I usually use LV display (found in Expo tab) 'Photo, Expo sim' as I mainly take photographs and want all shutter speeds. If I have selected that mode and start recording movie (even in M mode) exposure varies by scene, so it's actually not manual exposure anymore. Could this be fixed some how, maybe by automatically changing LV display to 'movie' when recording starts and back to previous mode when recording ends?
It's a bit strange behaviour because it work as supposed in standby (exposure follows manual controls) but when recording movies, exposure becomes automatic.
This is normal Canon behavior and can't be changed easily.