Been experimenting with the video function on my 5D but have run into problems with the camera seemingly auto correcting exposure the second I hit the record button. I am shooting in Manual mode and if i want to change exposure I'll do so myself I don't want the camera making adjustments for me.
I'm not sure what I'm doing wrong, and I even updated the firmware to version 2.0.7 hoping that the problem would be fixed but no such luck.
Here are some examples of video I took showing the issue.
(Notice the First 2 or 3 seconds) Neither of these are me changing exposure.