If there is not a reset button on the back of the TV you could try this to get to "out of the box" condition:
Press "INPUT", then "2580" ...you should be in the the service menu area which is a yellow-green screen at the top left.
Using the down scroll button on the remote control, scroll to "Other Setting".
Press the right scroll button once.
Scroll down this new menu to "EEPROM Init"
Press the right scroll button once.
Follow the next prompt to reset.
... this is suggested from another Dynex owner. Good Luck.

First off...optical zoom is always more desirable than digital.
The difference...optical is similar to when you use a magnifying glass and you move closer and farther from the subject making what you see larger.
Digital is when the optical has gone as large as it can and now the subject is artificially enlarged.
Go too large and this causes distortions and pixelization...stair stepping.

The EF-S lens is a lens using the EF mount system design for APS-C digital sensor cameras. The "S" in EF-S stands for short back focus.

If the projector has a VGA input on it it could be used as a second monitor for a computer.