Interesting! My first impression was the ISO 6400 image looked terribly noisy; basically useless. It seems to be a characteristic of my browser, or maybe there's some option or preferences box I've not ticked. After opening the full size image in Internet Explorer, one can toggle between a large thumbnail size and a 100% view. I don't understand why the default minimum size (large thumbnail) looks so noisy. When I set any custom size between the default minimum and 100%, or open the image in PS, the image looks much cleaner and very usable.