SIMMOUNT MAMIYA 645 - EF CONVERSION MOUNT

Medium format lenses were never designed for modern EF camera systems.
This is how you integrate them properly.

The Simmod SimMount Mamiya 645 to EF Conversion Mount is a precision-engineered system that converts Mamiya Sekor C 645 lenses into a native Canon EF mount, allowing seamless use across a wide range of cinema and still camera platforms.

A True Mount Conversion

This is not an adapter sitting between lens and camera.
This is a direct mount replacement system.

The SimMount replaces the original Mamiya 645 mount with a dedicated EF interface, creating a rigid, unified connection. By removing intermediary adapters, it eliminates tolerance stacking, reduces mechanical play, and improves overall system integrity.

The result is a lens that behaves as if it was originally built for EF.

Built for Mamiya 645 Lenses

Designed specifically for Mamiya Sekor C 645 lenses, this system allows you to fully utilize medium format optics within modern EF-based workflows. (simmod)

These lenses are known for their unique rendering and image coverage. The SimMount makes that character usable in a controlled, professional environment.

Precision Engineering, Maintained Accuracy

Each mount is CNC machined to exact tolerances, ensuring:

• Accurate focal flange distance

• Full infinity focus range

• Proper optical alignment between lens and sensor (simmod)

Without this level of precision, medium format lenses lose consistency. This system preserves it.

Durable, Production-Ready Construction

The SimMount is built from a combination of:

• Solid brass EF mount for strength and long-term durability

• Knurled billet aluminum sub-mount for secure handling and installation

Every component is designed to maintain rigidity under real production conditions, from handheld setups to fully rigged builds.

Why It Matters

Adapters allow lenses to fit.
Conversions allow them to perform.

With the SimMount Mamiya 645 to EF Conversion:

• Your lenses become native to EF camera systems

• Mechanical stability improves across all shooting conditions

• Focus accuracy and repeatability are preserved

• Medium format optics become viable for modern production

Installation Approach

The conversion process involves:

• Removing the original Mamiya 645 mount

• Installing the SimMount sub-mount and EF mount

• Fine-tuning alignment using included shims

No optical changes are made. Only the mechanical interface is upgraded.

The Simmod Approach

Simmod does not build shortcuts. It builds systems that elevate performance.

The SimMount Mamiya 645 to EF Conversion Mount is designed to bring structure, precision, and reliability to lenses that were never intended for this level of use.

Medium format character, now aligned with modern EF workflows.