# Sony - Question of a Differing Variety



## JohnDizzo15 (Nov 21, 2014)

Anyone happen to have a technical answer for why there isn't an EF to FE mount smart adapter that allows for usable autofocus speed and accuracy?

The reason I ask is because I own a Zeiss Contax N mount 50/1.4 that has been modded by Conurus (one of the main players at Metabones) which autofocuses very well on all my Canon bodies. This would lead me to believe that Conurus is significantly tapped into the Canon AF protocols somehow. However, every generation of the Metabones smart adapters for EF to FE so far have not been up to par with speed and accuracy of AF. 

Second question is, anyone think that it might be easier to accomplish with the A mount bodies?

Hoping someone here has an explanation for this.

If it were possible at some point to get usable performance with adapted EF lenses, I think full transitions into the Sony ecosystem would be much more painless especially with some of the new features being offered in the latest body announcements.


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## tayassu (Nov 21, 2014)

I am not a technician, but I could imagine that your Zeiss lens has a much less sophisticated AF than modern lenses. I think modern lenses are much more difficult to adapt than old ones.


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## Marsu42 (Nov 21, 2014)

JohnDizzo15 said:


> If it were possible at some point to get usable performance with adapted EF lenses, I think full transitions into the Sony ecosystem would be much more painless especially with some of the new features being offered in the latest body announcements.



It doesn't seem that easy as Canon doesn't release the lens protocol to everyone. Afaik some 3rd party lens manufacturers licensed it, and some tried to reverse engineer it. For the latter group, there's always some hassle and the danger they could have gotten something wrong and the next Canon lens won't work anymore. And Canon certainly won't help Sony/Nikon/Whatever use their lenses, it's one of the few things they've left in the competition.

Fyi the newest Canon bodies (5d3,1dx) and lens generations have enhanced af precision, usable only in this combination. I doubt 3rd party manufacturers have gotten around to tap into this yet.


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## Halfrack (Dec 9, 2014)

Here's the technical answer you're looking for - two different communications protocol methods on either side of the adapter, and you, in the middle have to make them speak accurately, quickly & reliably over many generations of gear. Lenses, bodies and firmeware that have been discontinued will be used, yet you are expected to work every time.

Here's a bit on the Canon side of the equation, and ask yourself, at what price is making said adapter worth wild.

http://www.eflens.com/lens_articles/ef_lens_mount.html


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