Mr. Ding Contax G45/2 Conversion V2.0

Mr. Ding Contax G45/2 Conversion V2.0

The Mr. Ding Contax G45/2 Conversion V2.0 rehouses the original Carl Zeiss Planar T* 45mm f/2 optical assembly from the Contax G system in a manual-focus Leica M barrel. The conversion is designed to be non-destructive and reversible, retaining the donor optical block without changing its glass arrangement. The new helicoid adds direct manual focusing, a Leica M bayonet, and mechanical rangefinder coupling, functions that the autofocus Contax G barrel did not provide for Leica cameras.

The retained Zeiss design has six elements in four groups, an actual focal length of 46.9mm, a maximum aperture of f/2, a minimum aperture of f/16, and T* antireflection coating. The original Contax G lens used an M46 by 0.75 filter thread and focused to 0.5 metres. Mr.Ding's current V2.0 conversion lists a 46mm filter, a brass body, 260g for the empty kit, and 333g with the optical assembly. The converted close-focus limit is not stated on the product page, so the donor's 0.5-metre specification should not automatically be guaranteed for every completed conversion.

This profile covers the Mr. Ding V2.0 product and its Funleader collaboration lineage. It does not represent every independent Contax G45 rehousing. Other makers can use different helicoids, cams, materials, calibration procedures, and support even with the same Zeiss donor optics.

Optical qualities

Rendering

Because the conversion preserves the original optical block, its basic imaging properties remain those of the Contax G Planar T* 45mm f/2. The six-element, four-group Planar arrangement was designed as the standard lens for the 24 by 36mm Contax G format. Rehousing does not add resolution or change the optical formula, although accurate spacing, shimming, and parallel alignment are necessary to preserve intended performance.

Zeiss's published data and performance curves apply to a correctly assembled optical unit, not automatically to a misaligned conversion or damaged sample. On Leica M, rangefinder calibration becomes part of the result, particularly at f/2. Digital live view can separate optical behaviour from cam error.

Contrast and colour

The donor optics retain Zeiss T* coating. Surface condition, baffling, and correct assembly influence contrast and flare. Promotional performance claims are not treated as independent measurements here.

Out-of-focus rendering

At roughly 47mm and f/2, the lens provides moderate subject separation with a normal perspective. The optical assembly retains its original diaphragm, but exact highlight shape depends on aperture, focus distance, and the condition of the donor unit. Rehousing changes focusing ergonomics, not the aperture's optical geometry.

Digital compatibility

The Leica M bayonet mounts directly on compatible M bodies and adapts to many mirrorless systems. There are no electronic contacts, autofocus, or automatic aperture communication. Digital M focusing relies on mechanical calibration; mirrorless use relies on live view and correct adapter depth.

History

Development and Launch

Carl Zeiss introduced the Planar T* 45mm f/2 with the Contax G1 system in 1994. In its original barrel the camera drove focus electronically through the Contax G mount. The optical unit remained attractive after Contax camera production ended, but adapting it to manual-focus rangefinders required a new focusing mechanism rather than a simple passive spacer.

Funleader and Mr.Ding Studio began their non-destructive Contax G conversion project with the G35 in August 2019. They followed with a G45 solution in May 2021, installing the complete optical assembly in a dedicated helicoid and providing Leica M rangefinder coupling. This approach preserved the donor barrel for later restoration instead of permanently machining the original lens.

Production Evolution

The current Funleader history records a revised G45 kit released in June 2024. It retained the 2021 optical and mechanical concept while refining the outer machining, edge profiles, focus-ring shape, and anodized finish. Mr.Ding's V2.0 listing offers the kit separately or as a complete lens containing original G45 glass.

These dates describe the conversion product, not the age of the Zeiss optical block installed in an individual lens. Donor optics were made during the Contax G era and may vary in condition. The conversion's present-day barrel and the 1994 optical design should be recorded separately when documenting provenance.

Special Editions/Variants

Mr.Ding lists black and silver finishes and both kit-only and complete-lens options. A kit assembled by its owner and a factory-completed lens share the concept but may differ in calibration quality. Funleader's commercial version belongs to the same collaboration lineage, yet unrelated third-party rehousings remain separate products and should not be merged into this profile.

Collector Notes

Identification should record both components: original Carl Zeiss Contax G45 optics and the specific Mr.Ding conversion barrel. Check that the aperture moves through its range, infinity is correctly shimmed, and the rangefinder cam agrees at several distances. The manufacturer's tutorial explicitly treats gasket selection as part of infinity calibration.

Reversibility depends on preserving the original Contax housing and completing disassembly without damage. A kit does not include donor glass unless the selected option says so.