Volume anamorphosis — where it appears
Named by 2 essays across one field — each of them below, with the objects they name alongside it.
Wide angle is not distortion
A wide lens stretches shapes at the edge of the frame by exactly 1/cos θ — 3% at 28° across, 41% at 90°. Every bit of that is what a correct rectilinear projection must do, and every bit of it disappears if the picture is viewed from the point it was made for. Nobody views it from there.
A set cut for one eye
Build a colonnade four metres deep and cut every column so that its picture is the picture of one eighteen metres deep. The taper is forced rather than chosen — height and width both scale as the real depth over the intended one — and the match from the design eye is exact to sixteen decimal places. What gives it away is the second eye, and not by the ratio anybody would predict.
Named alongside it
The objects these essays reach for when they reach for this one.
AnamorphosisViewing distanceBarrel distortionDemonstrationDepth compressionDepth cueDiminutionDisparityEdge stretchfield of viewForced perspectiveForeshortening