One problem that came about in the making of this film was that the casting had to be re negotiated and some characters had to be changed, for example Jennifer Lawrence replaced Rebecca Romijn as mystique.
Brian singer was the director of this film and was also the director of all the previous X Men films and "The usual suspects." Singer originally turned down the offer because of the fact that he didn't know about the comics.
Filming took place in Washington DC purely because it was where the film was set. The film was also filmed digitally.
The music label for this film was sony