The D610's Beautiful Sensor
I wondered whether Nikon had snuck in a few tweaks to the sensor when it came out with the D610. I think it did:
Compared to many others I have seen it is beautiful because of how consistent it is throughout the ISO range: consistent effective QE, consistently low PRNU, consistent relative gain. That means outstanding manufacturing quality control. With about 75k clipping and 5.7e- read noise at base ISO it has fantastic DR and noise performance.
I also think Nikon weakened (or dropped) the AA in one direction. And unlike its Sony cousins it looks like it didn't sacrifice the linear ADC ramp to the alter of faster readout, getting a true 14-bit output.
If one shoots raw, knows what they are doing and does not mind adjusting brightness during conversion it also looks like there is very little benefit in raising ISO much beyond 400