Photography Glossary

The amount of light reaching the sensor, measured in stops (EV) — one stop doubles or halves the light. Correct exposure stays within the 12-14 stops of dynamic range of modern sensors and depends on aperture, shutter speed and ISO.

The plane of optical sharpness — a slice typically 0.5 mm to 50 cm deep depending on aperture and focal length. Precise focus makes the main subject sharp, while the background can be intentionally blurred (bokeh) to isolate it.

A setting that corrects color cast based on the light source, measured in Kelvin (1800 K candle, 3200 K tungsten, 5500 K daylight, 8000 K shade). Incorrect WB gives overly warm (orange) or cool (blue) tones.

Roughly the hour after sunrise and before sunset, when warm light (3000–4000 K) skims low and stretches shadows. A short window — the most flattering for portraits and landscapes.

A 20–40 minute twilight window after sunset or before sunrise (sun between -4° and -6° below the horizon), when the sky takes a cobalt cast and natural and artificial lights coexist.

Light from a source whose apparent diameter, seen from the subject, stays under ~5° (midday sun, bare flash, undiffused spot). Contrast ratio commonly above 1:8, sharp shadows, abrupt transitions, marked specular highlights. A graphic and character tool.

Light from a source whose angular diameter, seen from the subject, exceeds ~20° (overcast sky, north window, softbox at 1 m, white wall). Diffuse, gradual shadows, soft tonal transitions. A modeling and softness tool.

Light source placed behind the subject, opposite the camera, typically at 0-30° elevation and within ±30° of the optical axis. Background-to-subject gap commonly 3-6 stops. Creates silhouettes, rim light and atmospheric halos.

A composition principle that divides the image into 9 equal zones with 2 horizontal and 2 vertical lines. Placing important elements on these lines or at their intersections creates a more dynamic and balanced image.

Natural or architectural lines that guide the viewer's eye toward the main subject. A line reads as a guide once it covers 20-30% of the frame diagonal: roads, fences, rivers, shadows, lines of sight.

Mathematical ratio φ ≈ 1.618 used in composition to divide the frame into harmonious zones. A simplified cousin of the rule of thirds, it guides the placement of subject and lines of force.

The sense that an image "holds" — the perceptual center of gravity falls within ~10% of the geometric center, or at a deliberate offset the frame justifies. A perceptual matter before a geometric one: a small high-contrast detail can balance an entire half of bright sky.

Empty — or perceived-as-empty — zones surrounding the subject, typically 50 to 80% of the frame depending on the intent. Uniform sky, smooth wall, fog, blur. An intentional choice about what is NOT there, not a default of what's missing.

Theoretical point where parallel lines of a subject in perspective converge. It structures the sense of depth and inherits from the geometric perspective of Brunelleschi (1413) and Alberti (De Pictura, 1435).

Composition technique that uses an architectural or natural element — doorway, arch, window, branches — as a secondary frame around the subject. It reads as enclosure when it surrounds the subject on at least two adjacent sides. Hierarchizes, contextualizes and adds depth in a single move.

Regular correspondence between elements of an image around an axis or center, with the eye tolerating no more than ~1° of angular deviation. Three families: bilateral, radial, reflection. A tool for stability and monumentality.

Diagonal composition grid: a corner-to-corner diagonal, two perpendiculars from the opposite corners, and four power points arranged on the diagonal. Ideal for oblique scenes.

Identical or near-identical motifs (repetition, typically 3-5+ occurrences) and the visual cadence they create (rhythm). Breaking the pattern produces a remarkably effective focal point.

The sense of three-dimensionality in a photo, built from at least three identifiable planes (foreground 0.5-2 m, subject, background) plus perspective and atmospheric haze. Not to be confused with depth of field.

A balanced combination of colors built on the color wheel, classically organized around a 60/30/10 ratio (dominant / secondary / accent). Three main families: complementary, analogous, monochromatic.

The diameter of the lens diaphragm opening, expressed in f-stops. A small number (f/1.8) = wide opening = more light and shallow depth of field (blurred background). A large number (f/16) = narrow opening = less light and deep depth of field (everything sharp).

The sensor's sensitivity to light. Low ISO (100-400) produces a clean image but requires more light. High ISO (1600+) allows shooting in low light but introduces digital noise.

The duration the sensor is exposed to light. A fast speed (1/1000s) freezes motion. A slow speed (1/30s or less) can create motion blur, useful for waterfalls or light painting.

The optical distance of the lens expressed in mm. A wide-angle (< 35mm) captures a broad field with distortion. A telephoto (> 85mm) compresses perspective and brings distant subjects closer. The standard focal length (50mm) is closest to human vision.

Acceptably sharp zone around the focal plane (from a few mm at f/1.4 in macro to several meters at f/11 on a wide-angle). Three governing factors: aperture, focus distance, focal length. Key tool to isolate a subject or keep everything sharp in landscape.

Aesthetic quality of background blur (≠ depth of field, which measures the quantity). Japanese word ボケ popularized in 1997. Depends on the diaphragm blade count and optical design.

System of three variables (aperture, shutter, ISO) that together determine exposure. Changing one by a stop forces compensation on the other two to keep the same amount of light.

Focus distance at which depth of field extends from half that distance to infinity. Key tool for landscape and street zone-focusing.

Horizontal (landscape, width > height) or vertical (portrait, height > width) orientation. Choice driven by composition and intent, not by the subject.

Cutting a rectangular portion of the original file in post. Aim to keep at least 70% of pixels for a clean A4 print, never go below 50% before grain shows. A second-chance tool, not a substitute for in-camera framing.

Genre centered on a person, capturing features and character. Subgenres: posed (Avedon, Penn), environmental (Newman, Leibovitz), documentary (Lange Migrant Mother 1936), street (Vivian Maier).

Genre whose subject is the environment (natural or urban) spread in depth. Subgenres: classical (Ansel Adams Yosemite 1927, Group f/64), intimate (Caponigro), cityscape (Gursky Rhein II 1999), minimalist (Kenna).