The lens itself is great, I love it, it's sharp even at f2.8. Metal, no plastic parts. The aperture is smooth not clicking. Very contrasty compared to Tamron 17-28mm and 28-75mm, and much more colorful, it just blows your mind. But there is a drawback, not only for me, but also for other people who own it from another place, there is some loosening of the focus ring, which leads to a lack of focus, or the infinity focus is at 40cm and at 1 meter it is already out of focus. at infinity, it's very blurry. Of course, anyone with a small screwdriver can adjust it, it's easy to do, and it's not a big deal. It takes less than 15 minutes. But the inconvenience of having to calibrate the lens yourself, write to the seller, who writes to the support so they replay back to me how to do it. This should been done at the manufacturing, I didn't like it at all. Overall the lens is great, calibration is done in 15 minutes if needed, but not everyone needs calibration.