Timphoto wrote in post #18985545
I can't speak to the original A7, but on the A7R2, R3, and R4, my go to adapter has been the Sigma MC-11. I also have a Metabones IV, but the MC-11 is 1/2 the cost of the MB and in most of my use, the MC-11 works just fine.
Klystron wrote in post #18985564
I would say a Sigma MC-11. But if your using manual focus or dont care about quick AF then get a cheap Ebay version. I use one with a couple of manual focus lenses.
Bill in Texas wrote in post #18985573
I used the MC-11 on the original a7 with a Tamron 150-600 and it did ok.
Thanks guys 
Sony 70-200/4 is about £850 upwards used.
Canon 70-200/4 is about £330 + adapter
MC-11 is about £185 new so that's up to £520
^^^ Both about the same weight with adapter, Canon will be bigger (because of adapter only) Canon is 67mm filters (72mm Sony) 
I think the Tamron is priced around £1000 supposedly...... But then it's FE mount, f/2.8, hopefully 67mm filters.... Looks like I could be letting the 85mm go.....