Every photography term,
clearly explained.
840 curated entries across 14 areas — each with a plain-English definition, the rule behind it and a real shooting example.
Lead Room
The space left in front of a subject in the direction they face or move.
Browse by subject
Fourteen areas of photography, from exposure and optics to printing.
Cameras, Formats & Systems
120 Roll Film · 35 mm Format · Action Camera and more
60 termsColour & Colour Management
3D LUT · Adobe RGB (1998) · Analogous Colours and more
60 termsComposition & Visual Design
Aerial Perspective · Aspect Ratio · Asymmetrical Balance and more
60 termsExposure & Metering
Aperture · Aperture Priority · Auto Exposure Bracketing (AEB) and more
60 termsFiles, Metadata & Workflow
3-2-1 Backup Rule · Archive · AVIF and more
60 termsFilm, Darkroom & Historic Processes
Agitation · Albumen Print · Autochrome and more
60 termsFocus & Depth of Field
AF Microadjustment · AF-assist Illuminator · Animal and Bird Detection and more
60 termsGenres, Movements & Theory
Abstract Photography · Advertising Photography · Aerial Photography and more
60 termsLighting & Flash
Background Light · Backlighting · Barn Doors and more
60 termsMotion, Video & Creative Techniques
180-degree Shutter Rule · 360-degree Photography · Bitrate and more
60 termsOptics, Lenses & Filters
Acutance · Airy Disc · Anamorphic Lens and more
60 termsPost-Processing & Retouching
Added Grain · Adjustment Layer · AI Denoise and more
60 termsPrinting, Display & Output
Alpha-cellulose Paper · Baryta Paper · Black Point Compensation and more
60 termsSensors & Digital Capture
Aliasing · Amp Glow · Analogue Gain and more
The numbers behind the picture
One rule or formula worth memorising from each corner of the dictionary.
APS-C
A sensor format roughly 23.5 by 15.6 millimetres, giving a crop factor of about 1.5× against full frame.
Colour & Colour ManagementCIELAB
A device-independent colour model with one lightness axis and two opponent colour axes, designed so equal numerical steps look…
Composition & Visual DesignAspect Ratio
The proportional relationship between an image's width and its height.
Exposure & MeteringAperture
The adjustable opening inside a lens that controls how much light passes through to the sensor, and with it the depth of field.
Files, Metadata & Workflow3-2-1 Backup Rule
The guideline of keeping three copies of data, on two different media types, with one copy off-site.
Film, Darkroom & Historic ProcessesC-41 Process
The standardised chemical process for developing colour negative film.