What speed do I use to shoot the night sky? I tried last night, first tried with 30", then 10", then even 6", but all the times there were movement from the stars themselves, like this:

enter image description here

And that was with 4 seconds speed! How do I shoot then? With speeds like 1 second, there is not enough light, and I have to use really high ISO, which adds lots of noise...

  • 2
    \$\begingroup\$ Also see What is the "Rule of 600" in astrophotography? \$\endgroup\$
    – mattdm
    Oct 25, 2015 at 10:51
  • \$\begingroup\$ Divide your sensor width in mm by the Pixel Width. this gives you the distance between pixels. The pixel Pitch. Then divide this figure with the focal length of the lens you are using and multiply by 13750 - This will give the time it takes for light to travel from the middle of one pixel to the next. for a 16mm lens on a full frame, that will be approx 5.5 sec. from there on, work out your tolerance level. Keep ISO high, Shoot in RAW and let it over expose. correct in Lightroom to bring back detail. talk in chat if you need more info. \$\endgroup\$ Oct 25, 2015 at 19:47
  • \$\begingroup\$ Do not overexpose, you will lose the color of the stars. If you have a recent camera, like D7000+, D5200+, D3300+, simply set at 800 ISO and use the time you calculated according to the previous comment. Then work with postprocessing. Colors of stars are retained, noise in dark areas about the same. Check DPreview for "iso invariance" \$\endgroup\$
    – FarO
    Oct 26, 2015 at 9:45
  • \$\begingroup\$ when I say, "Over Expose" I refer to ETTR. apologies for any confusion \$\endgroup\$ Oct 26, 2015 at 11:30

3 Answers 3


The rule of thumb is to shoot at 600/f to avoid star trails, where f is the "focal length" (35 mm equivalent).

For example with a 200mm, 600/200=3s. The minimum shutter speed is 3 seconds.

Anyway, the best approach is to try and eventually change your settings.

Have a look at What times and settings should I use for taking pictures of stars at night and falling stars? and What is the "Rule of 600" in astrophotography? (thanks to mattdm for this one)

  1. Use internal image noise reduction and image stabilization to get a photo of a bright astronomical object, such as the moon. By accident, I found that image stabilization kept the moon's image fixed, even though background stars left trails, during a long exposure.

  2. If you have access to an astronomical telescope with a clock drive or manual slow motion controls, mount the camera on the 'scope and use the telescope drive to track a star.

  3. Take a number of short exposures and use software to reduce noise (or create star trails) such as the free StarStaX. See Noise Reduction by Image Averaging for details.

The issue with all these techniques is that you'll need to compose scenes including terrestrial objects as well as the sky in layers, because the images move relative to each other.


First things first, you need a tripod. You want to pick a night with as little air traffic and as few clouds as possible. It should also help if there is little air pollution.

Next, pick your spot and angle. You may want a foreground context to make your photo more interesting. Take a few practice shots using flash to have a rough idea of what your background will look like.

If you want to shoot the Milky Way look for a long cloud stretching across the Milky Way. It will be almost foggy but not blocking stars.

So once you have your shot aligned, open your aperture as wide as it goes. Set your shutter speed to 600 divided by focal length (Anything longer will create star trails.)

Optimal ISO range is about 2000 but once you have taken a few shots you can adjust accordingly. Sometimes I go lower sometimes I go higher.

Try to time your shot when there are no planes in the sky. Also take a bunch of photos. Change it up and try different things.


Not the answer you're looking for? Browse other questions tagged or ask your own question.