Well, looking so far, from what I can tell, this filter won't work with many of my best lenses. <P>
It appears it will work with my 40mm 2.8 pancake and my 85mm 1.8, but my L lenses are all too large for it to mount to.
Still, VERY interesting, but right now I have a 50L and the 100L macro on my lens list to buy next, so barring a lottery win, I may have to put this on the back burner behind those lenses.
Then again, who knows what will happen one weekend after a few beers and impulse online shopping hits...
I'm keeping my eye on this however, it does look very interesting.