Name: Contax ZEISS Biogon T 21mm converted to M mount
Brand: Contax
Price: 1099 USD
Availability: InStock

Exhibits minimal signs of wear, noticeable only upon close inspection. Fully operational and includes all items shown in the listing photos. The actual item for sale is pictured unless specifically noted otherwise. The condition rating applies to the core item and not any accessories.

Excellent condition Contax G 21mm Biogon that has been converted to a Leica M mount helicoid. The optics is Contax G but the body allows you to...read more.

Merging an expansive wide-angle perspective with a sleek design, the ZEISS Biogon T* 21mm f/2.8 ZM lens for M–mount rangefinder cameras offers precise imagery with minimal distortion. The high-quality Biogon optical formula ensures sharp and true-to-life image capture. Furthermore, its T* anti-reflective coating enhances image quality by diminishing reflective interference, leading to improved color fidelity and contrast in brightly lit conditions. The lens's manual focusing capability enables close-up shooting at a minimum distance of 1.6 feet.

The ZEISS Biogon T* 21mm f/2.8 ZM Lens is a high-performance wide-angle lens designed for rangefinder cameras. It features the renowned T* anti-reflective coating for exceptional image clarity and contrast, making it ideal for landscapes, street photography, and architectural shots.

Optimized for use with Leica M-Mount rangefinder cameras.

Compatible with Leica M-Mount

Varying aperture settings from f/2.8 to f/22 for depth of field control.

Fixed Aperture

Incorporates ZEISS's T* anti-reflective coating to minimize glare and ghosting effects.

Optical Coating

Facilitates precise manual focusing with a close-up range down to 1.6 feet.

Focusing Mechanism

The ZEISS Biogon T* 21mm f/2.8 ZM is a **prime wide-angle lens** designed for cameras using the **Leica M mount**, covering a **full-frame** image circle. Its fixed **21mm focal length** places it firmly in wide-angle territory, well-suited for street, travel, and architectural photography where a broad field of view is an advantage. The maximum aperture of **f/2.8** gives photographers the ability to work in moderate low-light conditions while keeping the lens compact. Focusing is entirely **manual**, which complements the rangefinder shooting workflow and encourages a more intentional approach to composition. Weighing just **300g**, the lens is easy to carry all day without fatigue, and the **46mm filter thread** means accessory filters remain affordable and easy to find. With **no image stabilization**, users will rely on their own technique or in-body stabilization where available. For M-mount shooters looking for a capable, lightweight wide prime, the specs here make a straightforward case.

The symmetrical Biogon formula minimizes distortion and delivers sharp, rectilinear rendering across the full frame — well suited to architecture and landscape work.

Biogon Optical Design

Covers a full-frame image circle, providing a wide 90-degree angle of view on full-frame M-mount bodies.

21mm Full-Frame Coverage

Offers a useful light-gathering capability for a wide-angle prime, allowing handheld shooting in lower-light conditions.

f/2.8 Maximum Aperture

Natively fits Leica M rangefinder bodies and is also compatible with mirrorless systems via M-mount adapters.

Leica M Mount

Designed exclusively for manual focus, suiting the deliberate shooting style of rangefinder photography and careful composition work.

Manual Focus Only

Zeiss's proprietary T* coating reduces flare and ghosting, maintaining contrast and color fidelity when shooting in challenging light.

ZEISS T* Anti-Reflective Coating

At just 300g, this lens adds minimal weight to a rangefinder or mirrorless kit, making it practical for travel and all-day street photography.

Compact 300g Build

A small, common filter diameter keeps the lens footprint compact and makes compatible filters widely available and affordable.

46mm Filter Thread

User Manual

ZEISS Biogon T* 21mm f/2.8 ZM

ZEISS Biogon T* 21mm f/2.8 ZM Lens

2026-01-30-phase10-zeiss

2026-01-30T07:05:57.714Z

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Excellent condition Contax G 21mm Biogon that has been converted to a Leica M mount helicoid. The optics is Contax G but the body allows you to adjust focus and aperture manually with RF coupling. Includes box, caps, contax filter and original contax G AF body if you every want to convert it back.

<p>Excellent condition Contax G 21mm Biogon that has been converted to a Leica M mount helicoid. The optics is Contax G but the body allows you to adjust focus and aperture manually with RF coupling. Includes box, caps, contax filter and original contax G AF body if you every want to convert it back.</p>

Spec	Detail
Use Cases	Travel
Lens Type	Wide-Angle
Format	Full Frame
Zoom/Prime	Prime
Focal Length	21mm
Maximum Aperture	f/2.8
Camera System	Mirrorless
Lens Mount	Leica M
Autofocus	No
Focus Type	Manual Focus
Image Stabilization	None
Filter Thread	46mm
Weight	300g

Contax ZEISS Biogon T 21mm converted to M mount

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