I spent this weekend checking out the ISO performance of the Sony A35, and also against the A580 just for kicks. The A35 does a great job at dealing with noise, and it’s pretty much a draw between the two cameras as to which one is ‘best’. For starters, I posted the RAW performance in one column, then the
fine jpeg in the second, and finally the multi-frame noise reduction feature. Some reviewers are claiming Multi-frame NR will allow you two extra stops equivalent in ISO, so a multi-frame ISO 6400 shot would be as clean as a single shot ISO 1600; that’s total BS based on my use, although if you look at my crops you can determine you will gain almost a full stop, which is pretty darn good too!
If you have a Sony A100 (which has awful high ISO performance), try shooting an ISO 1600 shot, and then a single shot ISO 6400 shot with the A35 or Sony A580, or a multi-frame ISO 12800, there probably isn’t much difference.