When shooting the night sky, I recommend the following:
- Use a tripod and shutter release cable or remote to minimize vibration.
- Wear an indiglo wrist watch for timing the shutter without needing too much light.
- Coat and place to sit.
- Practice these directions indoors with your manual before heading outside.
Take your first photo using the camera's maximum ISO setting in program / automatic mode. I would use the 18-55 lens set to 18. Observe the following to make adjustments.
1) Do you like the framing of the shot? Adjust your zoom and aim and take more shots until you like the framing. Then don't touch it.
2) Is the photo in focus? Did the camera have trouble finding focus? I typically set the lens to manual and infinity and observe my test shots and make an adjustment as needed.
3) Turn on the histogram when you review your test shot. You cannot trust the camera display with your eyes in the dark. The image will always look brighter than it is.
Being a night shot, most of the histogram. Will be on the left side (black). That is ok, but you will want some distribution across to the right.
4) Now that the framing and focus is set, I set the camera to manual and take a ten second exposure at ISO 12800 at f/4 and review the histogram.
If the photo is too dark, you can double the exposure by dropping to f/2.8 OR opening the shutter for 20 seconds and check again.
Your camera has 3 ways to brighten/darken the image:
- ISO setting (sensor sensitivity) high numbers are more sensitive, but noisy.
- Aperture: low F numbers (F/2.8 or F/4) mean the lens is more open (more light) than at F/11 or F/22.
- Exposure Time: longer time = more light.
Your photo likely looks decent, but noisy. You need to drop the ISO for a clearer picture. Let's say test shot was 10 seconds at ISO 12800. If you drop to ISO 6400 (less sensitive, less noise), you must double the exposure time for same result (20 seconds). ISO 3200, you multiply by 4: 40 seconds. ISO 1600 multiply by 8: 80 seconds. ISO 800 would be 160 seconds.
Play with your settings, but only change one thing each shot so you can observe the difference.
Note that star travel will start to be visible at a 1 minute exposure or longer. For artistic reasons, you may want a longer exposure for longer star travel or a more saturated Aurora. To do so, keep dropping the ISO or try a higher F/stop to allow for longer exposure time.
Have fun and stay warm!