The Night Sky – Test Shots

I love night photography, especially astrophotography. A goal I’ve had for a long while is to get a nice, clean shot of a dark sky (i.e. no moon) that shows off the Milky Way and also has a bit of landscape in the scene to give a visual sea level.

Two weekends ago, I was hunting in the Texas Hill Country in a location that has little light pollution. I took several shots one evening about 2 hours after sunset and about 30 minutes before moonrise (the moon was waning and about 90% full, so if I tried shooting after moonrise, the sky would have been too light).

click to see larger pic

Canon 5D + 24-70mm f/2.8L
30 sec., 24mm, f/2.8, ISO 1600 (and then pushed +1 stop in RAW processing)

And here are two more shots taken at about the same settings as stated above:

click to see larger pics

The greenish light on the trees is from a sodium vapor light on a nearby cabin. The light streak in the photo just above (left) is from a couple of guys on 4-wheelers passing by.

Getting a shot like this is difficult given the limitations of the equipment. Exposure times are limited to 15 to 30 seconds because the goal is to NOT have star trails. With a reasonably wide focal length (24mm in this case), star trails will just start to become noticeable around 25 – 30 seconds exposure time (actually, it depends on the final output of the photo; for web-sized images you could probably go 60 seconds, but my ultimate goal is a nice, largish print: 8×10 or even 11×17).

I shot wide open (f/2.8) at ISO 1600. I found that the resulting exposure is still a little too dark. I pushed the exposure +1 stop during RAW processing, but that increased the digital noise in the file to a point where it greatly degraded image quality. ISO 1600 looked pretty good, but ISO 3200 (effectively) did not. Post-processing noise reduction works well, but it also kills the fine detail (there’s an amazing amount of tiny stars visible in the sky, and that’s the fine detail I want to see in the final print).

The exposure that worked out best (providing the best-looking sky) from my series of test shots was this: 30 sec., ISO 3200, f/2.8. However, ISO 3200 is not really usable and 30 seconds is just a little too long (star trails).

So, I’m going to have to get a faster lens or a camera that is better at very high ISO :-)

4 thoughts on “The Night Sky – Test Shots

  1. Thanks again for your test work you save me some time. I had planned a shot like this for my Eleuthera trip. I will post the results soon. You continue to help my photography, thanks so much.

  2. Thanks, Stacey. Give it a try! It’s fun. It’s amazing what shows up in the photos – the camera “sees” so much more than the naked eye.

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