14 Aug Simply put, the slave mode on your flash will allow you to fire that particular flash when it senses the flash from another speedlight. There are a. 31 Oct On-camera flash produces a coarse light that draws flat, shapeless subjects You can hold a slave flash in your hand, ask a friend to hold it. hi, need to know about the slave and master flash. is the strobe is a master? The master is triggered directly by the camera. One or more slaves.