[JohnH]

I have noticed that my Canon20d battery seems to run low very quickly when I use the supplied EOS capture software, ie by the time I focus and do a 10*30s imagaing run (NR on at iso 800 or 1600) the battery has pretty much had it. That is from a fully charged start.. If I use my TC80N3 to run an imaging session it lasts for many more shots, of course then the images are not being sent up the USB cable to the PC. Is USB a power hog? If yes how is this best solved - currently I use two batteries - must I get the AC adapter?