I realize that this is a highly specific question but it isn't a random request. I'd like to get a second Sony camera to to use as a low light alternative to my A850. So what I'd like to quantify is how the High ISO (1600 to6400) raw files for each camera compare in low light conditions. I've seen some comparisons of jpegs and some high ISO raw files under normal lighting conditions but I couldn't see very much difference (possibly a one stop advantage for the A580). I'd love to hear from someone who has both cameras and has done some comparisons of this type.
Thanks for your attention