Yes, cameras are a bit tricky, especially since their behavior changes depending on the current projection mode (orthographic / object-centered perspective / user-centered perspective). In orthographic mode especially, the depth doesn't change anything (as it's an infinite projection).
However you shouldn't experience this kind of issue: when you call setPivotPoint, I guess you have left the 'autoUpdateCameraPos' parameter to false?
And are you calling these methods before the window is actually displayed / resized by Qt maybe? (random guesses ;) )
Daniel, CloudCompare admin