Re: [Leica] How soft?

["Mike Durling" <durling@widomaker.com>]

I have to say that a fingerprint on the lens is definately a concern with
the Summicron of the DR vintage.  Mine, non DR but same age, has damaged
coatings because someone (before me) didn't clean fingerprints off.  Of
course the coating is plenty hard so that years of cleaning hasn't affected
the bad coating.

Mike D

- ----- Original Message -----
From: "Feliciano di Giorgio" <feli@d2.com>
To: <leica-users@mejac.palo-alto.ca.us>
Sent: Friday, November 23, 2001 10:50 PM
Subject: Re: [Leica] How soft?


> SthRosner@aol.com wrote:
> >
> > Hello Feliciano:
> >
> > It may depend on the serial number of your DR. The later series, the
ones
> > with the focussing ring grooves in the indented scallops rather than on
the
> > raised grips, have different coating material. It is supposed to be both
> > better in terms of light transmission and harder. I'm not certain at
what
> > serial number that started but believe it was in the 1,900,000 series
and
> > later.
> >Seth
>
> That would include mine. The serial number is #192xxxx. The coating
> looks a little
> more purple to me than other examples I have seen.
>
>
> >If you get a fingerprint on the lens, it is time to clean it
> >as soon as possible...acids and oils can permanently etch
> >the surface.
> >Regards, Bill Larsen
>
> Yep, I've seen that happen. I have a beautiful old set of coated
> Baush&Lomb 35mm cine lenses (Super Baltar). The 25mm has a nice
> fingerprint on it, that long ago someone didn't clean off.  Eventualy it
> ate through the coating. In that case it is more of a obssesive/
> compulsive/cosmetic problem, since I've never seen it affect the
> performance of the lens,
> but then again the print is about 1/4 inch big and the glass is about 4
> inches across...
>
> > Use just a drop of lens cleaning fluid (I learned this from experience
when I destroyed a
> >lens by having the tissue soaked).
>
> How did too much fluid destroy the lens? Did it attack the coating or
> get inside and lead to problems?
>
>
> >My first DR I had for 5 years and used it hard, no damage.  If you are
> >worried you could always dedicate it to B&W and keep a yellow filter on
it
> >all the time :))
> >Don Dory
>
> Oddly enough that's pretty much all I shoot and one of the main reason
> why I bought the DR.
> Now, the permanent yellow filter is a WHOLE different discussion...
> ;-)
>
>
> Thanks everyone.
>
> Cheers,
>
> feli
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