Epson 821p - Manual (Page 15)

Setting Up the Projector 15
Try to place the projector directly in front of the center of the screen,
facing the screen squarely. If the projector isn’t positioned this way,
the image will be “keystone” shaped, instead of square or rectangular.
If you place the projector below the level of the screen, you’ll have to
tilt it up by extending the front adjustable foot, as described on
page 37. This also causes the image to lose its rectangular shape, but
the Auto Keystone feature corrects the distortion automatically. If the
image does not regain its rectangular shape, the tilt angle is greater
than 15° or the Auto Keystone feature may have been disabled. To
turn it on, see page 58. To adjust it manually, see page 38.
Other Installations
You can also project from behind the screen or from the ceiling, with
the projector mounted upside-down:
To project from overhead, you’ll need the optional ceiling mount
hardware. (See page 12 for ordering information.) You’ll also need to
select
Front/Ceiling or Rear/Ceiling for the Projection option in the
Extended menu. To project from the rear, select Rear . See page 59 for
more information.
note
The Auto Keystone feature
corrects vertical distortion
automatically. For more
information, see page 38.
Front/ceiling projection Rear projection (using a
translucent screen) Rear/ceiling projection (using
a translucent screen)