BenQ W1300 User Manual page 18

For example,
if your have a 16:9 aspect ratio screen and your measured projection distance was
5.0 m (5000 mm), the closest match in the "avg" on page 19 column is 5008 mm.
Looking across this row shows that a 130-inch screen is required.
Checking the min. projection distance in the columns of "Projection distance <D>
[mm]" on page 19 indicates that the 5000 mm measured projection distance will also
fit the 110 and 160-inch size screens. The projector can be adjusted (using the zoom
control) to display on these different screen sizes at the projection distance. Be
aware that these different screens have different vertical offset values.
If you place the projector in a different position (to that recommended). you will
have to tilt it down or up to center the image on the screen. In these situations,
some image distortion will occur. Use the Keystone function to correct the
distortion. See "Correcting keystone" on page 30 for details.
18 Positioning your projector