Mounted between a mirrorless camera and a SLR lens, Speed Booster® increases maximum aperture (hence its name), increases MTF and makes lens wider. Optics designed by Caldwell Photographic in the USA (patent pending).

Sony NEX Speed Booster® Adapters are NOT fully compatible with full-frame Sony A7 or A9 series. When Speed Booster® is used with Sony A7 or A9 series, the camera is required to be used in "APS-C Size Capture" mode.

Metabones® celebrates Speed Booster®'s 10th anniversary from January 14, 2023, with a 20% discount on all Speed Boosters, limited to the first 500 units only.