|Canon EOS 3, tripod
Sigma 24-135 at 35mm
Fuji Provia 100F
f5.6, 10 minutes
I have to admit, this is a shameful copy of a technique I saw someone else use, and I had to try it out. If you like, take a moment to try and figure out how it was achieved before you go on.Undoubtedly, you figured out that I gradually defocused the lens, a very tiny bit at a time, over the period of the time exposure, while the rotation of the earth caused the star trails to curve across the sky. The result is vaguely reminiscent of paint drops spilled onto a wet sloped surface. The colors are courtesy of Provia 100F, which does a magnificent job of capturing the colors of stars. However, it's worth noting that it doesn't handle the light from the common sodium streetlamps very well, rendering them a curious green color, so it's best to keep light pollution from your frame.
If I remember right, I nudged the focus ring (set on manual focus, naturally) a mm or so every 45 seconds during the ten minute exposure. The full resolution version allows you to actually see the steps in the flares.