Jordan Steele:

However, Sony didn’t stop with those improvements: they’ve introduced a new shutter mechanism, rated for 500,000 actuations and with much lower vibration than the original A7R. Plus it gains electronic first curtain shutter and completely electronic shutter capabilities. They also added 399 phase-detect autofocus points to the sensor, which should give improved AF, even compared to the A7 II. The biggest thing with the new AF system? Adapted A mount lenses can use the PDAF autofocus system and focus as quickly as on the native DSLR (or at least as fast as the native E-Mount lenses can focus. DPReview noted that their testing even showed Canon EF mount lenses via the Metabones EF-E adapter to utilize the PDAF points and focus as quickly as a native Canon body. This is HUGE. Canon shooters can switch over now and use their lenses with near native AF speed if they so choose.

If this checks out it’s going to be huge indeed. Up until now, the only thing stopping me from buying one of the A7-series cameras had been the slow AF performance of adapted Canon glass. If this new AF system is indeed able to match the AF speed of native Canon bodies, many people are going to start wondering why the hell they should stay with Canon.