External battery pack w/ Canon Speedlights tip....

This one is from Dirk Dewachter. If you're using Canon Speedlghts with a quantum battery pack there's a custom function to make the flash work better with the Quantum pack, probably works with any external battery pack. For the 580ex it's Custom Function 7 -set to 1, on the 580ex II it's custom function 12 also set on 1. This allows the flash to use just the external battery pack for power and bypasses the AA batteries inside the flash, the batteries just power the light inside the flash and the lcd screen. Dirk says it makes the flash recycle faster. If anyone knows if Nikon has a similiar function let me know.