From the folks over at movieweb.
"Bleeding Cool reports that director Joss Whedon was originally set to shoot most of the East Coast-based Avengers in Manhattan. But now, the time spent in New York is going to be reduced considerably to mostly exterior establishing shots, with the vast majority of principle photography taking place on sound stages in and around Southern California
The move will not only cheapen the cost of having to shoot on location in New York, it will also sufficiently reduce the cost of having to transport and house the A list talent The Avengers has amassed, as most of the actors reside in the Los Angeles area. A great deal of the outside action that takes place in the movie will now either be moved indoors or take place in front of a green screen.
The decision to turn The Avengers into "The West Coast Avengers" (figuratively speaking), will certainly save the production money, but it now puts the New York crews, who passed over other projects to work on this, out of work.
"The Avengers" is set to start principal photography on February 2011.
The Avengers will arrive in theaters May 4th, 2012. Starring Robert Downey Jr., Scarlett Johansson, Chris Evans, Chris Hemsworth, Samuel L. Jackson, , Clark Gregg, Jeremy Rener, Mark Ruffalo. The film is directed by Joss Whedon.