Gary F. asks:
<< Are the lines per millimeter test results sometimes published in
today's Popular Photography comparable to the l/mm results Modern Photo.
published? >>
In theory, any test of lines per mm resolution is comparable. The
resolution limit is determined by observing which grouping still has all
it's lines countable both vertically and horizontally. That, folks, also
depends on the film used, not to mention the subjectivity of the person
evaluating. The higher speed the film, the worse its ability to resolve
lines, since they become obscured by the film grain, thickness of the
film emulsion and (for color film) number of layers in the emulsion.
My recollections is that Modern Photography started off using
Panatomic-X as their lens testing film. I have no idea what developer
was used, but us old darkroom hands know that Agfa Rodinal 1:100 and
Kodak D-76 1:1 were a higher acutance developers than Microdol-X. And,
of course, Panatomic-X improved over the years. My recollection is that
Panatomic-X was discontinued sometime early in the 1980s, replaced by
Technical Pan. What Modern Photography did at that point is anyone's
guess! If they were as smart as testing gurus Norman Goldberg and
Michelle Frank at Popular Photography, they would have stock piled a ton
of Panatomic-X.
Maybe, just maybe, when Modern changed the criteria in which they
awarded an Excellent, Very Good, etc. (and I think this was more than
once), it was associated with a significant change in the film they were
using??? Again, my fading recollection, is that they had a grade
inflation due to the improvement in optics from circa 1970-1980, as well
as maybe the improvement in film. They had to do something since
Excellent was turning up too often. A cynic might even say too many
generic lenses were obtaining Excellent ratings and they had to protect
the advertising dollars of the major camera manufacturers.
So, my conclusion would be that Popular Photography's current resolution
charts are no way comparable with the old Modern Photography data. BTW,
Popular has been forced to do this because they say 1) their SQF testing
procedure is getting redesigned 2) some optics can't be SQF tested. Hum,
I wonder what is really up? Maybe the cost of all those enlargements
for viewing was just too much for the accountants??? Or someone pointed
out they didn't have a glass negative carrier?!
Norman, where are you when we need you?
Gary Reese
Las Vegas, NV
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