I own a subject for more than a year, during which, finally, I understood two things. 1. Do not expect razor sharpness from him. So, in comparison with the Tamron 28-75 III on the Sony a7r2, it loses both in sharpness and contrast. But it wins significantly in terms of plasticity, bokeh, in short, in terms of pattern. Both for different purposes. 2. There was also a back focus. In the chamber (d750) there was an amendment of -11. Then, through the usb station, I ated the firmware both in the camera (12022) and in the subject (2.009), the adjustment was not needed, because. beat exactly. But, now the main thing, which almost no one writes about. When using the YN622II controller and AF illuminator (red grid) at 1.4, the focus smears. The controller also has the latest firmware (1.09). The same is true when using a Nikon flash light. Solved by turning off the backlight of the controller. Conclusion. The glass is magical, but requires careful attention, especially when fully open. Razor sharpness does not appear on the pursed hole, but the pattern is no longer the same.