It seem that Metabones started a trend with their Speed Booster focal reducers that allow you to use 35mm full frame lenses with their original field-of-view and one extra stop of speed on your APS-C camera. After the Chinese company Mitakon with its Lens Turbo, now the German/Chinese co-op between Kipon and IB/E Optics–the people responsible for the über-fast 40mm f0.85 mirrorless lens we recently reported on–have come up with another take on the same idea, which they named the ‘Baveyes.’ Wow. First ‘Handevision,’ now ‘Baveyes.’ What’s next?
Anyway, back to the topic. The Baveyes adapter, which will adapt Leica R, Canon EF and Nikon F-mount lenses to Sony NEX or Fuji X cameras, sports an 0.7x focal reducer optic which will turn any 35mm full frame lens into the equivalent needed on APS-C to yield the same fiel-of-view as on a full frame camera. With the added benefit of exactly one stop extra light gathering capability. In that regard, it is very similar to the Metabones Speed Booster and the Mitakon Lens Turbo, only that each company uses its own specific focal reduction ratio.
So what exactly does the device do? (For those not familiar with the general idea of a focal reducer.) When you put a Canon 50mm f1.4 lens on the Baveyes adapter, its focal length and relative aperture will both be reduced by a factor of 0.7x, so it will be turned into a 35mm f1 lens. On an APS-C sensor, a 35mm lens acts roughly the same in terms of fiel-of-view as a 50mm lens on a full frame camera. So you get the same (original) field of view, but a faster aperture which means faster shutter speeds at lower ISOs.
The adapters will be available from January 2014, which is next month, and will retail for around US-$300. That places them right inbetween the Lens Turbo and the Speed Booster.
Via Mirrorless Rumors