Sony VPL-EX281 Operating Instructions Manual page 72

Ceiling Installation
Caution
Never mount the projector on the ceiling or move it by yourself.
Be sure to consult with qualified Sony personnel (charged).
Height H from
center of lens to
edge of screen
* The number will be minus when the top of the projected image is higher than A.
72
Projection Distance
A
Projected
image
Projection distance L
Center of lens
Top side