The chapter from Vasily Grossman’s Life and Fate that supplies the text of Frederick Wiseman’s sublime film — which is showing at the Museum of Fine Arts with the cooperation of the Jewish Film Festival — takes the form of the last letter from a doctor to her son that’s written just before she’s to be exterminated along with the other Jews of the Ukrainian town of Berdichev, which has fallen to the Nazis. The letter tells of the Germans’ arrival, the resurgent anti-Semitism among the doctor’s long-time neighbors, the herding of the Jews into a ghetto, what they do and say there. The writer also expresses her love for her son and her thankfulness for his safety, and she describes the discoveries she makes and the dreams and memories that come as she faces her certain death.

Wiseman, who’s known for his vast body of work in documentary (this is his first fiction film), makes no attempt at a realistic representation either of the scenes the mother describes or of her own situation (no shots of her sitting in a room writing, etc.). But La dernière lettre isn’t a chaste film: on the contrary, it’s prodigal with expressive effects, though within strict limits: black-and-white; one actress; one text (spoken verbatim, without abridgment or addition); no musical score and almost no sounds at all other than the actress’s voice; for decor, only the blank surfaces (wall and floor) on which the actress’s shadow is projected.

Another restriction — the fundamental one — is harder to discuss. Catherine Samie’s performance is a tour de force, but it deprives itself of the flourishes expected from tours de force. What’s most striking is the denial of pathos, a denial the more painful for being not quite complete (as I said, the film isn’t chaste). Like its stage incarnation, which Wiseman presented widely during the past several years (at Cambridge’s American Repertory Theatre, at the Comédie-Française, and on a tour that included Cambridge’s Market Theater), La dernière lettre is (at various times, and sometimes at once) a chronicle, a monument, and a passionate cry of love. By doing painstaking justice to each of these aspects of the text, Samie refuses us the masochistic satisfaction of identifying with her character. The film fully respects the line between survivor and victim.

Wiseman chooses to sharpen, rather than blur, the brilliant theatricality of Samie’s performance, with its deliberateness and its spare visual eloquence. Although filmed largely in close shots, some of which are surprisingly sensuous (the film’s palette of grays, though not luxurious, isn’t parsimonious either), La dernière lettre suggests that the actress’s physical presence is distant and subordinated to her compelling voice. When audible, her breaths sound like the sharp, efficient breaths of an experienced actress, not the pathetic breaths an actress might use to portray strain. The film doesn’t refuse strong emotions — we’re shown the real tears that well up in Samie’s eyes and slide down her face — but it refuses to use emotion for escape or self-glorification.

Samie has several voices: some low, dry, and dark, like emanations from a dying planet; others fervent and tender. And Wiseman does much with her shadows, using them as a silent and variegated chorus. By multiplying Samie, he dramatizes the text without invoking the alibis of psychological depth. When near the end of the film the light changes during a shot and the blacks in the frame darken, this heightening of contrast seems to mark the mother’s imminent death as a visual boundary. Wiseman’s visual strategy reveals its scrupulousness in the simplicity of the final phase of the film, as it turns away from artifice to confront death and the survivor’s burden.

With this gesture, La dernière lettre becomes truly moving. For the text’s complicated act of bearing witness is also a letter from a mother to her son. And the great force of both the text and Wiseman’s film is that they speak to us from, and of, two unrepresentable depths: annihilation and that which gives and watches over life; absolute evil and absolute love.