Who produces 100mm screw-type filters?

[alex_b.]

I recently purchased the "bronthosaurus" - the 55/3.5 lens for

Pentax 67. It's a very nice lens, blah blah,... but I would like to

know who produces the 100mm screw-type filters that would fit on this

lens. I only need an UV protective filter to put in fornt of those

10cm of glass thus avoiding scratches and dirt in field use. I suppose

the filter must be properly thin not to cause vignetting. And, of

course, it must be primo quality (like Hoya Super HMC series or

something). Thank you for your kind answers.

[bob_cook]

Alex, I owned that lens for awhile, and sold it partially because I could not find any filters. I think your only option is to look for used Pentax filters, and I was unable to locate any. I called every manufacturer for a solution and came away with no answer. Bob

[steve_rasmussen]

Heliopan makes some 105mm filters and also adapter rings that allow the use of these filters on lenses with 100mm threads. SR