Author Topic: GOI MC Telegoir f2.8/200mm  (Read 445 times)

Dr Klaus Schmitt

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GOI MC Telegoir f2.8/200mm
« on: January 06, 2019, 13:33:39 »
Came to me by coincidence when checking out a fleamarket, had that in the back of my head somehow and bought it
as it was a good price, and f2.8/200mm is very nice to use focal length for me (like my CZJ 2.8/200mm Sonnar).

And now I find out that it seems to be a rather rare prototype lens a friend of mine told me, which hasn't been made often,
computed in 1975 and made by GOI in St. Petersburg, the Russian State Optical Institute! Mine is from 1991.

It has Pentax-K bajonet mount and supposedly a 7e/6g lens design (which sounds rather exciting).

Bit hard to find some info about it, but here is one source: http://www.photohistory.ru/index.php?pid=1207248189055283

My lens looks like this:



It has quite a nice modern multicoating:



Here now a size and look comparision with the Carl Zeiss Jena Sonnar electric f2.8 200mm, to show how compact it is:

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Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #1 on: January 06, 2019, 13:34:35 »
Well, I took a few shots, was after rain, already getting dark...
All shot at f2.8

#1


#2


#3


#4


#5


#6


#7


Quite sharp it is, snappy and very smooth focusing, auto aperture, high contrast images, CA visible but manageable.
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Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #2 on: January 06, 2019, 13:35:55 »
Here now a side-a-side comparision with the Carl Zeiss Jena Sonnar electric f2.8/200mm
[if you are able to view crosseye stereo, it is very easy to see..].

Comparison GOI Telegoir (left) vs CZJ Sonnar 200mm (right):

#1


#2


#3


#4


#5


I conclude the Telegoir is copy of the Sonnar, very sharp already wide open (all tests were done at f2.8 ),
very creamy bokeh, excellent contrast and color (Telegoir is a little warmer), CA nearly as good as the
Sonnar (just a little more cyan OOF). Focal lengths are nearly identical. Both have 7-blade iris. 

BUT - Weight: Telegoir 0.750 kilograms - Sonnar 1.130 kilograms (51% more).
Closest focus: Telegoir 1.5 meters - Sonnar 2.2 meters.

Carl Zeiss Sonnar 200mm is easy to find, GOI Telegoir is extremely rare, have only seen 3-4 in my life...
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Nasos Kosmas

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Re: GOI MC Telegoir f2.8/200mm
« Reply #3 on: January 06, 2019, 14:34:20 »
It seems almost identical to me except a little warmer as you stated,very good lens!

Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #4 on: January 08, 2019, 06:51:57 »
This lens has a surprising feature despite its modern multicoating...



... and a very small focus shift only.
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Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #5 on: January 08, 2019, 15:38:06 »
And it also works well in IR with a very small focus shift...

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Akira

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Re: GOI MC Telegoir f2.8/200mm
« Reply #6 on: January 08, 2019, 21:55:24 »
Looks unique and nice, Klaus!

Is it really of Sonnar type?  Isn't the design more modern?  It could be too slim and light for a Sonner type.  The non-ED Nikkor 180/2.8 was fatter and heavier.
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Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #7 on: January 08, 2019, 22:44:32 »
Looks unique and nice, Klaus!

Is it really of Sonnar type?  Isn't the design more modern?  It could be too slim and light for a Sonner type.  The non-ED Nikkor 180/2.8 was fatter and heavier.

It was originally designed 1975, but my lens was built 1991. I wasn't able to find any sort of design info, despite a lot or Russian sources I know and have checked out. All I found was the 7e/6g info, but no idea what that was based upon. I counted 12 strong reflections, which represents 6 elements (or glued elements). The design of the CZJ Sonnar 200mm I have, but is 6e/4g which would produce 8 strong reflections. It could be a modified Sonnar type with different. more modern glass types to achieve the slim and lightweight size. It still has a large 72mm front.
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Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #8 on: January 09, 2019, 09:09:23 »
I carefully re-checked the reflections, it is 10 reflections. Also was digging deeper in russian sources and found the lens design, it is 8e/5g which actually confirms 10 strong reflections (5 groups = 10 surfaces to air)
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Akira

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Re: GOI MC Telegoir f2.8/200mm
« Reply #9 on: January 09, 2019, 10:22:28 »
I carefully re-checked the reflections, it is 10 reflections. Also was digging deeper in russian sources and found the lens design, it is 8e/5g which actually confirms 10 strong reflections (5 groups = 10 surfaces to air)

Thank you, Klaus, for the follow-up!  If the lens is of a "5g" design, it may well be of a variant of Sonnar or Ernostar?
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Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #10 on: January 09, 2019, 12:37:04 »
Thank you, Klaus, for the follow-up!  If the lens is of a "5g" design, it may well be of a variant of Sonnar or Ernostar?

Exactly that I believe now! Top is CZJ Sonnar electric f2.8/200mm (produced 1978-1990), bottom the MC GOI Telegoir f2.8/200mm (1975-1991?)



I think it is even better corrected than the Sonnar, as it has no focus shift towards IR, but the Sonnar has.
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Akira

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Re: GOI MC Telegoir f2.8/200mm
« Reply #11 on: January 09, 2019, 13:39:28 »
You finally found the cross section of the optics!  The Russian optics design has indeed been great, provided that the QC is proper.
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Roland Vink

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Re: GOI MC Telegoir f2.8/200mm
« Reply #12 on: January 09, 2019, 20:44:40 »
By comparison, there are the optics of the Nikon AI-S 180/2.8 ED:


And here is the older non-ED Nikkor-P Auto / AI version:

Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #13 on: January 11, 2019, 08:44:52 »
Thanks Akira + Roland! Interesting similiarities!
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Dr Klaus Schmitt

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Re: GOI MC Telegoir f2.8/200mm
« Reply #14 on: January 12, 2019, 10:35:20 »
Found some design similiarity with another russian lens, the famous Yashma-4 2.8/300mm with internal focus.



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