[Diapositivo]

These distortions are a red herring, because they not because of inherent lens aberrations but because the camera has been pointed upwards to cause perspective distortion because it wasn't capable of lens movements in relation to the film plane.

What I mean is that those pictures DON'T show barrel or pincushion distortion because either it was not there or it was corrected (guess how). The perspective effect, the convergence of lines toward a vanishing point, is not "distortion". Why people lie this word so much that they use always use it?

"Distortion" is a lens defect and in images like those, when uncorrected, would show very clearly and would disturb the subject a lot.

Distorted means deformed, wrong, weird, not-straight. Geometric and perspective effects should be rendered with some other word than "distortion" because they are perfectly normal real-world phenomena and show nothing "deformed".

I understand that people use the term geometric or perspective "distortion" when talking about the exaggerated nose of somebody photographed with a wide-angle lens from short distance.

But in general how do we define "barrel-pincushion/moustache distortion"? Should we define each time "of the barrel-pincushion kind" to be clear?