raw file.
Depending on the levels of light pollution and clarity of the sky at the time of shooting, your photo may appear washed out and lacking in contrast and detail. More so if you used ETTR (see above). Raw files need some work to tease out the layers of details locked away in those pixels.
Make small adjustments
It’s easy to get carried away, and when doing large contrast adjustments some of the finer details can be lost. Treat your edit like a delicate balancing act of bringing out the fainter stars without loosing the subtle detail.
Note: If you are using ‘dark frame subtraction’ to remove hot pixels and sensor noise, you must do this first as editing will reduce the effectiveness of this technique - see step 7.
Start by adjusting the Exposure
Raise the exposure until the maximum amount of detail is visible and no more. Once you’re no longer seeing more start appearing (not to be confused with the noise) stop raising the exposure. If lowering the exposure due to shooting ETTR, lower until you start to see details disappearing, then back up a little bit. This won’t get rid of the washed out look if you had a bright sky, so bare with that for now, we’ll get onto removing that next.
Use the tonal curves adjustment tool for contrast.
Adjust the contrast using the curves editor to darken the pure blacks without losing the detail in the brighter areas. Making small adjustments adjust the curve for the desired result. Remember, sometimes a pure black sky isn’t always the best look.
This is a powerful tool for isolating the bright stars and dimming the background wash.
Edit as usual.
Once you’ve revealed the best of the details, edit the photo as normal. Use a natural white balance if you wish to keep the true details aim for a white balance setting of around 4600 and adjust to taste from there.
Apply noise reduction very lightly. Heavy reduction can remove stars from your photograph. Lightroom’s noise reduction has improved greatly in recent releases, however tools such as Topaz, and DXO Optics Pro offer the best results. Noise adjust with care. In some extreme cases, multiple subtle passes of noise reduction are required, meaning applying small amounts of NR then going over the image again until the noise is dealt with.
Advanced noise reduction - Dark frame subtraction (optional - advanced).
Advanced Photoshoppers can use dark frame subtraction to remove ‘hot pixels’
Hot pixels are bright, over saturated pixels in your image caused by the heating of your camera sensor over long exposures. They occur more in warmer environments but can happen on any long exposure.
To perform a dark frame subtraction you’ll need to put the lens cap back on right after taking your photo and shoot a dark frame of equal length to your main photo. By doing this under the exact same conditions as your milky way shot, the noise produced by your camera can be captured, and then removed in photoshop.
Note: Dark frame subtraction should be done before any additional editing.
There you go. Your guide to shooting the milky way.
In this guide you've learned what to bring with you on a milky way photoshoot, how to choose a perfect location, how to set up, and capture your milkyway shot.
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