Can anyone shed some light on the different spellings of Natasha's name? Specifically I'm thinking "Romanoff" versus "Romanov." I was noticing that the AO3 tag has "Romanov" while in the movie they spell it "Romanoff." I suspect it has something to do with Russian grammar/spelling and American bungling of same. There's also the "Natalia" v. "Natasha" thing, which if I understand right she changed when she defected. (Or did I just read that in a fic somewhere and now it's my headcanon?)
And as a follow-up, is there a good case to be made that the movie got it wrong by going with "ff" instead of "v"? Or to put it simply, why deviate from movie!canon?