I open a .NEF image from my Nikon D80 in the Windows Photos app (the modern/"metro" style app). I then zoom in, and it re-renders or something to display higher resolution, but the colours become less saturated, and the contrast decreases slightly. I presume it first opens the embedded jpeg, then draws the NEF file when I zoom in.
What puzzles me the most is that if I open the NEF in Photoshop and save it as a jpeg, the colours and contrast seem to be in between the first and second (zoomed in then out) previews in the Photos app. Interestingly, the Windows Photo Viewer (desktop app) displays the NEF similarly to the 2nd screenshot, but slightly differently.
So my question is this: why the discrepancies? (Apologies for poorly-worded title)
I have attached screenshots (seen in the Photos app) below:
^ The first preview that opens in the Photos app
^ The second (zoomed in then out) preview in the Photos app
^ After converting into a jpeg