Field of View

Another important choice to be made is that of the field of view of the camera. The size of this field describes the angles between the left and right sides and top and bottom sides of the frustum.

$\begin{defkey}{fov}{{\em hfov} [{\em vfov}]} Specify the horizontal and vertical field of view, in degrees. \end{defkey}$
The default horizontal field of view is 45 degrees. If vfov is omitted, as is the general practice, the vertical field of view is computed using the horizontal field of view, the output image resolution, and the assumption that a pixel samples a square area. Thus, the values passed via the screen keyword define the shape of the final image. If you are displaying on a non-square pixeled device, you must set the vertical field of view to compensate for the ``squashing'' that will result.