Much like death and taxes, the shower scene in Alfred Hitchcock’s Psycho simply is—an immutable, brilliantly cruel sequence that forever diminished Hollywood’s standard rubber monsters and brought horror into the most intimate of environments. Even if you’ve never seen it, you’ve seen it.

The documentary 78/52—the title refers to the fact that the scene in question required 78 camera setups and 52 cuts—is the best type of film nerdery: an informative, enjoyably obsessive dissection that somehow leaves the subject wholly intact. Beginning with an amusingly candid interview with Marli Renfro, the long-anonymous body double for Janet Leigh, director Alexandre O. Philippe assembles a murderers’ row of directors and editors, then lets them dig in. The resultant mixture of personal anecdotes and professional opinions make for an intriguing, breezy primer on how to read a film, pointing out Hitchcock’s career trademarks (those god’s eye shots! all those birds!), as well as illustrating the threads of voyeurism and repeated maternal references burbling throughout Psycho. Thankfully, whenever the conversation starts to get too Reddit-y pretentious, the topic switches to something like how the sound department spent a day stabbing a variety of melons in order to get exactly the right thwack. (For the record, Hitch favored casabas.)

Entertaining as these digressions are, however, the best moments in 78/52 are when the various interviewees are simply watching the scene for the umpteenth time, pausing to marvel at the editing, wonder about small details (how exactly do you shoot a shower nozzle head-on without splashing the lens?), and sometimes just sitting back and gawking at how expertly they’re being manipulated. At a time when so much film discussion is spent trying to retroactively one-up filmmakers and paper over imaginary plot holes, movies like this one show that it’s still possible to be taken in. Ree! Ree! Ree!