you use 16:9 mode most of the time.
Auto Wide: Automatically adjusts the picture size to the 16:9 aspect ratios.
16:9: Adjusts the picture size to 16:9 for DVDs or wide broadcasting.
Wide Zoom: Magnifies the picture size more than 4:3.
Zoom: Magnifies the 16:9 wide pictures vertically to fit the screen size.
4:3: The default setting for a movie or normal broadcasting.