This is almost just too good to be true, but according to Philip Bloom, the soon-to-be-released Metabones Speed Booster for Sony E-mount and Micro 4/3s system will increase the maximum aperture of a full-frame lens by 1 stop, widens the focal length of the lens, and increase MTF resolution of the lens!

So for example, a Nikon 50mm f/1.8G FX lens will become a 35mm f/1.2 lens with the Speed Booster adapter! A Canon TS-E 17mm f/4L Tilt-Shift lens now becomes a 12mm f/2.8 ultra-wide tilt shift lens!

The Speed Booster adapter also allows for electronic aperture control and lens stabilization, but not AF. The adapter also houses 4 lens elements/optical system to focus all the light to the smaller image area.

Below is a diagram that shows how the adapter shrinks area of coverage of a full-frame lens. An APS-C sensor and a m43 sensor can utilize the smaller coverage of a FF lens, and the m43 sensor should be able to utilize APS-C lenses as well.

Image Circle Comparison

The video below by James Miller demonstrates how a Canon 70-200mm f/2.8 II effectively becomes a f/2.0 lens when mounted on the Speed Booster adapter.. There is a clear difference when using f/2.8 through a standard EF to E-mount lens adapter and f/2.0 through the Speed Booster adapter.

Metabones Speed Booster lens test from James Miller on Vimeo.

So will this adapter be worth it? I think so, especially since wide-angle lenses with fast aperture can be expensive. However, the Metabones Speed Booster will not be cheap. The retail price when it is expected to ship later this month from is $599.

Be sure to read Philip Bloom’s article to see his sample images and read a more in-depth look to the Metabones Speed Booster adapter.

You can also read more about the adapter on The E-Mount version is the first to come out, followed by the Micro 4/3 and Fuji X-mount. If you want to read the technical white paper, it is available for download.

UPDATE:’s Image Sample Test Between Sony NEX-7 with Metabones Speed Booster adapter vs. a Canon 5D Mark III.

EOSHD metabones-to-5d3-comparison

These EOSHD image were taken with both cameras and a Canon 40mm EF f/2.8 STM Lens shot wide open. As you can see, the DOF of the APS-C NEX 7 (top photo) matches that of the Canon 5D mkIII’s DOF (bottom photo). The NEX 7 recorded the lens as a 28.4mm f/2.0..

To read the rest of the test, visit

Metabones Statement 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.