Resizing Camera View

[BrianR]

I was wondering if it was possible to resize the viewing area of the camera during operation. Would you have to put a physical lens on the camera, or is it possible to have the camera ignore say, the right half of the image that it takes in as input?

If this is possible, it would make it much easier to focus on a single light when you encounter an orientation that presents two lights in your field of view.