P-TTL in theory should be good, but somehow the programming in the system couldn't handle it well. The pre-flash is a problem in macros & people who are very sensitive to light. It is really fast before the main flash, so the shots you take will have someone eyes closing or opening 1/2 way. Normally I'll do a manual setting on the flash. My indoor event setting is normally f5.6 or f6.3, shutter 1/180, ISO400. On my flash I'll use HS mode, f8 or f11, ISO400 (if a bit under I'll switch this to ISO200). Since it manual flash you do not get the preflash, the shots have much lesser ppl blinking their eyes.