Exposure & Metering — 11 Terms Defined

Effective Aperture Exposure & Metering f-stops (EV) The working f-number of a lens once it is focused close, which is always darker than the marked aperture because the lens is extended away from the sensor. N_eff = N × (1 + m)

Equivalent Exposure Exposure & Metering stops (EV) Any different combination of aperture, shutter speed and ISO that yields identical image brightness. N₁²/t₁ = N₂²/t₂

Evaluative (Matrix) Metering Exposure & Metering A metering pattern that divides the frame into zones, compares their brightness against a database of scene types, and infers the photographer's intent.

Exposing to the Right (ETTR) Exposure & Metering stops (EV) The technique of exposing as brightly as possible without clipping, then darkening in processing to maximise signal-to-noise ratio.

Exposure Exposure & Metering lux-seconds (lx·s) The total amount of light that reaches the sensor or film, set by the combination of aperture, shutter speed and the scene's brightness. H = E × t

Exposure Compensation Exposure & Metering stops (EV) A deliberate offset applied to the camera's metered reading, expressed in stops, to make an image brighter or darker than the meter suggests. Setting = Metered EV − Compensation

Exposure Latitude Exposure & Metering stops How far an exposure can miss the ideal and still produce an acceptable image after processing.

Exposure Simulation Exposure & Metering A live-view or electronic-viewfinder mode that displays the scene at the brightness the current settings will actually record.

Exposure Triangle Exposure & Metering stops The teaching model that links aperture, shutter speed and ISO as three interdependent controls, where changing one requires compensating with another. Aperture ↔ Shutter ↔ ISO

Exposure Value (EV) Exposure & Metering EV A single number describing every combination of aperture and shutter speed that produces the same exposure. EV = log₂(N² / t)

Extended ISO Exposure & Metering ISO ISO settings outside a sensor's native range, marked with an L or H prefix, that are produced by digital manipulation rather than analogue gain.