Oh yes, that zoom tool. I forgot about that one. I never use it, I'm a scroll wheel only person. And the scroll wheel does zoom to where the mouse cursor is.
The actual zoom tool though yes, that also uses the mouse pointer to some degree. If you hold it over something close, you zoom quickly. hold it over something far and you zoom slower. Even if your mouse goes from being on top of something close to not on top of something int he same dragging event, the speed of zoom will vary. I'd never noticed that before.
The orbit tool (again, my scroll wheel) doesn't do what I was thinking it does. It does seem to just orbit around the center of the screen, and the distance of the z axis seems to be based on some sort of target. I'm wondering if it has to do with the near and far culling planes? Perhaps evenly spaced between them?
Chris