There are people who regard the suggestion – made by David Hockney, among others – that Johannes Vermeer used optical tools in the creation of his paintings as a heresy. This is a puzzling stance. Easels, brushes and palettes are all man-made devices. Are they not? Must we demand that all artists be cave painters?

Those purists will be driven to apoplexy by this workmanlike documentary from arch-magicians Penn and Teller (Penn Jillete presents and the economically named Teller directs). Tim Jenison, inventor, tech-wizard and self-made millionaire, sets out to prove that, using the technology available to the painter, almost anybody could have created his masterpieces. "It's possible that he was more of an experimenter, more of a tinkerer, more of a geek," the bearded polymath claims.

You certainly couldn't describe Mr Jenison as a member of the idle rich. He has time on his hands, but he's not shy of putting in the hours. Tim spends many months building a full-scale model of Vermeer's The Music Lesson , constructing a historically viable camera obscura, rigging up a mirror and copying the projected image with laborious precision. He even learns Dutch to assist in his researches.

Shot on grainy video, with some indifferent sound, Tim's Vermeer is an amusing study of obsession in action. But it's hard to tell what point is being made. It's giving nothing away to reveal that, at the end of it all, Jenison delivers a perfectly serviceable version of the great painting (though the director is cautious not to place it beside the original).

Tim is, however, no sort of ordinary Joe. Observing the fanatical way he goes about his business and the ease with which he conquers complex practical problems, we are left in no doubt that – like the Vermeer of legend – he is his own sort of genius.

Almost none of us could do what the Dutch master did. Very few could, even after watching this enjoyable film, replicate Jenison’s mad experiment.