Doug Kuntz, a photojournalist who turns his lens on populations in peril — from the dying days of the baymen culture of Bonac to neighborhoods ravaged by Superstorm Sandy to the “hell on earth” of Moria, the migrant camp on Lesbos, Greece — has returned recently from what might be his most harrowing, and awe-inspiring, artistic journey yet: documenting the voyage of a ship called the Sea Watch 3 as it rescued 47 migrants from a sinking rubber raft off the coast of Libya.