Extremely unsettling and thought- provoking, Yael Hersonski's "A Film Unfinished" puts an unfinished, hour-long film shot in Poland's Warsaw Ghetto in 1942 under the microscope.

Discovered in the Nazi archives after the war, the black-and-white images were originally considered a valuable document showing the lives of the half-million Jews who were quarantined into less than three square miles awaiting shipment to concentration camps months later.

But a reel of additional footage discovered later demonstrated just how much this "reality" was shaped by SS officers supervising the cameramen -- scenes were elaborately staged, sometimes with actors, and often filmed in multiple takes.

The film, simply labeled "Ghetto" and abandoned for reasons lost to time, was a piece of propaganda apparently aimed at justifying the Final Solution by showing well-off Jews callously ignoring the plight of others who were literally starving to death in the streets.

"A Film Unfinished" adds context by interviewing survivors who recall the monthlong shoot in Warsaw, which included a lavish, phony party in a restaurant juxtaposed with more genuine footage of residents stepping around corpses on the sidewalk.

The filmmakers have also tracked down one of the cameramen, Willy Wist, who abandoned his calling after working on this film. He provides a chilling eyewitness account of just how far the Nazis were willing to go to manipulate the truth -- staging riots and an elaborate funeral for the benefit of the camera.

Anyone who's ever seen a "reality" TV show knows the camera can easily be made to lie. "A Film Unfinished" honors its subjects by revealing the horrifying truth behind these 68-year-old images.

In its latest boneheaded move, the movie ratings board has slapped this film with an R rating because it contains a fleeting scene of nudity set in a ritual bath. Shame on them for making it harder to use this remarkable documentary as a teaching tool.

NEW YORK POST is a registered trademark of NYP Holdings, Inc.