There is a lot of conflicting information about diffraction. A high resolution 36MP sensor is NOT more diffraction prone. Diffraction is solely caused by the lens aperture and it will always be the same regardless of the resolution of the sensor. Of course, the more resolution you have, the more you will see the effects of diffraction evident. When using the same lens with the same aperture, the Nikon D800 will always have more resolution than the Canon 5D Mark III or any other current digital SLR on the market.