I shot this after my BMPCC Speed Booster finally arrived. When I mount the Tokina 11-16 f2.8 DX2 to it, I can notice a big problem with sharpness in the center, especially when wide open. The corners, ironically, seem to be way better. Even when stepped down, the sharpness is not really good. Does anyone else have that problem and/or a solution for it?