Irvin777,
здесь ваше спасение...
http://web.canon.jp/imaging/eosd/fir.../firmware.html
EOS 5D MarkII Firmware Update Version 1.0.7
Firmware changesFirmware Update Version 1.0.7 improves and mitigates the following two types of image quality phenomena that occur under certain shooting conditions.
1. "Black dot" phenomenon (the right side of point light sources become black)
2. Vertical banding noise