Product Overview

The Contax G series was introduced in the 1990s as one of the few 35mm camera systems to combine rangefinder viewing with autofocus operation. Developed jointly by Contax and Carl Zeiss, the system featured multiple Carl Zeiss T* coated lenses. Among them, the 35mm and 45mm lenses became the most popular focal lengths due to their compact size and balanced optical performance. The G35, based on a classic Planar design, offers a natural field of view suitable for documentary and everyday photography, while the G45 is known for its high resolution and image concentration. Both lenses remain widely recognized for their consistent and reliable optical performance.

Design Concept

As digital photography became dominant, Contax G camera bodies gradually fell out of regular use, but the optical value of G-series lenses has remained highly regarded. Many G-series users are also Leica M photographers, and the G35 in particular has long been considered a highly suitable focal length for the Leica rangefinder system. Early conversion solutions often required irreversible modifications to the original lens, which could compromise the integrity of the optical assembly.

In August 2019, Funleader collaborated with Mr Ding Studio to introduce a non-destructive conversion solution for the Contax G35. The main goal was to allow G-series lenses to be used on Leica M cameras without altering the original optical block. By installing the optical assembly into a dedicated Conversion Helicoid, users with basic technical skills can complete the conversion and achieve reliable rangefinder coupling, delivering an experience close to that of a native Leica lens.

Building on this approach, Funleader released a non-destructive conversion solution for the Contax G45 in May 2021, incorporating a vintage-inspired design language to create better visual integration with Leica M cameras.

Technical Notes

The current Contax G45 conversion kit was released in June 2024. It is based on the 2021 non-destructive G45 conversion concept, maintaining the original optical structure and conversion logic while optimizing the lens barrel’s external manufacturing process.

Compared to the previous generation, the 2024 version introduces more rational edge radii along the barrel, improving handling during mounting and everyday operation while maintaining visual continuity when attached to a Leica M camera. The focus ring edge has been reworked with an angled chamfer profile, enhancing finger placement stability and consistent torque throughout the focus travel.

In addition, the anodized surface finish has been refined. By adjusting the anodizing parameters, surface layer density and uniformity have been improved, resulting in a more stable and consistent appearance under varying lighting conditions while increasing long-term durability. These updates do not affect optical performance or internal mechanical alignment.

Compatibility & Notes

• Designed for original Contax G45 optical assemblies, with no optical modifications   

• Conversion process is non-destructive, preserving the original lens components       

• Fully supports rangefinder coupling on Leica M cameras                                       

• Optical performance remains consistent with the original Contax G45 lens               

• Updates focus on external structure and surface finish without affecting operational logic or system compatibility