Taking photos of the Milky Way requires a totally different approach than almost any other kind of photography. This is why we’ve dedicated an entire article to the Milky Way photography settings that we use for 98% of our shots.
Before we get started though, I want to make one thing very clear.
Always expose for the sky, not the foreground.
When you start adding foreground interest into a frame, it can be tempting to compromise on exposure so that both parts of the photo are correctly exposed. Resist the temptation.
If you want to get the best image of the Milky Way possible, you’ll want to expose for the sky.
One luxury of focusing at a single point of interest, millions of miles away, is that you don’t need to think about the depth of field. Even if you shoot at f/1.2.
So the question isn’t ‘Will everything be in focus’, it’s ‘Will I have enough light for my exposure’. After all, we capture photos of the stars during the darkest nights of the month.
For Milky Way photography, I recommend shooting at your widest aperture settings—f/2.8, for example. This will allow the most amount of light into the lens, and allow for a shorter exposure duration.
If you’re taking a photo where you include some foreground interest in the frame, such as the tree in the image below, then f/2.8 is the magic spot. It’s just wide enough to allow plenty of light into the lens while providing a deep enough depth of field to get the foreground in relative focus too.
If the aperture you choose for Milky Way photography is the widest possible, then the shutter speed should be the longest possible.
But how long is the longest possible?
We can set almost limitless exposures on our cameras. But there’s a very specific limit to how long you can expose for photos of the stars.
Set too long of a time, and the stars will start to move in the sky and those sharp dots of detail will look like soft smudges.
Fortunately, there’s a very easy way to work this out with a quick calculation involving your focal length, called…
The 500 Rule
The 500 Rule calculates the longest exposure time possible for Milky Way photography without capturing movement in the stars.
It does this by taking the number 500 and dividing it by the focal length of the lens you’re using.
For example, 500 divided by 14mm would be 35.7; this means 35.7 seconds is your maximum exposure length.
For that same calculation again, this time for a 24mm lens, the result is 20 seconds.
The reason for this is because when you zoom in, the you notice movement much faster. If you took a photo at 300mm on your lens at 1/50 of a second, it would be almost impossible to hold the camera steady and not detect any motion blur. But if you were to take the same photo at 24mm, it’s very easy to capture a sharp photo.
So the wider your lens is, the more time you have to expose for the stars.
There is one small caveat though, and that’s for people not using full frame cameras.
If you’re using a crop sensor camera, then your smaller sensor effectively magnifies the scene. It does so by cropping it.
So if you’re shooting with a Canon crop sensor, you would want to divide that final number by 1.6. If you’re using another model, you would divide it by 1.5.
For example, if you had a 14mm f/2.8 lens, but you put it on a Canon crop sensor body (like a Digital Rebel or a 70D), you would divide 35.7 seconds by 1.6 for a 22.3 second exposure time. If you were shooting on a Nikon crop sensor (like a D5000), you would divide 35.7 seconds by 1.5 for a 23.8 second exposure time.
All you have to remember is that you take 500, divide it by your focal length. And if you’re on a crop sensor camera, divide that number again by the magnification factor.
Unlike aperture and shutter speed, there are no rules on what you can set the ISO to. It’s always important to remember that the higher the ISO, the noisier the image will be.
Using a full frame camera, you will quite easily get away with setting your ISO to only 3200. But if you have to compromises due to your sensor size, or your lens, then I would recommend an ISO for 6400.
Any higher than that will show too much degradation in the image quality. At that point, you’re probably better off pushing it in post-production.
Focusing on the Milky Way is super simple.
All you need to do is to set your focus at infinity, which looks like the figure eight symbol in the image below:
On Canon cameras you want to line up the little sideways L with the line to focus on infinity. On other cameras you’ll want to align the infinity symbol with the line, so always check to see how it works on your lens.
Once you’ve set your focus to infinity, turn your focus mode to manual focus. This way, your camera won’t try to refocus in the dark when you go to take a photo. It will not do a good job!
Remember also to check your focus every time you recompose your shots. It’s very easy to knock the focus ring and send your photo into a blur.
In-Camera Long Exposure Noise Reduction
A useful, but time consuming function of digital cameras is In-Camera Long Exposure Noise Reduction.
The camera does this by first taking a regular 30-second exposure. Once that’s captured, the camera will close the shutter and capture another 30-second ‘blank’ exposure. The camera will then compare the blank exposure to the original photo, to identify the digital noise, and then remove it from the original photo.
And it does a pretty good job!
But as with everything to do with exposure, there is one major downside: time.
This process is very time consuming and will drain your battery life, so it’s not perfect. And if you’re taking a bunch of photos for a panorama, it simply won’t be quick enough to capture photos without the stars moving too much to stitch together later.
Our Go-To Settings
These are the settings we use for 98% of our Milky Way photography.
They’re specific to our gear. But once you’ve worked out what the settings are for your gear, you’ll find that you can also use the same settings for the majority of your shots.
Here they are:
- Focal Length: 14mm
- Aperture: f/2.8
- Shutter Speed: 30 seconds
- ISO: 3200
- Focus: Manually set to infinity
- In Camera Long Exposure Noise Reduction: Off
Your Free Milky Way Photography Settings Cheatsheet
Download this free one-page PDF to your phone, laptop, or tablet, and keep it with you when you go out to take photos of the Milky Way.
It has everything you need in one page so you can refer to it when you’re setting up your night time shot.
- Focal Length
- Shutter Speed