One of the most frequently asked questions is how to focus your camera and lens combination to be able to photograph the night sky. This article will aim to answer that question in a simple step by step way.
How to Focus
Focusing is one of the most important parts of taking photographs of the night sky. It is important to take the time to focus your photographs to pinpoint clarity, and it is one of the few times where you cannot rely on your camera’s autofocus system. Your camera’s auto focus system will not be able to focus on the night sky as there is not enough contrast for it to focus on specific stars due to the stars being too small and too little light being let into your camera’s sensors.
Follow the following steps to focus on the night sky:
1. Set your lens to MF (there are two options AF (Auto Focus) and MF (Manual Focus)),
2. If your lens has image stabilization, then switch it off (the reason for this is: in the evening your lenses will constantly try to stabilize due to the low light conditions, and may soften your sharpness of your image),
3. If your lens has the infinity symbol on the focus ring (∞) then set move the focus to there. But if your lens do not have this setting then do not stress, just continue to the next step,
4. Switch your camera’s live view on,
5. Place the light approximately 10-20 meters in front of your camera,
6. Point your camera to the light source,
7. Zoom your lens out to the minimum (widest field e.g. 18mm) ,
8. Turn your focus ring until you can see the light source with pinpoint accuracy. You achieve pinpoint accuracy when the stars do not look like blobs. This can be a painstakingly slow process, but well worth it, and lastly
9. Move your camera that it points to the Stars
Once you’ve achieved the perfect focus, and then lock your focus on your lens (another flip button on your lens. This will ensure that you have perfect focus for the whole evening’s photos.
Typical Focusing Errors:
There are two typical problems with focusing if it is not done right: Stars are not round and the foreground is blurry.
If the stars are not round then repeat the focusing process. In the case where the foreground is blurry then ensure that the wind is not interfering with your photograph, or that there aren’t any movement in your foreground (e.g. people walking past), If you aim to include trails from moving vehicles then a blurry foreground would then not be an issue.
The last big issue is if you have too much whiskey in you then do not try to focus, as your mind is blurry in any case and you will not be able to focus on specific dots or lines (spoken from experience)
Focusing Cheat sheet