Lens Compatibility. The Metabones Canon EF to Canon RF Speed Booster T Ultra allows full-frame Canon EF and third-party EF-mount lenses to be used on crop-frame RF-mount cameras like the Canon EOS R and EOS RP that can not shoot full-frame 4K video. This adapter does not support the Canon R5 or R6.

Camera Compatibility. This adapter offers limited autofocus, image stabilization, and aperture control with the RF-mount Canon EOS R and EOS RP cameras and Canon EF-mount lenses. For more information, you can check the manufacturer’s compatibility list here.

Wider Focal Length and Increased Aperture. This version of the Speed Booster widens the mounted lens’s focal length by 0.71x, reducing the Canon EOS R’s UHD 4K video capture crop factor from 1.75x to 1.24x and reducing the Canon EOS RP’s UHD 4K video capture crop factor from 1.63x to 1.15×. It also increases the mounted lens’s maximum aperture by 1 stop. This Speed Booster wasn’t designed for still capture, but it’ll work with a compatible camera set to APS-C mode. You can’t use this Speed Booster to capture 60p FHD video.

Electronic Communication. The adapter’s mount has electric contacts that allow you to use compatible lenses’ autofocus, aperture-control, and image-stabilization functions. For most lenses, the adapter doesn’t require a separate power source, and EXIF data is transferred and embedded into your footage.

Sturdy Design with Built-In Tripod Foot. The aluminum-alloy barrel and brass mounts give it a solid feel, with an Arca-Swiss compatible tripod foot that lets you mount the adapter itself directly to a tripod. This ensures the lens’s weight doesn’t put additional stress on the camera’s mount.