View Single Post
  #24  
Old February 17th 11, 08:32 AM posted to rec.photo.equipment.large-format
Richard Knoppow
external usenet poster
 
Posts: 751
Default Lens Cell Cleaning


wrote in message
...
On 2/15/2011 8:24 PM, Richard Knoppow wrote:

While its possible the coatings account for the
difference I think something else must be happening. What
I
suspect is that the cement in the rear element of the
Ektar
may have become hazy. This is a peculiar effect that I've
seen in other Ektar lenses. When examined under
magnification, and using grazing incidence light, you can
see that the cement layer has developed a sort of
orange-peel texture. You can see it using transmitted
light
as a light haze but its effect on contrast is enormous.


I used the wrong term saying "marginal coatings", this was
more what I was referring to and since I sold this lens
long ago, I have no way to know what the actual problem
was. The other issue I had was right after purchase I had
to have the old shutter repaired. Like I stated in another
post, I love my 135 WF ektar so it's not like I hate old
lenses..

I guess what I was trying to get across is: in my
experience this "novice" lens produced MUCH better
results, especially on color slide film, than my
commercial ektar did so some statement that one of these
old "classics" is always a better choice didn't pan out
for me. Nor have I seen anything in the results from this
lens that would have me go look for a replacement.
Whatever was wrong with that ektar lens wasn't obvious but
I don't doubt there was likely something like you stated
wrong with it. Given their age, I also wouldn't doubt
others have this same issue, that doesn't sound easy or
cheap to resolve. I would suspect that finding a good
working sample of a geronar would be more likely that
finding a good sample of a lens that is many years older,
YMMV.

Stephey


Well, results is what counts! It would be interesting
to know if the Ektar had something wrong with it. Coating in
general should not affect sharpness so but does affect
contrast and color purity and saturation, all of which are
interepreted by the eye as sharpness. OTOH, its possible
that this Geronal is just a better lens than the Commercial
Ektar you had.
If your Wide-Field Ektar has satisfactory contrast and
color rendering its a good indication that the problem with
the C-E was not the coating. The WF Ektar has the same
coating plus it has _four_ glass-air surfaces.


--
--
Richard Knoppow
Los Angeles, CA, USA