Glass Bodies a variant-level encyclopedia of vintage lenses and cameras by iwillpat

Jupiter-8 50mm f/2

KMZ · Contax RF + LTM · 1948 · Sonnar

single source, unconfirmed

Also known as: Jupiter-8 50mm f/2 · ЮПИТЕР-8 · Jupiter 8 Sonnar copy · ZK 50mm f2

Variants & identification

Variant Mount Years Serial ranges Production
Contax/Kiev bayonet Contax RF 1948–1990 #4900247, #4901422 — 1949; the first Kiev-mount lenses of this family to carry the year in front, on sovietcams' PT3520 and PT3525
#5005289, #5007192 — 1950
#5400050 — 1954, sovietcams' earliest recorded Arsenal-built example
#8100082 — 1981, its earliest recorded example of the last Jupiter-8M version
7939120 — 1979, the Jupiter-8M supplied with the Olympic Kiev-4M s/n 7902251 		No figure published; the standard lens of over a million Kiev cameras
Leica thread (M39) LTM 1950–1990 #4900101, #4900431, #4900648 — 1949
#5100441 — 1951
#5767445 — 1957; #6051610 — 1960; #6200205 — 1962; #6309464 — 1963; #6860000 — 1968; #7467456 — 1974
#580034 — 1958, a GOMZ-built example rather than a KMZ one
#013894, #0257950 — leading-zero numbers that carry no year; see the serial notes 		No separate figure published
ZK (Sonnar Krasnogorsk) Contax RF 1948–1950 #000021 (1947), #000140 and #000378 (1948) — Kiev bayonet; sovietcams' earliest recorded ZK 2/50 lenses
#001109 (1948) — Leica thread, its earliest recorded ZK in that mount
Six digits, plain sequential, no year in front: the ZK lenses predate the dating scheme 		No figure published
  1. Corroboration pass, September 2026 — a partial result, and the single-source badge stays. What was searched: camera-wiki, sovietcams and its mirror at Mike Eckman's site, the USSRPhoto forum, JAPB, CameraQuest, 35mmc, the mflenses forum, Fedka, and Radojuva, which could not be read because it refuses automated access. What was corroborated: the year-in-the-first-two- digits rule, which Stephen Gandy states independently for the Soviet lenses sold onto Contax bodies; and the existence and character of the Leica-thread focus problem, which Hamish Gill measured on three lenses. What was NOT corroborated: every version-level serial figure on this page. The "earliest so far known" numbers for each variant, the ZK serials #000021, #000140, #000378 and #001109, the Arsenal floor at #5400050, the Jupiter-8M floor at #8100082, the T suffix on the 1966–1977 Arsenal version, and the commemorative #1000000 all trace to sovietcams and to nothing else found. They are a collector registry, not a factory record, and no second registry exists to check them against.
  2. Two explanations for the Leica-thread focus error, and they are not the same claim. This entry has carried the focal-length account: that the Soviet and the Leica rangefinder standards assume slightly different focal lengths, so the lens's helical travel does not match what the Leica rangefinder reads. Hamish Gill, writing from measurement rather than theory, attributes it instead to register — that the Soviet bodies the lens was made for have "a very slightly different register" from a Leica. Both are on the record; nothing consulted here reconciles them, and the practical consequence is the same either way. A specific figure for either standard is quoted freely on forums and was not found in any source this entry would cite, so none is given here.
  3. The direction of the error, corrected. This entry said a Jupiter on a Leica "sometimes front- or back-focuses". Gill tested three late black Jupiter-8s on a Leica M9 and found all three back-focused, by as near as makes no difference the same amount — the plane of focus sitting roughly 1–2cm behind the target at a 1m subject distance. He notes the Sonnar design's own focus shift moves the plane further back again on stopping down, so the two errors compound rather than cancel, and reports the result unusable on distant subjects even at f/8 while barely mattering on close ones wide open. Consistent back focus is the reported behaviour; a front-focusing example is not something any source consulted describes.
  4. No plant published a serial-number table or a production table for the Jupiter-8. The figures that exist are a collector registry: sovietcams gives, for each of its versions, an "earliest so far known" serial contributed by owners, which is a floor and not a start date. In several places that floor postdates the version's own stated first year, and the two should not be read as the same fact.
  5. The dating scheme is not Soviet-wide. FED serial numbers run straight through from 1934 to the mid-1980s with no year encoded at all, and Zorki bodies made before 1955 are unreliable on the same point — so a Jupiter-8 can usually be dated from its number while the body it is screwed into cannot.
How to tell them apart (expand)
  • Six elements in three groups, identical in arrangement to the Zeiss Sonnar 5cm f/2
  • Often marked in Cyrillic — ЮПИТЕР-8

Contax/Kiev bayonet:

  • Contax internal bayonet; no focusing ring of its own

Leica thread (M39):

  • 39mm screw thread, for Zorki and FED bodies

ZK (Sonnar Krasnogorsk):

  • Marked ZK rather than Jupiter

Serial-range notes

the exception the rule hides
The year-prefix convention is Arsenal's from 1947 and the lens plants' from 1949 — it is not Soviet-wide and it is not KMZ-wide. KMZ's own Zorki bodies of 1948–54 run in a single sequence with no year prefix, so the rule fails there silently and plausibly: a 1951 Zorki 55325 reads as 1955, a 1953 254580 reads as 1925.
the first two digits
THE RULE. On a Soviet lens the first two digits of the serial number are the year of manufacture: 5100441 is 1951, 6309464 is 1963, 8100082 is 1981. What follows is a running number within that year, and its length varies — six, seven and eight-digit serials all occur — so the year is read off the front of the number and not by counting digits backwards. Mike Eckman states it plainly for Kiev cameras and lenses; JAPB states it for Soviet equipment generally; Stephen Gandy states it a fourth time, from the Contax side, in his note on the Soviet lenses that fit a Contax IIa or IIIa; and sovietcams' variant tables, which quote a dated "earliest so far known" serial for nearly every version, are the working evidence. This is the one claim on the page that is firmly multiply sourced.
#000021, #000140, #000378, #001109 — six digits beginning 000
THE FIRST EXCEPTION, and it is the one that catches people out on this lens. KMZ's 1947–48 output — the ZK lenses, before the Jupiter name — was numbered plainly from 000001 with no year in front. A ZK 2/50 numbered #000140 is a 1948 lens, not a 1900 one. sovietcams marks the changeover explicitly, noting of the 1949 versions that there is a "date prefix in the serial number already"; from #49xxxxx onward the scheme holds.
#013894, #0257950, #0231479 — numbers beginning 0
THE SECOND EXCEPTION, on the late black KMZ Jupiter-8 in Leica thread. sovietcams records these versions as having no date prefix at all. A USSRPhoto forum thread reads them differently: no Jupiter-8 serial beginning 69, 70, 71 or 72 has been found, while 68 and 73 are common, so the leading-zero run is taken there to fill 1970–1972, the black lens having been given its own sequence to keep it apart from the chrome one. Both readings are on the record and neither rests on a factory document.
#1000000
A Jupiter-8M marked for the millionth Kiev (Contax) camera, dated 1975 by sovietcams — a commemorative number that is not a date and not a position in any sequence.
a letter T appended to the digits
sovietcams separates one Arsenal Jupiter-8M version of 1966–1977 by a character T added to the serial. It is a suffix on the number, not part of it; the year still reads from the first two digits. No source consulted here says what the T stands for.

Specifications

Formula
Sonnar
Construction
6 elements / 3 groups
Aperture range
f/2
Min. focus
1 m
Weight
125 g
Filter
40.5 mm
Years manufactured
1948–1990
Country
Russia

What reviewers say

History

The Jupiter-8 is the Zeiss Sonnar 5cm f/2 continued in the Soviet Union. Six elements in three groups, the same arrangement, from design data taken as war reparations along with the equipment and the staff. It became the standard lens of the Kiev exactly as the Sonnar had been the standard lens of the Contax, and it was made in enormous numbers — over a million Kiev rangefinders were built, most of them with this lens on the front.

Its first form was not called a Jupiter at all. The earliest Soviet lenses were marked ZK, for Sonnar Krasnogorsk, and were built from remaining Jena glass; the name changed around 1950 and Soviet glass took over by 1954.

The Leica-thread versions carry a caution. Soviet lenses of this family were often calibrated to the Contax rangefinder standard rather than the Leica one, and the two assume slightly different focal lengths — so a Jupiter in screw mount on a Leica can focus consistently in front of or behind the intended plane. That is a property of the design, not a defect in a particular lens, and it is why “Jupiter on a Leica” is a subject with its own literature.

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This history is AI-written, from the sources listed at the foot of the page. Where the record is silent it says so rather than filling the gap — but no human wrote these sentences.

Example photos

Sample photo taken with the Jupiter-8 50mm f/2
Jupiter-8 50mm f/2, red P (Tranpan23) — Tranpan23, via Wikimedia Commons (CC BY 2.0)
Sample photo taken with the Jupiter-8 50mm f/2
Cloud — shot on a Jupiter-8 (Mike Maguire) — Mike Maguire, via Wikimedia Commons (CC BY 2.0)

Sample photo wanted — shot with a Jupiter-8 50mm f/2? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $85 across 39 fixed-price listings on 2026-09-11 (middle half $60–$120). Tracked since 2026-09-06, 2 days: unchanged from $85.

By day
DateMedianMiddle halfListings
2026-09-11$85$60–$12039
2026-09-06$85$60–$12039

Asking prices from the listings scanned, not sales; junk-flagged rows and auction lots excluded; other currencies are not converted.

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Listings updated 2026-09-11. Links go to the shop or marketplace that carries the item.

Related: Jupiter-12 35mm f/2.8 · Jupiter-3 50mm f/1.5 · Jupiter-9 85mm f/2 · Sonnar 5cm f/2

Sources (10)

Every page here is assembled from public sources, and the gaps are real ones. If you own this lens, know a serial number I'm missing, or can see where I have it wrong, tell me — corrections, serials and sample photos are all worth having.