Why did Robert Frank sometimes take photographs without looking through the viewfinder?

Robert Frank often photographed without looking through the viewfinder because he preferred to leave the composition to chance, welcoming the resulting imperfections and ambiguity.1

By departing from traditional photographic methods, Frank sought to move away from the pursuit of a single, perfect masterpiece—a goal common among his peers and predecessors, such as Henri Cartier-Bresson. Instead, his approach was driven by a desire to evoke emotion and subjectivity, allowing him to create a visual narrative experience similar to the stream-of-consciousness technique used by prose writers. This philosophy is central to his highly influential book, The Americans, which prioritized a sequence of images that expressed his personal perspective over technical perfection.1