Just seeking some clarification on the ISO performance DX versus FX. By way of background, I shoot a lot of low light shots mainly of my little boy (soon to be joined by his little sister) with my D7000. I'm not in any major hurry to upgrade to FX but will head in that direction. One thing that may sway me though is the ISO performance. I'm very happy with the noise up to 1600 on the D7000, but above that the loss of detail is noticeable. My question is - if I were to go FX (say D600) my thinking is that I should pick up about 1 full stop of ISO performance so that 3200 on the D600 would be roughly equivalent to 1600 on the D7000. Is that roughly right or am I dreaming?