Design Nomenclature / Composition
Rule of thirds
Also called thirds grid
A convention placing the frame's divisions at one-third and two-thirds on each axis and subjects near the four intersections. It is a coarse approximation of off-centre placement that happens to be easy to remember and easy to overlay on a viewfinder. No perceptual finding stands behind it.
In practice
Taught as a law. It is a fast way to stop centring everything, and it stops paying the moment you can judge weight directly.
Not to be confused with
- Golden ratioThe ratio 1:1.618…, in which the whole stands to the larger part as the larger part stands to the smaller. A rectangle carrying it subdivides indefinitely into a square and another such rectangle — a genuinely useful self-similar property, and the honest reason to reach for it.
- Optical centerThe point a viewer takes for the centre of a field, which sits above the geometric centre — conventionally by around five percent of the height, more in tall formats. Anything centred by measurement therefore reads as low, and has to be raised in order to look centred.