Metabones and Caldwell Photographic have joined their forces and created a new optical accessory, designed specifically for ASP-C and MFT mirrorless cameras.
The new Metabones Speed Booster is supposed to be mounted between a mirrorless camera body and a SLR lens. The optical and lenses design is made by Brian Caldwell, the man behind Caldwell Photographic Inc. He explains in Metabone Speed Booster’s white sheet, that the new accessory does somewhat the same thing as a teleconverter, only backwards: instead of increasing the focal length and f/ stops, it decreases them.
Speed Booster has a focal length multiplier of 0.71x, resulting in an increase of one aperture stop. Combining Speed Booster’s focal length multiplier with an ASP-C mirrorless camera, results in a total FF (Full Frame) lens-to-image crop of almost 1:1, or full-frame view. This means that by using a full-frame lens on a ASP-C sensor camera, while having the Speed Booster attached, it will make the image look like it’s shot with a full-frame camera.
Unfortunately, the new adapter is available for usage only with Canon EF (EF-S not supported) lens on Sony NEX camera bodies. It delivers auto-aperture, image stabilization, WXIF and autofocus. Shortly after the official release, there will be support for Leica R, ALPA, Contarex, Contax C/Y and Nikon F lenses. It will be available from January 2013 on Metabone’s site and its worldwide dealer network, at a price of $599.