DK-Optic Chiaro 2-inch 51mm f/1.9

DK-Optic Chiaro 2-inch 51mm f/1.9

The DK-Optic Chiaro 2-inch 51mm f/1.9 is a modern, rangefinder-coupled Leica M-mount lens based on the optical concept of the British Dallmeyer Super Six 2-inch f/1.9. Introduced in 2026, it combines a six-element, four-group double-Gauss formula with a newly manufactured focusing barrel, full-frame coverage and a 0.7m minimum focusing distance.

The lens uses a dampened manual preset aperture covering f/1.9 to f/22. This provides smooth, clickless adjustment rather than the indexed aperture stops normally found on still-photography M lenses. Its twelve-blade diaphragm is intended to maintain a rounded opening when stopped down. The exterior barrel is manufactured from 7075 aluminum, while the focusing helicoid and aperture mechanism use CNC-machined brass components.

DK-Optic lists the lens at 52mm long with its threaded hood fitted, 52mm in maximum diameter and 188g without caps. The body accepts 37mm filters and is supplied with a metal hood, metal front cap, rear cap and bamboo presentation box. Both coated and uncoated optical versions are offered in the same silver-chrome barrel.

Optical qualities

Rendering

Independent optical testing of the production Chiaro 51mm f/1.9 remains limited. DK-Optic describes the lens as a direct recreation of the six-element, four-group Super Six formula rather than a modern optical redesign. The company reports defined in-focus detail at f/1.9, rapid transitions into defocused areas and a visible increase in contrast and resolution when stopped down. These remain manufacturer-reported characteristics until broader independent testing becomes available.

Bokeh and transitions

The combination of a 51mm focal length, f/1.9 aperture and twelve-blade diaphragm is intended to produce gradual subject separation and rounded out-of-focus highlights. The Super Six-type double-Gauss formula is historically associated with residual spherical aberration and non-uniform peripheral rendering, but the exact strength of these effects in the Chiaro depends on focusing distance, background structure and coating version.

Contrast and flare

The coated edition should provide greater contrast and better control of internal reflections. The uncoated edition is expected to show lower contrast, stronger halation and more visible flare around bright light sources. No independently measured transmission or flare comparison between the two versions has been published.

Digital use

The Chiaro is manufactured in native Leica M mount and is rangefinder coupled down to 0.7m. Its 51mm focal length closely corresponds to the standard 50mm Leica viewfinder field. Accurate calibration remains important at f/1.9, particularly near the minimum focusing distance. Compatible digital M cameras can also use live view for critical focusing and composition.

History

Development and Launch

The Chiaro series was developed by DK-Optic as a group of modern lenses based on the British Dallmeyer Super Six family. Original Super Six lenses were made in numerous focal lengths, normally with an f/1.9 maximum aperture and a six-element, four-group Gauss-type construction. Original 2-inch lenses are particularly relevant to Leica collectors because uncommon examples and later conversions have appeared in Leica-compatible mounts.

The Chiaro 51mm f/1.9 was publicly listed by July 2026 as part of DK-Optic’s expanding Leica M catalogue. It joined the longer Chiaro 76mm f/1.9 and the separate Septac-inspired Impastolite 51mm f/1.5.

Production Evolution

Only the initial 2026 specification is documented. It uses a silver-chrome aluminum and brass barrel, twelve-blade preset diaphragm and 37mm filter fitting. DK-Optic notes that the listed weight may receive minor adjustments between production batches.

No optical revisions, alternative barrel finishes or complete production totals have been confirmed. A separate factory model or catalogue number has not been located.

Special Editions/Variants

The Silver Chrome Coated version uses coated optical surfaces and is intended to provide the more controlled rendering option, particularly in backlighting.

The Silver Chrome Uncoated version uses the same mechanical construction without anti-reflection coating. It is intended to emphasize lower contrast, flare and halation associated with early uncoated lenses.

Production quantities for the coated and uncoated 51mm editions have not been confirmed. The limited quantities published for the Chiaro 38mm should not be applied to this lens.

Collector Notes

Collectors should distinguish the 51mm Chiaro from the visually related 38mm and 76mm models. The front engraving, focal-length marking, twelve-blade diaphragm and 0.7m focusing scale are useful identification points.

Historical lenses should not be judged from one sample alone. Haze, fungus, separation, cleaning damage, displaced elements and dried lubricant can alter contrast and focus more than modest design differences. Film choice, processing, digital sensor cover glass and adapter tolerances also influence results. A hood may reduce oblique flare but cannot correct internal contamination.