Finally got to see it. The catalogue is worth having and is discounted if you buy it at the Tate. Lots of really interesting early work, including some 19th Century colour photography, some new (to me) documentary stuff from the 60s and 70s by various lesser-known photographers, many of them excellent, and a reasonable selection of less familiar work by well-known photographers. The big disappointment is the contemporary work, virtually all of which is colour, very big, derivative, and bit depressing, with a postmodern wannabe-Martin-Parr-ish cynicism which I didn't like at all (Martin Parr himself seems much more sympathetic to his subjects), and a basic lack of originality. I blame art schools 🙂
Ian