Okay where do I start! My viewpoint comes from having used a Pentax K-100D for the past seven years, and then some fixed lens SLR’s before that. The improvements I see are very good, let me start with the ISO’s. Previously I had only been able to go up to ISO 3200 max, and usable up to ISO 800. Now I think that I can go up to about ISO 6400 usable, with a max of ISO 51200. Here are some 100% crops at every other ISO available.