"Richard Knoppow" <dickburk@[EMAIL PROTECTED]
> wrote in message
news:13oo43l5gstve4e@[EMAIL PROTECTED]
>
> "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.
What about for mono films? I think because of this problem I
would never use this lens for color films!
> 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.
Interesting! Who sells these adapters? Is there a brand name?
> I am surprized that your lens has no focal length
> markings. What markings does it have? Perhaps I can identify
> it.
Front lens rim says:
" Gundlach Manhattan Opt. Co. Rochester, N.Y. Turner
Reich Anastigmat F: 6.8 Series II No. 1 Pat. May 14 - 95"
And then what looks to be a short five figure serial number
with one or two letters, B6568 or another B as the last figure,
I think. I can tell both cells have matching numbers. The rear
cell has that number and "Turner Reich", and that's it.
I suspect the "No. 1" is the key, if you have a production list?
It might be for 4x5, or maybe related to image circle size, or the
degrees of view angle.
> 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.
Yes, I read (online) that Edward Weston had a hard time with one
and complained to Ansel Adams, who in return recommended a Zeiss
Protar.
> 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.
This one seems different than your description. Let's say the aperture
scale is on the bottom, one the face, and the shutter speed sacale is on
top of the front face. There is a tall button of steel color at 10
o'clock
and just to it's left, about 1/8" is a steel rimmed hole which is where I
suspect there was installed that nipple for an air hose, not there now.
At 2 o'clock is another button that is identicle to the on on the left.
Both buttons are at the edge of the speed scale. The buttons and hole
are on the rim.
> 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]
>
>
--
Giant_Alex }<)))*>
not my site: http://www.e-sword.net/
|
