People assume they can retrospectively zoom in on footage after the event to improve detail. You see it in the movies, some guy types away on a computer and magically a blurred image suddenly becomes clear enough to read the dry cleaning instructions on the villains jacket. Back in the real world I'm afraid all that simply isn't possible. Zooming in after the event is done digitally on either the DVR recorder or a computer. All this does is enlarge pixels and in doing so distort the image.
Optical zoom is very different. This is done on the camera during installation, zooming in optically improves the level of detail capture, all be it over a smaller area. Widening the angle of view covers a larger area but captures much less detail as you move away from the camera. With optical zoom the lens is doing the work before the image gets captured by the cameras electronics.
We have optically and digitally zoomed in on the emblem of the antique car. As you can clearly see digital zoom produces no extra detail whereas with optical zoom there is a huge increase in the amount of detail.