Quote Originally Posted by Keith B
So if I understand correctly, ISO 160 on my 5D mkII isn't necessarily a bad thing as 125 would be?

Correct.


Quote Originally Posted by Keith B


But 200 would be better and then bump my lights down a third. Right?

I wouldn't call it "better". Think of ISO 160 as "ISO 200 with +1/3 EC". ISO 200 with +0 EC is better in that it has slightly less highlight clipping, but it's worse in that it has slightly more noise. If you use them with the same light (fixed exposure), and ignore the meter, then they both result in the same SNR and dynamic range.