Positioning Your Projector; Obtaining A Preferred Projected Image Size - BenQ Joybee GP2 User Manual

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.
16:10 is the native aspect ratio of this projector.
4:3 aspect image in a 16:10 16:10 aspect image scaled to a 4:3 aspect
aspect display area display area
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).
The modern digital projector does not project directly forward (like older style reel-to-
reel film projectors did). Instead, digital projectors are designed to project at a slightly
upward angle above the horizontal plane of the projector. This is so that they can be
readily placed on a table and will project forward and upwards onto a screen positioned so
that the bottom edge of the screen is above the level of the table (and everyone in the
room can see the screen).
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 16, 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 proportional to
the projection distance.
BenQ has provided a table of screen size to assist you in determining the ideal location for
your projector. Refer to "Projection dimensions" on page 16 depending on the projector
you are using. 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).
15
Positioning your projector