Benq MP780 ST, MX750 User Manual

Obtaining a preferred projected image size

Positioning your projector
Obtaining a preferred projected image size
The distance from the projector lens to the screen, the zoom setting (if available), and the 
video format each factors in the projected image size.
The projector should always be placed horizontally level (like flat on a table), and positioned 
directly perpendicular (90° right-angle square) to the horizontal center of the screen. This 
prevents image distortion caused by angled projections (or projecting onto angled surfaces). 
If the projector is mounted on a ceiling, it must be mounted upside-down so that it projects 
at a slightly downward angle.
You can see from the diagram on page 
, that this type of projection causes the bottom 
edge of the projected image to be vertically offset from the horizontal plane of the projector. 
When ceiling mounted, this refers to the top edge of the projected image.
If the projector is positioned further away from the screen, the projected image size 
increases, and the vertical offset also increases proportionately.
When determining the position of the screen and projector, you will need to account for 
both the projected image size and the vertical offset dimension, which are directly 
proportional to the projection distance.
BenQ has provided a table of 4:3-aspect-ratio screen sizes for MX750 and a table of 16:10-
aspect-ratio screen sizes for MP780 ST to assist you in determining the ideal location for 
your projector. There are two dimensions to consider, the perpendicular horizontal distance 
from the center of the screen (projection distance), and the vertical offset height of the 
projector from the horizontal edge of the screen (offset).