Tom Hogan is banging on about MP again but I have never seen my view on the subject discussed or validated.
12MP I have a friend who does portraits D700 85mm lens ..superb detail
24MP I use a D7100 for most of my wedding shots 5-8 people superb and my wife who does the processing likes to crop to perfection.Nikon 18-140
36MP now if I use the D7100 and a 10mm lens for big scatter groups (30 people spread over a 15x15 yard area) or a heart shape 60 people the definition is terrible,,you would not want to zoom in on an individual. Now use the D800 with an old $60 sigma 17-35mm D and the results are superb. I am sure a nikon lens would do a better job but I am here to make money not spend it
So I do think the wider you go the more MP you need and wide FX lenses must be easier to design than DX retrofocus and all that.
I also conclude that using the Nikon lens with the nikon camera is the way to go because of the built in corrections
I have not seen the wider you go more MP required expounded elsewhere so have you experienced the same ??