Photography terms starting with F

Flag Lighting & Flash cm An opaque black panel placed to block light from reaching a specific area.

Flange Focal Distance Cameras, Formats & Systems mm The distance from a camera's lens mounting flange to the sensor or film plane.

Flash Duration Lighting & Flash seconds How long a flash's burst of light actually lasts, which sets its ability to freeze motion independently of shutter speed. t.1 ≈ 3 × t.5

Flash Exposure Compensation Lighting & Flash stops (EV) An offset applied to TTL flash output, in stops, independent of the ambient exposure compensation.

Flash Exposure Lock Lighting & Flash A control that fires the metering preflash in advance and holds the resulting power setting for subsequent frames.

Flash Sync Speed Lighting & Flash seconds The fastest shutter speed at which a focal-plane shutter is fully open, and therefore the fastest speed at which flash can light the whole frame.

Flat Field Correction Sensors & Digital Capture Dividing an image by a frame of evenly illuminated field to remove vignetting, dust shadows and photosite sensitivity variation. Corrected = (light − dark) / (flat − bias)

Flat Picture Profile Motion, Video & Creative Techniques A camera setting that reduces contrast and saturation to retain more information for later adjustment, without the full complexity of log.

Flicker Reduction Exposure & Metering Hz A camera function that times the shutter release to the peak of a pulsing artificial light source, preventing exposure and colour shifts between frames. Cycle = 2 × mains frequency

Fluorite Element Optics, Lenses & Filters count An element made of grown calcium fluoride crystal, which has exceptionally low dispersion and enables near-perfect colour correction.

Focal Length Optics, Lenses & Filters mm The distance from a lens's optical centre to the sensor when the lens is focused at infinity, which determines magnification and angle of view. 1/f = 1/u + 1/v

Focal Point Composition & Visual Design The element in a photograph that the eye is drawn to first and returns to.

Focal Reducer Optics, Lenses & Filters × reduction An adapter containing glass that compresses a lens's image circle onto a smaller sensor, shortening focal length and gaining light. f_new = f × reduction factor

Focal-plane Shutter Cameras, Formats & Systems seconds A shutter made of two curtains that travel across the sensor just in front of it, exposing the frame as a moving slit at high speeds.

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.

Focus Limiter Focus & Depth of Field m A switch that restricts a lens's focusing range, so autofocus does not search through distances the subject cannot occupy.

Focus Lock Focus & Depth of Field Holding the current focus distance so that further movement of the camera or subject does not trigger refocusing.

Focus Magnification Focus & Depth of Field × magnification A function that enlarges part of the live image so focus can be judged at a pixel level.

Focus Peaking Focus & Depth of Field A display aid that outlines the highest-contrast edges in the live image, marking what is currently in focus.

Focus Priority Focus & Depth of Field A setting that prevents the shutter from firing until the camera confirms focus has been achieved.

Terms starting with F