I have the RRM adapter, the one with the 9 volt external battery pack. When it works,it works fine. Not for run an d gun scenarios , on a tripod with stationary speakers. NOT WORTH THE $600 i paid for it, First day on trying it out, my lens wouldn't release. had to go back to RRM. Then a month later the cable broke. If was was under $300 , i would buy it. Hoping Metabones makes a non Speedbooster EF-to m4/3 live mount.