I have the DP#Merrill cameras, which have made me pay most attention to landscape photography. I would like to get a rectangular filter set, basically holder plus GND set, perhaps plus reverse GND, if the trick of layering two GNDs in opposite orientation doesn't simulate a reverse GND well enough . Right now I have only a CPL. I do not have 4" (100mm) filter system holders or filters, but I do use standard DSLRs as well as the Merrills. I would like to hear experiences, pro and con, with the various filter system holders and filters out there.
1. Lee 100mm
2. Lee Seven Five
3. Formatt Hitech 67mm - a new system with new holder
4. Formatt Hitech 85mm
5. Cokin A and P
6. any others