One might expect Coppola’s proximity to the material to lend it a measure of intimacy. Here is the woman who attended his earliest shows in the 1990s, appeared as a muse in his 2000s campaigns and orbited his scene throughout. But both subjects — if we can call Coppola a partial subject of her film — mostly come across as guarded. Two creative decision makers more at ease behind the scenes, they are, perhaps, not the most natural chroniclers of their own careers and social lives, and as the film goes on, it strains to arrive at even the most basic personal revelations.