سلام
علاوه بر 2nd Curtain قابليت High Speed فلش هم در حالت واير لس كار نخواهد كرد. اينجا دليل اين نقيصه توضيح داده شده است:
the 7D wireless flash isn't by radio control - it is controlled by pre-exposure light pulses (see bottom of page 121 of the English language manual: "The slave unit is controlled by the built-in flash's light pulse signal"
So, second curtain synch isn't possible because the trigger pulse would potentially occur while the shutter is open, possibly interfering with the exposure.
Likewise, high speed flash is essentially a series of pulses that fire while the shutter slit is moving across the frame - so integrating control pulses with that may be impssible (or perhaps would require processing power beyond the scope of what the camera and flash are capable of?)