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Old February 16th 11, 02:18 AM posted to rec.photo.equipment.large-format
Richard Knoppow
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Default Lens Cell Cleaning


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On 2/13/2011 3:22 PM, Richard Knoppow wrote:

However, the Geronar is a Cooke Triplet, a
three-element, air-apaced lens with no cemented surfaces.
Its of high quality and such lenses are capable of good
performance at moderate stops.


From my use, it's a very nice lens given a bad rap mainly
because it was sold at a low price as a "novice lens". Who
wants that when you can buy a pro lens? :P

It's multicoated, comes in a modern, reliable shutter and
is small/lightweight. It actually folds up in my super
graphic.

Given most LF lenses are used around f22, the wide open
edge performance isn't an issue for most people. I've
actually done some portraits with mine on 4X5 at f11 and
they look great. The only disadvantage I see with this
lens is the smaller image circle compared to the much
Larger/heavier/more expensive plasmat types. If I had to
choose this over some vintage lens that has questionable
coatings and flaky/ancient shutter, I would get this one
in a heartbeat.

Stephey

A carefully designed Triplet is capable of excellent
performance and Rodenstock is noted for making good lenses.
I am not sureprized it works well. Somewhere around f/22 is
the "optimum" stop for many LF lenses. The limit of a
Triplet is that they are hard to correct for either high
speed or wide angle, if it isn't required to be either it
can perform entirely satisfactorily.


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Richard Knoppow
Los Angeles, CA, USA