Fisheye-Nikkor 6mm f/2.8

Nippon Kogaku · Nikon F · 1972 · Retrofocus fisheye

our own finding

Also known as: Fisheye-Nikkor Auto 6mm f/2.8 · Ai Fisheye-Nikkor 6mm f/2.8 · AI-S Fisheye-Nikkor 6mm f/2.8 · Fisheye-Nikkor 6mm 1:2.8 · Fisheye Nikkor 6mm F2.8 220 · Nikon 6mm f/2.8 fisheye · Nikkor 6mm f2.8 220 degree · フィッシュアイニッコール 6mm F2.8

Variants & identification

Variant	Mount	Years	Serial ranges	Production
Fisheye-Nikkor Auto 6mm f/2.8 (pre-Ai)	Nikon F	1972–1977	628001–628029 (confirmed examples 628003–628024)	29 (Vink, from collected serial numbers; Cavina gives the same count)
Ai Fisheye-Nikkor 6mm f/2.8	Nikon F	1977–1981	628030–628147 (confirmed 628035–628147) 628501?–628561 (confirmed 628556–628561)	179 across the two blocks — 118 and 61 (Vink)
Ai-S Fisheye-Nikkor 6mm f/2.8	Nikon F	1982–1998	629001–629020 (confirmed 629004–629020) 629400–629436	57 across the two blocks — 20 and 37 (Vink)

Auction record. Leitz Photographica Auction (Wetzlar) has offered the f/2.8 three times in four years, always at €80,000–90,000 (Auction 40 estimate €80,000–100,000) from a €40,000 start: no. 628561, Ai, lot 367 of Auction 40 (June 2022), unsold; no. 629421, Ai-S block, lot 356 of Auction 45 (November 2024), unsold at a €65,000 high bid; and no. 628651, Ai, lot A04029 of Auction 49 on 28 November 2026 with a Nikkormat FT, still to be sold as I write. The 628561 lens then appeared on eBay in July 2023 at a fixed €130,000 (PetaPixel). Two cautions: the house dates lenses loosely (the 628xxx lot is called "1990", the block Vink puts in 1977–81), and its 628651 sits ninety numbers above the highest Ai serial in the table — if the reading is right, the second Ai block runs further than the recorded 628556–628561 and Vink's 61 is a floor, not a count.
Quantities are Vink's, derived from the span of collected serial numbers rather than from any Nikon production record. No factory figure has been published. The three mounts total 265 by that arithmetic; Cavina, working from the same blocks, states 266 plus the prototype.
Two sets of dimensions circulate. Nikon's own specification sheet gives 236mm diameter, 171mm overall length and 160mm of extension from the flange. The 1974 Nikon book published by Amphoto gives 263mm diameter and 171mm length; 263 appears to be a transposition, since every other source and Cavina's own measurement agree on 236mm.
The lens was sold on order only, and the Italian importer's 1970 Photokina brochure already warned buyers of a twelve-month wait.
The projection is equidistant — image height rises in proportion to the angle off axis, y = f·θ — across all twelve elements in nine groups. The 1969 pair of prototypes numbered 1014–1015 used an equisolid-angle projection instead, and never reached production.

How to tell them apart (expand)

220° of coverage — 40° more than a conventional fisheye, which means a 20° band of what lies behind the plane of the lens is recorded
A 213mm front element in a 236mm barrel, 5.2kg, standing on a cantilevered foot that carries the camera as well as the lens
A 23mm image circle inside the 24×36 frame
No mirror lock-up: the back focus is 37.7mm on a 6.3mm design, so the mirror swings freely

Fisheye-Nikkor Auto 6mm f/2.8 (pre-Ai):

Meter-coupling prong only — no Ai ridge; Ai conversion kits 56, 57 and 58 fit it
Six filters in the turret, including the yellow-green XO that later versions drop
A threaded socket on the focusing ring for an auxiliary focusing pivot — carried over from the prototype and deleted on the Ai
Metal focusing ring with alternating raised sectors; the rubber inlay of the 1974 K series never reached this lens

Ai Fisheye-Nikkor 6mm f/2.8:

Ai coupling ridge, diamond knurling on the aperture ring, and the second aperture-direct-readout scale
Meter-coupling fork rotated 180° and set back
A coupling pin on the aperture ring for the DS-12 EE servo — so a 5.2kg fisheye can be run in shutter priority on an F2AS
Five filters: the yellow-green XO is gone

Ai-S Fisheye-Nikkor 6mm f/2.8:

MADE IN JAPAN rather than LENS MADE IN JAPAN
L1BC replaces the L1A skylight filter in the turret on late examples

Fisheye-Nikkor Auto 6mm f/2.8 (pre-Ai): The first production example was assembled in March 1972, seventeen months after the prototype was shown at Photokina. Cavina reads the delay as time spent settling manufacturing procedures and finishing the details that separate 261001 from 628001.
Ai Fisheye-Nikkor 6mm f/2.8: Vink records two separate blocks with a gap between them, consistent with the lens being built in batches rather than continuously. Nothing published confirms that.
Ai-S Fisheye-Nikkor 6mm f/2.8: Vink notes no serial recorded between roughly 6290xx and 629400 — a gap of some 380 numbers in a run of 57 known lenses, so the block boundaries are inferred, not documented.

Serial-range notes

261001: The single prototype, built in autumn 1970 for Photokina. Engraved 6.3mm rather than 6mm (the true focal length is 6.25mm), marked Nippon Kogaku rather than Nikon, with the filter turret projecting to the right instead of the left, the distance scales running the other way, a wider aperture ring with uniform knurling, and the serial in white on a black barrel instead of black on a chrome sector. The optics and mechanics were already final.
620001–620005: A different lens: the mirror-up Fisheye-Nikkor 6.2mm f/5.6 prototype, 5 recorded. Two more prototypes numbered 1014–1015 carry a 230° equisolid-angle projection design of 1969 that never reached production.

Specifications

Formula: Retrofocus fisheye
Designed by: Shimizu Yoshiyuki (清水義之) — optical design
Construction: 12 elements / 9 groups
Aperture range: f/2.8–f/22
Diaphragm blades: 7
Min. focus: 0.25 m
Dimensions: 236 × 171 mm
Weight: 5200 g
Years manufactured: 1972–1998
Country: Japan
Coating: Nikon Integrated Coating from the first production example — the first Fisheye-Nikkor to launch multicoated
Original price: ¥600,000 (today ¥1,884,000) — Japanese list, 1972 (Cavina)

What reviewers say

Bellamy Hunt (Japan Camera Hunter) (blog) — Handling one rather than testing it: he calls it the world's most extreme wide-angle lens and the most stunning piece of photographic equipment he has ever handled, and declines to give the price his customer paid. single source, unconfirmed

Optical formula — Retrofocus fisheye

Marco Cavina — cross-section, patent drawings, mechanical section and the full glass table for the 6mm f/2.8

History

Nippon Kogaku filed the Japanese priority patent application for this optical system on 30 September 1970. Photokina opened in Cologne on 3 October. A lens carrying serial 261001 was on the stand. Three days is the measure of the effort: Shimizu Yoshiyuki finished the calculation, and the glass, the mount and the assembly of a single example followed fast enough to reach Germany. The first lens actually sold carries serial 628001 and was built in March 1972 — seventeen months later. Most English accounts still date the lens to 1970, which is the date of the object on that stand and of nothing else.

What Shimizu had found was a way past the limit of the conventional fisheye. A 180° design fronts itself with one deep negative meniscus; the patent’s claim is that splitting that meniscus into three separate elements, then following them with a biconcave divergent element and a converging one, buys a half-angle of 110°. Ninety degrees is the horizon. A hundred and ten is twenty degrees past it, on every side — the lens records a band of whatever lies behind the plane of the camera, and behind the photographer holding it. Distortion reaches 100% at the 90° mark, exactly where an ordinary fisheye stops, and then simply stays at 100% for the remaining twenty degrees.

The Fisheye-Nikkor 6mm f/5.6 of February 1970 had already covered 220°, so coverage was not the novelty. What the f/2.8 added was the ability to use the camera. Its back focus is 37.7mm against a true focal length of 6.3mm, very nearly six times, which leaves the reflex mirror free to swing. The f/5.6 pushed its rear group to within millimetres of the shutter and had to be used with the mirror locked and an accessory finder that covered only 160° of the 220 being photographed. On the f/2.8 there is reflex viewing, focusing down to 0.25m, an automatic diaphragm, and full-aperture TTL metering — two stops faster, and pointed at the sky or down a boiler with the picture visible in the finder. It was also the first Fisheye-Nikkor to leave the factory multicoated; the 8mm f/8, the 7.5mm f/5.6 and the 10mm f/5.6 OP kept single coating for their whole production lives.

The price of all that is 5.2kg of lens with a 213mm front element, sold on order only, at ¥600,000 in 1972 — and the Italian importer’s Photokina brochure was already telling buyers to expect a twelve-month wait. Roland Vink’s serial blocks give 29 in pre-Ai mount between 1972 and 1977, 179 in Ai between 1977 and 1981, and 57 in Ai-S between 1982 and 1998: 265 lenses in twenty-six years. The optics never changed across the three. Neither did the barrel beyond the minimum needed to keep up with Nikon’s metering standards — the metal knurled focusing ring survived the 1974 K series and its rubber inlay, and survived Ai and Ai-S after it, because nobody was going to retool a barrel built at ten a year.

The record stops short in several places. There is no factory production figure; the counts above are arithmetic on serial numbers people have reported. Vink lists no serial at all between roughly 6290xx and 629400 in an Ai-S run of 57 known lenses, so where one block ends and the next begins is inferred rather than documented, and whether the lens was assembled in batches or trickled out continuously has never been stated. Even the dimensions are unsettled: Nikon’s specification sheet says 236mm across, the 1974 Amphoto Nikon book says 263mm, and only one of them can be right.

Expand Collapse

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 Fisheye-Nikkor 6mm f/2.8 — Fisheye-Nikkor Auto 6mm f/2.8 at the Nikon Museum, 2015 — Morio, via Wikimedia Commons (CC BY-SA 4.0)

Sample photo wanted — shot with a Fisheye-Nikkor 6mm f/2.8? We'd love to feature it (with credit).

Live listings

No current listings found — a quiet market right now (or my keyword filter needs work).

Listings updated 2026-09-05. Links go to the shop or marketplace that carries the item.