Originally posted by flyer In wireless flash mode, the on board flash always discharge since the discharge also triggers the external flash. But, if you go in "Custom Settings", you can set the on board flash to work as "control" only, so it doesn't participate to the exposure, or you can set it to "master", where it is use as part of the exposure. When use as "controller", the flash will trigger just before the exposure to relay info to the external flash, but it won't be part of the exposure.
Ok Thanks! I saw that in the menu but didn't really understand its purpose. I'll give it a try!