Photography sales have saved many charities from extinction but the recent explosion in number has induced auction fatigue. Nothing about this collection arouses that.

The third edition of A Positive View —
a fundraiser for homeless charity Crisis
— takes the form of a gallery exhibition
at Somerset House and a viewing at Christie’s during the week of the auction, which takes place on 15 April.

The 118 photographs set a remarkable standard. Curator Nadim Samman has hung work by Chinese, African and Korean photographers, and legendary, emerging and unknown ones.

Those by homeless students from the Crisis Skylight photo-mentoring project are equal to many university graduates; Stella Labo Joseph’s depiction of light in her hostel room — filled with trapped flies — forms a poignant metaphor for her life.

Fifty Pence Diptych is by the homeless Paul Kelly, who paid his subjects 50p to expose their battered faces.

The most talked-about of this group is Jeff Hubbard, whose life-sized portrait appears alongside Prince William’s in a well-publicised shoot supervised by Rankin. Hubbard’s mock salute matches the prince’s coy pose, reminiscent of his mother’s portrait by Mario Testino.

William’s presence as Crisis patron inevitably contributed to the quality of the donated images, but Samman’s enthusiasm also prevents the stale over-familiarity of some auctions. Ranging in price from £500 to £20,000, the works include Henri Cartier-Bresson’s Seville, 1933, showing boys playing in an alley (on reserve at £15,000). There is also work by Elliott Erwitt, J P Masclet, Juergen Teller (Porn series), and Robert Polidori’s wrecked New Orleans.
Exhibition runs until 5 April. Tel 020 7845 4800; www.crisis.org.uk.