Considered to be one of the 20th century’s greatest street photographers, Vivian Maier’s genius would not be truly realised or appreciated until after her death – a special fate reserved for many creative minds. This documentary, as the title suggests, provides the microscope with which the world of photography is currently examining the late Maier’s enigmatic life.

Like most ripe fodder for modern documentary makers, the subject’s activities were hidden beneath a veneer. In this case, Maier worked in Chicago as a nanny for approximately four decades while secretly taking 150,000 photographs of the people and architecture of L.A, New York and, of course, The Windy City itself. Had it not been for a chance discovery at a Chicago thrift auction in 2007, the world would still be unaware of the natural flair and keen photographic eye possessed by Maier. The credit for this falls at the feet of John Maloof, who, amidst the daunting task of compiling a historical tome on Chicago’s Northwest Side, came about another daunting task: sifting through the photos, possessions and archival evidence of Maier’s past.

The question is raised numerous time in this documentary: would Vivan Maier want her work to be seen on this scale – to be blown up and shown in galleries in New York, L.A, Chicago, Denmark and the small French towns she would visit from time to time? Of course, it is impossible to emphatically answer this question. The meticulous work of Maloof and his inquisitive cohorts form the backbone of this documentary. His curious and compulsive nature – coupled with the sheer quality of his subject’s work – paint his intentions sincere rather than selfish, even if he does afford himself a healthy portion of unnecessary screen time.

It is clear from Maier’s work that she was someone that operated on the fringes of society, electing to get close enough to her subjects or employees to make a small difference – be it artistically, within the beauty of her portraits and landscapes, or professionally, in the care of the various small children she was charged with looking after. Maloof’s compilation of her life story, or whatever he could glean from the evidence he procured and subsequently interrogated, depicts an intrinsically private woman. But for someone so reticent, she accumulated a wealth of empathy and kind words from those who knew her. Even those who described her as “mean” were moved to speak kindly of the formative years they spent together.

With an artist as intriguing as Maier providing the furtive character on which this documentary is founded on and the painstaking work carried out by Maloof and the ensuing bodies involved in unfurling her mystery, this production delivers on its promise: to find the enigmatic nanny-cum-seminal photographer that was Vivian Maier.