Quote:I know AF protocols in Nikon, Canon and Pentax cameras are proprietery (hence the common AF issues with 3rd party lenses). I assume it is the same with Sony and Fuji.Didn't Sony release the specs (how much of them is another story) and invite everyone to the party a while ago - back when their limited lens lineup was the second most popular target for bashing after Obamacare? That was when a bunch of companies have subscribed, but most were only making "dumb" lenses that they would have still been making otherwise. That Samyang has released its first AF lenses in the E mount is a pretty good indication that the arrangement is working.
On the other hand, MFT is open.
Are you saying the Sony FE AF protocol is fully open? I'm doubtful.
Of course, the 4/3 and µ4/3 mounts are a different story since they were a collaborative effort from the get go. But in both cases, the story is similar because the second tier manufacturers are for some reason reluctant to release AF lenses, even though they've been greenlighted to do so (Sigma has made 4 lenses and that was it; Tamron has made exactly one for each mount and Tokina was nowhere to be seen).