I am fascinated by the stars and I’ve always wanted to photograph them, especially the Milky Way. My first attempts were lousy, and my final images were riddled with noise. That didn’t deter me however. It was just a matter of gaining the knowledge and trying agin. I’ve found that I must be willing to make mistakes in order to learn and grow. If I don’t try I will never succeed.
There are quite a lot of issues to consider so let’s address them one by one.
Noise in low light situations
In order to capture the stars a higher ISO and longer shutter speed are required. With higher ISO’s noise becomes an issue. A couple of years ago this was a very big problem as the sensor in most cameras would struggle with noise at anything round about 1000 ISO. This has changed remarkably over the last couple of years and most of the newer cameras can easily handle ISO’s of 2500 and above. Post processing techniques have also improved significantly and eliminating any unwanted noise is also easier than it has ever been.
What lenses are good for photographing stars
My first attempts I was using a kit lens, then a fairly decent fast ultra wide lens (Tokina 11-16mm f/2.8). The kit lens wasn’t wide enough to capture enough of the stars or milky way. The Tokina was much better but I struggled with coma and chromatic abberation. After moving to a full frame system, I’ve used the 17-35mm, the 14-24mm and the 14mm (all Nikon). These lenses were all far better than the Tokina, with much reduced coma and chromatic abberation. The 14-24mm lens seems to have the least issues and I really like the 14mm focal length.
Focus on the stars
My first couple of attempts at capturing the stars I had no idea how to focus. Often the camera would search and search to find focus and I struggled to even trigger the shutter. Over time, I found that manual focus is essential and the best method is to focus on infinity and then review your image by zooming way in to see if the stars are in focus. It’s really good to know your lens well, and to know exactly were infinity is.
Framing your star shot
Star photographs are very cool, but the better ones I found have a good balance with something else in the frame and the interesting sky. Adding enough of earth elements into the scene contribute to the effectiveness of the final image. It really is no different than composition for traditional landscape photography. I need to make sure that I am thinking about foreground, midground and background at all times. The better images lead the eye into the scene and generate the feel of three dimensions. This is especially important with astrophotography as the sky is incredibly two dimensional. 🙂
Adding a tree, reflections, some leading lines, etc. can really enhance the final image.
How long to keep the shutter open?
The first couple of images that I captured I used 25 or 30 seconds as my shutter speed and was dissapointed when I noticed small star trails in certain sections. I quickly discovered the rule of 600 and determine that I should be able to get 25 seconds with my new lens. 500 divided by my effective focal length of 18mm was 27, so I should be able to get 25 seconds. Rounding down to 25 seconds gave me good results and I was set.
After uprading to a full frame camera with a 36MP sensor I quickly discovered that I had too many pixels for the same capture and I was seeing trails again, so even though the focal length was effectively the same, I needed to shorten the exposure to 20 seconds to get no movement. What was really happening was the increased pixels were allowing me to zoom further into the image and see the movement that was there. Really all that matters is how big you plan on printing it or displaying it. Testing this for your specific focal length is very important.
Which part of the sky you are shooting is also important as the earth spins around the North Star (Polaris). Stars close to the North Star move slowly while stars further from the North Star travel a further distance in the same time. (Actually we are the ones moving. 🙂 ) The best advice I can give on this subject is to use the rule of 500 and then review your image. DSLRs are incredible
We’ve addressed a number of different issues when shooting the night sky. The only way to learn this stuff is to get out there and make mistakes. Have fun! Look for a future article discussing some processing techniques to enhance your astrophotography.
If you want to join us on one of our workshops to learn these techniques and how to process astrophotography then check out the two astrophotography workshops that we have later this year.
- Milky Way over the Water and Grandfather Mtn
- Constellations and Nebulas
- Star Tracking
- Post Processing workflow, tips and tricks
- Milky Way over the ocean
- Some of the Darkest Skies on the East Coast
- Constellations, Nebula and Star Tracking
- Post Processing to showcase the stars