Deep focus is a cinematographic technique that keeps foreground, middle ground, and background all in sharp focus simultaneously.
Deep focus uses small lens apertures, wide-angle lenses, and high-intensity lighting to keep every plane of the image equally sharp. The technique was pioneered for Hollywood by cinematographer Gregg Toland, whose work on Orson Welles's 'Citizen Kane' (1941) made it famous. André Bazin, the great French critic, championed deep focus as more democratic than montage: it left the audience free to choose where to look within a single composition rather than having meaning imposed by editing. William Wyler's 'The Best Years of Our Lives' (1946) used the technique to layer emotional information across multiple characters at once. Today's digital cinema can achieve deep focus almost effortlessly, but the deliberate choice to compose in depth — Paul Thomas Anderson's 'There Will Be Blood' (2007), Jeff Nichols's 'Take Shelter' (2011) — remains one of the most powerful tools in a cinematographer's vocabulary.