Fujifilm S2 Pro has a
6.0MP APS-C (23 x 15.5 mm ) sized CCD sensor . On the other hand, Nikon D200 has a
10.0MP APS-C (23.6 x 15.8 mm ) sized CCD sensor .
Below you can see the S2 Pro and D200 sensor size comparison.
Fujifilm S2 Pro and Nikon D200 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.