"AAvK" <notforspam@[EMAIL PROTECTED]
> wrote in message
news:PmRij.43603$1C4.41844@[EMAIL PROTECTED]
>
> Hello LF public
>
> I recently bought a very old GTR triple convertable (5x5
> glass), have been reading about them in public forums by
> search in Google and learnt that they have bad
> "chromatic aberation" (as it were), so it is necassary to
> use a yellow, orange or red
> filter on the front or back for sharpness. I read one
> fellow uses green.
>
> I would like to know which glass does what with which
> color of the spectrum so as
> to klnow which color filter to use! This would be
> interesting. I would use the filter
> on the front because I could also screw a lens shade into
> the filter. I wonder if I
> could find such an adapter for the front, if the front
> cell were not in use.
>
> But, this lens is a series II No. 1 patented in 1895, yet
> the rims do not state either
> of the focal lengths, and they are in an old wollensak
> Regno shutter (working!),
> which must have been a later adaptation, it has a proper
> triple aperture scale in
> brass (fancy work!).
>
> Would anyone know the focal lengths, and whether a cable
> or air hose can be adapted? It does have push button type
> finger release(s).
>
> Any help much appreciated,
>
> --
> Giant_Alex }<)))*>
> not my site: http://www.e-sword.net/
> cravdraa - at - yahoo - dot - com
Turner-Reich lenses were made until the late 1940's.
The individual cells are not well color corrected so there
is a noticable color fringe when they are used. When both
cells are used the symmetry seems to cure this fringing so
its probably lateral color. The use of a green filter should
improve sharpness when a single cell is used. It seems to me
without firing up my T-R and looking at the image that the
worst fringing is red so a green filter would be better than
a yellow one.
If you use the single cells on the back of the shutter
you can use a push on type adaptor on the lens cell just as
you would in front. While the performance should, in
principle, be optimum with the lens behind the stop, in
practice it makes very little difference and the bellows
draw needed is significantly less.
I am surprized that your lens has no focal length
markings. What markings does it have? Perhaps I can identify
it. The patent notification may not mean much. I don't
believe there was ever a law preventing the notice of a
patent after the patent had expired. That would be 1912 for
an 1895 patent.
Basically, the T-R lens is a Zeiss convertible Protar
with one of the elements split and replaced by two cemented
elements. The lens was probably designed by Ernst Gundlach
who used this trick on other lenses to avoid infringing
patents. The extra element in the T-R has no benifit over
the Protar and, in fact, the Protar seems to be a better
lens. Turner and Reich were officers of the Gundlach company
and probably had nothing to do with the design of the lens.
A great many T-R lenses were made in the late 1930s
into the WW-2 period to meet a government spec probably
written around the Dagor. Most of these are in Ilex
shutters.
The Regno should have an air release nipple on the
lower left (facing the shutter) at about8 o'clock. The
setting lever is at about 4 o'clock and the releast lever at
about 11 o'clock. The shutter is regulated by an air brake
located under the cocking or setting lever. I don't know
over what period the Regno was made but I think it was
probably superceded by other shutters by the mid to late
1920's. Wollensak made good shutters. All the springs are
hair springs and can be made from spring wire so the
shutters can be maintained provided they don't need broken
parts replaced.
The T-R lens is capable of good results but was not one
of the better LF lenses despite some pretty strong claims
being made for it.
Rudolf Kingslake has some biographical information
about Ernst Gundlach. Evidently, he was a very difficult
person who started and left several companies, eventually
went back to Germany and disappeared into obscurity.
--
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@[EMAIL PROTECTED]
|
