So......I finally picked up some rechargeable batteries for my SB-600 flash. Recycle Time is insane. I did a test indoors....With normal batteries I would fire 4 shots about 1 second apart and the flash would only fire for the first....the other 3 it wouldn't fire due to the flash recharging. With the rechargeable batteries doing the same test the flash fired every single one of the 4 times....(same lighting conditions, same spot in the room). So......if you have a non-onboard flash and you aren't using rechargeable batteries, you're missing out so go buy them. I picked up the 2450 NiMH which is the higher of the 3 "levels" they make.