WGBH steps right up with ‘Circus’

Filmmakers Maro Chermayeff and Jeff Dupre were behind the Emmy-winning series “Carrier’’ in 2008. They and their crew followed the Big Apple Circus during its “Play On!’’ season of 2008-09, from the first practice sessions at base camp in Walden, N.Y., to teary goodbyes at the end of the road.

We meet Big Apple founder, artistic director, and ringmaster Paul Binder and director Steve Smith, a couple of canny circus veterans who empathize with their performers when they can but make unsentimental choices when necessary. For all the talk of magic under the big top, the circus is a business, and they’re responsible for making it go.

It’s clear from the first hour, “First of May,’’ that the business is built on the backs of the crew members who raise the tent and hang the rigging. Many are on the margins of society, accepting low pay and long hours in exchange for room, board, and a sense of belonging.

That’s still not enough for one young worker to keep it together without his medication. When he’s taken away by police, you can almost sense the filmmakers’ excitement as they join his wife on a trip to bail him out. Unexpected drama is a documentarian’s fondest hope, but this tangent brings us the flavor of a segment from “Cops’’; it feels out of place.

Some story arcs do provide compellingly specific looks into circus life. New clown Glen Heroy has a tough time adjusting to Big Apple’s style and soon fears that he’ll be fired. He seems like a savvy showbiz veteran, but his layers of insecurity are slowly revealed, and you’ll root for him. Ditto German-born wire walker Sarah Schwarz, who wonders how many years of work she has left; a practice-room scene in which a teenage girl attempts to duplicate her grace on the wire is compelling.

That scene plays out without embellishment, but “Circus’’ isn’t cinema verite. There are direct-to-camera interviews, time-lapse shots, split screens, and indie rock on the soundtrack. The cinematography is beautiful, and there seems to be nowhere around the Big Apple’s tents and trailers that the camera won’t go.