Even the tightest sets can't control everything, which can be awkward for studios but fun for fans who want an early look at what's going on with their favorite movies.
On an unoffcial Facebook fan page for "Man of Steel," viewers can get a sense of what things look like.
For now, the studio has no comment on the pictures.
Zack Snyder is directing the movie, which, in addition to Cavill, stars Amy Adams, Kevin Costner, Diane Lane, Julia Ormond and Laurence Fishburne.
It's been shooting in Chicago and Vancouver and is set for a June 14, 2013 release date.