Night photography is something I have tried to do more of this past year. It is so much fun to do and it really gives you so many creative opportunities. I enjoy shooting the Milky Way, but even though we live several miles outside of any city, there is still too much light pollution. Star trails are the next best thing, and I have thousands of images on my hard drive to prove it.
This image was created back in late June. The hay had just been baled, so I decided to take advantage of that for some foreground interest. Without any kind of foreground, these usually turn out to be pretty boring images. There are a couple of different methods for creating star trail images. You can take a single, really long exposure. Somewhere in the neighborhood of at least 30 minutes. Or, capture a series of shorter exposures and stack them together. Either way will show the apparent movement of the stars over time, as the earth rotates on its axis.
I choose the use the multiple exposure method for a variety of reasons. With several different exposures, it is possible to throw out one or two that have issues. If you take one really long exposure and something messes it up, then you have to start all over again. One longer exposure will also tend to have more digital noise (grain) due to the sensor heating up.
The creation of this image consisted of capturing about 50 exposures. Each image was exposed for 30 seconds, with only about 2-3 seconds in between each image. They were shot at the relatively wide focal length of 14 mm, at an aperture of f/2.8 to allow in as much light as possible. I kept the ISO at around 1,000, which is about all you need for star trails. A small flashlight was used to light paint the hay bale in one of the images to provide a little more foreground accent.
After shooting, the images were loading into the Lightroom, minor exposure adjustments were made, then exported as JPEGs. The JPEG images were then stacked together in a free software program call StarStax, which works really well. Finally, the resulting star trail image was blended together with the light painted image in Photoshop.
Another thing I should mention is that the camera was pointed in the general direction of the North Star. This makes the circular pattern in the star trails. The extra light trails in the final image are actually fireflies that were buzzing around as I captured the images. I originally thought about removing them, but feel that they add some interest and context to this image. What do you think?