In a era when some mainstream entertainers have transitioned to targeting faith-based audiences, David Bazan is moving in the other direction.

The gifted songwriter’s ersatz band Pedro the Lion was perhaps the most successful Christian indie rock act of its time, and the first to significantly cross over to secular fans. Then he ditched that persona (and lost much of his fanbase), not in an attempt to “sell out,” but rather amid public acknowledgement that he’d suffered a serious loss of religious faith.

Brandon Vedder’s “Strange Negotiations” is a music documentary whose interest goes beyond the usual realms of performance footage and personality, since Bazan is so forthcoming about the “breakup with God” that continues to impact his art, career and life. Particularly with U.S. evangelicals in greater political ascendance than ever before, Bazan’s personal issues lend a larger philosophical depth to this insightful DIY-style portrait.

Bazan was raised in the Pentacostal church (we see home videos of what looks like a consummately wholesome New Mexico childhood), expecting he’d be a pastor until music became his primary expression. For about a decade starting in 1995, Pedro the Lion was a significant indie success story, releasing four albums and several EPs, becoming a major attraction on the Christian music circuit and beyond. But in 2006 Bazan “disbanded” Pedro (he’d played most of the instruments on its recordings while numerous personnel flitted through the live act), feeling it was no longer a vehicle he was comfortable with.

The issue wasn’t that he’d outgrown the music so much as he felt it was an identity he no longer fit. Just 19 when Pedro began, he later started to question beliefs he’d always taken for granted. “Hell was one of the first things to go, heresy came pretty soon after,” he says. Then God’s very existence began to seem dubious. It was a painful process that spurred more than a little heavy drinking — and a first solo album, 2009’s “Curse Your Branches,” which not only addressed his loss of faith but included some hair-raisingly frank songs about alcoholism.

Much of Pedro’s audience found the change bewildering and alienating. But a fair number of fans (also including other self-identified “recovering evangelicals”) stuck with him, supporting years of solo touring in which he largely played people’s private homes. After all, much of his songs’ appeal had been that they expressed relatable feelings of personal doubt and fallibility, as opposed to the straight-up inspirational tenor of most mainstream Christian pop music.

Much of “Strange Negotiations” follows Bazan on the endless road that leads to these “house shows,” taking him away from wife and children for more than half the year. (Just recently, he’s reconstituted Pedro the Lion, its larger drawing power enabling him to make a living with less time absent from family.) While we see his relatives and fans, he’s really the sole interviewee here, whether speaking to the camera in his car or doing innumerable radio and podcast appearances.

Bazan has less to say about his own trials than about a cultural climate — as we hear news of Trump’s ascendency on his car stereo — that is further distancing him from organized religion. “The values that I think make Christianity worthwhile are missing from the politics: compassion and care for the poor,” he says. He thinks the fact that 80% of evangelical voters supported Trump at the polls is “proof that we’re doing Christianity fundamentally wrong in this country.”

There’s something endearingly earnest and straightforward, but not simplistic, about Bazan as both personality and musician, lending “Negotiations” dual sources of viewer enjoyment. For this first directorial feature, Vedder followed the subject around sporadically for several years, achieving a degree of intimacy that’s similar to that generated by Bazan’s songwriting. This is hardly a slick documentary — though the sound recording in performance sequences is solid. Still, a glossier package might have felt inappropriate here.