Re: 580EX II Troubleshooting
Is your flash going into sleep mode? That's the only time I have seen this with mine. Once I turned sleep mode off the problem went away. If you already have it off then my next guess would be the batteries. What kind do you use?
Re: 580EX II Troubleshooting
Flash isn't asleep. Example happened a few weeks ago - flash (with CP-E4 battery pack) was on my Rebel XTi. Camera set for continuous shooting. Shutter button down, all of a sudden one of the shots is super-bright and then several are dark.
Since TTL seems to be only selectable as a Custom Function, the fact that I can't get back into the flash to change that CF tells me something else is going on.
I'm starting to suspect my batteries. I have about 10 sets of Impact (B&H store brand?) 2900mAh NiMH batteries and 6 sets of Sanyo Eneloop batteries. Since I "know" the Eneloops will hold their charge, I try to use the Impact batteries first. If the flash comes out of its pouch, the batteries get recharged (and a shelf set goes in). Maybe it's time to try the Eneloops as first-round batteries and perhaps ditch the Impact batteries.