Omnar CX38-28

The Omnar CX38-28 is a M-mount lens for Leica rangefinder cameras. Leica price index ↗

Reference maintained by Thomas Boots

Model number(s): CX38-28

Focal Length: 38mm

Aperture: 𝑓/2.8

Release Year (from): 2024

Diameter: 51 mm

Length: 17 mm

Minimum Focus Distance: 0.45m

Elements in Groups: 5/3

Aperture Blades: 7

Mount: M

Material Weight: Brass, 120g

https://omnarlenses.com/

Omnar CX38-28

The Omnar CX38-28 is unusual among rangefinder lenses because its optics are not newly computed but salvaged. Omnar Lenses, a small UK maker, takes the Carl Zeiss 38 mm f/2.8 Sonnar built into the Contax T and T2 compact film cameras and rehouses the original glass and aperture assembly into a fully rangefinder-coupled Leica M-mount barrel [1][3]. The result is a pancake-thin lens that brings a celebrated point-and-shoot optic to interchangeable-lens cameras for the first time, which is the main reason it draws collector and enthusiast interest [3].

The conversion keeps the existing five-element Sonnar glass and the original aperture blades, mounting them in a new optical block designed so the full image circle reaches the film or sensor plane [1]. Omnar quotes an effective focal length close to 37.5 mm, which the maker notes sits near the 35 mm frame lines of M4 to M6 era bodies and is straightforward to compose with using standard 35 mm framing [1]. The lens is rangefinder coupled from 0.65 m to infinity with a short focus throw, and offers an uncoupled close-focus option down to 0.45 m [1]. To stay compact, Omnar combined the aperture ring and the 40.5 mm front filter thread into one component, giving a protrusion of about 17 mm from the camera and a weight near 120 g, while retaining an all-brass helicoid [1]. Because the original Sonnar projects an image circle exceeding 60 mm, the lens can also be adapted to mirrorless cameras and even to Fuji GFX and Hasselblad XCD medium-format bodies without hard corner vignetting, where it behaves roughly like a 29 mm f/2.2 full-frame equivalent [1][2].

The lenses are designed, manufactured, hand painted and hand assembled in the UK [1]. The first batch totalled 17 units, comprising two prototypes, one production test lens, two lenses for regular customers, and 12 production lenses offered for sale in eight matte black, two silver chrome, and two high-gloss black with antique brassing [1]. Omnar also lists matte black, silver chrome and high-gloss black with antique brassing as the standard finish options [1]. The maker has stated it was not accepting customer Contax cameras for one-off conversions during this run but would take them in part exchange [1].

Optical qualities

Rendering The CX38-28 uses the original Carl Zeiss Sonnar optics with their native T* coating, and reviewers describe the Sonnar formula as performing strongly even when adapted to larger sensors [1][2]. Documented impressions emphasise strong contrast, color rendition and noticeable sharpness, with users reporting a degree of three-dimensional rendering [3]. Because the lens is a faithful rehousing, Omnar states it performs on Leica film cameras the same way the optic did on the Contax T and T2, with the addition of full manual control [1].

Digital use When the lens is adapted to medium-format digital bodies that use the front-side-illuminated Sony IMX161 sensor, such as the Fuji GFX 50 and Hasselblad X1D series, an occasional purple edge color shift can appear at the frame edges, a behavior shared with other wide adapted lenses [2]. On bodies using the back-side-illuminated Sony IMX461 sensor, such as the Fuji GFX100 and Hasselblad X2D, that color shift is reported to be resolved [2].

History

Development and Launch The CX38-28 grew out of Omnar's practice of rehousing high-quality fixed-lens optics, in this case the 38 mm Sonnar from the Contax T and T2 [3]. The project began as a collaboration between the 35mmc blog and Skyllaney Opto-Mechanics, and Omnar Lenses was later established as its own entity [3]. The lens was readied for sale around early-to-mid 2024 [3]. According to Omnar, the CX38-28 was the first lens on its bench designed to work both on Leica rangefinders and, via adaptation, on XCD and GFX medium format, which shaped its larger-than-usual image circle and the effort to avoid mechanical vignetting [2].

Special editions No separate factory special editions are widely documented; the variation within the first run is limited to finish, namely matte black, silver chrome, and high-gloss black with antique brassing [1].

Collector Notes The CX38-28 is produced in very small, numbered batches, so availability is limited and Omnar indicated no second run before at least the end of 2024 [1]. Each lens depends on donor glass from a Contax T or T2, so buyers may wish to confirm the condition and originality of the optics and coating [1][3]. The finish and the all-brass construction are points to verify, since high-gloss black is offered with deliberate antique brassing [1]. The official product page lists the lens as a 37.5 mm f/2.8 design while the model name and LeicaLensList record it as 38 mm; the figures reflect the original Contax Sonnar focal length and Omnar's stated effective focal length, and should not be confused when identifying the lens [1].