"murrayatuptowngallery" <murrayatuptowngallery@[EMAIL PROTECTED]
>
wrote in message
news:1193211281.829633.228220@[EMAIL PROTECTED]
> Seems that the old shutter blades and iris diaphragm were
> removed. The
> shutter lever release was still banging around at the top
> because it
> was captive by virtue of a swaged in pin that prevented
> it's non-
> destructive removal.
>
> The slot at the bottom is apparently for the former
> stop-adjusting
> lever. The one at the was for the shutter release.
>
> Shutter speed was set by a rotating ring, still there, but
> nothing to
> couple to.
>
> The scales are still interesting. I was wrong about
> 6.2-45. It said
> 6.2 - 64 and sideways 45S across two scales. The second
> scale has a 1
> 2 3 4 5 crammed very close together above the roughly
> 22-64 postion of
> the f-stop scale. the t-stop between 32 and 64 is '44'.
>
> Lastly, the W.A. marking is way down by the 6.2 on the
> lower f-stop
> scale.
>
> I imagine someone would have said something already if
> W.A. meant
> something else like Weston Aperture, but I don't think he
> went back
> that far anyway.
>
> Anyway, there's nothing there functional but the glass. I
> left the
> other things on for cosmetics.
>
> Oddly, I have never been able to recognize a 'weak
> reflection' on more
> modern lenses. On these cells it is distinctly visible.
>
> This made real question/realize whether cement existed
> yet, and the
> yellowish ring around the lens outer perimeter I was
> trying to clean
> off is probably delaminating cement. This is over about
> the outermost
> 1/8" and the entire lens diameter is roughly 1.25".
>
> I degreased it which loosened all kinds of paint inside. I
> think I'll
> seal off the light-leaking openings at the top, repaint
> the interior
> dead/ultra flat black & try my hand at Waterhouse stops.
>
> Of course no mounting flange - that's an unwritten rule...
>
> It's a Murray-rig project from here on -
>
I have no idea what the extra markings on the stop plate
indicate. For US stops US-1 is f/4, which is the fastest
lens the British Royal Society thought would ever be needed!
Other speeds are the time of exposure in comparison with
US-1.
I don't know for certain when cemented elements were
first used but I am sure it predates the Rapid Rectilinear
of 1866. The cement used until about WW-2 and to some extent
afterward, is Canada Balsam. Beginning about the late 1930's
this was supplanted by various synthetic cements. The
synthetics were first used for aerial camera lenses which,
at high altitudes, are subjected to very low temperatures.
The low temperature will nearly intstantly crystalze a
Canada Balsam cement resulting in the layer becoming milk
white and making the lens useless.
The yellow or brown ring is from cement near the
periphery of the lens becoming oxidized. This is from air
leaking in at the edge. Eventually, the balsam will also dry
out and crystalize around the edge. If the right edge paint
was used this effect will not take place so there is great
variation in the condition of the cement in old lenses.
It would be interesting if the shutter had any clue as
to its manufacturer. Its possible Gundlach, or one of the
companies who used that name, also made shutters but it
could have been made by a number of other companies.
--
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@[EMAIL PROTECTED]
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