Pincushion Distortion
A geometric distortion in which straight lines bend inward toward the centre, pinching the frame corners outward.
Measured in
%
In depth
Pincushion is the mirror image of barrel distortion and typically appears at the long end of a zoom, where magnification increases toward the edges. Most zooms transition from barrel at wide to pincushion at telephoto, crossing through near-zero somewhere in the middle — a focal length worth knowing for architectural work.
Examples in practice
A 24-105 mm zoom shows barrel distortion at 24 mm, none around 50 mm, and visible pincushion by 105 mm.