What is the function of these graduations

[MikeBradley]

I came across this eyepiece recently. What is the purpose of the 10 to Infinity scale? Is it a dioptre adjustment?
It functions normally as an 23mm eyepiece.
Thanks
Michael

[mnmyco]

Not sure. Maybe to adjust for the difference distances that the image of your specimen is in focus. This way it could be used in more microscopes.

Mnmyco

[PeteM]

Is it a photo eyepiece?

[Scarodactyl]

Yeah, I'd guess fk f=fotograf k=kompens
Not sure why it's variable though.

[MikeBradley]

So if it's a photo-compensating eyepiece does this mean that it is also a projection eyepiece and so could be used for direct projection to a sensor?

If not then what is its advantage over a regular KPL? I always understood that Kpl eyepieces were fully compensated and could be used for AFocal photography though not for direct projection.
Michael

[75RR]

I always understood that Kpl eyepieces were fully compensated and could be used for AFocal photography though not for direct projection.

.
Afraid I can't help with that eyepiece but a 'normal' kpl eyepiece can be used as a projection eyepiece if raised by a collar a few millimeters above the tube.

This image shows a selection of collars made from electrical pvc 1" wall pipe.

The shortest is 2.5mm, the rest are in 5mm increments.

The projected magnification changes by the amount it is lifted.

Curiously, the micpro (Projektiv f = 63) is an afocal projective. It projects a parallel image.
.

[MicroBob]

Hi Mike,
I have never seet this item before. We can try to get a bit closer by dating it. It sais "Zeiss Wnkel". Winkel was a microscope manufacturer in Göttingen, bought in 1911 by Zeiss to remove an upcoming competitor. From then on the name was "Winkel-Zeiss Göttingen".
The Winkel works was kept running separately and much later the Zeiss West microscope went to Göttingen.
After the end of WW II Zeiss was divided up into Zeiss Jena and Zeiss Oberkochen (West Germany), and most of the production machinery was removed to the USSR.
In Oberkochen they developed the W Stand (nothing to do with the later WL). It was sold under the name "Carl Zeiss", was extremely well made and much too expensive to satisfy the expected high demand of the next years. Then in Göttingen the Zeiss Standard was developed by a team supervised by Kurt Michel. It came to the market in 1949. These Instruments were called "Zeiss Winkel". This chaned in 1955 when the Göttingen works was fully integrated into the main company, and from then on the name of the microscopes was "Carl Zeiss".
This dates your "eyepiece" in the era 1949 to 1955 and shows that is was made in Göttingen microscope works, so probably a microscope part.

The distance scale could have been used for projection purposes.

Bob

[Hobbyst46]

In continuation of the important history data provided by MicroBob, here are some pages from a brochure about the Zeiss GFL microscope. It was published by Carl Zeiss Oberkochen/Wurtt. And indicates that this is a photo eyepiece. In view of the film camera and adapter shown in the picture, I am guessing that our non-identified focusable (?) eyepiece is either inside the adapter, or, more likely, in the side-arm of the adapter, and its function is inspection of the image prior to exposure:

[MicroBob]

more likely, in the side-arm of the adapter

Hi Doron, I think you solved the riddle: There has to be a means to make observation eyepiece and camera parfocal and to repeat the setting a graduation would be useful.

Your GFL brochure is quite interesting: This trino head without movable prism is uncommon. And I would expect the camera to be parfocal with the eyepieces of the bino which would make the photo adater superflous??? Maybe the photo adapter is used for framing the image perfectly?

Bob

[Hobbyst46]

more likely, in the side-arm of the adapter

Hi Doron, I think you solved the riddle: There has to be a means to make observation eyepiece and camera parfocal and to repeat the setting a graduation would be useful.

Your GFL brochure is quite interesting: This trino head without movable prism is uncommon. And I would expect the camera to be parfocal with the eyepieces of the bino which would make the photo adater superflous??? Maybe the photo adapter is used for framing the image perfectly?

Bob

Hi Bob, in the brochure, this multi-tube gadget is called an inclined binocular plus photo tube, is no 3 in the table below, whereas the "proper" trino is no. 4.
I believe there is a 50/50 beam splitter prism inside, but otherwise, admittedly I do not quite understand the optical path; here the head is fixed, and the camera is fixed at some height, so indeed, possibly the whole setup is initially parfocal (verified during assembly), and as you suggest, the sidearm eyepiece is just used to select fields of view. But hopefully someone can clarify...

[MicroBob]

Thank you for posting this overview over the Zeiss tubes, Doron. Is this from a paper source or can it be found online somewhere?
I know this document: http://www.mikroskop-online.de/Mikrosko ... %20GFL.pdf
To me this seems to be a slightly older version, the trino head with the sliding prism is not yet included.
For me today a beam splitting version would be more attractive as I could take a picture while observing. This would be a consiedrable advantage, especially for fast moving plancton crtters. With the old bicycle lamp one will have had a very dim image in the eyepieces and a little less light for photography too. There were different ratios for the beam splitter, I don't know which one Zeiss used.

Bob

[Hobbyst46]

Hi Bob
The source of the pages that I posted is a file called "40-115 III - Zeiss Winkel GFL lr"
I downloaded it from the Zeiss archive. Many of the pages are identical to those of the document in the link.

[MicroBob]

Interesting. It is nearly the same document, but issued in english from the US representation and it includes the sliding prism trino. Maybe this was also a question of the market in focus. When a high power lamp was available the sliding prisma was probably not that necessary.

[MichaelG.]

The source of the pages that I posted is a file called "40-115 III - Zeiss Winkel GFL lr"
I downloaded it from the Zeiss archive. ...

A cry for help from an innocent Englishman: Is this the archive page that you used ?
https://www.zeiss.com/corporate/int/abo ... tml#aufbau

If so ... could you please explain how to navigate it, to find the file that you mention.


Many thanks [I must be having a bad day]
MichaelG.

[Hobbyst46]

The source of the pages that I posted is a file called "40-115 III - Zeiss Winkel GFL lr"
I downloaded it from the Zeiss archive. ...

A cry for help from an innocent Englishman: Is this the archive page that you used ?
https://www.zeiss.com/corporate/int/abo ... tml#aufbau

If so ... could you please explain how to navigate it, to find the file that you mention.


Many thanks [I must be having a bad day]
MichaelG.

Remedy within seconds:
Either just type the following text in the Google window: 40-115 III ZEISS GFL
It will open it from Geocities.

Or, what I did two years ago, searched google for the Zeiss archives, ( not the physical archives in Jena) there is a list there of old, dust-covered documents from around ~1920-1970 where I read the titles one by one and downloaded a few. Let me see if I can fetch it again.
Were it not so warm around, I would suggest a cup of tea...

[Hobbyst46]

No way, can't find it ! there WAS once a Zeiss web archive where in a violet font, titles of files of those old brochures and manuals of the Standards and other old machines resided. Looks like it disappeard without notice.

[MichaelG.]

Remedy within seconds:
Either just type the following text in the Google window: 40-115 III ZEISS GFL
It will open it from Geocities.

That worked just fine ... thank you
I had previously searched for the exact reference that you gave, and found nothing.

MichaelG.

[Scarodactyl]

Whatever its intended purpose, I wonder if you could do some cool things with it as a photo eyepiece.

[MikeBradley]

I tried projecting an image directly onto the sensor of a hand-held DSLR and got a shaky but respectable image. I'll try to arrange a fixed support for the camera and post the images.

Thanks everyone for all the detective work in answer to my query!

michael