Tokyo's principal photography museum usually holds three different exhibitions at once, drawing on both its extensive collection of Japanese artists and images on loan. Shows may include the history of photography, retrospectives of major artists or surveys of up-and-coming ones.
The museum is at the far end of Yebisu Garden Place, on the right side of the complex if you're coming from Ebisu Station. There's a branch of the excellent art bookshop Nadiff here, too.