It doesn't even have to be printing large. I was at a concert and had to use a 50mm lens. I had to crop one photo so much that with a 12mp camera I really don't think I would have it for the purpose I wanted it (I would probably have it just as good at a smaller size but I would have no use for it then). It was borderline but usable with the 24mp. Actually I didn't think I could use it but then saw even that extreme crop was ok. It wasn't the end of the world and I could manage overall with a D700 (or whatever other camera) but this is worth it to me to have the D600.