SM's response:

Again, I think this is just a display issue. Basically more data than your Video Card can handle quickly. When you Zoomed in, did you also change the Focal to match the Face Camera? The Cameras are the same, so the issue should be able to be duplicated with the Main Camera.

You can confirm if this is just a display artifact by Rendering out the scene at full quality with Camera Animation. You may be able to remove the issue by increasing the Focal and Zooming out a bit with the various Cameras that are affected.

Let me know your Focal Setting for the affected Cameras and if increasing the Focal and Zooming out helped lessen or remove the artifact of motion.

My reply:

The focal length of the main camera is 55mm.  The focal length of the face cam is 95mm.  I just tried zooming in on V4's face with the main camera and then changed its focal length to 95.

Result: I was not able to duplicate the problem.

I also tried switching to the face cam, and then changed its focal length to 55.

Result: The problem persists.

Unfortunately, I believe we may be reaching an em pass with this issue.

I've shared this discussion with others, and at least two people have related the same problem.  One of them told me that it's been a prevailing issue with every version of Poser since 6, including Poser Pro, and only effects different systems and OS's.  A third person is only able to duplicate the problem when they have a large number of high-resolution figures populating a scene, and at that point camera movement slows to a crawl when they select the same camera views.  Apart from those three, no one else is able to duplicate the problem.

This leads me to believe that there may be some inconsistency with Poser's performance on various PC's with no logical explanation as to why.