To add to the first answer, because the renderer uses a linear transformation to transform the projected points from world into camera space, there is no way to create such a camera without firing trace rays as mentioned by Dan. This is because such a camera ( as well as cameras like fish-eye etc. ) would require a non-linear transform.
However, the multiple camera option is definitely a good way to go, as for some scenes firing trace rays ( i.e. complex scenes ) it far too costly, especially where the scene is already basically maxing our your machine resources.
By:
luke emrose
[ Editor ]