I have a Leica R lens F2 with Leitaz conversion to EF mount, then modified by Duclos for cinema use. On my BM Ursa Mini it works great. When using on Canon 5dmk3 it has problems; it sometimes( most of the time ) won't let u take a picture, the shutter becomes unresponsive. When using on Sony A7R2 with Metabones adaptor, it sometimes won't let u take a picture, and then when shooting video it sometimes records for 1 second and then stops. With both cameras sometimes it will continue working for a few frames after turning camera off, taking lens off, and then turning back on. Any suggestions?