Quick answer

The Fotodiox Pro Mamiya RB67/RZ67 to Canon EOS adapter with built-in focusing helicoid is your best choice for mounting medium format lenses on Canon EF/EF-S SLRs, giving you infinity focus and precise manual control without modifying your lens.

Why you need a helicoid adapter for RB67 lenses on Canon

Mamiya RB67 and RZ67 lenses are designed for medium format cameras with a longer flange distance. When adapted to a Canon EOS SLR, the lens sits too far from the sensor to achieve infinity focus without an optical element or a helicoid mechanism.

A helicoid adapter like the Fotodiox Pro model adds a built-in focusing tube that moves the lens forward or backward, restoring infinity focus and giving you a macro-like close-focus capability. This is essential for landscape, architecture, or any shot requiring distant sharpness.

Without a helicoid, you would need a corrective glass element that can degrade image quality. The helicoid approach keeps your lens optics pure.

Trade-offs: Manual focus and no autofocus

This adapter is purely mechanical. You will focus manually using the helicoid dial and the lens's own focus ring. There is no electronic communication with the camera body, so aperture must be set manually on the lens (if it has an aperture ring) or via a separate control.

For studio work, still life, and deliberate shooting, this is a non-issue. For fast action or event photography, the lack of autofocus and auto-aperture can be frustrating. Plan your workflow accordingly.

Decision rules for choosing this adapter

  • You own Mamiya RB67 or RZ67 lenses: This adapter fits both RB67 and RZ67 mount lenses. Check that your lens is compatible; most standard RB67 and RZ67 lenses work. Confirm your lens mount before purchase.
  • You shoot with a Canon EOS SLR (EF or EF-S mount): The adapter is designed for Canon EOS (EF, EF-S) mount SLR cameras. It will not fit Canon RF mirrorless bodies without an additional adapter. If you use a mirrorless Canon, look for a dedicated RF adapter.
  • You need infinity focus: The built-in helicoid allows infinity focus without corrective optics. If you only shoot close-ups, a simple tube adapter might suffice, but the helicoid gives you flexibility. For landscape or general use, the helicoid is essential.
  • You prefer all-metal build quality: The Fotodiox Pro uses precision all-metal construction for a tight, wobble-free fit. Plastic adapters may flex or wear over time. If durability matters, metal construction is a key advantage.

Product facts

Who this adapter is for

Best for

  • Photographers who already own Mamiya RB67 or RZ67 lenses and want to use them on a Canon EOS SLR
  • Studio, landscape, and still-life shooters who need precise manual focus and infinity capability

Not for

  • Shooters who need autofocus or electronic aperture control
  • Canon RF mirrorless camera users (requires an additional adapter)