Can anyone explain why the canon 580EXII does not allow second curtain function while it is in the master mode?
Keith B
05-05-2010, 05:22 PM
I don't know the exact specifics, but it has to do with the signal that would control this function has to be transferred through a pin that only works when connected to the camera. Said pin doesn't have wireless equivalent. Again I don't know the specifics. So I imagine it won't work even when the flash is set to master on camera because it won't be able to send the signal to slaves.
I hate the fact you can't do second curtain off camera.
peety3
05-05-2010, 07:05 PM
Some situations call for the on-camera 580 to act as a trigger-only device. As a result, wireless flash requires that the trigger signal get sent before the shutter curtains open. Second-curtain wireless flash would require the trigger to signal an exact timing message to all flashes, and the remotes would all have to have ridiculously precise timing circuits so that the flashes all fired together. Aside from the challenges of accurate timing from a battery power source that's subject to some serious punishment, the wireless signal would have to have room in the signaling language for a lot of data: I just took a rough hack, and I think it could take the data stream from 17 bits to 36 bits, which probably isn't possible.
Second-curtain wireless flash is available with at least one type of RF trigger (I've done it, and it's oh-so-cool).