I use the Main camera with just V4 and it swivels around her just fine. I add a island sized terrain and suddenly the camera thinks the island's center is the true center.

So, okay I try the dolly camera... same thing. I swivel a little and it flies out to Australia. Only the Auxiliary cam seems to swivel around some close center... but even then the Auxiliary isn't following the true Poser center of the scene... it circles some odd ellipse center... I dunno.

Is there a way to make cameras just circle around the true center of the scene?

The Pose camera isn't optimal because it pops around the scene every time you choose a new figure

Open the Poser manual and search for "orbit selected". It will show you why this happens and which little buttons turn it on and off.

There's also a keyboard shortcut Ctrl-0

In the Poser 11 manual it is explained or mentioned in Chapters 4, 5, 7, 10, and 35.

I don't know which version of Poser you're using, but in PP2014, there's an icon above the top right of the preview screen that looks like a sphere. (There are seven icons; this is fourth from the left.] When you click it, your current camera will go into orbit selected mode [the icon will change into a sphere with an arrow around it) and it will revolve around the center of the object or figure that you have selected.

I don't recall which version this feature first appeared in, however. So you may not have it.

One thing I have noticed is that the Main camera seems far more sensitive than the Aux camera. I use a 3D Navigator for camera movement and the Main can fly off at the slightest touch yet control of the Aux is fine. I did try making sure the settings for both were the same but I still have the same issue. I gave up in the end and use the Aux camera for all my work and never use the Main. It could be my system mind and as I have a work around it is not a problem I'm just curious why it should be, that's all.