Method of fix the focus problem
If you have a focus problem that out of focus in one side.
It might be not parallel with lens and sensor.
Please try this method of fix the focus.
Remove the lens holder
Long screws for left and right side.
Short screws for top and bottom.
Put on the spacer ring between the lens holder and body.
Spacers are punching metal that bundled inside of the lens box.
These are different thickness.
Please attach the lens holder again.
If you do not have a spacer, you can use patch of paper instead of the punching metal.
Check the focus on a Monitor
Please connect the camera and monitor with a HDMI cable and check the focus.
When you calibrate the focus you would better use a focus checker.
Please check around the image circle.
This is trial and error solution to solve the problem.
If could not get right focus, please change the spacer position or thickness and check the focus again.