Thanks for your very helpful reply. I accept that the D4 is the better choice for wildlife photography but given that I already use a D3s and am looking for a smaller/lighter FX camera to carry around that only leaves the D700 or D800. So the question is which of these to go with? I would have thought the D800 is generally a better camera than the D700 (newer technology and so on)and would be the better choice. Or perhaps I should wait for a true successor to the D700??