Dof

Depth of field, abbreviated as DoF, is the range of distance in a scene that appears acceptably sharp in a photograph. It results from the way a camera lens projects a scene onto the image plane and from how sharpness is judged in the final image. Points closer or farther than this range appear increasingly blurred. The precise DoF depends on the acceptable blur level, commonly described by the circle of confusion, a threshold that translates how much a point is spread on the sensor.

Several factors influence DoF. Aperture is central: stopping down to a higher f-number increases DoF, whereas a wide aperture reduces it. However, very small apertures can cause diffraction and reduce sharpness. Focal length matters: longer lenses produce shallower DoF for the same framing, while shorter lenses provide more depth of field. The distance to the subject has a strong effect: moving closer sharpens near objects but blurs distant parts more. Sensor size affects perceived DoF: for the same field of view, larger sensors tend to yield shallower DoF because the circle of confusion scales with sensor size.

Hyperfocal distance is a commonly used concept to maximize DoF. For a given focal length f, aperture N, and circle of confusion c, the hyperfocal distance is H = f^2 / (N c) + f. Focusing at H yields acceptable sharpness from roughly half H to infinity. In practice, photographers estimate near and far limits with DoF calculators or lens scales.

DoF and its aesthetics are central to photography and cinematography. It interacts with exposure, perspective, and bokeh, and is influenced by format, lens design, and viewing conditions. The term DoF is widely used to describe sharpness range and serves as a practical guide for composing images.