I have a Hasselblad 50mm Distagon on order and was curious about Series VIII filters. Are these the same as Bay 50 filters? My version is a later model black "T*" model. Ultimately, I'd like to shoot with a 3, 6 and 10 stop ND. Thanks for any input.
Bay 50 filters have a bayonet male flange that mates with the bayonet female flange on the lens. Bayonet mount filters cannot be used on lenses designed for series filter use without an adapter of some sort.
Series VIII filters have a simple smooth bezel surrounding the filter elements and are designed to be used with an appropriate series filter retaining ring that screws in the lens. Many times the retaining ring is an embedded part of the lens hood for the lens, like it is for my mid-'70s generation Hasselblad Zeiss Distagon 50mm f/4 T*.
BTW: with respect to Hasselblad Series VIII filters, for the Biogon 38mm mounted on the SWC and maybe for the Distagon 40 and 50 mm lenses designed for the reflex cameras, it's best to buy Hasselblad filters because the filters are not symmetric in their mounting. For the SWC's Biogon, and maybe for the 40 and 50mm reflex lenses, if you use a standard Series VIII filter, it could rub on the center of the lens's front element and cause damage. Hasselblad Series VIII filters mount the filter element slightly forward of the centerline of the bezel and prevent this problem.
G