Now that Schneider has posted the theoretical MTF curves for the new 80mm XL, I am really curious about the performance of this lens. I should preface this ques tion by noting that I am interested in the 80 for use on 6x9 roll film, and that I have the 110XL for 4x5 and find it to be a wonderful performer.
The curves seem to show that at f/8, MTF fall off is so dramatic as to make the lens very soft in the corners of a 6x9 (~50mm off axis). No curves are posted fo r f/11 or f/16 which would be the sweet spot for use with roll film formats.
At f/22, the off-axis performance is better, but the 20 lp/mm the tangential per formance still falls off pretty markedly.
Comparing this to the MTF curves from Rodenstock on the 75mm f/4.5 Grandagon-N, the Grandagon seems to provide better evenness of performance across the field. For example, at 50mm off-axis, at f/22, the Grandagon curves show 60% sagittal a nd 45% tangential, vs. about 65% sagittal and 32% tangential for the Schneider 8 0mmXL.
So it's not clear that at f/22 the XL is any better than the existing Grandagon- N (although the XL is about 150g lighter). My main concern is performance at f/1 1-f/16, where it is not at all clear that the 80XL will even equal the Grandagon -N.
Schneider doesn't show longitudinal chromatic curves, so it is hard to compare p otential color fringing.
So, as soon as some people have the 80, I would love to hear about real world pe rformance. And I would love any input from Schneider folks or Rodenstock folks, or optics guru's on whether the 80XL really represents any improvement over the existing 75mm Grandagon.
BTW, I don't fret about such things with 4x5, but with roll film, I find the tol erances are tight to produce sharp 20x24's, and it looks like the 80mm XL is goi ng to be 30% more costly than the Grandagon.
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