The photographer Daniel Arnold is eerily adept at capturing perfect moments in his pictures, although “perfect,” in his case, doesn’t mean glossy or unblemished. Arnold’s work often traffics in the quotidian and the flawed, the discordant and the mottled; to him, perfection means locating beauty in what might otherwise be overlooked. Like his forebears in the art of street photography, from Garry Winogrand to Joel Meyerowitz to Helen Levitt, Arnold trains his lens on people going about their lives in New York City. In “Pickpocket,” his first monograph, which was released earlier this month, we see many of these subjects, intent and determined on completing their private daily tasks: an old bald man, his creased head and neck captured from behind, while he walks down the street on a sunny day; a large Orthodox Jewish salesman, crouched in the too-small window of a jewelry store in order to clean it; a pillowy lipped, long-haired woman mid-phone call, a street stall piled high with hats just behind her.