Here's another composite from the lightning I was able to catch (ouch!) that night. Same data, 40D 17-85 lens, 17mm, manual everything, 0.3sec at f/4. The teeny bit of lightning to the right of mid image is the bit composited in and layer masked to blend. The brighter clouds to the right are part of the same photo as the bigger flash just left of mid image. Here's a more cropped version posted in the Sky theme.