Focus & Depth of Field — 60 Terms Defined

AF Microadjustment Focus & Depth of Field steps (typically ±20) A camera setting that applies a per-lens correction to compensate for consistent front or back focus.

AF-assist Illuminator Focus & Depth of Field A lamp or patterned light that projects onto the subject to give autofocus something to measure in darkness.

Animal and Bird Detection Focus & Depth of Field Subject recognition trained on animal anatomy, able to find and hold an eye on a creature rather than a human face.

Autofocus Focus & Depth of Field A system that measures focus error and drives the lens to correct it automatically.

Automatic Servo Selection Focus & Depth of Field A mode, marked AF-A, in which the camera decides whether to lock focus or track continuously based on whether the subject appears to be moving.

Back Focus Focus & Depth of Field mm A calibration error in which a lens consistently focuses slightly beyond the intended subject.

Back-button Focus Focus & Depth of Field A configuration that moves autofocus activation from the shutter release to a separate rear button.

Circle of Confusion Focus & Depth of Field mm The largest blur circle that still reads as a point to the viewer, and the value on which every depth-of-field calculation depends. c ≈ diagonal / 1500

Continuous-servo Autofocus Focus & Depth of Field An autofocus mode, marked AF-C or AI Servo, that keeps adjusting focus for as long as the button is held.

Contrast-detection Autofocus Focus & Depth of Field A focusing method that drives the lens back and forth, measuring image contrast, and settles at the point of maximum contrast.

Cross-type AF Point Focus & Depth of Field count A phase-detection point sensitive to detail running in both horizontal and vertical directions.

Deep Depth of Field Focus & Depth of Field m A wide zone of sharpness in which foreground, subject and background all hold detail.

Depth of Field Focus & Depth of Field m The range of distances in front of and behind the plane of focus that appears acceptably sharp in the final image. DoF ≈ 2u²Nc / f²

Depth of Field Scale Focus & Depth of Field m / ft Markings on a lens barrel showing the near and far limits of sharpness for each aperture at the set focus distance.

Depth of Focus Focus & Depth of Field µm The tolerance in sensor position, on the camera side of the lens, within which the image stays acceptably sharp. ≈ 2Nc

Diopter Adjustment Focus & Depth of Field diopters A viewfinder correction that matches the eyepiece to the photographer's eyesight.

Dual Pixel Autofocus Focus & Depth of Field An on-sensor phase-detection design in which every photosite is split into two independently readable halves.

Eye AF Focus & Depth of Field A refinement of face detection that locates and focuses on the eye itself, and usually lets the photographer choose which one.

Face Detection Focus & Depth of Field A system that identifies human faces in the frame and prioritises them for focus and often for exposure.

Focus Focus & Depth of Field m The condition in which light from a point on the subject converges to a point on the sensor, rendering that part of the scene sharp. 1/f = 1/u + 1/v

Focus and Recompose Focus & Depth of Field The technique of focusing with a central point, locking, then shifting the camera to place the subject elsewhere in the frame.

Focus Bracketing Focus & Depth of Field count An in-camera function that automatically shoots a sequence of frames at incrementally different focus distances.

Focus Breathing Focus & Depth of Field % A change in a lens's angle of view as it is focused, so the framing appears to zoom slightly during a focus pull.

Focus Confirmation Focus & Depth of Field An indicator, usually a dot or the illumination of an AF point, showing that the camera considers focus achieved.