Russell Crowe agreed to do the film with Joel Schumacher when the film was slated to be a "dirty, handheld gritty thriller". Crowe had one stipulation to all this and it was the scene where his character is looking at the kiddie porn and throws it in the trash he throws a cigarette so it would start burning inside the trash can. Schumacher agreed. Then out of the blue, Nicolas Cage's agent called Schumacher and told him that he wanted to do the film as well. Schumacher then contacted John Calley at Sony and told him that we can do the film with Crowe as a "low budget, dirty handheld camera thriller" or a much bigger film with Cage. Calley then agreed to do the film with Cage as the lead which eventually led to a much bigger budget.
The actress (Jenny Powell) playing the character of Mary Ann Mathews was originally a stripper hired to act as a stand-in. Joel Schumacher gave her the part of the victim on the 8mm film as she had a suitably "haunted" look about her.
Nicolas Cage's Oscar award (for Leaving Las Vegas (1995)) makes a cameo in the film. Look for it, wrapped up in black string/laces on Eddie Poole's desk when Cage breaks in to tap Poole's phone.
The location of the final battle between Tom and Machine was a great place to shoot, according to Joel Schumacher, because the neighbors and owners of the house were very hospitable. In turn, Schumacher gave them signed posters of his Batman movies, and t-shirts and assorted gifts for their hospitality.