I just caught the Cameron exhibition at the National Portrait Gallery in London and wanted to put in the good word for it. It will be up through may, then moves to the National Museum of Photography, Film and Television in Bradford from the end of June to the middle of September, and then to the Getty in L.A. from October to January. Details at http://www.npg.org.uk/live/cameron.asp
It is great to see what the real prints look like and to see so many of them assembled in one gallery. Despite the allegorical settings, angel wings, and sentimental titles, one really gets a sense that she was photographing the people around her, her children, friends, and friends children, to produce a body of work with strong personal coherence.
It is also refreshing to see how forthright she was about setting aside technical concerns about which most of us tend to obsess. Some of her letters are on display, and in one she responds to critics who objected to her often less than sharp focus with the question, "Who is to decide where to set the focus?" This is still before the age of the soft focus lens, but she did have a sense that this was an artistic decision without an objective answer.
Up close, you can also see how she scraped away emulsion from some of her plates to remove distracting elements or to get a stronger black on the print. Sometimes it is clumsy, but in some cases very effective.
The NPG has an interesting service now, where you can order a reproduction of any image in the collection as well as most of the works from the Cameron show. They have scans stored on a laptop in the gift shop and print them out on a Fuji Pictrography printer. The quality is much better than a four-color poster, and the prices are reasonable. I think I paid about 12 UKP for a 10x12" of Cameron's "Madonna," believed to be a photograph of her eldest daughter.
Also very much worth seeing right now at the NPG is the show of works by Seydou Keďta and Malick Sidibé, two commercial portrait photographers from Mali. Info at http://www.npg.org.uk/live/ylblt.asp