At 11:32 PM 7/16/03, Joel Wilcox wrote:
Except that 100F also doesn't resolve as well as Velvia 50, according to
the Pop Photography review this month (81 lines to 100F's 72 lines).
Joel W.
At 12:16 AM 7/17/2003 -0500, John L. wrote:
I think this is what he said, although the sentence was long with fair
number of pronouns (can cause ambiguities). In any event, their
respective MTF curves explain why this is.
I omitted my understanding of how to interpret MTF graphs in my previous
posting (mea culpa). Look at the curve from about 10 lppmm through about
40 or 50 lppmm. IIRC, Velvia 50 actually rises above 100 0.000000or a portion
of this region. Those films (and print materials and lenses) that have a
very high curve in this region tend to have higher accutance; i.e. they
are capable of producing photographs that look sharper. This is in spite
of how the curve rolls off in the high lppmm.
<snip>
This is what Peter Kolonia wrote in PP (have the article before
me): "Velvia 50, however, trumped the competition [between Velvia 100F and
E100VS] in resolving power, with the ability to distinguish 81 line pairs
per millimeter (lp/mm) in our resolution tests, compared to 72 lp/mm for
both Velvia 100F and E100VS. Is this significant? Probably not for general
photography, but it could be a factor in mural-sized enlargements" (PP, Aug
2003, p. 66).
John, where do you see the potential for ambiguity?
Joel W.
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