I don't go higher than 640 iso on any camera. Even on the Red Scarlet I told my DP not to go higher than that. So yeah that's sensors for me. I'm not a run-gun shooter I take time for my shot. I rather shoot on a 7D with poor low light performance than a BMPCC with HOT pixels on the native 200ASA. Maybe I have bad luck.... But if you read the black magic forums and reviews you see that more people had "bad luck".
I shot on the GH2 in poor low light conditions with good fast lenses with limited dynamic range and still I had very good images. With GH2 I never go higher than 320 iso.
Not sure thats the smartest piece of advice i've ever read...
The Reds native ISO is 800, thats where it performs best, the Canons native is at 100 and the native steps are 100, 200, 400, 800.
A colleague of mine liked 640 on the 7D too, but we've decided to be rather careful about it after looking at the DXO information about the camera.
"Low light performance" is a misnomer, its a non technical way to describe lots of different things. Lots of people have this obsession with tiny ISOs or clean files at stupidly high ones. Neither is totally smart. Dynamic range will be best at native speed settings, there should a be a good reason for not being there.
Remember that these days you can get rid of a bit of noise, you can't fix a badly lit scene, or recover a scene without sufficient dynamic range.
