I know the infrared assist in some cameras can mess up IR film. Does this only happen if you use the autofocus? Or is the IR assist "on" at all times? I have a Pentax PZ1P and am pretty sure it has some type of assist 'cause I could see a red beam when shooting in a cave this spring. So, would it be safe to try HIE in it as long as I don't use the AF ('cause I rarely use AF anyway)?