PT8505. Seems to be an earliest version of "Jupiter-11" lens. Under initial name "ZK-135" ("Sonnar Kransogorsk"). Very few lenses released by KMZ in 1948-1949. These first samples are totally assembled from Zeiss (Germany) optical glasses. Focal length - 13.5 cm, aperture range f4 - f22. Focusing range from 2.5 m to infinity. Number of elements/groups: 4/3.  Angular field - 18º. Kiev (Contax) mount. An earliest so far known lens has s/n #000511 1948 (private coll.).

PT8505 - ZK-135 lens.

PT8510. Almost identical to its predecessor "ZK-135", but under name "ZK Zorki". Very limited batch of these lenses released by KMZ in 1949-1951. Partially or totally assembled from Zeiss (Germany) optical glasses. Date prefix in the serial number. An earliest so far known lens has s/n #4902011 (Aukro 2011).

PT8512. Identical to PT8510, but under regular name "Industar-11". Very limited batch of these lenses released by KMZ in 1950-1952. Partially or totally assembled from Zeiss (Germany) optical glasses. Date prefix in the serial number, many numbers are mixed with PT8510. An earliest so far known lens has s/n #5000452 (A.Terechin coll.).

PT8515. Regular KMZ lens under name "Jupiter-11". Released by KMZ in 1951-1959.  New KMZ logotype on the faceplate, the same as on PT8512 lens (see picture below). Some lenses have an additional enagravings "MADE IN USSR" on body. Late numbers are quite common to find nowadays. An earliest so far known lens has s/n #5102141 (D.Krivosheev coll.).

PT8515 - Jupiter-11  #5701228.

PT8520. Another version of Jupiter-11 lens, released by KOMZ ("Kazansky Optiko-Mechanichesky Zavod") in 1957-1960. Signally changed body construction (see comparison picture below). Lens opposite from Ilya Stolyar (USA) collection.

PT8520 - Jupiter-11  #6001726.

PT8525. Released by KOMZ ("Kazansky Optiko-Mechanichesky Zavod") since 1960. Body construction changed again (see comparison picture below). Some lenses have an additional markings "MADE IN USSR" on body. Quite common to find nowadays. Lens opposite from Ilya Stolyar (USA) collection.

PT8530. Almost identical to PT8525, but with new markings on the lens faceplate already: markings "1:4  F=13.5 cm" replaced by "4/135". "Jupiter-11" markings in Cyrillic characters. Released by KOMZ since 1961. Some lenses have an additional markings "MADE IN USSR" on body. Investigated lens has s/n #6502573 (SovietCams).

PT8525 - Jupiter-11  #6021653.