Persisting camera angle problem

I have asked about this before, but I just can’t wrap my head around how the camera in ZBrush is working. I find it impossible to loosely match it to a camera in other 3D apps, like blender in my case. The camera angle does not even change at shorter lenses. I know that it has to do with scale, but why can’t I match my cameras when I exported objects to blender, placed a camera for rendering there, loosely resembling my camera view in ZBrush, then for further editing re-imported the same objects, without any transforms, back into ZBrush, and voila, the camera in ZBrush ( saved as custom view in ZApp links ) is completely off again and also seems impossible to match the old view.
I would appreciate any links for further reading on the ins and outs of the ZBrush camera.