Posted by James Miller on January 13, 2013 •
(...) "I have been using the Canon EF to E mount adaptor from Metabones / Conurus since they released them last year. They were revolutionary, as they were the first Canon to E-mount that interfaced with your camera. The iris was controlled via the camera, the adaptor was powered by the camera and IS also worked. It’s compact, cheap and works…not on every lens – the odd one did strange things, but version two is a big improvement.
At the beginning of the year, I was emailed by them asking if I wanted to borrow and test out a revolutionary new lens adaptor for EF to E mount. I said yes but to be honest, I couldn’t imagine what could be revolutionary about another one of their adaptors…ND maybe? I then received it. I was puzzled, as it looked the same but had glass at the lens side, not open like the current one. How could that be a good idea, and what does it do. Not long after that I found out via another email with an attached white paper. It was called the “Speed Booster”. What on earth is a speed booster?!?"
Via Thierry Saint-Paul