Originally posted by Rondec But I still think the question is what happens when you print at a given size or view at a given size .
Well, sizing doesn't have anything to do with it, Rondec, because the noise and dynamic range are the same whether they're from the cropped portion of a frame or outside it. A RAW file is a RAW file, and the pixels don't know where they are on the sensor.
As for resolution, if the output device is, say, 150 dpi, if you resize there is no difference in a 5x7 print or a computer monitor.
You would need to go to A3 to see an effect.
If you resize down to 8Mp, there is no change in noise or dynamic range, either. That's impossible.
There are folks around here who are uncomfortable with postprocessing. But to the rest of us, that's part and parcel of photography.
So if you're not just resizing, you're also doing some sort of postprocessing that includes downsampling, in poor light conditions you'd expect to see about a stop's difference between your K-5 and K-1. Alright, it destroys details too, but the idea is that details aren't random, noise is, and so to a point, averaging is desirable.
You can see from my night concert shot above, I think it was worth my money to chase that marginal improvement. And you obviously feel the same about your very delicate landscapes. If there's anyone we should crowdsource a 645Z for, it's you, Vincent!