If you use enelope batteries or regular AA's you probably won't have
any overheating issues. So, overheating is not the norm unless you're
firing over and over like a baboon with a camera. You will probably
never reach the thermal cutoff and I've used mine extensively with
multiple shots and never had it cut out. I personally can't see a
reason to shoot continuously with the flash so much that it would get
to that level of heat.
Don't be worried about it unless you shoot at continuous high speed
every shot and use and external battery pack and expect the flash to
shoot a ton of high speed continuous shots. I know how to pace my
flash and have never seen a situation where I'd need to pop the flash
that often.
Don't dog the SB-900, it's not that bad and I think it's an
improvement over my old SB-800.
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