So someone suggested to me that I put unexposed, but developed film over the flash and use that. Apparently it blocks most visible light, but allows IR through. And I happened to have a hunk or two to try. I found that it throws iTTL off quite a bit - I have the flash at -3EV, but for some reason or other the results are better. More detail? And less coloring effect when I use a grey card to set the WB. This one is a 100% crop, no color processing at all. Nothing other than a little sharpening. For me, the most incredible thing is doing IR hand held. Even freezing motion! This one converted to b&w using NC. This one has a little of the coloring effect, but I think the tones are nicer than before. And amazingly, I am shooting this with very little visible light leaving the flash head.