I bought a used 580EXIIwich looked in excellent shape. Made a few test-shots, all seemed fine.Now the batteries that came with it have run out, I put in a set of rechargeable batteries. But the flash won't work with them. I tried another set, same th...
I tested the batteries (NiMH) and they seemd okay, not overly enthusiastic but okay. Bought a new set anyway and that solved it. Seems what my battery tester sees as okay is not good enough. Thanks for the help Skirball and TCampbell!