A train passes an old Santa Fe caboose during a long exposure made in the Mojave Desert town of Boron on a very cold night in November, 2010. The neighborhood dogs were barking, and the moon loomed large in the sky as we got out of the car. Conditions looked great for shooting this lonely red caboose with a long stretch of desert in the background. The only thing that would make the shot better would be if a train came by -- and before we could even get our tripods setup, a slow moving train rumbled and clanked through the desert night.
Four exposures of 4 minutes at f/8, ISO 200 were combined for the first version of the image. The foreground is from the first exposure, and the sky contains all four exposures for 16 minute star trails. This split exposure for the sky and foreground was accomplished using a simple layer mask in Photoshop. Theoretically the same effect could have be accomplished in camera by physically masking the bottom of the lens after the first train passed. That would certainly be a difficult task, though!
The alternate version of the image is composed of five 4 minute images and includes a second train heading the other direction. This version has no masking and is exactly what the camera would have seen had I opened the shutter for a single 20 minute exposure. The five exposure stacking technique was used to avoid using in-camera noise reduction, which improves productivity and saves batteries. Using multiple exposures also gave me a wide range of variations in light patterns from the passing trains, depending on how many exposures were combined together.
Which one do you like better?