Featuring an advanced 5-element/4-group optical design incorporating ultra-high index tanatalum-based optical glass to achieve extraordinary optical performance with improved corner sharpness, distortion and reduced vignetting. Plus aperture ring covers a 8-stop range markings, clearly indicating actual number of f-stops.
Like the revolutionary original Metabones Speed Booster announced in January 2013, the Speed Booster ULTRA has a magnification of 0.71x, and so it effectively reduces the crop factor of mirrorless cameras with DX-sized sensors, such as Sony E-mount and Fuji X-mount cameras, from 1.5x to 1.07x. However, the new ULTRA design makes very effective use of exotic materials at the furthest limit of glassmaking technology, and as a result is well corrected for use with virtually all fullframe SLR lenses regardless of exit pupil distance. Thus, the Speed Booster ULTRA performs extremely well with professional-grade f2.8 zoom lenses such as the 24-70mm f2.8 and 70-200mm f2.8 zooms by Canon and Nikon to produce 17-50mm f2.0 and 50-142mm f2.0 high-speed zooms, respectively. Similarly, high-speed fixed focal length lenses such as a 50mm f1.2 will be transformed into a 35.5mm f0.9 lens with excellent contrast and resolution from the centre all the way to the edges of the image.