DSLR Astrophotography: What settings to use for each type of target?
Updated: Jun 5, 2023
A DSLR camera is the easiest way to get into Astrophotography. We started out with a very cheap Canon t3i from eBay, and upgraded to a Canon 7D Mark II about a year and a half later. We have gotten great images with these, but we also had to trash lots of files over time because the settings we used weren't great for the type of target.
We often get questions on how we choose our DSLR camera settings depending on what we image, and decided to make a tutorial explaining our reasoning.
You can view all the settings we use for each target in our online gallery if you'd like to know what we used for a very specific object.
In this tutorial, we will be talking about the Moon, the Milky Way, Star Clusters, Nebulae, and Galaxies. Woo!
Best DSLR Camera Settings for the Moon
Aperture:
11-16
Shutter speed:
1/125 - 1/250
ISO:
100-200
Other:
Crispness level to the Max
Spot Metering
For this target, we need to tighten our aperture so that our big, bright satellite doesn't look all white and washed out in the photo. An F-number between 11 and 16 usually works pretty well. The shutter speed needs to be fast, because you are, in general, just using a tripod and not tracking the Moon on a motorized mount. We like to do either 1/125 or 1/250 depending on the phase of the moon during the night. Both usually work great.
As for the ISO, the lower it is, the less noise you'll have, so 100 is the best you can choose. If the moon phase is currently thin, making your image not as bright as you'd hope, you can increase the ISO to 200 or 400.
We also like to tweak some other settings, such as the sharpness, which we put to the max so that the craters are as visible and defined as possible. We also use Spot Metering to focus as precisely as we can.
Now, let's answer the question of what ISO is best for the next targets in this list.
The ISO number will mostly depend on 2 things: your camera and the temperature where you will be taking images. Our basic go-to number for ISO is 400 during the hot summer nights, and 1600-3200 when the temperature outside is chilly. You can go higher if you'd like, but we would not recommend going above 6400 unless you have a very good camera and it is really cold outside.
As a rule of thumb, know that the higher the ISO is, the more you will pick up in your image… including noise.
Temperature has an effect on this, as seen in our 11th Episode of Galactic Hunter.
Best DSLR Camera Settings for the Milky Way
Aperture:
f/4 or wider.
Shutter speed:
Depends on the lens - Use the 500 rule if you are a beginner, or the NPF rule for best results.
ISO:
800, 1600, or 3200 depending on the temperature and your camera.
Other:
N/A, we keep all the other settings as default.
You may want to play with the temperature slider depending on your personal taste.
For example, a lower temperature (3400 Kelvin) will give you a more blue-ish Milky Way as seen on the image here.
The settings for the Milky Way mostly depend on what lens you are using. If you'd like to know our pick for the 3 best affordable lenses to photograph the Milky Way, check out our video and blog post about it!
Best Aperture Setting for Milky Way
The Aperture you'll want to choose is often the widest possible one, so that you can capture as much light as possible in the shortest amount of time before seeing star trails appear on your images.
There is a trick though, we learned it the hard way, but even if you have a camera lens that allows for, let's say, an aperture number of f/1.8, we recommend not going below f/4. The reason for this is that if your aperture is too wide, you will see some slight chromatic aberration around the edges. This is often not noticeable on daytime images, but very visible in Astrophotography as the stars won't look round and sharp.
You can see the comparison between Barnard's Loop at f/1.8 and Barnard's Loop at f/4 HERE.
In short, pick the lowest possible aperture your camera lens allows, but we often avoid going below f/4 and end up happy with the results.
Important: High-end lenses are usually great even with the aperture wide-open! So feel free to stay below f/4 if your stars on the edges are round!
Best Shutter Speed Setting for Milky Way
For the shutter speed, you can either do the 500 Rule or the NPF rule, unless you are using a star tracker. We go over both of these rules in-depth in the Galactic Course, but we recommend starting with the 500 Rule if you are a complete beginner:
500 divided by the focal length of your lens equals the longest exposure time you can do without getting obvious star trails.
Example with a 10mm lens: 500/10=50 seconds.
Example with a 24mm lens: 500/24=20.8333, rounded down to 20 seconds.
Note that this is for full-frame cameras. If you are using a crop sensor, you'll need to do slightly shorter exposures.
For the last three types of targets, recall that the ISO may vary with temperature, but the F-number will stay the same for all of them…
Well… actually the F-number won't apply if you are using a telescope, since it will serve as your lens. However, if you are NOT using a telescope to photograph deep sky objects with a camera lens, you will need to repeat what we advised for the Milky Way:
The faster the better, but f/4 is a great number to ensure you don't have coma on the edges.
Learn all about capturing the Milky Way in our Milky Way online course. Or, get our Milky Way Processing guide to get the very best out of you Milky Way data.
Best DSLR Camera Settings for Star Clusters
Aperture:
N/A (your telescope)
Shutter speed:
BULB - 30 sec
ISO:
400 to 3200 depending on temperature and camera
Other:
N/A, we keep all the other settings as default.
Star clusters can be tricky to photograph. We choose to do 30 seconds for our exposures. We actually started with 3 minutes, but quickly realized that this was not necessary. Doing more than 30 seconds for globulars will make the stars too bright, and will also make the cluster look too bloated if your tracking is not absolutely perfect or you encounter wind. This is why we now do 30 second exposures for pretty much every globular star cluster we image.
Best DSLR Camera Settings for Galaxies
Aperture:
N/A (your telescope)
Shutter speed:
BULB - 3 minutes
ISO:
400 to 3200 depending on temperature and camera
Other:
N/A, we keep all the other settings as default.
Although we used to always do 6 minute exposures for galaxies (ex: M101, the Pinwheel galaxy from the first episode of Galactic Hunter), we now find it better to do 3 minutes.
Cutting the exposure time for each shot does not make much of a difference in the quality of the stacked image. Most importantly, it cuts the chances that we'll have to trash some files due to wind gusts or cars passing by with their lights on… by half!
Get our Galaxy Processing guide to get the best out of your galaxy data with PixInsight!
Best DSLR Camera Settings for Nebulae
Aperture:
N/A (your telescope)
Shutter speed:
BULB - 3 minutes - 6 minutes
ISO:
400 to 3200 depending on temperature and camera
Other:
N/A, we keep all the other settings as default.
Lastly, nebulae! We prefer to take 10-minute exposures for nebulae, unless they are very, very bright like the Orion nebula where we would do a mix of 30 seconds and 5 minute shots instead.
We also choose to do 5-minute exposures instead of 10 if we feel there might be a few gusts of winds, or if we are imaging from a location during the weekend where we know cars will pass by often. During a very quiet, week night, we definitely prefer to do 10 minutes as we think it gives us more of the very faint gases.
We hope this helped you out a little bit. Let us know if you how you feel about our settings.
If have your own advice on ISO and F number settings, comment below and tell us why!
Our Online Astrophotography Courses
Want to learn how to capture deep sky objects, the Milky Way, and more? Join the Galactic Course to have access to all our astrophotography courses, as well as all our processing guides!
Get courses and processing tutorials individually, or sign up for a bundle to get access to it all!
We'll see you next time!
Clear Skies,
Galactic Hunter
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