Follow the “Rule of 500” to Take the Best Pictures of the Night Sky.
Photographing the night sky is a lot of fun , but also challenging. Assuming you have the right hardware, it basically comes down to adjusting camera settings. And the Rule of 500 can help.
To take a good photo of the sky at night, you need the correct exposure settings , one of which is shutter speed. The shutter can be opened from 6 to 45 seconds to get enough light into the frame. But if you leave the shutter open for too long, your camera will detect the movement of the stars and your image will end up blurry. They are also called star trails. They can really add a pretty cool effect if you want to, but if you don’t, you will need to adjust the speed.
This is where the Rule of 500 comes into play. As a rule of thumb, the slowest shutter speed you can use before the photo becomes blurry is 500 divided by the focal length of your lens. If your focal length is 18mm, the maximum shutter speed is 27.8 seconds (assuming you are using a full frame camera). It’s basic math, but PhotographyLife has done all the work for you. Here are the slowest shutter speeds you can use for night photography, depending on your lens:
- 11mm: 45.5 seconds
- 12mm: 41.7 seconds
- 14mm: 35.7 seconds
- 16mm: 31.3 seconds
- 18mm: 27.8 seconds
- 20 mm: 25 seconds
- 24mm: 20.8 seconds
- 28mm: 17.9 seconds
- 35mm: 14.3 seconds
- 50 mm: 10 seconds
- 85mm: 5.9 seconds
As the site explains, some people now follow the 600 rule or the 400 rule. Since cameras have more pixels, they detect less movement of the stars, so the numbers need to be adjusted accordingly. As with any rule of thumb, this gives you a rough idea of what you can get away with, but you definitely need to tweak your exposure settings anyway. To find out more, navigate to their full publication at the link below.
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