The Metabones EF-E Mount 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. The fifth generation speed booster benefits from positive locking EF mounts.
The ULTRA design makes very effective use of high end materials at the furthest limit of glassmaking technology, and as a result is well corrected for use with virtually all full frame SLR lenses regardless of exit pupil distance. Thus, the Speed Booster ULTRA performs extremely well with professional-grade f/2.8 zoom lenses such as the 24-70mm f/2.8 and 70-200mm f/2.8 zooms by Canon and Nikon to produce 17-50mm f/2.0 and 50-142mm f/2.0 high-speed zooms, respectively. Similarly, high-speed fixed focal length lenses such as a 50mm f/1.2 will be transformed into a 35.5mm f/0.9 lens with excellent contrast and resolution from the centre all the way to the edges of the image. The Speed Booster ULTRA is equipped with a rubber gasket to protect the E-mount connection from dust and moisture. To promote ease-of-use, an LED indicates the adapter’s operation mode, optical image stabilisation operation and communication status. A dedicated switch controls in-body image stabilisation (IBIS) on Sony cameras equipped with SteadyShot INSIDE.
The Cine Speed Booster ULTRA features positive-locking EF mounts that firmly lock the lens in place to prevent any movement of the lens when focusing. This is useful when using a remote focus or follow focus system.
Like all Metabones Speed Boosters, the Speed Booster ULTRA is optimised to fully account for the camera filter stack located near the sensor surface. This is especially critical at the extremely large apertures made possible by Speed Booster technology. As a result of this careful optimisation, an enormous range of full-frame optics ranging from vintage film lenses to the latest digital designs will function flawlessly when adapted to Sony E-mount and Fuji Xmount DX format camera bodies.