In the Camera Editor,
select the Anamorphic predefined film
back, or create your own film back.
In the Image File Output section
of the Render Globals window, set
the X Resolution and Y
Resolution to values appropriate for an anamorphic lens
(for example, 500 and 423), and set the Pixel Aspect Ratio to
an appropriate value (for example, 2). The Pixel
Aspect Ratio (under Render Globals)
produces the same effect as the Squeeze Ratio (in
the Camera Editor).
Render your scene.
View the image file. Note that
this image file will be distorted.