Rare item. This is the earliest model of the Nikkor-Q.C 13.5cm f4, manufactured by Nippon Kogaku. Serial number 611x, part of the discarded-number 611 series. Leica screw mount with rangefinder coupling.
The 135mm f4 lens was designed in 1946, and mass production began in October of the same year (the exact launch date is unknown). As indicated by the last digit of the serial number, this is the fourth unit produced—an extremely early specimen. It is a historically significant piece in the legacy of Nikon lenses. It bears the engraving Made In Occupied Japan, commonly known as MIOJ, indicating it was manufactured during the Allied occupation.
It features a 3-group, 4-element telephoto Tessar-type construction with very faint early coating. The minimum focusing distance is 5 feet (1.5m), engraved in feet. It uses a straight helicoid focusing mechanism. The front barrel has a clean, step-free design, which differs from later versions.
It is said that around 200 units were produced in the 611 series, with only a very small number in Leica mount. An ultra-rare version was made in Exakta mount—only one is known to exist. It would be a dream to see it one day.
On page 322 of Robert J. Rotoloni’s book The Complete Nikon Rangefinder System, this very unit, number 6114, is mentioned. Despite most lenses being Nikon S mount, this Leica mount example is highlighted as a confirmed existing piece. It is also a valuable reference in the study of Nikon S mount history.
According to Episode 43 of the Nikkor Thousand and One Nights series, after the lens design was completed in 1946, the first units produced were Leica L-mount lenses intended for Canon and Nippon cameras. Considering that the Nikon S mount had to wait until the release of the Nikon I in 1948, it is entirely reasonable that Leica mount lenses were included among the earliest 611 series units.
There are minor scuffs and scratches, but the plating is well-preserved, and the overall appearance is quite clean. The finish feels premium, reflecting Nippon Kogaku’s commitment to quality craftsmanship in that era.
Fully overhauled in June 2025. The aperture and helicoid movements are now smooth. When used wide open, the rangefinder coupling tends to front-focus from about 5 meters to infinity. Stopping down two stops brings proper alignment. At infinity, the double image slightly overshoots.
Interestingly, the rangefinder coupling cam appears to have a different construction compared to standard examples. As this was produced during a period of small-batch, hand-assembled manufacturing, individual variation is likely.
Some separation is visible along the edge of the middle element. Aside from this, the glass is relatively clean with no haze or notable cleaning marks.
Comes with a metal hood cap marked NIKKOR, a one-piece hood, a heavy rear cap, and a bright brown leather case. The included viewfinder is marked Japan, indicating it is from a slightly later period. The viewfinder case has the EP mark.
