I would recommend a book entitled "Crisis of the Real" by Andy Grundburg. Andy is a former photography critic for the New York Times. The book discusses photographic modernism at great length, but this is in the context of describing what post-modernism is in photography. It's pretty thick with critic-speak, but if you are interested in these topics, it a good place to start.
Below is a description of the book.
http://journalism.nyu.edu/portfolio/books/book400.html
Bookmarks