Archived posting to the Leica Users Group, 1999/05/22

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Subject: Re: [Leica] coating and water
From: "Dan Post" <dwpost@email.msn.com>
Date: Sat, 22 May 1999 08:40:32 -0400

At last a definitive answer! Thanks Erwin!
Dan
( Rub-a-dub-dub, 3 Elmars in a tub, scrubbing the salt rings away!
 Along comes Erwin, to put us at ease, and we can do it everyday!)

- -----Original Message-----
From: Erwin Puts <imxputs@knoware.nl>
To: leica-users@mejac.palo-alto.ca.us <leica-users@mejac.palo-alto.ca.us>
Date: Saturday, May 22, 1999 5:12 AM
Subject: [Leica] coating and water


>J.L. Adams wrote  most sensible about lenses and their coating's resistance
>to abrasive actions.
>Indeed modern coating techniques  use a process of  ion-assisted deposition
>of cold substrates to deposit a thin film on a glass surface. The older
>type of physical vapour deposition of heated substrates has the same
>characteristics.  The coating cannot be washed off by water, salt or
>otherwise and even the length of time of being immersed in water is of no
>importance. To give an autentic story. Mr Crawley from BJP once dropped a
>Summilux-M 50mm into the sea after taking pictures on a boat. SIX months
>later the lens was recovered, being exposed to salt water all the time. He
>cleaned the lens, lubricated it and image quality was as before. This is
>recorded and not a hear say story.
>
>Erwin