>> they could only be seen in the diffraction pattern from
light reflected off the lens coating. <<
This can be seen with a 15X Loupe (if it is there to be seen)
Paul M. Provencher
(ppro)
-----Original Message-----
From: Bob Blakely [mailto:[EMAIL PROTECTED]]
Sent: Monday, April 23, 2001 2:12 PM
To: [EMAIL PROTECTED]
Subject: Re: Fungus question
The etching on the coating of my lens could not be viewed with any
magnifying glass. They consisted of microscopic "trails" so small (and also
close together), they could only be seen in the diffraction pattern from
light reflected off the lens coating. Also, as I said in a previous post, I
suspect there are probably many strains of fungus that can do this with,
probably with varying effects. FYI, the fungus does not "eat" the coating.
There nourishment comes from the air. It's some excitement that etches the
coating.
Regards,
Bob...
Give blood. Play hockey.
----- Original Message -----
From: "Provencher, Paul M." <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, April 23, 2001 8:36 AM
Subject: RE: Fungus question
> I just disassembled a beautiful Super Takumar 70~150 Zoom (yes it was
really
> fun...) to remove fungus from between the front elements. This lens is
SMC
> (although not so labeled). I just took it apart, made a pencil mark on
the
> edge of the element in question to show which way round it belonged, them
> simply washed the thing in warm water with some dishwashing liquid, using
a
> jiffy pad scrubber (NOT!). No really I used warm water and some
dishwashing
> liquid. When it was dry I just put it back together. Examination of the
> element surface with a 15X loupe showed no signs of etching. I might have
> to use the solution to kill the fungus if it comes back, but it cleaned up
> really easily.
>
> Paul M. Provencher
> (ppro)
>
> -----Original Message-----
> From: Chris Brogden [mailto:[EMAIL PROTECTED]]
> Sent: Sunday, April 22, 2001 10:01 PM
> To: [EMAIL PROTECTED]
> Subject: Fungus question
>
>
>
> I have a couple of questions about fungus on internal lens elements. I
> understand that it's possible to remove it with no damage to the glass
> provided that it hasn't etched the glass or coatings. Is this correct?
> What are some of the best methods to remove fungus? How likely is it to
> stay gone provided that I only use the lens in a dry climate? Does
> exposure to UV light (leaving it on the windowsill on a sunny day) help
> much? How hard is it to mark the coatings on an SMC Pentax lens? IOW,
> how many years might it take for some fungus to damage the coatings? I've
> heard estimates of around 5 years or so with single-coated elements, but I
> have no idea how accurate these estimates are. Has anyone had
> experiences--good or bad--with having fungus removed from SMC elements?
>
> Thanks!
>
> chris
>
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