Mounting between a mirrorless camera and an SLR lens, the Speed Booster adapter from Metabones and Caldwell Photographic increases maximum aperture by a full stop (hence its name) and has a focal length multiplier of 0.71x. This essentially means that full-frame SLR lenses can be used on a compact system camera with an APS-C sized sensor with (almost) the same angle-of-view coverage as originally designed. For example, a 28mm lens becomes a 19.9mm with the Speed Booster - if you then mount it on a camera with a 1.5x “crop factor” you’ll end up with a 29.8mm equivalent solution. The first Speed Booster enables users to mount Canon EF lenses to Sony NEX bodies, with auto-aperture, image stablisation, EXIF and (slow) autofocus support for post-2006 Canon-brand lenses. It will be available in later this month from Metabones’ website and its worldwide dealer network for $599 plus shipping and applicable taxes and duties.

Metabones Press Release

Metabones and Caldwell Photographic Introduce Speed Booster

Petersburg, VA, USA, January 14, 2013 - Metabones® and Caldwell Photographic jointly announce a revolutionary accessory called Speed Booster™, which mounts between a mirrorless camera and a SLR lens. It increases maximum aperture by 1 stop (hence its name), increases MTF and has a focal length multiplier of 0.71x. For example, the Canon EF 85mm f/1.2L II lens becomes a 59mm f/0.9 lens on a Sony NEX camera, with increased sharpness. The faster F-stop allows for shallow depth-of-field and a lower ISO setting for decreased noise.

Speed Booster is also particularly pertinent to ultra-wide-angle SLR lenses. The combined focal length multiplier of Speed Booster and an APS-C mirrorless camera is approximately 1.09x, making the combination almost “full-frame”. Full-frame ultra-wide-angle SLR lenses largely retain their angle-of-view on an APS-C mirrorless camera when Speed Booster is used.

The optics of Speed Booster is designed by Brian Caldwell, PhD, a veteran of highly-corrected lens designs such as the Coastal Optics 60mm f/4 UV-VIS-IR APO Macro lens with exemplary MTF performance (focusing done with visible light requires no correction whatsoever for the full spectrum from UV to IR).

Speed Booster serves double-duty as a lens mount adapter, from Canon EF lens (but not EF-S) to Sony NEX, with auto-aperture, image stablization, EXIF and (slow) autofocus support for late-model (post-2006) Canon-brand lenses. It will be available in January 2013 from Metabones’ web site and its worldwide dealer network for US$599 plus shipping and applicable taxes and duties.

Other mount combinations will follow shortly afterwards. Leica R, ALPA, Contarex, Contax C/Y and Nikon F (with aperture control for G lenses) will be supported, as will Micro 4/3 and Fuji X-mount cameras. Support for other mounts will be added in the future.

To learn more details about this revolutionary technology, read the Speed Booster White Paper on Metabones’ web site.

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