Obtaining A Preferred Projected Picture Size - BenQ Mainstream MP510 User Manual

Obtaining a preferred projected picture size

The distance from the projector lens to the screen, and the video format each factors in the
projected picture size.
The native resolution of the projector is 800 x 600 pixels, which is a 4 to 3 aspect ratio
(expressed as 4:3). To be able to project a complete 16:9 (widescreen) aspect ratio picture,
the projector can resize and scale a widescreen picture to the projector's native aspect width.
This will result in a proportionally smaller height equivalent to 75% of the projector's native
aspect height.
16:9 aspect picture scaled to a 4:3 aspect
4:3 aspect picture in a 4:3 aspect display area
display area
Thus, a 16:9 aspect picture will not utilize 25% of the height of a 4:3 aspect picture displayed
by this projector. This will be seen as darkened (unlit) bars along the top and bottom
(vertical 12.5% height respectively) of the 4:3 projection display area whenever displaying a
scaled 16:9 aspect picture in the vertical center of the 4:3 projection display area.
When determining the position of your projector, you should consider its intended use and
input signal aspect ratios. All inputs (other than composite Video being fed a 16:9 aspect
signal) will display in a 4:3 aspect ratio (and will require an additional 33% display height
than that of the scaled 16:9 aspect picture projection area).
Do not select a permanent projector position based upon a 16:9 projection if you will ever
need to select an input (other than composite Video being fed a 16:9 aspect signal).
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 picture 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 picture to be vertically offset from the horizontal plane of the projector.
When ceiling mounted, this refers to the top edge of the projected picture.
If the projector is positioned further away from the screen, the projected picture 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 picture 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 to assist you in determining the
ideal location for your projector. There are two dimensions to consider, the perpendicular
14 Positioning your projector