D700 with One Lens

[K3N]

I guess this reply might be too late but if you are going to photograph Elephants in Chiang Mai you might like to have that 70-200mm VR. It might also be useful for some portraits of Karen people etc.

 

[G Zero]

Agree with N above, Tamron 28-300 VC ver, just post process with stauration and one mask or two on sharpest, no worrys in B&W thou. Do aware there is foucs hunt in low light, low contrast or dusty 1005 pixels RGB sensor. But I'm also tempted to use Sigma 12-24 HSM, just to get that extra wide perspective or extra end of reach in crowed place. Cheers.