IVa centerfilter on Nikkor-SW 150mm

[Marco Annaratone]

Would you use a Schneider IVa centerfilter for the Super Symmar XL 150mm on a Nikkor-SW 150mm? Has someone done this by any chance? If I am not mistaken the Schneider has a cos3 light fall-off while the Nikon has a cos4 fall-off, so it may not work out that well ... on paper. But in reality?

I have the filter already and an opportunity to get a Nikkor-SW 150mm, hence the reason for the question.

Thanks a million!

[Michael S. Briggs]

I think you have the illumination behaviors reversed. To their credit, Schneider publishes graphs of the relative illumination versus angle off-axis of their lenses. These graphs make it clear that the Super-Symmar-XL has the cosine to the fourth illumination of simple lens designs. In this characteristic the Super-Symmar-XL series is a step backwards in wide-coverage lens design. (Of course, the Super-Symmars have other desirable improvements such as size and weight.) Unfortunately the Japanese manufacturers don't publish similar graphs, but from the cross-section diagrams and examining the lenses, I believe that the Nikkor-SW series use the tilting pupil trick. This should improve the illumination, theoretically to cosine to the third. So I would expect the 150 mm Nikkor-SW to have more uniform illumination than the 150 mm Super-Symmar-XL. Perhaps you will find that you don't need a center filter with the Nikkor-SW, even if you find it useful with the Super-Symmar-XL. It depends on how your usages and tastes.





Some previous discussions: 8x10 Wide Angle Lenses at http://largeformatphotography.info/lfforum/topic/503195.html and Center filter for Nikkor 90mm f4.5 at http://www.largeformatphotography.info/lfforum/topic/501033.html.

[Marco Annaratone]

Thanks Michael. Yes, I got it reversed. And thanks for the links.

[jarrod connerty]

Dunno if the scenario's identical with the 150mm variants, but I use the 110XL's center filter with my 120mm SW and am more pleased with the results when employing the filter than without.