@staticmethod
def _zExtentCamera(viewport):
    """Return (far, near) planes Z in camera coordinates.

        :param Viewport viewport:
        :return: (far, near) position in camera coords (from 0 to -inf)
        """
    bounds = viewport.camera.extrinsic.transformBounds(viewport.scene.
        bounds(transformed=True, dataBounds=True))
    return bounds[:, (2)]
