On 2/18/2011 2:15 PM Donn Cave spake thus:
Quoth (Thor Lancelot Simon):
...
| On the other hand, maybe it's not "uncharacteristic". Wollensak made
| some awful Tessar lenses and so did a few others. Maybe Richard knows:
| is there something about the Tessar design that makes is particularly
| prone to manufacturing or Q/C error?
I believe one way to make a Tessar awful is to use it for LF
applications that require a larger circle than it really delivers.
While comparing the reputations of various Tessars, it might be
interesting to correlate with the absolute coverage circle -
that's not the right word, I mean the farthest extent of any
kind of coverage, irrespective of optical quality. My hunch
is that identical glass could have a better or worse reputation
depending on artificial cutoff from its mounting etc.
Interesting you should mention coverage as it relates to Tessars.
Some time ago I did an experiment (a successful one as it turned out)
with a Tessar that was "too short" for the format. Not sure it qualifies
as LF, but I was shooting 9x12 (cm) film with the "next smaller size"
lens, a 105mm (made for 6x9) instead of the usual 135mm or so. (The lens
was a Carl Zeiss Jena f/4.5 Tessar).
It covered beautifully, sharp and tasty looking from corner to corner.
Not an extreme example, I'll grant you: the 9x12 image circle is 150 mm
(nominal), while the 6x9 is 110 mm. And I believe that these older,
uncoated lenses are exceptionally well-made, high-quality examples of
the species.
--
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