Lens Mount Adapter K&F SB6419 — Canon EOS R/RA/RP to M42 (M-42) mount

The K&F SB6419 lens mount adapter allows photographers to attach M42 screw-mount lenses to Canon EOS R, RA and RP mirrorless cameras. This mechanical adapter provides the correct flange distance and secure connection for manual-focus and manual-aperture M42 lenses, enabling use of classic optics on modern EOS R-series bodies. It does not add electronic communication; exposure and focus are controlled from the lens and camera manually.

Advantages

The adapter is constructed to maintain accurate flange focal distance and firm mechanical fit between lens and camera body, preserving infinity focus with compatible lenses. Its simple, all-mechanical design is durable and lightweight, making it convenient for field use. By enabling M42 lenses on Canon EOS R, RA and RP cameras, the adapter expands creative options and access to a wide range of vintage optics without altering lens characteristics.

Suitable for

• Photographers who want to use vintage M42 screw-mount lenses on Canon EOS R, RA and RP cameras
• Manual-focus portrait, landscape and street photography with adapted lenses
• Creative projects requiring distinctive lens rendering, vignetting or flares from classic glass
• Users adapting lenses for video work where manual focus and aperture control are acceptable

Key specifications

• Mount type: M42 (lens side) to Canon RF (camera side)
• Compatibility: Canon EOS R, RA and RP mirrorless bodies
• Design: all-mechanical adapter without electronic contacts
• Material and finish: metal construction for mechanical stability
• Function: maintains correct flange focal distance for infinity focus with compatible lenses

How to use

Attach the M42 lens to the adapter by screwing the lens into the M42-thread side until secure, then align and mount the adapter onto the Canon EOS R/RA/RP camera body, turning until the adapter locks into place. Set the camera to manual exposure or an appropriate exposure mode to allow the use of manual-aperture lenses. Use focus assist aids in the camera, such as focus peaking or magnification, to achieve precise manual focus. Check framing and exposure in the viewfinder or on-screen and adjust aperture and shutter speed as required.

Usage recommendations

For best results, verify the adapted lens achieves infinity focus on your specific camera body before critical shoots and use focus peaking or magnified live view to ensure accurate focusing. Because the adapter lacks electronic communication, confirm exposure settings manually and consider using a tripod or remote release for slower shutter speeds.