Omnar NK35-25

Name: Omnar NK35-25
Brand: Omnar

The Omnar NK35-25 is a M-mount lens for Leica rangefinder cameras. As of June 2026, it sells from €1,234 used across 1 listing, with a 30-day median of €1,234. Leica price index ↗

Reference maintained by Thomas Boots· prices updated June 2026

Model number(s): NK35-25

Focal Length: 35mm

Aperture: 𝑓/2.5

Release Year (from): 2023

Diameter: 51 mm

Length: 18.8 mm

Minimum Focus Distance: 0.35m

Elements in Groups: 6/4

Aperture Blades: 6

Mount: M

Material Weight: Brass, 146g

https://omnarlenses.com/

Omnar NK35-25

Rather than a freshly computed optical design, the NK35-25 is a rehousing project: Omnar Lenses extracts the optical unit and iris from the amphibious W-Nikkor 35mm f/2.5 made for Nikon's Nikonos and Calypso underwater cameras and fits them into a purpose-built M-mount barrel [1][2]. The original Nikonos design dates to the 1960s and is noted for correcting spherical and chromatic aberration despite its wide angle and small size, which is part of why Omnar selected it as a conversion candidate [3]. Unlike the dedicated underwater UW Nikkor lenses, the W version was intended to work both submerged and on dry land, making it suited to terrestrial rangefinder use [3]. During conversion the flat front element that formed part of the original water-proofing is removed, which Omnar states improves performance over the amphibious original [1].

The six-element, four-group optical block is mounted in an all-brass helicoid body that is designed, manufactured, hand finished and assembled in the United Kingdom by Skyllaney Opto-Mechanics, the workshop behind the Omnar brand [1][2]. The lens is rangefinder coupled from 0.65 m to infinity with a short focus throw, and buyers can add an uncoupled close-focus range down to 0.35 m [1][2]. Its iris uses six aperture blades and the lens is extremely compact for its class; Skyllaney describes it as barely larger than its earlier CN26 conversion, making it one of the smallest 35mm rangefinder lenses available [4]. Because the optics are repurposed from vintage parts, each lens reuses an individually selected optical specimen rather than newly manufactured glass [2].

The NK35-25 is built to order in limited batches rather than mass produced, so individual examples differ. Documented finishes include black matte chrome to match Leica black chrome bodies, gloss black lacquer, and gloss black with antique brassing, and clients could specify a light or heavier focus feel and up to three lines of custom engraving on the focus ring [1][2]. An optional E46 filter thread can be added, though this increases the size of the lens [1]. Coatings vary depending on the donor lens version, and the original Nikonos glass is recognisable by its aquamarine and purple coating tones [2][4].

Optical qualities

Rendering Documented rendering reflects the character of the underlying Nikonos optic. Skyllaney reports that these 35mm lenses are very sharp for their size, able to out-resolve the 60-megapixel Leica M11 sensor when stopped down to about f/5.6 to f/8, with good central sharpness already wide open [4]. The rendering is described as classic Nikon, combining saturated, vibrant colour with relatively high contrast, a more HDR-like palette than the subtler tonality of comparable Leica lenses [4]. Omnar notes that corner performance is stronger on Leica bodies than on adapted mirrorless cameras such as the Sony A7R III, while still making for an impressive and compact 35mm on either [2].

Digital use The lens has been used on digital rangefinders including the Leica M9, M10 and M11, and via M-mount adapters on Sony mirrorless bodies, including autofocus operation through the Techart Pro LM-EA9 adapter [2][4][5].

History

Development and Launch The W-Nikkor 35mm f/2.5 that supplies the NK35-25's optics was introduced for Nikon's underwater camera systems in the 1960s and enjoyed a long production run owing to its corrected, compact design [3]. Omnar's M-mount conversion was offered publicly from 2023, with the rangefinder-coupled NK35-25 made available to owners of original Nikonos W-Nikkor 35mm f/2.5 lenses [3]. Omnar Lenses is a joint venture between Hamish Gill of 35mmc and Chris Andreyo of Skyllaney Opto-Mechanics, and the project was described as a stepping stone in a broader programme; the NK35-25 helped solve rangefinder cam translation for 35mm lenses and the control of an iris built into an extracted optical block, work that fed into later conversion projects [3].

Special editions A hand-painted Safari Special Edition was produced as part of a 2023 batch, finished by Pierro of PPP Cameras, and was offered as the last remaining example of that run [4]. Skyllaney also produced batches in finishes such as clear gloss lacquer over polished brass with black satin highlights, supplied with a custom solid-brass push-on front cap [6].

Collector Notes Because every NK35-25 is a made-to-order conversion of a vintage donor, condition and finish vary between examples, and Omnar cautions that the reused 1960s optics may carry minor marks or dust specks even after servicing [2]. Buyers should confirm whether a given lens includes the optional uncoupled close focus to 0.35 m, the E46 filter thread, the specified focus feel, and any custom engraving, since these were per-order choices [1][2]. The lens is not six-bit coded. It should not be confused with the related Omnar NK35-18, a separate conversion based on the f/1.8 S-mount Nikkor with a seven-element design [7].