After switching from CANON to SONY a7III, there were lenses ( 17-40 f / 4, 70-200 f2.8) / Expensive, hard to sell and not very bad. The variant with the adapter caused tears when hovering and focusing. Sony demanded a transition to their system. Tamron, in whose owners Sony, came to the court as well as possible)). Everything is built in it to get the result, there is no unnecessary and superfluous. Supports everything put in the camera, you stop thinking and being distracted. Eye tracking autofocus works great. The percentage of marriage has decreased to negligible. That is, if he says that he has aimed at his eyes, then it is so. Reliable partner. You can rely on him. And cheaper than the show-off Canon, Sony, Carl Zeiss. Definitely!