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On 10/25/2010 1:52 AM, Richard Knoppow wrote:

Your Commercial Ektar has some problem, these
should be
exceptional lenses. However, I have found some Kodak
lenses
have an odd sort of problem with the cement in the rear
component. If you look at it using grazing light it will
have an orange-peel look. That will cause a lack of
sharpness and loss of contrast. The lenses can be
recemented
and, if this is the trouble with this lens, it might be
worth doing.



That likely was the problem as the contrast is what was
the real issue with it. The geronar I replaced it with was
MUCH better which shouldn't have been the case given it's
a cheap, 3 element lens.

Stephey

The Ektar may also be hazy inside. This is a common
problem with old lenses. Even a slight amount of haze will
destroy image contrast. Fortunately, the inner element
surfaces are easy to get to. I think all of the Commercial
Ektars have back caps. First, shine a flashlight through the
lens and look at it from the other side. If you see any haze
inside it is the cause of the low contrast. To clean it
remove the front element from the shutter or barrel. Then
look at the back of the cell, there should be a threaded
cap. Remove the cap and the center element will come out.
Clean both of its surfaces and the inside of the front
element with any window cleaner, I find the "streak free"
kind to be best. That should take off any haze and leave the
glass perfectly clear. Also clean both surfaces of the back
cell. Unless the cemented surface in the back is bad this
cleaning should improve the contrast noticably even on the
ground glass. Don't worry about centering, the lens mount is
designed to automatically center the elements.
To check the cemented surface remove the rear cell and
shine a flashlight obliquely at the lens and use a
magnifying glass to see the cemented surface. Do this from
both sides since it may be easier to see it from one of the
sides. The surface should be invisible. If it looks hazy or
you can see a sort of orange peel texture, the cement has
begun to separate and the lens needs to be recemented. Note
that all of the Commercial Ektar series have synthetic
cement so it does not yellow or become crystalized at the
edges. It _should_ last forever but I've seen the above
effect in a couple of lenses. I don't know what caused it
but the early synthetic cements were thermosetting and may
not have been cured exactly right. These lenses are all
getting on to be sixty or more years old and probably did
not exhibit any problems for decades. I think Commercial
Ektars are worth the cost of re-cementing. John van Stelten
at Focal Point is the fellow to contact about the work. He
can give you an estimate on the cost. Hopefully, the lens is
just dirty.
Let me know what you find.


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Richard Knoppow
Los Angeles, CA, USA