Canon Mount Adapter EF-EOS R

The Canon Mount Adapter EF-EOS R is a straightforward optical adapter that allows photographers to use their existing Canon EF and EF-S lenses on Canon’s EOS R series mirrorless cameras, preserving compatibility with a large existing lens ecosystem when transitioning to Canon’s RF mount system. It’s designed as a simple, no-compromise bridge between the two mounts rather than a specialty adapter, making it the standard choice for most photographers moving from EF-mount DSLRs to EOS R bodies.

The adapter maintains full electronic communication between lens and camera, preserving autofocus, image stabilization, and automatic aperture control exactly as they function when an EF or EF-S lens is mounted directly to an EF-mount body. There is no optical element inside the adapter itself, meaning it introduces no image quality degradation, change in effective focal length, or light loss, functioning purely as a mechanical and electronic pass-through. This differs from the Control Ring and Drop-In Filter versions of Canon’s mount adapters, which add extra functionality but at a higher cost and, in the case of the Drop-In Filter version, additional bulk.

Build quality matches Canon’s other lens mount hardware, with a metal lens mount on both ends of the adapter for a secure, precise connection to both the lens and the camera body. The adapter maintains the original lens’s minimum focusing distance and magnification, since it simply extends the flange distance to match the EOS R system’s shorter mount-to-sensor distance rather than altering the optical path in any way.

Because it supports full EF and EF-S lens compatibility, photographers can carry over their existing autofocus lenses, including USM, STM, and older micro-motor designs, without any loss of functionality on EOS R bodies. This makes it a practical option for photographers who want to adopt EOS R mirrorless cameras while continuing to use lenses they already own, or for those building a mixed system that spans both EF and RF mount lenses.

Key Features
– Adapts Canon EF and EF-S lenses to EOS R mirrorless camera bodies
– Maintains full autofocus, image stabilization, and aperture control
– No optical elements — no image quality loss or light loss
– Metal lens mounts on both ends
– Preserves original lens focal length, minimum focusing distance, and magnification
– Compatible with EF and EF-S USM, STM, and micro-motor lenses