No son cosas totalmente distintas como dices, están relacionadas, acá está la respuesta, tercer párrafo:
Evan Powell ,Analista de esta Web (Reviews) ProyectorCentral https://www.projectorcentral.com/son...al-Impressions
Textual
''Meanwhile, the powered vertical lens shift is limited to a range of almost two picture heights. In neutral position the centerline of the lens intersects the center of the projected image. From that point, the projected image can be raised or lowered a total of almost 50% of its height, so that the centerline of the lens at maximum offset will intersect close to the top or bottom of the image. This variance is more than ample for most rear-shelf mounting situations. However, if the unit is ceiling mounted, the lens shift may not provide enough of a downward projection angle to get the image low enough on the wall. In that event, a drop extension tube is the only solution. Tilting the projector and using keystone adjustments to correct the trapezoid is not recommended under any circumstances,
as it will force a rescaling of native 1920x1080 video. That is something you absolutely do not want to do on a 1080p projector if you want maximum image definition from 1080p sources.''
Eso hará el software de tu proyector al intentar ''ordenar'' esa
imagen deformada, yo en realidad le cambiaría el nombre a ''deformación trapezoidal''

Así que NO a la ''deformación trapezoidal'', disculpa....''corrección trapezoidal''