Zhong Yi Optics has now also announced three Speed Booster Clones, or focal reducers for Nikon mirrorless cameras. The so-called Mitakon Lens Turbos have been around for a while now and basically enjoy the reputation of offering good image quality at a much lower price compared to the original Metabones SpeedBoosters. Currently, three new versions are offered for the Nikon Z cameras, which can adapt Canon EF, Nikon F or M42.
The principle of this focal reducer remains the same: the adapted optics are "reduced" from the image circle area of a full-frame sensor to the area of typical APS-C/S-35 sensors, making the optics appear wider-angled by a factor of 0.726 and increasing the speed accordingly. A 50mm F1.8 full-frame lens with Lens Turbo interposed on an APS-C sensor then appears roughly like a 35mm lens with F1.2.
The Mitakon Lens Turbo Adapter Mark II for Nikon Z Cameras (APS-C)
At first glance, however, this Lens Turbo is hardly interesting for filmmakers, because there are currently only two Nikon Z cameras with APS-C sensor (Z50 and fc) - neither of which shine with particularly high-quality video functions. In addition, the Lens Turbo Adapter Mark II for Nikon Z is purely passive, i.e. active lens functions such as autofocus or aperture cannot be used. Especially for Nikon F lenses, this would certainly have been an interesting option for some Z system switchers.
Nevertheless, these Lens Turbo adapters could enable interesting niche applications for some Nikon users. First, there's recording with passive lenses beyond the actual image circle, as we detailed 
in this article five years ago.
And then there is also the possibility of filming in APS-C crop on many Z cameras (DX mode). Whether the new Lens Turbo makes sense for these applications is best decided by which special optics you have access to as a filmmaker.
The Mitakon Lens Turbo Adapter Mark II for Nikon Z Cameras (APS-C) can be ordered in three versions from the manufacturer's web store for 149. However, Mitakon adapters are usually available in Europe via alternative sales channels (e.g. Ebay) at much lower prices after a short time.
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