Twin brothers stand in front of a farmhouse—first in 1975, then again in 1995. In the span of 20 years, they grow from middle-aged to old, becoming sun-weathered and wind-beaten. Another diptych shows Tim and Tom Kehoe, also twins, posed before a barn and flanked by Holsteins. In the first image, they are boys; in the second, men. Their outfits change, haircuts shorten and lines deepen, but their demeanor is unwavering. Then there’s the portrait of five generations of women, lined up like living matryoshka dolls. This is the quiet power of Art Rogers’s unblinking portraits: the things they reveal about shapeshifting, inheritance and time’s sleight of hand. A selection from his archive is on display this month as part of Western Weekend, alongside early 20th-century photographs by Marett Burridge Boissevain (pronounced BOY-sa-VANE), Marin’s first U.C. Cooperative Extension farm advisor, who served from 1920 to 1950. Both men devoted themselves to chronicling the agrarian rhythms of West Marin—its people, its landscapes, its slow transformation. Mr. Rogers, who moved to the area in the early 1970s and began publishing photographs in the Light  under his series “The Point Reyes Family Album,” often revisits his subjects across the years. But even his stand-alone shots reveal the relentless transformation of bodies, families and communities over time. The world evolves, and his camera takes note. As part of his official duties, Mr. Boissevain crisscrossed the county introducing progressive agricultural methods and, in the process, capturing hundreds of large-format photographs: hillsides of grapevines, fields of corn, pastures of cattle, flocks of chickens. Like Mr. Rogers’s portraits, Mr. Boissevain’s images don’t presume to explore the mystical auras of inner lives. Both men photograph their subjects in casual, familiar settings, often at home or outdoors, but with a plain formality that evokes a planned occasion rather than mere happenstance. Their subjects stand still and meet the camera’s gaze, fully aware of being seen. The show, curated by photographer Denise Rocco-Zilber, came together in a matter of weeks thanks to a collective effort and, as Mr. Rogers put it, “synchronicity.” The exhibit opens June 6 and runs through June 29 Fridays through Sundays from noon to 4 p.m. at the Russell Chatham Gallery at 11101 Highway 1. An opening reception will be held from 2 to 4 p.m. on June 7.