Entrance pupil — where it appears
Also named here as parallax — the same set of essays touches all of them, so they are one junction rather than several.
A turn of the head is not a step sideways
The textbook says a short baseline makes reconstruction ill-conditioned. Measured, the algebra does not notice — a two-millimetre baseline recovers the courtyard to nine digits from exact marks. What fails is the ratio of baseline to reading error, and it fails without refusing.
The eye is a place, not a point
Rotate a camera about the wrong point and the sky still stitches perfectly while the foreground slides. The misregistration falls as one over the distance, exactly — which is what says the fault is the pivot and not the lens.
The port that is not there
A flat window into water costs a lens a third of its field. A sphere centred on the entrance pupil costs nothing at all — not nearly nothing, exactly nothing — and six millimetres off centre costs 0.635°.
Named alongside it
The objects these essays reach for when they reach for this one.
ParallaxHomographyResidualBaselinecentre of projectionConditioningCritical angleDegeneracyDome portEpipolefield of viewFlat port