Endless is the stream of programs that have, over the last 70 years, documented the life of Queen Elizabeth II. Yet “Portrait of the Queen” takes on a unique angle, examining the creation of the queen’s public image by, in its most effective moments, speaking to a handful of photographers who have taken her portrait throughout her reign.

It’s a relatively interesting perspective to use in considering a monarch who remained obstinately inscrutable from her coronation in 1953 to her death in 2022, at 96. Indeed, the documentary’s most illuminating beats come from the photographers’ recollections of private moments with the queen, when they observe her guarded persona punctuated by flickers of vulnerability.

Unfortunately, these scenes are few and far between in a film bogged down by superfluous sequences and formal inconsistencies: an overused, tonally confused score; two narrators (one of whom is a too-moodily-shot Charles Dance); and talking-head interviews that flit…