Omnar NK35-18

Omnar NK35-18

The NK35-18 is not a newly computed optic but a rehousing project: Omnar (the lens brand of UK workshop Skyllaney Opto-Mechanics) takes the optical block of Nikon's S-mount W-Nikkor 35mm f/1.8 and rebuilds it into a rangefinder-coupled Leica M-mount barrel [1][2]. The donor lens matters historically, because the W-Nikkor 35mm f/1.8 was the fastest wide-angle of its day when it appeared in the mid-1950s, beating Leica to a sub-f/2 35mm by several years until the 35mm Summilux arrived in 1960 [3]. The conversion keeps that 7-element formula and brings it to modern M bodies with full rangefinder coupling, something the original S-mount glass cannot do without modification because its rear group is too large to clear the M rangefinder mechanism.

Omnar offers the NK35-18 as a made-to-order conversion rather than a stock product. The customer supplies a clean, working donor lens, and the workshop CNC-machines a slimmer rear optical cell so the block clears the rangefinder swing arm, retaining the original aperture ring and front filter thread; because of these changes the conversion is non-reversible. The lens is designed, machined, hand painted and hand assembled in the UK, and uses an all-brass barrel. It is rangefinder coupled from 0.65 m to infinity with a short focus throw, with an optional uncoupled close-focus range continuing down to 0.35 m. Buyers can specify a light or heavy focus feel, several finishes (black matte, semi-gloss black, silver chrome, and gloss black with antique brassing) and custom engraving on the focus ring. The compact result protrudes only about 29 mm from the camera and weighs under 200 g.

Because both the original and Nikon's later reissue of the 35mm f/1.8 can be used as donors, individual NK35-18 lenses can differ in their coatings depending on which donor was supplied. The current housing design was developed with cinematographer Jean-Marc Ferriere, who wanted to use his 2005 reissue lens on M-mount cameras with full coupling and assisted with the design and beta testing. The conversion batch tied to the original 2023 release closed in May 2023, with further runs offered on request.

Optical qualities

Rendering The underlying W-Nikkor uses a modified double-Gauss design with single-layer blue and amber coatings and lanthanum glass. Reviewers describe it as sharp wide open with a slight softness in the highlights, holding a moderate level of contrast even at maximum aperture and giving solid, well-defined images. Color rendering is noted as vibrant and true to life, with reds and greens reproducing particularly well.

Distortion and vignetting The front and rear elements were originally computed for an f/1.4 lens but optimised at f/1.8 to keep vignetting in check, which makes the lens usable wide open with well-controlled corners. Stopped down to about f/2.8 it is reported to reach excellent sharpness with no obvious distortion.

Bokeh and transitions The converted lenses are described as having attractive bokeh and pleasing focal transitions alongside their vibrant color, characteristics carried over from the original Nikkor optic.

History

Development and Launch The NK35-18 originates from Nikon's W-Nikkor 35mm f/1.8, marketed as the world's first super-speed wide-angle and a premium option for Nikon's 1950s rangefinder cameras, reflecting Nikon's effort to outpace German makers with an optic faster than f/2. The original LTM version of the W-Nikkor is regarded as scarce, with collector accounts citing roughly 1,500 made for Leica thread mount. Omnar's conversion project, released in 2023, adapts the more common S-mount version into an M-mount, rangefinder-coupled lens, with the housing developed in conjunction with cinematographer Jean-Marc Ferriere.

Production Evolution The NK35-18 is built to order rather than mass produced, so units vary by donor lens, coatings, focus feel, finish and engraving. Skyllaney/Omnar machine a new slimmer rear cell to clear the rangefinder mechanism while keeping the original aperture ring and filter mount; the modification is permanent.

Collector Notes Because the lens depends on a donor, buyers should verify that the supplied W-Nikkor is haze and fungus free before conversion, as Omnar requires a good working-order lens. The conversion is non-reversible, so a converted example cannot be returned to S-mount, and the original LTM W-Nikkor (distinct from the converted S-mount used here) remains the rarer collector item in its own right. Confirm which donor and coating version a given NK35-18 carries, and check the all-brass barrel finish and any custom engraving against the original order specification.