Voigtländer Ultron 28mm f/2

The Voigtländer Ultron 28mm f/2 is a M-mount lens for Leica rangefinder cameras. Leica price index ↗

Reference maintained by Thomas Boots

Focal Length: 28mm

Aperture: 𝑓/2

Release Year (from): 2008

Diameter: 55 mm

Length: 51 mm

Minimum Focus Distance: 0.7m

Elements in Groups: 10/8

Aperture Blades: 10

Mount: M

Material Weight: Metal, 244g

Colors: Black

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Voigtländer Ultron 28mm f/2

When Cosina introduced this Voigtländer Ultron in 2008, it offered Leica M users a genuinely fast 28mm in a body far smaller and cheaper than the comparable Leica options, slotting in below the 28mm f/2 Summicron-M and 28mm f/2.8 Elmarit-M on price while staying competitive on optical behaviour [1][2]. It was the M-bayonet successor to the earlier screw-mount Voigtländer 28mm f/1.9 Ultron, and it later became the first of several distinct 28mm f/2 generations from Cosina, predating the redesigned aspherical "Vintage Line" Type I and Type II lenses that followed with a 39 mm filter thread and a closer 0.5 m focus limit [3].

Optically the lens uses a ten-element, eight-group design that behaves much like a conventional, near-symmetrical wide-angle rather than a retrofocus SLR-style layout, which helps explain its very low distortion [1]. It focuses down to 0.7 m, a typical figure for an M-mount wide-angle, and is rangefinder coupled for use on film and digital M bodies. The aperture runs on ten blades, and the barrel takes 46 mm filters. At roughly 244 g and only about 51 mm long it is light and pocketable, and reviewers have praised the mechanical quality of the focusing and diaphragm action [1]. Because it is moderately fast rather than extreme, it tends to avoid the rangefinder calibration problems that can affect faster wide-angles [3].

The main point of confusion for buyers is version identity. This entry covers the original black VM Ultron 28mm f/2 with the ten-element, eight-group formula, 46 mm filters and a 0.7 m minimum focus distance; the later aspherical Type I and Type II lenses share a different ten-element, seven-group optical formula, a 39 mm filter thread and a 0.5 m minimum focus distance, and they exist in different finishes and barrel styles [3]. Lens correction profiles are not interchangeable across these generations, since profiles made for one version can degrade results on another [3].

Optical qualities

Rendering Documented character points to a clean, modern rendering with strong sharpness and contrast and notably low distortion, traits that suit landscape, street and architectural work [1][3]. On a native Leica M sensor the lens resolves well across the frame from wide open, with only a small mid-zone dip at f/2 [3].

Sharpness On a 24 MP Leica M10 the lens performs strongly from f/2, close to a more complex Voigtländer 35mm despite its simpler construction; center resolution is high wide open and the frame tightens further on stopping down [3]. It is generally regarded as not quite matching the very sharpest Leica 28mm ASPH lenses for pixel-level detail, while still being highly capable [1].

Distortion and vignetting Distortion is low and easily corrected, consistent with the near-symmetrical optical layout [1][3]. As is normal for a compact, symmetrical fast wide-angle, corner light falloff is significant wide open and eases as the lens is stopped down [3].

Digital use On Leica M digital bodies with their thin sensor cover glass the lens shows its best corner and bokeh behaviour. On mirrorless cameras with a thicker filter stack, such as Sony A7-series bodies, the corners need more stopping down and a slight green corner colour cast can appear, a limitation shared by many rangefinder wide-angles rather than a fault of this lens specifically [3].

History

Development and Launch Cosina launched the M-mount Ultron 28mm f/2 under the Voigtländer name in 2008, giving rangefinder photographers a fast yet compact 28mm at a fraction of Leica prices [1][2]. It replaced the older M39 screw-mount 28mm f/1.9 Ultron in Cosina's lineup and positioned itself as an affordable alternative to Leica's own 28mm wide-angles [1][3].

Production Evolution The 28mm f/2 designation was carried forward through several distinct lenses. After this original 10/8 version, Cosina released revised aspherical "Vintage Line" models, identified as Type I and Type II, which moved to a 10/7 formula, a 39 mm filter thread and a 0.5 m minimum focus distance [3]. Type I and Type II are reported to share the same optics and differ mainly in barrel styling, with Type I using a small focus lever and Type II a more conventional focus tab [3].

Special editions No widely documented military, export or rare factory variants of the original Ultron 28mm f/2 are recorded; the meaningful variation in the 28mm f/2 family comes from the later aspherical Type I and Type II redesigns and their finish options rather than from special editions of this version [3].

Collector Notes The most important check is which generation a listing actually refers to, since the 28mm f/2 name has been reused across optically different lenses. The original here is the black 10/8 lens with 46 mm filters and a 0.7 m close-focus limit; confirm the filter thread and minimum focus distance to separate it from the later aspherical 39 mm-filter versions [3]. Hoods are sold separately for the Cosina M-mount line, so verify whether a hood is included, and check the rangefinder coupling and focus and aperture action when buying used [3]. Note that lens-correction profiles are version-specific and should not be carried over between generations [3].