[vlad]

This product sure looks promising. Long story short, it makes mirrorless fullframe.

Specialist accessory manufacturer Metabones and optics company Caldwell Photographics have jointly announced the 'Speed Booster', a lens adapter for for mounting SLR lenses on APS-C and Micro Four Thirds mirrorless cameras that reduces the focal length by a factor of 0.71x and increases the maximum aperture by 1 stop.

http://www.dpreview.com/news/2013/01/14/...ss-cameras