Zunow 5cm f/1.1

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.