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

Zunow 5cm f/1.1

Zunow (Teikoku Kogaku) · Nikon S + Contax RF + LTM · 1953 · Sonnar type

Also known as: Zunow 5cm f/1.1 · Zunow 50mm f/1.1 · Zunow 5cm F1.1 · Zunow 50/1.1 · Zunow 1.1 · Teikoku Kogaku Zunow 5cm f/1.1 · Zunow Opt. 50mm f/1.1 · 帝国光学 Zunow 5cm F1.1 · ズノー 5cm F1.1

Variants & identification

Variant Mount Years Serial ranges Production
Type I · Nikon S · Sonnar type, 9 elements in 5 groups Nikon S 1953 Below ~5,400¹ Total "said to be 800 or 1000" across all types — no factory figures¹; Type I survivors believed <50²; reputedly the smallest of the three mounts³
Type I · Contax RF · Sonnar type, 9 elements in 5 groups Contax RF 1953 Below ~5,400¹ Total "said to be 800 or 1000" across all types — no factory figures¹; Type I survivors believed <50²
Type I · Leica screw mount · Sonnar type, 9 elements in 5 groups LTM 1953 Below ~5,400¹ Total "said to be 800 or 1000" across all types — no factory figures¹; Type I survivors believed <50²
Type II · Nikon S · Sonnar type, 8 elements in 5 groups (flat rear group, new glass, hard coating) Nikon S 1955 ~5,400 onward¹ Total "said to be 800 or 1000" across all types — no factory figures¹; reputedly the smallest of the three mounts³
Type II · Contax RF · Sonnar type, 8 elements in 5 groups (flat rear group, new glass, hard coating) Contax RF 1955 ~5,400 onward¹ Total "said to be 800 or 1000" across all types — no factory figures¹
Type II · Leica screw mount · Sonnar type, 8 elements in 5 groups (flat rear group, new glass, hard coating) LTM 1955 ~5,400 onward¹ Total "said to be 800 or 1000" across all types — no factory figures¹
  1. From MAP Camera's collection piece on a Nikon-S example (a PDF read 2026-09-10): the wartime products and records all burned, so the postwar lens began from memory; the 1950 twelve-element prototype was 'hard to mass-produce'; the 1953 lens was launched under the slogan 'the brightest lens in the world' with its rear element protruding about 1 cm; the 1955 improved type used three elements of the new glass; the list price of ¥95,000 stood against a monthly salary of about ¥10,000. The price year is taken as 1955, MAP's example being a Type II — the original 1953 price is not given. Nikon-S-mount lenses are scarcer than the thread ones because the S mount was then a far smaller market.
  2. Serial break and circulating totals per Old Lens Junkies; no factory production records survive.
  3. Survivor estimate is a single expert opinion relayed by Old Lens Junkies.
  4. MAP Camera dealer claim — their own phrasing is "it is said."
How to tell them apart (expand)
  • Nikon S: Mounts physically on Contax bodies as well but focuses correctly only on Nikon S — a persistent listing misidentification trap.
  • Contax RF: Mounts physically on Nikon bodies as well but focuses correctly only on Contax — a persistent listing misidentification trap.

Type I · Nikon S:

  • Protruding "ping-pong ball" rear element
  • 55mm filter (Type II is 54.5mm)
  • Red "N" on the bayonet mount — an unmarked bayonet version is Contax

Type I · Contax RF:

  • Protruding "ping-pong ball" rear element
  • 55mm filter (Type II is 54.5mm)
  • No mount marking — the unmarked bayonet version is Contax; Nikon versions carry a red "N"

Type I · Leica screw mount:

  • Protruding "ping-pong ball" rear element
  • 55mm filter (Type II is 54.5mm)

Type II · Nikon S:

  • Flat rear group — no protruding rear element
  • 54.5mm filter (Type I is 55mm)
  • Aperture ring turns the opposite direction from Type I
  • Red "N" on the bayonet mount — an unmarked bayonet version is Contax

Type II · Contax RF:

  • Flat rear group — no protruding rear element
  • 54.5mm filter (Type I is 55mm)
  • Aperture ring turns the opposite direction from Type I
  • No mount marking — the unmarked bayonet version is Contax; Nikon versions carry a red "N"

Type II · Leica screw mount:

  • Flat rear group — no protruding rear element
  • 54.5mm filter (Type I is 55mm)
  • Aperture ring turns the opposite direction from Type I

Serial-range notes

3000 series
Early Type I; blue coating observed .
5000 series
Later Type I running up to the type break; purple coating observed.
~5,400
Approximate Type I → Type II changeover point.

Specifications

Formula
Sonnar type
Construction
9 elements / 5 groups
Aperture range
f/1.1
Min. focus
0.91 m
Weight
415 g
Years manufactured
1953
Country
Japan
Original price
¥95,000 (MAP Camera; against a salaried man's monthly pay of about ¥10,000 — the better part of a year's wages) (today ¥614,000)

What reviewers say

Optical Ratings

Aggregated from the reviews above — follow the links for the full picture.

Spherical aberration
heavy
Vignetting
noticeable
Flare & ghosting
heavy
Coma
minimal
Optical formula — Sonnar type
Both formulas, drawn from the cross-sections published at Old Lens Junkies: the 1953 Type 1 with nine elements in five groups, and the 1955 Type 2 redesign with eight — an extended Sonnar either way, with the huge front group that made f/1.1 possible. Curvatures stylized.
Both formulas, drawn from the cross-sections published at Old Lens Junkies: the 1953 Type 1 with nine elements in five groups, and the 1955 Type 2 redesign with eight — an extended Sonnar either way, with the huge front group that made f/1.1 possible. Curvatures stylized. — Drawn for this site, CC BY 4.0

History

Every telling of the Zunow story starts in wartime. As both MAP Camera and Old Lens Junkies recount it, the Imperial Japanese Navy asked for “a brighter lens” for aviation search and reconnaissance work at a time when f/1.5 defined the state of the art. Old Lens Junkies traces the conception to Michisaburo Hamano (浜野道三郎) in 1943; MAP Camera credits the founder of the Teikoku Optical Research Institute (帝国光学研究所), Sakuta Suzuki (鈴木作太), with carrying an experimental f/1.2 forward into the postwar project. However the credit divides, the outcome is not in dispute: a 12-element prototype was working by 1950, and in 1953 it was refined into a 9-element, 5-group Sonnar-type design and sold as the Zunow 5cm f/1.1 — the fastest lens yet offered for a 35mm camera, and the opening shot of the decade’s ultra-fast-lens race.

The first version wears its ambition on the wrong end: the rear element bulges out of the barrel, earning the collector nickname “ping-pong ball.” Wide open it flares seriously and renders as if through a soft filter — MAP Camera’s staff, shooting an early blue-coated 3000-series example, describe rainbow ghosts that come and go “as capriciously as a cat,” and even speculate that many Type I lenses were computed for the smaller 24×32mm “Nihon” format, which would explain corners that stay dark well after stopping down. When Fuji Photo Film answered in 1954 with an f/1.2 built on newly developed rare-earth glass, the marketing panic pushed Zunow into a full redesign. The 1955 Type II — credited to Kenji Kunitomo, recruited from Nippon Kogaku, and Yoshitatsu Fujioka (romanizations of both names vary across sources) — flattened the rear group into an 8-element, 5-group formula with new glass and a hard coating. The filter shrank from 55mm to 54.5mm, the aperture ring reversed direction, and the changeover falls at roughly serial 5,400.

The lens was sold in Nikon S, Contax RF and Leica screw mounts, with a trap for the unwary that persists in marketplace listings today: the Nikon bayonet version carries a small red “N,” the Contax version is entirely unmarked, and the two mount physically on either body while focusing correctly only on their own. Production numbers are lore rather than record — the total is “said to be 800 or 1000,” no factory figures survive, and surviving Type I examples are believed to number under fifty, an expert opinion passed along by Old Lens Junkies and best treated as exactly that. The S mount is, “it is said,” the smallest production of the three — a dealer’s claim from MAP Camera, offered in their own hedged words.

Teikoku Kogaku renamed itself Zunow Kōgaku Kōgyō (ズノー光学工業) in December 1956 and moved on to a 35mm f/1.7, a 100mm f/2, 8mm cine lenses and the Zunow camera before closing for good on 1 January 1961; no other Zunow focal length has ever been documented in S mount. Survivors trade at $5,000–10,000 today, with exceptional examples reaching $20,000 — steep tribute for a lens whose most loved trait, the veiling glow its designers fought to eliminate, is exactly what the Type II was built to fix.

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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

More sample photos elsewhere

These photographers keep all rights to their work — enjoy it at the source.

Sample photo wanted — shot with a Zunow 5cm f/1.1? We'd love to feature it (with credit).

Live listings

Asking price, USD: a median of $12,700 across 5 fixed-price listings on 2026-09-11 (middle half $9,900–$13,400). Tracked since 2026-09-06, 2 days: unchanged from $12,700.

By day
DateMedianMiddle halfListings
2026-09-11$12,700$9,900–$13,4005
2026-09-06$12,700$9,900–$13,4005

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

eBay links are affiliate links. If you buy through one, Glass Bodies earns a small commission from eBay at no cost to you. It does not change which listings appear, their prices or their order — those come from the search and the sort described above.

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

Related: Nikkor-N(·C) 5cm f/1.1 · Fujinon 5cm f/1.2 · Hexanon 60mm f/1.2

Sources (9)

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.