Jonathan Winters has an inviting interstate of a pure American face etched in pure pouches and clover dimples that, aside from the inevitable swelling of age, has changed very little in the past fifty years. He conveys jokes with the deceptively leisurely delivery of your grandfather telling you a tall tale. These two qualities, also shared by the great actor Walter Matthau, may have taken you far as a comedian or a light entertainment actor in the 1950s or the 1960s. But the 21st century’s less elastic notions of masculinity and comedy no longer allow for such talents to persevere.

This is a great shame. Because James David Pasternak’s flawed but fairly entertaining mockumentary Certifiably Jonathan (only just being released in New York, despite being in the can for four years) shows that the old man still has it.

The film opens with Winters sitting in a makeup chair, preparing for a talk show appearance. He asks the makeup lady how long she’s been married. “Twenty years,” she replies. “Well,” Winters improvises, “there’s no sense in getting out if you’ve been in that long. It’s a disease that doesn’t go away.”

Now if you laugh at that answer (and I certainly did), you’re probably over the age of 35 and you’re probably going to enjoy Pasternak’s little movie for what it is. While Certifiably Jonathan makes several disastrous attempts at low-rent improvisational Curb Your Enthusiasm-style scenes featuring Winters refusing to leave Jeffrey Tambor’s home, Winters golfing with Ryan Stiles, Winters with Sarah Silverman at the video store, and every member of the Arquette family who has ever worked in the acting business, it does succeed as a somewhat accidental chronicle of changes in contemporary comedy.

Winters, incidentally, was married to Eileen Schauder for 61 years (until her death in 2009). She’s seen in the film twice: young and dutiful in an archival clip and, in recent years, where she and Winters are sleeping in different rooms. “She snores,” quips Winters, who then commends the many pictures of himself in his room and the fact that they can both appreciate different Presidents this way. Much like his face, Winters’s comedy before the camera is like a familiar friend who hasn’t changed too much over the decades. His wife, on the other hand, wants the cameras to go away by the time Pasternak comes around.

The film’s “story” is about Winters trying to pursue a late-life art career. But as Winters’s website reveals, he’s actually been painting for quite some time. His art, featuring frequent coat hangers and neatly aligned bunches of blunt metaphors, has been making the rounds since the 1970s.

When the film forces Winter to be funny, it is uninteresting. Pasternak, a man who cannot carry a convincing screen moment to save his life, has this obnoxious tendency to want to “act” with Winters. And one greatly wishes that Pasternak had blown his vanity on a midlife crisis Camaro rather than taking the spotlight away from an underrated comedic legend.

What Pasternak does not understand is that Winters is simply funny, and especially funny when Certifiably Jonathan enlists old television clips. There’s one clip featuring a series of improvisations with a stick that uses the same comic science that Robin Williams famously employed with a pink scarf on Inside the Actors Studio. Both Winters and Williams are funny. But Winters came first. I can’t find the specific Winters clip Pasternak uses on YouTube, but this marvelous clip of Winters monkeying around with a pen and pencil sit should give you an idea just how much debt Williams owes Winters. At one point in the film, Winters confesses that Williams gave him an $8,000 watch as a gift. “He should,” says Winters. “He stole a lot of my material.”

Pasternak does manage to get Williams and Winters together for a number of scenes. But strangely enough, Winters has better chemistry with the tremendously underappreciated Howie Mandel when the two men are running around a Target. The footage appears to have been shot shortly before Mandel sold out to become a game show host (and who can blame him? Mandel almost quit showbiz in 2004), but Mandel squeezes his entire body into a shopping cart and is just as quick with the quips as Winters. These two men want to make each other look good. And that’s what great comedy is about.

Jonathan Winters certainly deserves a first-rate documentary. I don’t think this one entirely cuts the mustard, but better Certifiably something than nothing.