Interesting! With your H camera experience and Nisi filters, I have to ask: since I will be using the 80mm lens (and I have a 503cxi w/ 80mm lens), at least for awhile only I will be using only the 80mm lens, should I stay with the 4"x4" (100x100) filters and holder with CPL? At what point with H lenses do the 100x150mm, or 150x180mm filters become necessary?
Thanks!
Dave, if you're only using the 80mm, the 100mm square ND filters be just fine. The 100x150mm size is generally for graduated ND filters, which will also be fine on the 80mm HC lens.
For best results on the H system, larger filters than that generally are used on the 24mm HCD, 28mm HCD, 35-90mm HCD, and 35mm HC (ie wide angles). The potential issue with the 100mm filters on these lenses is vignetting. I never had any issues with 100mm filters on the 35-90mm HCD but can't speak for the rest. I did also use 165mm x 165mm filters on the 35-90mm and 28mm HCD, but the tradeoff with those is that they were very large and difficult to keep free of debris (dust, etc) in the field because of sheer surface area. They're also a lot more expensive than smaller filters. 150mm square ND or 150mm x 180mm grad ND filters (or larger, like the 165mm filters I used) would work best on these lenses, but you can get away with smaller filters depending on use.
If you're only planning to stick with the 80mm HC, the 100mm x 100mm filters for ND and 100mm x 150mm grad ND filter sizes will be just fine for now, although you may want to think about larger filters at some point if you're ever thinking about picking up any of the above lenses (24mm HCD, 28mm HCD, 35-90mm HCD, or 35mm HC).
-Todd