(Via PictureCorrect) Here’s an easy to follow video tutorial by photographer Ben Canales (video above) that helps to take out a lot of the guesswork when it comes to proper exposure for shooting the night sky. Canales goes over a couple different cameras and what you can expect of them, and although he’s using DSLRs in his tutorial, you can apply the same principles when using your mirrorless system. If you’ve been meaning to learn about this fascinating photography genre, this is a great place to start.
From PictureCorrect: Canales instructs us to take a variety of sample shots to find areas which have unwanted light pollution and see if there are any lingering or passing clouds that may be difficult to see with the naked eye in the middle of the night; both of which we can use to establish composition. For his sample shots Canales sets his camera to it’s lowest aperture setting, the highest ISO, and an exposure time of 30 seconds. He recommends overexposing the samples so they are brightly lit, making it easier to evaluate.
For your final shots, you will want to make sure you camera is set to capture RAW images and leave your aperture wide open. Canales prefers to keep his ISO in the 3500 to 4000 range for his final images. Exposure time will vary, but Canales prefers to set his [shutter speed] to it’s highest setting before switching over to the bulb setting. A rule of thumb for photographing stars is to divide 600 by the focal length of your lens; the result is the amount of seconds you should expose. For example, Canales shot on a 20mm lens, so he divided 600 by 20 to get 30 seconds. This rule of thumb will let you avoid the stars tracking, or streaking across your photograph as they move through the sky. It’s a pretty handy equation to keep in the back of your mind. (Read article on PictureCorrect)