The night sky is an incredible phenomenon. Whenever I take a minute to gaze up at a clear star-filled sky, I am filled with awe and wonder at the magnitude of space and the depth and quantity of stars on display. Capturing this in photographic form can be a tricky business, but hopefully the following tips will get you started.
Step 1 - Getting Set Up
First, you need to find a location with the right conditions to maximise your chances of getting a great shot. I live in a city in the North of England and a starry sky is basically impossible to see. You'll need to head somewhere remote, away from the light pollution of the city. It also helps to pick a clear night. Check the weather in advance because you don't want to be hindered by cloud cover.
It is essential that your camera remains totally still during the length of the exposure, so the one thing you'll definitely need is a sturdy tripod. It is also useful to have a cable release to avoid touching the camera during the exposure. Any small vibrations will affect the results of your exposure. One trick is to use a piece of dark cardboard to cover the lens when you first open the shutter, then pull it away once the camera has settled down.
Photo by Fishtails@Taipai.
Step 2 - Clear, Focused Shots
Due to the movement of the earth, it is very difficult to capture a clear, focused shot of the stars unless you have specialized telescopes and equipment. The maximum exposure time without noticeable movement is limited to about 15 seconds. In order to capture still stars in focus, you'll need a clear night with bright shining stars. Use the widest aperture possible, e.g. f/2.8 and set your shutter speed between 15 and 20 seconds. You'll need to experiment with ISO levels. 100 or 200 ISO is ideal to minimise noise levels, but you may need to push it up a bit to get the exposure you want.
Photo by Forestgladesiwander.
Step 3 - Star Trails
One of the most fundamental things to understand about photographing stars is that the earth is rotating, meaning as you freeze the night sky in your shot, the stars will appear to be moving. This effect is known as 'star trails', as you can see in the example shots. To capture round star trails, set your aperture as wide as possible, anything from f/1.8 to f/4, set the focus to infinity (the symbol looks like a sideways 8), and point your camera towards the North Star, which will remain motionless while the other stars move around it.
Again, experiment with the ISO, starting out at 100. You may need to compromise a little on the noise for increased exposure quality. Exposure times will vary depending on the light being cast from the moon. If there is a new moon, you can expose for roughly an hour. For a half moon, limit exposures to 20 minutes. It's a case of experimenting with the available light. But remember the longer the exposure time, the longer the trails will appear.
Photo by Jordan Hackworth.
Step 4 - Equipment
There are also a few basic items to remember to take along that will help your evening run smoothly. First, a torch or flashlight will help with setting up and finding steady ground for your tripod. Just don't make the mistake of turning it on while your shutter is open. It's definitely worth taking a spare battery or two as your camera will be on for extended periods. A stopwatch or timer is also helpful to check on the length of your exposure without touching your camera. If you're feeling lazy or tired, a stool or chair can be quite useful!
Photo by lrargerich.
Step 5 - Heading Out into the Night
Photographing stars can be very labour intensive, especially because you have to wait for extended amounts of time for a single exposure. Though when you get it right, it can be extremely rewarding. If you're struggling, try starting out by photographing the moon. This should help you appreciate the basics of what is required and help you practice for your star shots.
It is very hard to capture what your eyes are seeing in the sky, but once you've mastered some of the basic exposure settings, all you need to do is to keep practicing, fiddling with composition, and finding the right conditions. After one or two late nights, you'll come away with some great shots.
Photo by Velo Steve.