Olympus-OM
[Top] [All Lists]

Re: [OM] OM1 Viewfinder Black Cloud

Subject: Re: [OM] OM1 Viewfinder Black Cloud
From: clintonr@xxxxxxxxxxxxxxxx
Date: Thu, 19 Jul 2001 12:15:01 -0500
Thanks, Mark!  You took the words right out of my mouth!  We've noticed the same
thing -- we can polish off the degraded area of the prism, but there's always a
line between the silvered and exposed glass.  Only a new (or undamaged) prism 
looks
new.

Mark Dapoz wrote:

> On Thu, 19 Jul 2001, O.C wrote:
>
> > The problem described that occurs with the foam and prism is that the foam
> > rots and becomes bound to the prism surface. When stuck on the glass it
> > alters the glass to air interface that is required for the total internal
> > reflection to occur. What you see instead is the foam through the glass.
> > Thats why cleaning the prism of the gunk and restoring the original glass
> > air interface will restore things.
>
> In theory what you describe is true, but I've found in practice that's not
> the case.  I have a prism which is about 80 0e-silvered.  I can get it
> to work reasonably well if the prism surface is perfectly clean.  Unfortunatly
> problems arrise at the sharp edges of the prism (at the top and around the
> eyepiece).  At these points you can clearly see a faint line in the 
> viewfinder.
> No amount of cleaning will make these lines disappear.  I suspect the silver
> backing which is applied to the prism somehow "fixes" this problem.  A prism
> with no silver backing is still useable, it's just not as good as one with a
> silver backing.
>                                         -mark
>
> < This message was delivered via the Olympus Mailing List >
> < For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
> < Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >


< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >


<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz