no difference.
Should I maybe output to prores, or quicktime as prores is not supported in this version.
Post some before and after stills. This may be what THomas was referring to, that if you're using CS5 then it's not as much of a difference versus using ProRes/Quicktime formats. For me, in FCP, it's a huge different. If you're in FCP, then yes, you should be using ProRes 422HQ (or something around that).


