If he is reacting to the sound of the sutter and THEN is closing his eyes they
you will be ok. figure the time for the sound to travel from the cam, and his
reaction time his eyes will be open.

In article , Petros
writes:

My question has to do with a wedding that I'll be shooting for a friend
of mine next weekend. I did some test shots with the couple today, and
found out that the groom has a reaction to the shutter that makes him
close his eyes when he hears it, even if the flash is turned off. Does
anybody have any advice for what I can do to minimalize his reaction?
I'd hate for all the shots of the "happy couple" to be with his eyes
closed.