DxOMark, possibly the biggest sensor database in the world, proclaimed Nikon D800 sensor being the best one that DxOMark ever analysed. The 4.7um-pixel, 36.8MP full-frame sensor has shown 14.4 stops DR, color reproduction comparable with medium-format sensors and won score of 95 - the highest ever score in the database.
Comparing with Canon's older generation 6.4um pixel 5D Mark II, the 4.7um D800 shows notably higher SNR:
Comparing with Canon's older generation 6.4um pixel 5D Mark II, the 4.7um D800 shows notably higher SNR: