The present application relates to an X-ray device having an X-ray radiation source (7), a collimator (6) and an X-ray detector (4). The reduction in the radiation dose to which a patient (5) is exposed, said reduction being generated by the collimator (6), is calculated by a data processing unit (2) from the current setting of the shield and filter elements of the collimator (6) and displayed on a display unit (3), for example, as an area shielding factor AA and/or a dose reduction factor DRF. The user can in this way detect the potential of the collimator that still exists for image improvement and for minimizing the exposure to radiation.