HSS (FP high speed sync) for shutter speeds to 1/8000th of a second Good Power – only around 3/10th of a stop off the top end Canon/Nikon alternatives Fast Recycle – from 2 – 3 seconds at full power Both Canon & Nikon Optic Wireless slave functions built in. S1 & S2 simple Manual optic slave – for regular or TTL pre-flash Sound Beep – indicates recycle ready and low exposure + or – 5 stops of Exposure Compensation in ETTL 1/3rd and 1/2 stop Manual power adjustment, even both methods combined Compatible with Canon’s built in Flash Control Menu 2.5mm Sync Port – Instead of the troublesome traditional PC sync port Full Head Swivel 180 degrees left and right Powerful AF assist light (though centre focus point only) Regular simple shoe locking ring – no complex lever system to break Settings saved automatically Instant switch on/off option New Body Design Instead of just adding HSS to the previous YN-565EX TTL flash model (which was a close copy of the Canon 580EX II body