Originally posted by Rondec Of course. But the question is if you have a K5 image at iso 1600 and a K-1 image at iso 1600 (or whatever iso) and you print both of them to an 8 by 10, can you tell the difference. What I have found is that after iso 800 the K-1 image will look better. Downsampling or not, you just see the noise in the K5 pixels more easily than you do in the K-1 image and at a certain iso level, it really starts to make a difference. The end result is that you have a little better than a stop improvement in iso you can shoot for the same size printing.
I think that matches closely with what I said in post 32, Vincent:
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.
Just in this thread, Mee and BarryE seemed a little underwhelmed by the K-1 vs APS-C images they've taken at good light levels, and Rupert thought even at poor levels.
Expectations must be understood by looking at the RAW files and their SNR and Dynamic Ranges, which is DxOMark's Screen tab.
Biz-engineer found the pics hard to tell apart at ISO 400 ... these pics, like all JPEGs, have certainly been downsampled. See if you think one is twice is good as another!
K-1 vs K3, which is which - PentaxForums.com
And even at ISO 6400, you can see if that's also true in the famous Imaging Resource RAW files:
The superiority of FF over APS-c re: Depth of Field - Page 12 - PentaxForums.com