The ARRI PL Lens to Canon RF-Mount T Cine Speed Booster ULTRA 0.71x from Metabones uses an advanced 5-element/4-group optical design, incorporating ultra-high index tantalum-based optical glass to achieve optical performance with improved corner sharpness, less distortion, and reduced vignetting. The Speed Booster ULTRA has a magnification of 0.71x and makes effective use of exotic materials at the furthest limit of glassmaking technology, and as a result, is well corrected for use with virtually all full-frame SLR/Prime lenses regardless of exit pupil distance.