During a short period in World War II, the Carl Zeiss Otical Factory at Jena built their famous Sonnar lenses in a lens mount that was used by their biggest competitors in the market, Ernst Leitz Cameras in Wetzlar.
 
The president of Carl Zeiss was appointed by the German government to coordinate export of German products during World War II. The Germans needed foreign currencies for their trade with other countries, but trade with Nazi Germany was either restricted or forbidden in most countries.
Various German military organizations were also commissioning Leica cameras to be used by their personnel, most notably by Kriegsberichters, German journalists that were assigned to Luftwaffe, Kriegsmarine and the Wehrmacht to deliver heroic images that Joseph Goebbels used to uplift moral with civilians and soldiers.
 
All in all, Ernst Leitz in Wetzlar still had some business going for them. Leicas were even traded with Switzerland for minerals! The Carl Zeiss-made Contax camera sales had dropped since the war started. To make sure not all profit remained with Leitz, the president of the Carl Zeiss Jena plant ordered that the Leicas should be fitted with Carl Zeiss lenses.
 
And so Carl Zeiss in Jena made several lenses in Leica Thread Mount. They issued a Carl Zeiss Jena Sonnar 50mm f2.0, a Carl Zeiss Jena Sonnar 50mm f1.5, a Carl Zeiss Jena Sonnar 85mm f2.0 and a Carl Zeiss Jena Sonnar 135mm f4.0.
 
At the end of the war, the Russians overran the Jena plant on their race to reach Berlin before the Allied Forces. They immediately started dismantling the factory and transplanted it to Charkow in Ukraine. The FED factories in that city had earlier been demolished by the German military advance. They took everything they could get with them to Charkow: designs, machines, stock, and even workers were forced to relocate to Charkow. The famous Sonnar lenses were the ancestors of the Jupiter-8 (50mm f2.0), the Jupiter-3 (50mm f1.5), the Jupiter-11 (135mm f4.0) and the Jupiter-9 (85mm f2.0). The Russians even adapted the Contax-mount Biogon 35mm f2.8 to their Jupiter-12 35mm f2.8 in LTM (source: http://www.portretteur.nl/index.php?option=com_content&view=article&id=104:sonnars-ltm&catid=37:lenses&Itemid=58)


  

An ultra rare to find ancestor of the "soviet" ZK 2/50mm lens (see PT3005 below), released by Zeiss in war-time Germany.

It's interesting to mention, that GOI ("Gosudarstvennij Opticheskij Institut") had recalculated Sonnar lens by Bertele in late 1948 (very few GOI lenses under name "Jupiter-8" in Kiev mount were released in 1948-1949), since the Russian glasses had different optical characteristics in comparison with German ones.

That's why ZK 2/50mm lens (PT3005) should be considered as CZJ Sonnar 2/50mm assembled in the Soviet Union. And the ZK Zorki 2/50mm (PT3010) should be considered as an earliest productional version of "Jupiter-8" lens.







    

CZJ Sonnar 2/50mm  #2709795.

PT3005. Carl Zeiss Jena Sonnar 2/50mm lens, from the original parts assembled in the Soviet Union. Under initial name "ZK 2/50 mm" ("Sonnar Kransogorsk"). Very limited batch of these collapsible lenses released by KMZ in 1948. Focal length - 5 cm, aperture range f2 - f22. Focusing range from 1 m to infinity. Number of elements/groups: 6/3.  Angular field - 45º. Zorki (M39) mount. An earliest so far known lens has s/n #001109 1948 (Leica Copies by HPR).

Lens #002437 opposite from private collection in Russia.

PT3005 - ZK 2/50 mm #002437 (1948)

PT3010. Almost identical to PT3005, but under name "ZK Zorki 2/50 mm" already. Limited batch of these collapsible lenses released by KMZ in 1949-1950. This version should be considered as an earliest version of Jupiter-8 lens, since released with recalculated optical scheme already. Date prefix in the serial number already. An earliest so far known lens has s/n #4900431 (Leica Copies by HPR).

PT3010 - ZK Zorki  #4900939.

PT3015. An ultra rare version to find. Rigid body of new construction. Focusing lever. Under name "ZK Zorki 2/50 mm". Date prefix in the serial number. An only so far known lens has s/n #4900648 (SovietCams).

PT3015 - ZK Zorki  #4900648.

PT3020. New construction of rigid body, which becoming regular now. Under name "ZK Zorki". Released by KMZ in 1949-1950. These first samples are partially assembled from Zeiss (Germany) optical glasses. Date prefix in the serial number. An earliest so far known lens has s/n #4900101 (Princelle book).

PT3020 - ZK Zorki  #5003205.

PT3030. Seems to be an earliest version of the regular Jupiter-8 lens. Released by KMZ in 1951-1960. No more "ears" for diaphgram settings. Signally changed body design (see comparison picture below). Slightly different body design changes within this version, especially the width of meter scale ring, different markings, etc. An earliest so far known lens has s/n #5100441 (A.Terekhin coll.).

PT3030 - Jupiter-8  #5108990.

PT3050. An unique version of Jupiter-8, released by GOMZ in 1958. It seems, that these very few lenses were mounted on Leningad (Gomz) cameras at Brussels Grand Prix 1958. Totally different body construction with clockwise aperture settings and f-stops (counterclocwise aperture settings on KMZ lenses without f-stops.).  Aperture range f2 - f16. Different size of markings, 6-digits serial number, etc. (see comparison picture below).

PT3050 - Jupiter-8  #580034.

PT3060. The regular version of Jupiter-8 lens. Focusing lever replaced by  textured ring, thereafter changed body design (see comparison picture below). Released by KMZ in 1957-1960. An earliest so far known lens has s/n #5767445 (Murat Can Mert coll.).

PT3060 - Jupiter-8  #5768088.

PT3065. Identical to PT3060, but with new markings on the lens faceplate: "1:2  F=5 cm" replaced by "2/50". Released by KMZ in 1960-1968. No more red character "П" on the faceplate. Some lenses have an additional "MADE IN USSR" markings on body. Late samples have "N" prefix in serial number, instead of "No" one in previous lenses (see picture below). Very common to find nowadays.

PT3065 - Jupiter-8  #6051610.

PT3070. Identical to PT3065, but with export name markings. Released by KMZ in 1961-1968. Some lenses have an additional "MADE IN USSR" markings on body. Late samples have "N" prefix in serial number, instead of "No" one in previous lenses. Very common to find nowadays.

PT3075. Less common to find version of Jupiter-8 from private collection in Russia. Some parts of body is painted in black. No otherwise different.

  

PT3075 - Jupiter-8  #6811677. 

PT3070 - Jupiter-8  #6200205.

PT3077. very nice and rare version of Jupiter-8 lens. identical to PT3070, but with body made of brass (!) Very heavy in comparison with regular aluminium lenses (220g vs 130g). "Made in USSR" engraved on the barrel. A very limited quantity of these lenses were released by KMZ in 1963-1964. The particular lens opposite was mounted on GOMZ Leningrad camera (1963). An earliest so far known lens has s/n #6309464 (E.Bell coll.). 

PT3077 - Jupiter-8  #6309507.

PT3078. Very uncommon version of the Jupiter-8 lens with totally black body finish. "Made in USSR" markings on body.

Lens opposite from private collection in Poland.

PT3078 - Jupiter-8  #6620796.

PT3080. Totally new body construction (see comparison picture below). Released by KMZ since 1968.  Export markings. Some lenses have an additional "MADE IN USSR" markings on body.

PT3090. Identical to PT3080. but without date prefix nor "N" prefix in the serial number. 6-digits serial number. "MADE IN USSR" markings on body. Investigated lens has s/n #013894 (SovietCams).

PT3080 - Jupiter-8  #6860000.

PT3100. Totally black lens already. 6-digits serial number engraved on the side-plate (faceplate on PT3090). Without  date prefix nor "N" prefix in the serial number. Name markings in Cyrillic characters. 

PT3100 - Jupiter-8  #0257950.

PT3110. Seems to be the latest version of KMZ Jupiter-8 lens. Totally black body. Name markings in Roman characters. 7-digits serial number with date prefix engraved on the side-plate. Meter scale markings in green or white colour. Some lenses have an additional "MADE IN USSR" markings on body. 

PT3110 - Jupiter-8  #7467456.

PT3120. Almost identical to late PT3110 lenses, but under name "Jupiter-8-1". name markings in Cyrillic characters. 7-digits serial number with date prefix engraved on the side-plate. Meter scale markings in green colour. Limited quanitity released by KMZ in 90'ies. Less common to find nowadays.














Lens opposite from private collection in Russia.

PT3120 - Jupiter-8-1 lens.

PT3130. An ultra rare lens, very limited batch released by Arsenal (Ukraine) in 1974. Under name "Jupiter-8H". Name markings in Cyrillic characters. 7-digits serial number with date prefix. Zorki (M39) mount.

PT3130 - Jupiter-8H prototype lens #7400040.