Acer PD100 PD100 User's Guide - Page 22

User Controls English ... 22 Image (Computer / Video Mode) Keystone Adjust image distortion caused by tilting projection. (±16 degrees) Aspect Ratio Use this function to choose your desired aspect ratio.  Auto : Keep the image with original width-higth ratio and maxi mize the image to fit native horizontal or vertical pixels.  4:3 : The input source will be scaled to fit the projection screen.  16:9 : The input source will be scaled to fit the width of the screen.  480p : Provide the best display for a 480p 16:9 signal. Source Lock When source lock is turned off, the projector will search for other signals if the current input signal is lost. When source lock is turned on, it will "Lock" the current source channel before you press "Source" button on remote control for next channel. Projection  Front-Desktop The factory default setting.  Rear-Desktop When you select this function, the projector reverses the image so you can project behind a translucent screen.  Front-Ceiling When you select this function, the projector turns the im- age upside down for ceiling-mounted projection.