Nikkor-T 35cm f/4.5

No other lens in the Nikon rangefinder system has anything like its diaphragm. The Nikkor-T 35cm f/4.5 — introduced in June 1959, the last of Nippon Kogaku’s four reflex-housing telephotos to appear — is the only Nikon RF lens with a semi-automatic diaphragm: cocked to full aperture by hand for focusing, it snaps down to the preset taking stop by spring action the moment the release button is pressed. It has no rangefinder coupling at all. Like every long Nikkor of the era it focuses only through the Prism Reflex Housing, which turns an SP or S3 into an improvised single-lens reflex — and only about 620 to 650 of them were ever made.

The housing it depended on was itself a modest seller. The Model I — announced in 1952, though apparently not marketed until late 1954, and patterned on the Leitz PLOOT — sold fewer than 200 units. The Model II of around May 1956, at $129.50, did better: serials run 471101–471769, still under 800 housings, paired first with 45° prism finders and late in life with a 90° pentaprism. Onto this platform Nippon Kogaku had already hung the 50cm f/5 (1952), the 18cm f/2.5 (1953) and the 25cm f/4; the 35cm f/4.5 completed the set in the same month the Nikon F arrived to render the whole contraption obsolete — which is precisely what explains its diaphragm, an SLR convenience grafted onto a rangefinder accessory system in its final hour.

Physically it is a simple, massive thing: three elements in three groups behind a nine-bladed iris stopping down to f/22, about 1.7 kg and 300 mm of all-black barrel — a few examples wear black crinkle paint with a black rather than chrome aperture scale — focusing to 4 m, with a reversible 82mm screw-in shade that doubles as a Series IX filter holder, priced at $398. The serial record is unusually tidy: a single prototype numbered 101507, then one continuous production block from 354501 to 355121. Two independent serial datasets agree on roughly 620–650 lenses — Pacific Rim Camera counts about 650, and the confirmed span accounts for 621 — while a lower figure of 429 circulates via lens-db but cannot be verified and would leave nearly a third of a continuous serial block unused. The date carries its own small confusion: June 1959 is the best-supported introduction, Japanese Wikipedia gives February 1960, and the 1958 sometimes seen in English Wikipedia is simply an error.

It stayed in the rangefinder price sheets until 1964, but the optics outlived the mount. By January 1963 Nikon’s US price list was already cataloging it for the Nikon F as a short-mount telephoto — mounted via a rotating adapter coupler and still carrying its semi-automatic diaphragm — and it remained in the 1965 list; a number of examples were also delivered in Bronica mount, drawn from the same serial block, for that system’s 6×6 SLRs. For a lens built in the hundreds, it led a surprisingly mobile life across three systems.