Yes, the 'zoom' feature of real-life cameras is the
equivalent of the field of view of director 3d camera objects.
Physically moving the camera forwards and backwards towards the
target is actually called 'dollying' in real life.
To narrow the field of view by one degree per frame, you
could use something like this:
if gZoomIn then pCamera.fieldofview =pCamera.fieldofview - 1
You'll want to limit it to a minimum though, which can easily
be achieved by using the 'max' command:
if gZoomIn then pCamera.fieldofview
=max(30,pCamera.fieldofview - 1)
The above line will zoom in, but keep the field of view from
going lower than 30 degrees. The matching 'zoom out' would look
if gZoomOut then pCamera.fieldofview
=min(120,pCamera.fieldofview + 1)