Abstract: An exemplary embodiment comprises an X-ray tube having at least two selectively engageable different focal points, a primary radiation diaphragm adjusted relative to the X-ray tube, and comprising an image layer. When changing the focal point, an adjustment of the primary radiation diaphragm occurs in prior X-ray tubes, the adjustment resulting in a displacement of the illuminated beam field on the image layer. The present disclosure provides that the diaphragm plates of the primary radiation diaphragm are synchronously displaced in the same direction and by approximately the same amount by which the focal point is displaced when switching from the one to the other focal point. An inventive X-ray examination system is particularly suited for employment in X-ray diagnostics.