“Focus” opens Friday at Point, Eastgate, Star Cinema and Sundance. R, 1:45, three stars out of four.

“Focus” is like the beginner con artist that Margot Robbie plays in the film — not nearly as smart as it thinks it is, but smart enough to steal the price of a ticket from your pocket without you minding too much.

Stylish, charming and completely implausible, this is one of those caper films where the real man on the inside is the screenwriter, in this case writer-directors Glenn Ficarra and John Requa (“Crazy Stupid Love”). Their capers are so ridiculously elaborate, their twists so outlandish, that we never for a second feel the heroes are in any peril at all. We just enjoy the sleight of hand at work.

Will Smith plays Nicky, a master criminal for whom confidence games and pickpocketing were the family business. When a newbie scammer Jess rather clumsily tries to fleece him at a New York hotel, Nicky is amused rather than upset, and offers to show her a few tips. This leads to one of the film’s two best scenes, in the snow outside Lincoln Center, where Nicky deftly explains the ropes while swiping the same objects off Jess two or three times. It’s like an exquisitely choreographed dance sequence.

Intrigued on both a emotional and felonious level, Jess follows Nicky down to New Orleans, where Nicky is running a 30-person pickpocket team in the weak before a very big football game which is not the Super Bowl because the movie couldn’t get the naming rights. This leads to the film’s other best scene, in which Jess and Nicky attend the not the Super Bowl with a duffel bag of ill-gotten gains, and Nicky gets into an escalating series of foolish wagers with a grinning Chinese businessman (a scene-stealing B.D. Wong).

At first we think Nicky has lost his touch — maybe. But more significantly, it’s here that “Focus” loses its last tenuous connection to reality and floats off into heist-movie wonderland, where no scheme is too far-fetched to hatch and there’s no situation too dire that the screenwriters can’t find a way out. This holds true for the film’s final section, set in Buenos Aires, where Nicky is running some kind of scheme involving an auto racing magnate (Rodrigo Santoro) under the watchful eye of his security chief (an extra-cranky Gerald McRaney).

Smith is on the rebound a little after the failures of “After Earth” and “Seven Pounds,” and a little hunger has loosened him up on screen, making him sharper and more charming, and a little rougher. And Robbie, who stole the show in “The Wolf of Wall Street” and is also excellent in the upcoming “Z For Zachariah,” has sharp comic timing and an appealing openness. If anything, the screenplay sells Jess short, more interested in making her Nicky’s love interest than his partner in crime.

It’s not that it’s not fun to watch — the production design is alluring, the cast knocks around some snappy dialogue, and Requa and Ficarra add some playful touches, such as the scene in which a henchman is shopping in a drugstore for items that only make sense later. But I prefer my caper movies David Mamet-style, with an edge of danger and amorality to them. Nicky was nicknamed “Mellow” by his father, as in “Marshmallow,” and “Focus” is a marshmallow of a caper movie, soft and sweet and not very filling.