I too am thinking of making the switch. I had a gig in NY and rented both the A7S and 5dIII (had my 5dII as well). I was super psyched to use the A7s with my canon lenses. Yikes, I had so many issues it made my head spin. I wanted to love this camera -- ready to buy one. But one minute it wouldn't even turn on -- the next no f-stop data or non responsive to changes. I have to believe it was the Metabones adapter. I noticed someone above mentioned Commlite adapter ... is this the secret sauce?? Help.