It’s a Monday morning, and the documentarian Lauren Greenfield and I are at the Robert Frank exhibit at MoMA. She’s in town for some talk-show appearances but didn’t want to miss it — it was Frank’s photobook The Americans that inspired Greenfield to pursue photography in the first place, she says. “This looks like outtakes from … well, actually I’m not sure,” she says, gesturing to a contact sheet. A gaggle of teenage girls enters the gallery and gathers around one of their phones.