InFocus IN3902LB User Manual page 12

What is Aspect Ratio?
Aspect ratio is the ratio of the image width to image height. Standard TV
screens and older laptops are 4:3; HDTV and most DVDs are 16:9; and
widescreen computers are 16:10. If you are projecting onto a screen, the
size/shape of the screen will influence the aspect ratio you decide to use. If
you are projecting onto a blank wall, there are no screen size restrictions.
What you plan to project will also help you choose between 4:3, 16:9 or
16:10. Many TV shows are 4:3, while most movies are 16:9.
If you have a 16:9 screen then you should select an aspect ratio of 16:9 for
widescreen movies or HDTV, and Native for 4:3 content. If you have a 4:3
screen you should still use 16:9 for widescreen movies or HDTV, but you
also have the option of using either 4:3 (to fill the screen) or Native (for
direct pixel mapping) for 4:3 content. Force Wide can also be enabled to
automatically resize less common aspect ratios to 16:10.
4:3 screen
11
16:9 screen
4:3
mode
16:9
mode
Native
mode
(NTSC
only)