Matthew Blanchette steered me to an even earlier surviving film from Louis Aimé Augustin Le Prince than the one I've previously mentioned, Roundhay Garden Scene. This one is called Man Walking Around A Corner and it dates from 1887 or 1888. Thanks, Matthew! It was shot on an earlier version of Le Prince's camera, this one with sixteen separate lenses. Looks more like a spider's eye than a camera, don't you think?
I've added this note as a postscript to my original essay, but what are the chances you comb through old blog posts looking for updates, right?
Anyway, here's the film. Oh, and check out Matthew's blog, A Day In The Life, while you're at it.