Thank you for Your constant support to Tokina brand.
We found functional issue with Tokina opera 50mm f/1.4 FF (Canon EF mount) and Canon EOS-1D X Mark II combination, that results in exposure problem.
We are asking for your cooperation in contacting the camera shop where the lens was purchased, or your local Tokina official distributor for further firmware upgrade procedure.
Should you have any other questions, contact us via contact form.