Archived posting to the Leica Users Group, 1998/11/09

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Subject: [Leica] HELP! Marks on glass
From: "Martin V. Howard" <marho@ida.liu.se>
Date: Mon, 09 Nov 1998 15:13:46 +0100

I attended an auction this weekend and bought a 50mm NF-Summicron at a
very reasonable price.  I had examined the item prior to the bidding,
but only after buying it did I notice, upon shining a flashlight through
the lens, that there are markings on the internal lens elements.

The marks are faint, light/white "scratches", fairly numerous, that are
shaped as concentric circles.  They appear to be on one of the surfaces
of the element closes to the rear element and seem perfectly circular.
If you think of photographs of night skys, with startrails, that's
pretty close to what it looks like.

I don't actually know if they are scratches, hense the quotation marks.

Does anyone know what these are?  Can it be removed?  I suspect that
they will affect contrast and sharpness.  They are quite faint (only
detectable when shining a flashlight through the lens), but they are
also quite numerous.  Does anyone know for sure how these will affect
the image quality?


M.

- -- 
Martin V. Howard, Application Systems Laboratory,     | 
Dept. of Comp. & Info. Sci., Linkoping University,    | Just "DOHH" it!
SE-581 83 Linkoping, Sweden.  Tel +46 13 282 421,     +----------------+
Fax +46 13 142 231; marho@ida.liu.se; www.ida.liu.se/~marho