I now have what I believe is the most expensive glass I have for my camera in terms of cost per unit weight of glass (I haven't weighed all my lenses).
The past few times I've gone waterfall photography shooting I've kicked myself for not bringing my neutral density filters. I have a 1 stop, 2 stop, and 3 stop 4" rectangular filter. They are good, but kind of clumsy at times.
I am familiar with the trick of stacking two polarizing filters on top of each other to use that as a variable neutral density, but the mechanical vignetting gets a bit much on several of my lenses.
Singh-Ray came out with the combination I've been waiting for. A "