When using an L plate on the Metabones EF to E (Canon to Sony NEX) adapter there is insufficient clearance for some lenses to be mounted. For me the ZE100 and Canon 70-300L. It is also insufficient room to mount the adapter plus lenses on a monopod. I did not want to use the camera L plate as I don't think the camera mount itself is strong enough. I obviously did not want to test till it broke to find the limits either.
I asked Chris Hejnar, http://www.hejnarphotostore.com/, iof he could help. I sent a sketch of what I thought would work and after a couple of little "try this, change that" he came up with the perfect L plate for the Metabones.
This little additional height gives plenty of clearance for lenses as desired.
Chris has made a few extras in case anyone else needs one but I'm not sure if he has them on his web site yet. And I get to pay for mine as well. in case you are wondering.
well you should scream at Metabones as that adapter is a less then adequate sdesign and execution for what it is supposed to do in the clearance department at best. Hejnar should be highly praised for resolving said design inadequacy.
in case you are wondering.