Star trail photography—capturing the movement of stars in the sky—is a surprisingly easy and inexpensive method for vivid nighttime photographs. The process is possible with consumer-grade gear. If your camera isn't super schmancy don't fret, if you have a DSLR camera with manual functions--you're on your way!
Here’s a tutorial:
What you’ll need
• camera that allows manual settings
• wide angle lens (the wider the better)
• steady tripod
• intervalometer (some cameras have this built-in)
• software to process the photos
• warm clothes
Ben's shot from this past winter | Canon t3i - f2.8 - ISO 800
What is an Intervalometer?
For star trails and timelapse, some cameras (including most Canon DSLRs) need an external device called an intervalometer in order to take a series of photogaphs within set intervals over a specific period of time.
Where and When to Shoot
Optimal conditions for Star Trails are cool, dry, cloudless nights. Try to avoid nights with a full moon, which can dominate the sky with its light and presence. Humidity in the air can fog your lens. Wind will blur any natural foreground objects.
Choose a location away from light pollution (get out of the city!). Light pollution will not always be visible to the naked eye, so take some test shots. Consider featuring a foreground object to help your composition and establish perspective, perhaps in the lower 1/3 of the frame. Shoot in a wide open area with no overhead obstructions.
Startrail Ben shot on a lake | Canon t3i - f2.8 - ISO 800
The Technical Plan
• Manually focus your camera to infinity (the point of farthest focus)
• Set your camera to shoot “wide open” at your lowest f-stop (f/2.8, f/1.4, etc.)
• Set your shutter speed to 30 seconds
• Set your ISO from 400 to 800
• Configure, start and lock your intervalometer for ongoing 30-second exposures
• Shoot for at least 15 minutes (the longer the better)
• Touch up the images and run them through a compositing program such as StarStaX
Shoot in RAW format if possible. RAW images are more and adaptable to cropping and manipulation.
Since a star trail image is really a composite of a many time-lapse images, you could also use a video editing program to add motion.
When shooting, if the foreground looks too dark as compared to the sky, shine a flashlight on the foreground for a short period of time. Experimenting with light painting is a great to brighten specific areas in a long exposure. You can also use a flashlight to assist in composing your image in the dark, while looking through the viewfinder of your camera.
Ensure your gear can withstand the outdoor conditions. Check into your camera’s weatherproofing specifications (or lack thereof) if shooting in negative temperatures or harsh weather.
Ideal shooting conditions can be hard to come by, but keep at it–night photography is an art of experimentation and patience. Have fun with this style of shooting, take chances and be creative, and you’ll have amazing star trail photos to show off to family and friends.