Just entered the world of light magic. Brought two 300w monbloc flash heads. I can fire one as slave using the 40D on camera flash, the other one seems dead. I can fire the live one synched to the wife's 30D but I cannot fire it synched to the 40D. I get a message telling me the flash is not compatible or is turned off. The other flash will not fire no matter what is done.
Result, one brand new dead flash and one live flash but I can only synch it to the 30D.
Any clues.