Center Filter for 150mm Super-Symmar XL

[Tim Hyde]

I'm thinking about getting the 150 SS XL for my 8x10 and 4x10s. I notice Schneider wants to sell me the #4a 95mm center filter for almost 500 bucks. I already have the #4b 95mm for my 72mm XL, so why can't I use that? What is the difference between these two cener filters? Thanks

[Eric Leppanen]

Both filters provide 1.5 stops of correction. The difference would be how quickly that level of correction kicks in as you approach the edge of the image circle while applying movements.

For my usage (landscapes and architecture), I find that I generally do not need the CF with my SS150XL when shooting B&W or color print film. I do need it when using chrome film. I would suggest trying your lens out first without the CF, and if you decide you need some correction, experiment with your existing IVb filter. If the illumination pattern provided by the IVb doesn't look quite right (or goes beyond what can be corrected with Photoshop), you can of course go for the IVa (Midwest and Badger sell them for around $395). Once in a while a used IVa will pop up on Ebay at significant savings, but they are pretty rare.

[Ling Z]

#4a -- 1.5 stop correction
#4b -- 2 stop correction

They can be swapped as the difference is small. More info can be found here: http://www.schneideroptics.com/photography/accessories/center_filters/pdf/centerfilter.pdf

[Michael S. Briggs]

As Eric says, I'd first try not using a center filter, then using trying your existing IVb center filter.

If you look at the footnote in the pdf file that Ling linked, while Schneider recommends the IVb for the 72 SA-XL, the footnote gives the IVa as an alternative. So if you find that the IVb overcorrects on the 150 SS-XL, you could get a IVa and try it on your 72 SA-XL and perhaps settle on this one as a common filter for the two lenses.