Tue 13-Nov-12 11:03 AM | edited Tue 13-Nov-12 11:06 AM by walkerr
It sounds like you're mixing up two different settings: D-Lighting and ISO.
D-Lighting won't be read by anything other than Nikon software when shooting NEFs, but it's easy to replicate its results with most raw processing programs and do it more precisely. Raw processing programs will often have highlight and shadow sliders or a means of adjusting mid-tone brightness and those are what you use, coupled with a good exposure. Where D-Lighting might be handy is if you shoot in a jpeg format since that file format doesn't allow for highlight recovery and is less flexible at recovering shadow details.
ISO is not dependent on the software you use and changing that setting will certainly change the results. It's the same with any digital camera and any software - the D3X is no different than your other Nikon bodies. In fact, that's true for the D-Lighting feature as well.