There are three galleries offering a change of photographic exhibitions from photographers around the world.
Admission is free and the small gallery can be found at 5&8 Great Newport Street WC2H, tel: 020 7831 1772, website: www.photonet.org.uk From 4th October to 16th November, there is a great exhibition called Brixton Studio which looks at local photographer Harry Jacobs and four other contemporary artists. There's a great bookshop too.
The nearest tube is Leicester Square, so you could combine this with a visit to the great National Portrait Gallery that is close by, followed by a Chinese dinner in China Town, or a film in Leicester Square.