As technology progresses, sensors getting better and better, it does not make any sense to go back to full frame. Photographers, pro or enthusiasts want lighter glasses, FF cannot compete on that arena. Pentax K-3 is a winner for many reasons, first is the fact that it requires lighter and smaller glasses(APS-C sensor), and second, it has amazing image quality, auto-focusing system and features. I just tested the camera over the last weekend and this one with couple of long glasses and to my surprise its auto-focusing system is the best! It tracks better and more precise then my Canon EOS 1D X, Mark VI, and 7D! believe it or not that is true, amazing what its 27 auto-focusing sensors do. I am selling all my Canons and all my glasses, especially the heavy ones. I am coming back to Pentax, bye bye heavy stuff! FF... not even thinking about anymore. Pentax K-3 it is, an impressive little camera! more later about that beauty
Oh! by the way Nikon is making a fuzz about investing on FF because it pays patent for canon on almost everything it does to its glasses and they don't want to loose that battle let alone be left behind with that heavy stuff they have! Again, the future is now and that is leaning towards smaller sensors, not big ones. We are living in a moment very similar to the 70s and 80s where the discussion was the same. Oh! are you shooting with 35mm film! Oh no! that is not professional! 6x4,5, 6X6, 6x7 and the likes are pro, better image quality... sure! no doubt about that, but look what happen to those cameras and specially to its glasses when Kodak and Fujifilm launched better and better films, the big glasses lost a lot of market share, because tons of pros started to move to 35mm film cameras! so, to end this, yes the future is now, so instead of moving towards big and heavy glasses (Full frame cameras) it is best to move towards lighter and smaller glasses. I just keep thinking how awesome the Pentax K-1 is going to be
smaller guys! not bigger! Technology is already very good today and it is going to cover us up even better in very near future, wake up! Have a great day