Alan Yentob and Annie Leibovitz's sister Barbara present an intimate portrait of the American photographer who, now in her fifties, is still universally in demand from pop stars to political leaders, rabble-rousers to royalty.Those who have not heard her name will certainly have seen her pictures - from a naked and pregnant Demi Moore to Bruce Springsteen's famous Born in the USA album cover, or a naked John Lennon next to a fully clothed Yoko Ono.And in her personal life too, Leibovitz has veered from the customary path by having a lengthy relationship with the late Susan Sontag and giving birth at the age of 51.