Thanks Audionut, that is interesting. You say your 30 sec exposures "ensure you almost always get every lightning strike". Do you have Canon's 'Long Exposure Noise Reduction' switched on or off? I tend to leave this on as otherwise the noise is horrible - but then I lose 50% of my time as the software does its thing. If you have it switched off - what do you use in its place?
ps Nice photo!
ps Nice photo!