Lens Adapter Ring for Mamiya 645 M645 to Canon EOS R - Full Metal Fit

In this review we look at the Lens Adapter Ring that lets photographers mount Mamiya 645 M645 lenses on a Canon EOS R full frame camera. The bottom line: this is a no-frills, solidly built mechanical adapter for users who want to reuse Mamiya medium format glass on a Canon EOS R body; it delivers a precise fit and maintains infinity focus while requiring full manual control. If you need electronic coupling or autofocus, this adapter is not for you, but for manual shooters it makes older lenses practical and reliable on modern EOS R cameras.

Key Features

• Full metal mount: Solid metal construction provides a rigid connection that prevents play and ensures durable long-term use.
• Manual operation: Supports full manual focus and aperture control with camera set to shoot without lens or stop-down metering for accurate exposure.
• Compatibility: Specifically lets Mamiya 645 M645 mount lenses achieve infinity focus on Canon EOS R full frame bodies while preserving correct registration distance.
• Secure fit: Precision machining produces a snug, gap-free connection so the lens does not wiggle or require adjustments after mounting.
• Simple package: Single-piece adapter includes no electronics, minimizing failure points and keeping the adapter lightweight and reliable.

Who It's For

This adapter is aimed at experienced photographers and enthusiasts who already own Mamiya 645 lenses and want to use them on a Canon EOS R for their distinctive rendering and build quality. It is ideal for manual shooters who are comfortable setting exposure in Manual or Aperture Priority and using stop-down metering.

Photographers who rely on autofocus, electronic aperture control, or in-camera lens communication should look elsewhere for an adapter with electronic coupling. Studio users who need integrated EXIF reporting or lens stabilization will not get those features from this purely mechanical ring.

Pros & Cons

Pros

• Robust full metal construction provides a secure, wobble-free mount.
• Designed to reach infinity focus and preserve registration distance for CRC and floating-element lenses.
• Simple, reliable design with no electronics to fail or require compatibility updates.

Cons

• Requires manual focus and manual aperture control; camera must be set to allow shooting without a lens.
• No electronic communication means no autofocus, no EXIF lens data, and stop-down metering is required.

Specifications

Brand	Foto4easy
Mount In	Mamiya 645 M645
Mount Out	Canon EOS R (Full frame)
Material	Full metal mount
Operation	Manual focus and aperture; no electronics
Infinity Focus	Designed to maintain infinity and correct registration distance
Package	1x Lens Adapter Ring

Our Verdict

The Foto4easy Lens Adapter Ring is a practical, well-made option for photographers who want to put Mamiya 645 glass on a Canon EOS R body. It delivers a precise, solid mount and preserves infinity focus, making it good value for manual shooters and creative users who prioritize optical character over electronic conveniences.

Frequently Asked Questions

Will this adapter allow autofocus?
No. This adapter has no electronic elements, so autofocus and electronic aperture control are not supported.

How do I meter with the lens attached?
Set the camera to allow shooting without a lens and use stop-down metering or manual exposure modes for accurate exposure.

Will the lens reach infinity focus?
Yes. The adapter is designed to maintain the correct registration distance to reach infinity and support CRC or floating-element lenses.