Visual Plane
every picture states the point it is correct from
Concept

Panorama — where it appears

3 essays name this object, across 3 fields. What follows is each of them, and the objects they name alongside it.
fitted conic: 1.467 from being a circlecylinderthe samples, fitted

The cylinder, and the price of going all the way round

A cylindrical picture can hold three hundred and sixty degrees, keeps every vertical vertical, and bows every horizontal. Its cost is a stretch of sec φ in elevation, which is also the equirectangular surface's cost exactly — two surfaces that are always described as different and are identical in the one respect anybody notices.

curved · cylinder flat picture plane — straight lines stay straightcylindrical picture surface — even stretch, bowed linesone scene, two picture surfacesneither is the distorted one

When the picture surface is not flat

A flat picture plane keeps straight lines straight and stretches the edges without bound. A cylindrical one spreads the stretch evenly and bends every straight line that is not through the axis. Neither is the distorted one — they are answers to different questions, and the choice decides what a wide view can be.

viewing · surface the far field — where the stitch was fitted2.2 m — 3.2 px out24 m — 0.3 px outthe sky registers to 1e-13 pxthe foreground does not — up to 3.2 px

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.

lens · pupil

Named alongside it

The objects these essays reach for when they reach for this one.

Cylindrical projectionEquirectangularAnisotropyAzimuthcentre of projectionConicEdge stretchElevationEntrance pupilfield of viewFisheyeFocal length

All concepts