Re: Stuff Within Objectives
From: Gordon Couger (gcouger_at_NOSPAMprovalue.net)
Date: 10/22/04
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Date: Fri, 22 Oct 2004 03:41:19 -0500
http://www.skgrimes.com/ Steve Grimes should fill the bill. He is not cheap
but his prices are reasonable for eh work he does.
Gordon
"Klaus D Schmitt" <kds315@yahoo.com> wrote in message
news:cl7the$k09$04$1@news.t-online.com...
> I had the very same problem with the Photars and the Minolta 12.5/25mm
> RMS lenses. A very skilled repair technican mentioned that this might be
> some lubricants from the aperture blades (these RMS lenses have that).
> They used no oil but some molybdenum sulfite / molycote which after
> some years gets onto the inner glass surfaces.
>
> I wanted it cleaned, but he convinced me NOT to do it, since the effect
> of that (black) dust inside would be minimal on the quality of the
results.
>
> I did not notice any degradation of the image quality. I have some high
> resolution images showing that stuff but to my surprise, he was right.
>
> The chance to damage these delicate lenses or decenter some lenses
> when taking them apart is VERY MUCH HIGHER.
>
> Dr K Schmitt
> www.macrolenses.de
>
> "scopes_r_us" <scopes_r_us@yahoo.com> schrieb im Newsbeitrag
> news:2b729dfe.0410022114.43e886ab@posting.google.com...
> > Hi,
> >
> > I recently found a Leitz Photar 25mm objective. This objective is
> > designed for macrophotography and has a RMS thread.
> >
> > Upon close examination of the objective, I noticed some dust
> > particles and a small hair in the viewing field. Thinking that the
> > lens needed to be cleaned, I proceeded to do just that. Well to my
> > surprise, I then discovered that the foreign bodies were in the
> > INSIDE of the lens. With closer examination, I can see particles
> > (including a small hair) on a number of different INTERNAL glass
> > surfaces. Now I have seen lens with fungus before and this particles
> > do not look like what I have ever seen before as in any fungus. Also
> > the small hair is located several glass surfaces deep within the
> > lens. To my knowledge, this lens has never been disassembled.
> >
> > Thinking that perhaps this lens was unique in this respect, I reached
> > for a like new Minolta (made by Leitz) 12.5mm objective I have. Upon
> > examination, I too noticed some dust on its internal glass surfaces
> > but not to the extent the 25mm objective has.
> >
> > Now when I insert the Leitz 25mm objective into a macro photography
> > setup, I do not see any of the dust particles or the hair in the
> > field. I am assuming that is because they are not located in the
> > image plane.
> >
> > So the question to the group is this...have you ever seen foreign
> > bodies within your objectives that would appear to have been present
> > upon initial assembly? Other than for some light scattering, can you
> > think of any harm these foreign bodies would cause?
> >
> > Considerng that I have dealt with a number of optical devices over
> > the years, this is the first time I have seen this type of effect in
> > a sealed lens.
> >
> > Thanks for any information you might be able to offer.
> >
> > SRU
>
>
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