[thxbb12]

The D4 sensor is better in higher ISO than the D600/610. The D4 sensor is a nice sensor.

 

The D4 sensor has only a slightly better DR (less than 0.5 stop) at 1600 ISO and above. On the other hand, from ISO 100 to 800, the D610 is better by quite a margin (1.5 stops at base ISO).

Also, the D4's SNR figures are not any better than the D610's at any ISO.

Plus, the D610 has higher resolution.

 

That being said, the D4's sensor is good too, just not as good B)