Am I crazy to speculate that the reason 5D MK III has pillar boxes around HDMI output is because that is what the sensor actually resolves. We all guessed 1080 mode resolves around 800 lines and of course, Canon will never admit to this. Maybe, just MAYBE, this clean HDMI firmware HAS TO include the sensor resolving more lines in order to output 1080 image.
Back to Alpha 2. Gradual ISO works great. With MK III's silent mode, it's quiet and smooth!