AFAIK, the show was filmed on film like any other, but they were trying to be forward-thinking so they did some nice things like filming in widescreen even when they knew there was (at the time) no market for a widescreen TV show. But they fell for the hype of "digital" so they had all of their camera film scanned shortly after it exited the cameras, and then they edited and mastered the series digitally (in standard definition).
So now the only "cut" of SG1 is an increasingly-worthless digital SD one.
Now if they want to do a remaster, they'll have to bring directors back in and "re-cut" the entire show, this time using actual film cutting, on top of the usual expenses of doing a remaster (basically just re-scanning the film in HD).
