Bob, I haven't had a chance to use the lee/Calumet system, but i do have extensive experience with the Sinar 100mm filter system and a little with the Hightech version of the same. Basically all three systems are made in the same plant in England, or so I'v e been told by a current/former US distributor of one of the brands. One of the differences might be the thickness of the filters, and the design of the holders. THAT said, my experience with the Sinar system has been that with when using my 90mm f/4.5 (4x5 format) I can just get away with using the first shade ring if I make use movements. (Instead of a hood, the 100mm Sinar holder comes with three rigid plastic rings that snap into each other and into the holder. the holder itself has three filter slots, the first and third can grip a filter in place, while the second cannot. Various size threaded adapters(up to 95mm) fit into the back of the holder and are held in place by a thumbscrew. There are also three size-ranged adapters that can be used to mount the filter holder to the barrel of a lens.) For wider lenses or for using the 90mm w/ movements or with my V-pan 6x17 I either use no shade or I can remove the ring that holds the shade in place by unscrewing it and then screwing the filter frames back into place. Using the latter method I can eassily use this excellent system on lens as short as 20mm on my Nikon. Hightech makes two filter holders, one is normal and one is designed for a wide angle. Sinar is sdistributed by you know who; and Hightech are distributed by Visual Departures, Ltd. their tel # is 1.800.628.2003 and their e-mail is VDINFO@aol.com. Good luck, Ellis Vener email@example.com
Lee is now coming out with a wide angle lense hood. Call 800-576-5055 for info.