RE: [Leica] Lens Coating

["Vick Ko" <vick.ko@sympatico.ca>]

From what I know of coatings, it is a deposition of magnesium flouride.
I understand that it needs to be polished off, and the trick is to
polish off the coating without changing the figure of the glass.

I'm not sure of the thickness, but I recall it being 1/4 the wavelength
of the light that you are reducing the reflections of, so 400 to 700
nanometers being the eye-visible range, the thickness of the coating
would be 100 to 175 nanometers thick (0.1 microns to 0.175 microns).  

I'm not aware of a solvent that will remove magnesium flouride without
damaging the glass.

The "Focal Point" site is a good starter for information on how to
repair coating damage:

http://www.focalpointlens.com/fp_intro.html

regards,
Vick





- -----Original Message-----
From: owner-leica-users@mejac.palo-alto.ca.us
[mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of
www.geocities.com/curtisbliss
Sent: Wednesday, December 17, 2003 5:05 PM
To: leica-users@mejac.palo-alto.ca.us
Subject: [Leica] Lens Coating


Does anyone know of a solvent to remove lens coatings?  I have an old
Elmar 90 that fungus has attacked.  The back element especially has
several spots sans coating now.  Is there a way to remove the rest of
the coating that can be done by hacks at home like me?

Thanks,

Curtis

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