A BOY sits astride a cannon, slightly askew. The vista beyond is Edinburgh’s Princes Street, punctuated by towers, the tall symbols of male authority and power. The photographer lines up the barrel in the centre of the composition to emphasise its dominance but the boy looks uncertain and vulnerable with this phallic symbol between his legs. This is as much a disconcerting image of puberty as it is an icon of Edinburgh. Welcome to the arresting and provocative world of Robert Blomfield, as revealed in his book Edinburgh 1957-1966. The street photographer is a paradox. He is a presence that must efface himself in order to reveal the world and the instant that he captures is both ordinary and unrepeatably universal.