Fujinon 5cm f/1.2

When Fuji Photo Film entered the 50mm speed race, it was answering a shot already fired: Teikoku Kogaku’s Zunow 5cm f/1.1 had seized the world’s-fastest crown in 1953, and every serious Japanese optical house felt the pressure. The Fujinon 5cm f/1.2 arrived as one of the “Big Four” ultra-fast lenses of the decade — Zunow’s f/1.1 (1953), the Hexanon 60mm f/1.2 and this Fujinon (1954), and finally the Nikkor 5cm f/1.1 (1956). A memo in Asahi Camera shows it announced by June 1954, and Fujifilm’s official company history puts it on sale that November. By May 1955, Modern Photography was calling it the fastest lens yet made for a 35mm camera.

The design was the work of Ryōichi Doi (土居良一), who told his own story in a 1955 account in Shashin Kogyo: a lineage running from his Solinon 50mm f/1.5 patent through an f/1.3 study to a nine-element trial design — the version the June 1954 Asahi Camera memo diagrams, its two thin rear elements later merged into one for the improved eight-element, four-group production lens. Along the way it became the first Japanese lens to adopt new-type rare-earth glass, though sources dispute how many of the eight elements used it (three, four, or six, depending on who is counting). Doi described the finished formula as deliberately readable two ways — an improved Sonnar or a modified double Gauss — and the literature has split along exactly that line ever since. One thread stays unresolved: whether the earliest silver-barrel Leica-mount lenses carry the nine-element formula. Fotoborse described a white example as nine elements in six groups; MAP TIMES calls the silver an eight-element Sonnar with no optical difference.

Most production went to Leica screw mount, in the 500xxx serial block the lens shares — confusingly — with the “C”-marked Contax version, so serial alone will not tell you the mount. The Nikon S version occupies its own 260xxx block, with observed examples spanning just 2600xx–2601xx and none higher. A production split of “800 LTM / 50 S” circulates in two sources, but Yaotomi’s expert puts S and Contax combined at “a few dozen” — under 100, with quasi-prototypes mixed into early production — and no official figures exist. The S lens is also mechanically its own creature: an inner-bayonet design focused by the body helical, its aperture scale engraved twice because the whole lens rotates with the helicoid, its 12 near-circular blades set steplessly where the LTM version clicks. Early examples add a curious f/1.6 intermediate stop — an early-batch tell.

The lore is as good as the glass. Fujinon’s new-glass coup threw Zunow into a marketing panic that helped drive its 1955 Type II redesign — the incumbent speed king scrambling to answer the newcomer. And the market has rendered its own verdict: a lens whose mid-1950s price is reported — on the strength of a single shop blog — at ¥70,000–90,000 went from roughly ¥500,000 in mint condition in 2016 to $20,000 and up today, with the sharpest appreciation since 2020.