The motion blur shows up at medium length exposure times (which is incidentally the same speed as I want to shoot most pictures at) around 1/3rd to 1/200th of a second. And is the worst at 1/10th to 1/30th of a second.
Its not a problem with external vibrations in the rig, as the Live View shows a perfectly still and sharp image. Lengthening the exposure to 2 seconds provides a sharp picture as the initial vibrations dies off quickly enough to not show up. Cranking the ISO up to 8000 to get an exposure time of 1/2000th of a second also gives a sharp image, however its hard to tell how sharp it would actually be if the high ISO noise wasn't there.
Updated the camera firmware from 1.1.7 (or whatever it was) to the newest 1.1.8 version, and used the "Clear all camera settings" (although this seems to have done nothing). Also restarted it several times.




Info on the settings, if its of any help?

The problem is not always occurring, as I thought it was fixed the other day when I changed some things to try to figure out where the blur originated from. After changing the diffuser and subject (and maybe some settings on the camera, I sadly cant recall), the image at 1/15th of a second suddenly got sharp 2 minutes later. But as its now back again I realise its something I need to figure out.
a cropped 100% view of the change:

Anyone know what to do about this? I've tried searching the forums and google, but using the terms "live view/LV 6D shake blur problem" etc etc gives me a lot of hits of how good the Electronic First Shutter Curtain is for removing problems with shake/vibrations.
Grateful for any help or input!
/Alex