Samsung SP-A800B Owner's Instructions Manual page 19

Zoom Knob Focus Ring
You can adjust the size of image within zoom range by manipulating the
Zoom Knob.
Focus the picture on the screen using the Focus Ring.
If your product is installed at a location out of the specified projection
distance (refer to
be adjusted correctly.
Leveling with Adjustable Feet
For level placing of the projector, adjust the Adjustable Feet of the projector.
You may adjust the level of the projector up to 3 degrees.
Depending on the position of the projector, Keystone distortion of
image may appear.
Adjusting the Lens Position Moving Dial
Move the picture projected on the screen up and down within the lens range by
turning the Lens Shift Dial on the top side of the projector with your fingers.
Screen Size and Projection Distance
Install the projector on a flat, even surface and level the projector using the adjustable feet to realize optimal picture quality. If
images are not clear, adjust them using the Zoom Knob or Focus Ring, or move the projector forward and backward.
Screen Size and Projection Distance), the focus cannot