Exposure Correction for Automatic Iso in Manual Movie Recording Mode

[lonavera]

Hello,

i'd like to set the shutter and aperture manually in movie recording mode, but the iso should be determinated automatically. Where can I correct the "target brightness" (I don't know how to call that) for the ISO-Automatic? For example if i want to record within a low light athmosphere and automatic iso the picture will be to bright and I want to get it darker.

Thanks for any help in advance
lonavera

[butchdon]

Still no answers for this question? I've searched the web and found nothing there either. It sure would be nice if I could get my 6d to do this.