This comparison is based upon the Imaging-Resource Still Life standard JPEG ISO test.
There is a greater difference between D200 and D300, than between the D300 and D700.
D700: Sigma AF 70mm f/2.8G EX DG macro, f8
D300: Sigma AF 70mm f/2.8G EX DG macro, f8
D200: Nikon AF 105 f/2.8D Micro, f8