My previous post showed a couple pictures of a thunderstorm with a rainbow and lightning. Here is a time lapse video from that shoot. The rainbow seems to emanate from a vortex in the clouds (OK, the sound track may be a little overboard…).
Click the Vimeo link in the embedded video to see it in HD.
My intention was just to catch some lightning, I had no idea the rainbow would be there or how the clouds would swirl. The way I shot the sequence was pretty simple – shoot long enough exposures that camera would have enough time to write the images to the memory card and not fill up the buffer. This means there would be very little missed time between exposures so if a bolt struck, I was likely to catch it. I used a Canon 5D Mark III at ISO 100 on aperture priority (so it could adapt to changing light conditions) with a 24-70 2.8 L II at F/22 and a circular polarizing filter. This worked pretty good while it was daylight as exposures were around 2.5 seconds. That gave the camera plenty of time to write to the memory card but as it evening progressed into night, the exposures quickly maxed out at 30 seconds and the frames are totally black. I toyed with the idea of opening up the aperture to keep the exposures under 30 seconds, but decided to just let it run.