Shutter Speed: 15 seconds
BackgroundAs many regular readers know (since all two of you are friends anyway), we go home for the holidays to east Tennessee, where my parents live on a small farm. There’s not a great deal of that farm that’s still in use, but there are bees and some small-scale crops, and, importantly, quiet. It’s a great place to shoot night sky photography because of the minimal light pollution, the buildings on the property and the property’s location near the McGhee-Tyson airport. I will say this now: I’m not particularly enthralled with this image. But, I understand what I need to improve it next time, and I think efforts to improve the image were pretty successful, even though the original wasn’t what I wanted. As a blog that’s largely aimed at beginner photographers, I wanted to profile the mistakes I made and what I’ll do to correct them in the future.
The ImageThe end image is a collection of unfocused natural objects placed against a nighttime sky with light trails that look like shooting stars, but are from a passing airplane in the night sky. Haunting and somewhat dream-like, the silhouetted trees and structure (the wood shed, in Stovall family parlance…) provide the subject for the foreground, and the light trail of the turning airliner gives it something of an other-wordly quality.
ProcessThis image was captured after an hour of shooting in the other direction and failing to get a balance between the night sky and the crescent moon. Using a tripod and remote shutter, I was doing long exposures and attempting to get saturated star-scapes. It was too dark for the autofocus to work, and so I would fire a short shot at a very high ISO and then check the preview for framing and focus. I’d then switch back down to a low ISO and pop the aperture into the range of 6.3 to 11, and attempt the shot. I was regularly frustrated because the really long exposures that were required, 3 minutes to 20 minutes, were not coming out in focus. It was quite cold, and when you’re standing still for 5 or 8 minutes at a time to avoid camera shake, you’re not generating a whole lot of heat, so I gave up after a bit more than an hour and went to work with what I had. The image you see has heavy noise reduction, some sharpening and then surface blur applied, as well as some color manipulation to make it cooler than it was originally. Normally, I wouldn’t apply this much post-processing, but I made the decision to not stay a true to life as normal and create more of an art shot.
- Bring gloves. And a thicker jacket.
- Going long exposure wasn’t actually my best move here. The Rule of 600 says to divide 600 by your focal length to get the maximum number of seconds you can have the shutter open before the stars’ movement becomes unacceptable. Based on this, I actually should have kept my exposure under 30 seconds; the blurring I was getting isn’t camera shake, it’s the stars moving.
- I was trying for long exposure to get saturated colors and staying in the “sweet spot” of the of the aperture range to keep things sharp, and using my 18-55mm to get a wide angle. These priorities were all sorts of warped for night sky photography. I should’ve been shooting my 55mm 1.8 at a medium-to-high ISO to minimize all the moving variables—like, the earth itself.
- Usually, I’m prepared with something to help the camera’s autofocus, but I didn’t have a laser or powerful enough flashlight, so I forced into something of a guessing game.
- I’ve never used the dark frame subtraction technique, and I should’ve planned to at least try it, but I didn’t take a dark frame while I was out. I can probably still recreate the settings and try it, but I don’t know if temp affects that sort of thing.