how to output a 16x9 widescreen qt movie from After Effects

Hello There,

I am trying to output a 16x9 widescreen movie from After Effects.
I am using still images. My image size is 853x480 which is supposed to
be equivalent to NTSC 16x9 widescreen, which is what I want. It is that size in the AE canvas. When I place it in the render queue, and render said movie, it come out (in FCP and QT) as 4:3. What am I missing? The comp settings appear to be correct (although 720x480). It says "widescreen" and "anamorphic" when I open the comp settings and check them.

Thanks,

Eric