Im wondering if they have actually changed the focus motors too? Im not very technical when it comes to this stuff but their press release states that the AF is optimised for Sonys hybrid AF system and I thought thats what the adapted canon mount versions struggle with? So in addition to bolting a spacer on the back with the sony mount do you think they have changed out the motors and kept the lens elements and the casing? Could that be what took time?
seriously doubt it
from what I can tell about the Sigma 30 e-mount, it has a loud focus motor for video, so it's probably USM/HSM style. The conversion service exists! So they'll swap out the mount for $80-250, with that sort of price, doubt they'll change out the focus motors as well.
I'm sure they can make it work with USM motors, because it does eye AF just fine as is, however it wont be optimal and probably wont track as well as native with STM motors.
That said, I'm happy with the AF ability of the lens, would love if it were stepper motor for the occasional videos I do with it, but I have workarounds like shooting the 85 in crop mode if I really need faster Video AF.

But I did throw a cover over the top for the camera.



