Alan Chan http://www.pbase.com/wlachan
The filter mount on the DA 14 flares out, which I suppose is to avoid vignetting with filters.
I don't think this lens vignettes with Pentax or Hoya filters. To be safe, though, I usually use B&W filters on wide angle lenses, or wide telezooms. The B&Ws are thinner, but still have outer rings.
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I don't know how many varieties B+W make. On my DA 14 I keep the following:
B+W 77 KR-1.5 Skylight 1.1x MRC. It is labeled F-PRO on the side.
According to my calipers the protruding part (excluding threads) is 4 mm. thick.
I also have the following:
Pentax Skylight SMC 77 mm.
My calipers claim that this one is 6 mm. thick.
I originally considered putting the Pentax filter on my DA 14, figuring it to be the better filter. I first tested for vignetting with the Pentax, the B+W, and the lens with no filter. I thought I could perceive a very slight corner darkening with the Pentax, so I use the B+W instead. The Pentax filter is on my Sigma 70-200 f2.8.
Joe
