Without any doubt ABOVE... unless B+W makes filters and a holder that keeps them right in line with the lens... even if they did I'd still say above with no doubt.
If you were to measure lines of resolution in the print you would be able to quantify it. I won't even argue the point. If you are happy that is fine. But I am not projecting an image through a nice Rodenstock lens and then throwing those image bearing photons though a dusty piece of plastic with micro scratches. The light will scatter and reflect within the plastic. I have been using above the lens plastic 6x6 filters just below the cold light for 25 years.
For the record, my Ziess T* lenses bought new never had a skylight filter, and still have no ill effects on the elements from heavy professional use. Oh I did buy a B+W skylight filter on when I shot in rolling steel mills.
Only color correction minus blue and Orange filters when needed.
Last edited by vpwphoto; 03-09-2011 at 07:07 PM. Click to view previous post history.