I am using the Nikon 300mm f/4 AF-S lens with TCs on the D200 for photographing wildlife. When the available light is low, even the fastest available (effective) aperture may not yield a fast enough shutter. Under these conditions, is it better to: (a) use a low ISO and underexpose the picture and then pull up the EV in post processing with Capture NX (upto a max of +2 EV using exposure compensation and then levels), or (b) use high ISO and expose normally. In both cases, there is amplification leading to noise. What are the differences in these processes and the character of the noise? Is one approach better than the other or are they both equally bad in the sense of removability of the noise in post-processing using noise-reduction software like Neat image? Thanks.