Originally posted by filoxophy Pardon my ignorance, but do any of the OEMs license their lens AF/communication protocols? I thought it was all reverse engineered...
Others replied aleady but yes, OEM do licences mounts.
They do not, however (at least Pentax) license flash system stuff: Metz is reverse engineeering PTTL and this leads to frequent problems.
Sigma doesn't play the game at all
which isn't a problem (compatibility wise) for Pentax. Ask Sony/Canon users ..
But... until now Samyang did use older mounts because of free (expired patents) which is why Nikon lenses went AE after a time.
But Canon lenses have never communicate with Canon bodies AFAIK hence the fully manual aperture and stop down metering (if there's a meter at all).
So, license or not ?