Nikkor-Q 25cm f/4

No Nikkor longer than 135mm could couple to the Nikon rangefinder at all: the Nikkor-Q 25cm f/4 focused through the Prism Reflex Housing, a mirror box that turned an S-series body into a makeshift single-lens reflex, with the photographer composing on ground glass rather than through the rangefinder patch. Of the four telephotos built for the housing it was the most numerous — roughly 2,300 to 2,700 across its run, against about 1,200 of the 18cm f/2.5, ~620–650 of the 35cm f/4.5 and a few hundred of the 50cm f/5 — which still leaves it a rare lens by any ordinary standard. Even its launch date is genuinely contested, two sources each way: Pacific Rim Camera puts it at January 1951, launched together with the reflex-housing program itself, and CameraQuest likewise says 1951, while Japanese Wikipedia and the serial record’s first-batch dating say November 1953. Neither camp has a document that settles it.

The housing’s fortunes shaped the lens’s. Nippon Kogaku patterned its Prism Reflex Housing on the Leitz PLOOT; the Model I was announced in 1952 but apparently not marketed until late 1954, and fewer than 200 were sold. The Model II of around May 1956 — $129.50, serials 471101–471769, with 45° prism finders and, late in the run, 90° pentaprisms — put the system on a somewhat firmer footing, and the lens’s two mechanical generations track the two housings. The manual-diaphragm original accounts for some 584–600 lenses across serials 271801–272400, in three distinct trims: the earliest examples wear an evenly ribbed focus ring and an infinity mark spelled INF., a first style sometimes claimed at perhaps 50 units even though the confirmed serial span covers about 170 numbers; scalloped-ring Q·C lenses follow to 272200; and the ·C drops from the engraving on the final manual block. The preset-aperture version arrived with the Housing II era — sources put its start anywhere from 1956 to 1959 — and accounts for a further ~1,700–2,100 lenses across blocks 272405–274047 and 277211–277662, first with feet-only scales and a white depth-of-field scale, later marked in feet and metres. Both versions sold for the same $224.50.

Optically every one of them is the same lens: four elements in three groups — Q for quattuor, per Nikkor’s element-count lettering — a kilogram of glass and brass (1,042g) some 133mm long, focusing to 3 metres. The design’s image circle far exceeds a 35mm frame, enough to cover 6×6, and Nippon Kogaku — by then also building Zenza Bronica’s lens line — offered a Bronica S2/S2A version whose examples sit interleaved among rangefinder units in the 273008–274047 block; its rear mount and focusing ring differ, and the two versions do not interchange. An N-F adapter carried the reflex-housing outfit onto the Nikon F, and by the 1965 price list the same optics were simply cataloged as F-mount preset lenses — a quiet end for a lens whose final serial block ran out in 1963, absorbed by the SLR system its mirror box had been imitating all along.