P3D Viewer Lemons

[Brenda Nowlan <bknowlan@xxxxxxxxx>]

Dr. T writes:

-Brenda asked if there are viewers that are "lemons" (bad to start)
like some cars.  Viewers are very simple instruments.  They might
suffer from some common or not-so-common problems, but there are
no real lemons out there.-

What about the actual glass?  I have known photographers to "test"
various lenses within the same brand and focal length.  I have even seen
articles in photo mags addressing lens testing.  You test sharpness of
lenses on Realists.  Does every Realist with David White lenses test at
the exact same sharpness or distortion?  Does every Realist with Ektar
or I1 ex Paragon lenses test at the exact same sharpness or distortion? 
I thought with all the testing that is talked about, the implication to
me is there can be some variation.  Am I misunderstanding this?

Brenda


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