I'm trying to use optical slave to fire these two flashes together and I'm having no luck. On-camera flash as the trigger in all cases. The M50 works fine in "wireless" control mode. It will not work in manual slave mode because the G6 preflash triggers it out of sync. The Y560 works in manual slave is S2 mode. It ignores preflash. It does not work in wireless control mode. It doesn't know what to do with the control flashes. Does anyone have an idea on how to mix the two? Anyone know how to kill the preflash on the G6?