I have cameras that uses a conventional flash as well and IR ones. I have found that there is no difference. They do get used to the flash. I keep my cams going year round so I am sure that makes a difference too. I wouldn't just put one out a month before the season and not expect them to react to it. It is like anything else that is foreign in thier environment..they will adapt to it. This is the same reason I put dummies in my tree stands. Deer get used to seeing the form in the stand...come hunting season, they dont get spooked by a figure up in the trees.