(I think) Dr Neuro explained fairly persuasively that the x1.3 crop on the 1D4 vs the FF 1DX is essentially meaningless. Cropping a 1DX file in post to a x1.3 value will deliver a file almost indistinguishable from the 1D4 file. Want to chime in here Dr Neuro?
No chance of this i'm afraid
have a look at the iso samples indicating the crops here with the 18MP vs 16MP
edit: if you apply a 1.3 crop to the 1Dx resolution of 5184 x 3456 you get 3987x2658 which is 10.6 MP or basically the 1Dmk3
The ISO samples on the TDP review aren't relevant to this issue - those are scaled equivalently across sensor resolutions (i.e. the more MP, the bigger the image). The issue being discussed is what happens when you crop the FF image to the FoV of a 1.3x crop, or even a 1.6x crop. The answer is that for approximately equivalent sensor technology, the images aren't too different in terms of IQ, although obviously with the cropped image you end up with far less resolution after cropping. The crop magnifies the effect of IS noise, alters the DoF along with the framing, etc.
Put another way, if you buy a FF camera but then have to crop all your images to 1.3x or 1.6x FoV, you're throwing away the IQ advantages of FF over the smaller sensors, and so you might as well just get the cheaper camera (from an IQ standpoint). Conversely, if you only need to crop a few of your images, the IQ with the FF will be a decided advantage. That might mean getting longer lenses to compensate for the loss of 1.3x crop...which suits Canon just fine...
So if I am able to frame what I need with FF or the 1.3, then my IQ (image quality, not my intelligent quotient will be NOTICEABLY improved over my 7d images? I am not a pixel peeper but when I enlarge posters to 16x24, should I expect cleaner/sharper images, or at this size, is it only a theoretical advantage?