How to photograph Stars – Working out the settings

In this blog post I want to help you learn how to work out the right settings for your camera. It doesn’t matter what you use as long as have a manual mode where you can manually set ISO, Shutterspeed and Aperture AND ideally, can photograph in RAW format (this will require post processing, if not, give JPG a shot you just can’t change the end result much).

The lens does not matter either, this technique works for kit lenses to high end professional lenses. The main difference is a lens with a wider aperture (opening) will capture more stars than say a kit lens with a narrower aperture, but more on that to come.

The aim here, is take a photograph where the stars are sharp points and not stretched. Most people like to photograph the Milky Way doing this, which I just love to do as well 🙂

A quick point about gear. A tripod (sturdier the better) is a must. A Camera, A lens, Warm clothes, a good chair (this gets addictive and you’ll be out for hours), spare batteries (long exposures like to drain batteries), a good torch (take 2) with plenty of batteries are all recommended. Extra would be a remote trigger for your camera but you can get by without it.

Before getting into the nuts and bolts of all of this, I highly recommend that you take your night photographs in RAW format. Yes this means you have to post process your photos using a program like Lightroom or Photoshop. The big advantage here is you can reduce noise much much more than a JPG out of camera, and record just so much more information all around. If that isn’t an option, not to worry, shoot in JPG but play with your white balance to get colours that you like in camera and maybe turn on some noise reduction. Trial and error will work here.

Okay, Lets go! Start with the angle of your lens. The rule here is, the wider the view of the lens, the longer you can take a photograph for and keep the stars as points. This is why most star photos are taken with a wide angle lens, but a narrower lens can work too, you just have to change your settings, that’s what I’ll explain now.

There are 3 settings that are vital for this to work:

  1. Aperture, or how wide the hole in your lens opens up. Setting this is dead easy, open it as wide as it will go (the lowest F/number possible on your lens at your chosen angle). A pro lens it might be f/2.8. A kit lens might be f/3.5 or f/5.6 if it’s less wide angle. Once that is set, you can forget all about it, it’s done.
  2. Shutter speed. This is often the most confusing setting, and to make life easy a bit of maths helps, but you can just use trial and error as well. The hardest part is you need to know what is the angle of my lens if it was on a full frame camera.If your using a full frame camera, easy, 24mm = 24mm for example.If you’re using a Micro Four Thirds camera where the sensor is 1/2 the size of a full frame camera, 12mm = 24mm (multiply your focal length x 2).If you’re using a Canon APS-C sized sensor, 15mm = 24mm (multiply your focal length x 1.6).If you’re using a Nikon, Sony or Fuji APS-C sized sensor, 16mm = 24mm (multiply your focal length x 1.5).If you are unsure what you have, search Google for “your camera name crop factor” and you should find an answer. Multiply the angle of your lens by the crop factor to get the full frame equivalent.

    NOW! A touch more math and we have a great starting point for shutter speed. Simply divide 500 / full frame focal length equivalent. So for all the examples I gave above, divide 500 / 24(mm) = 20.83 so we can use the next lowest, 20 seconds, as our starting point. If you were using say a 18-55mm kit lens on a Canon and shooting at the widest focal length, the full maths would be : 18 x 1.6 = 28.8mm (full frame). 500/28.8 = 17.36 so you would set your shutter speed to 15 seconds. You can see the wider the lens, the longer the shutter speed (which equals more light and stars, but it will still work!)

  3. Great! Now we have only one setting to go, ISO. This is the one setting you use to get the correct exposure. This needs to go high, and quite possibly higher than you’ve used before. Your sensor will limit just how high you can go as noise/quality will get too bad at some point on any camera. It also depends on just truly how dark the skies are where you are photographing. I find a good starting point is 1600 ISO for a Micro Four Thirds or APS-C sensor camera, and 3200 for a full frame camera. ISO is a balancing act as the higher the ISO generally the more noise you get, but under exposing can also cause noise so best to get it brighter.

Now, before we press the shutter we need to do one last little thing, and that is focus! There are two ways really to do this easily. First is use your live view and zoom in on the brightest star you can see and try focusing on that. I find this works very well for me, especially with mirrorless cameras. The other way is to focus on the brightest light you can see that is the most distance from you. If there is no light, time to break out another torch and go for a walk, leave it turned on, lighting up something at least 30+mtrs away, go back to your camera and focus on the light. I suggest carefully putting some tape on your lens once focused if doing this to save a lot of walking!

Okay, lets get ready to take a photo! If you have a trigger, use that, if you don’t, put a 2 or 10 second delay on your shutter (details will be in your manual, you’ve read it right?) to avoid camera shake during the photograph. Aaaaaaand. Take a photo!

Now one of several things just happened:

  1. A photo appears on the back of your screen that looks amazing! Well done, you just photographed the stars! First time out this doesn’t happen often, but will get better as you take more and more photos.
  2. Your photo comes out but it’s very dark. Time to increase the ISO! If your at 1600 try 3200, if your at 3200 try 5000.
  3. Your photo comes out completely overblown or too bright. Happens a lot close to light pollution (towns, cities etc). Decrease your ISO and try again. You may end up having to try another location away from the light however.
  4. The stars are blurry. Your focus is out, go back and fix it, also, check it after taking a photo as you can bump it, focus can shift as temperatures change.
  5. The stars a not pins, they are stretched or lines. Shutter speed too long for your focal length. Either go with a wider lens, or simply decrease your shutter time and take another photo. You may need to increase your ISO to counter the loss of light from the shorter time.

Really by the end of all of this you should be able to get a photograph with some great stars in it and even the Milkyway if it’s the right time of year for your location (and you’re looking the right way, look up the Photopills App to help you with this, a post for another day).

So to sum up, here is exactly how quickly I can get a photo. I setup the tripod and put the camera on it. I set my lens to 12mm (24mm full frame), I set my shutter speed to 20 seconds. I set my ISO to 1600. I focus, I take a photo. I adjust ISO, I take another photo. Done.

When you get a photo that is perfect, be sure to right down those settings or record it on your phone. You can then reuse those settings time and time again as your starting point, and use the knowledge above to adjust for changing light or focal length.

This is a lot of information for first time users to digest. Practice and giving it a go is the key here, you can even try this in your backyard in the city or suburbs and see what happens, just lower the ISO. This will help you develop knowledge and muscle memory of your camera and how to quickly changes settings, a good thing to have when shooting in the dark.

So get out there, give it a go, and enjoy! Comment below if you have found this helpful or if you have any questions. I will be continuing this series over time to cover all aspects of photographing the stars and astrophotograph.

12 Responses

  1. That is awesome Murray…very well written and so easy for people to understand. Everyone will be off to a great start…Looking forward to another episode….Thank you…

  2. Wow. Thanks so much for all the great advice and information. Most people would charge $$ for that.
    I love taking photos and have a good eye but it’s my knowledge of the equipment that lets me down.
    Look forward to seeing better results.
    Thanks again.

    1. Thank you very much Suzanne. I believe in sharing. I do charge but only for 1 on 1 workshops where you can learn so much more in the field as there are always things you forget about when writing 🙂 I wish you luck and hope you get some great photographs.

  3. I have just recently attempted to take night shots. Thank you for your blog which explains how to approach night photography. I will attempt another night photography shot after reading your blog.

    1. Thank you Sharon, best of luck with it, don’t be afraid to play with settings and experiment. A lot of the time you never quite know how good it is until you get it back onto the computer. Pixel peep a lot out when shooting, checking focus. Follow me on Facebook if you don’t already as I’ll be adding more and more tutorials over time.

    1. Thanks Sandra. I have a good friend with the Samsung S10 who can get astro photos. Not saying they are the best but he can do it. Amazing how far technology is coming. Thank you for taking the time to read, hope you end up with a camera soon 😉

  4. Thanks Murray, very helpful and I will attempt another night of Astro. Focusing was a major issue for me, and will try out your tips. One question, what metering setting would you suggest?

    1. Hi Steve, metering really doesn’t matter as it’s so dark. I keep it on matrix the under over will five you some indication for initial ISO to use, but a review of the histogram is usually a better way to go. Finding the balance between not blowing anything out, and getting it as bright as possible, without creating too much noise, can really only be learnt through some trial and error and reviewing on the computer. Happy shooting!

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