A silent and mild-mannered photographer drives into the woods to capture pictures of the local insect life – only for an Instagram model to fall out of a nearby tree. It reads like the opening to some kind of over-the-top comedy. Part of the genius of Woman of the Photographs, a new Japanese drama premiering at the Osaka Asian Film Festival, is that while the set-up is amusing the story it sets up is soaked in longing and sensuality. It is lightly but profoundly unsettling. It is the sort of artistic gem that sticks in the mind long after the film itself is done.

Hideki Nagai plays Kai, a solitary middle-aged man. He runs his father’s photography studio, and spends his days capturing portraits and then digitally retouching them to remove perceived flaws and imperfections. His passion, however, is insects. He photographs them, studies them, and dotes on his own pet praying mantis. Kai does not speak, and is awkward around strangers. He also does not like to be touched. Everything points to a past trauma, and Nagai does an exceptional job of playing both his stiffness and his underlying fragility.

When Kyoko literally falls out of a tree, Kai tries to drive her to the nearest hospital – she has been cut very badly below her left collarbone – but instead she insists on going to chemist to mop up the injury herself. She then insists on taking him to dinner, and then equally insists she be able to sleep the night in his house. On it goes: Kyoko never leaving, and Kai digitally retouching her Instagram posts to remove any sign of her wound.

What seems like a stereotypical romance, in which an outgoing attractive woman “saves” a lonely and emotionally damaged man, soon shifts into a far more interesting type of story. Kyoko’s own emotional troubles are revealed – masterfully played by Otaki Itsuki – and Kai’s own vocation of manipulating photographs to distort reality is interrogated. This also plays out via two sub-plots involving supporting characters: one a single woman (Toki Koinuma) obsessed with changing her image for a dating website, the other a funeral director (a superb Toshiaki Inomata) ordering idealised portraits of the dead to use at their memorials. The former provides a comic highlight. The latter leads to the film’s most touching and haunting moments.

Kai’s praying mantis is prominent enough to seem a supporting cast member in its own right. The idea of the female mantis eating the male after mating draws comparisons to Kai and Kyko’s growing intimacy.

Director Takeshi Kushida instils the film with a growing portion of fantasy sequences, each sensitively conceived and effectively realised. It is combined with a relatively formal cinematography – like much of Japanese cinema it sits in Ozu’s shadow – and together it forms a deeply impressive aesthetic and tone. It provides a powerful insight to its protagonists, and moderates the pace to a languid height. It is a film that the viewer can not just watch but also soak themselves in. It is deeply romantic, gently tragic, and enormously effective.

Woman of the Photographs makes its world premiere at the Osaka Asian Film Festival.