Umm...overcast shots are not a great way of testing anything, just saying.

how is this a low light test - when there is a very ugly key blasting the talent?

it would be great if they would show some footage from a setup where the lighting is actually controlled and intentional.

also don't care who shot that balloon footage, not great footage and the judder in the balloon (bad operating) and the terrible artifacts in shadow areas also not very compelling. maybe they are trying to show you where the camera fails?

Underexposed areas - like the man's suit and back wall are pretty awful