Metabones T II ULTRA Speed Booster T 0.71x Adapter w/ Support Foot for Canon EF-Mount Lens to Sony E-Mount (MB_SPEF-E-BT4) Review

The Metabones Speed Booster T II ULTRA 0.71x adapter bridges Canon EF glass to Sony E-mount bodies, a well-established solution for hybrid shooters and filmmakers who want to retain their EF collection. The 0.71x optic design widens the field of view and increases maximum aperture by approximately one stop, effectively turning full-frame Canon lenses into faster, wider equivalents on APS-C Sony sensors. The T II ULTRA generation uses Metabones' advanced five-element optical design to minimize aberrations and maintain edge sharpness. The integrated support foot is a practical addition for balancing heavier telephoto lenses on smaller mirrorless bodies. Electronic contacts pass through autofocus and aperture control, though performance varies by lens and camera generation. At $288, this sits in the mid-range of the Speed Booster lineup and competes directly with alternatives from Sigma and Viltrox, but Metabones remains the reference standard for build quality and optical consistency in the speed booster category.