Camera settings and composition for night sky photography
The night sky provides an awe-inspiring – and challenging – subject for photography. In a previous post, I gave some tips on the equipment you’ll need. Now, let’s look at the camera settings that will set you up for success.
To capture sharp pinpoint-looking stars, you’ll need to keep exposures as short as possible to avoid “star trailing” caused by the Earth’s rotation (seen in the above photo). There are apps to calculate the optimal shutter speed for a given lens/camera, but I usually do well with exposures of 20 seconds or less when using a wide-angle lens in the 16-18mm range. Keep in mind that the shutter speed must decrease as the lens focal length increases (e.g., if you’re using an 85mm lens, you’ll only need a 6-second exposure).
The ISO setting relates to a sensor’s (or film’s) sensitivity to light. A higher ISO setting makes the sensor more sensitive to light, meaning it needs a shorter shutter speed to properly expose an image. This almost guarantees no star trailing. Most cameras made within the last three years have wonderful results at high ISO settings. The downside is that high ISO causes noise. Test your camera at high ISO settings to see how far you can push it and still produce a satisfying image.
Aperture - Use the widest aperture setting that your lens will allow. If your lens opens to f2.8, use that. If it opens to f1.4, even better. The goal is to let in the maximum amount of light as possible.
It’s best to manually focus using the ‘live view’ mode on your camera’s LCD screen. Find a bright star in the sky and zoom in. Rock the lens focus ring back and forth until the star becomes a pin point circle of light. This technique takes a bit of practice, but in time you’ll become more comfortable with it.
I tend to set my images up to include something of interest in the foreground. This may be anything that catches your eye: a lighthouse, an abandoned car, a unique tree, a barn, a bridge, a road, etc. The goal is to have a main subject to base the composition around, with the night sky being a compliment to it.