Selective Focus

Selective focus, also called differential focus, is the practice of restricting sharpness to a chosen point, subject, or plane while allowing the rest of the scene to become unsharp. In photographic discourse it is closely associated with naturalistic photography, especially Peter Henry Emerson's argument that a photograph should approximate human vision rather than display the camera's capacity for equal detail everywhere. Drawing on physiological accounts of sight, this view treated limited sharpness as a way to make photography seem less mechanical and more artistic. It also helped distinguish self-consciously artistic work from ordinary descriptive or snapshot photography by reducing anecdotal detail and giving subjects a more generalized, atmospheric presence.

In practice, selective focus directs attention by making one element visually dominant and subordinating the surrounding space. Portraits often place emphasis on the eyes or face, while genre scenes may separate figures from their setting and landscapes may isolate a tree, boat, or other motif within haze, mist, or a softened field. Technically, the effect is commonly produced with wide apertures, longer focal lengths, shallow depth of field, or lenses whose optical behavior softens parts of the image. Some photographers also introduced blur in printing through gauze, slight separation between negative and paper, or local manipulation of detail in processes such as carbon printing.

The term overlaps with soft focus but is not identical to it: soft focus usually suggests overall diffusion, whereas selective focus preserves a distinct area of sharpness within blur. It has been debated as both a naturalistic correction to the camera's excessive precision and a physiological oversimplification, since the eye scans rather than fixes a whole scene like a static lens. Later advocates of straight photography and deep focus rejected pictorial blur in favor of clarity across the frame, while later discussions of bokeh shifted attention toward the visual quality of out-of-focus areas rather than the original claim to natural vision.