An adaptive X-ray filter for varying a local intensity of X-ray radiation includes a first chamber containing a magnetorheological or electrorheological first liquid, a second chamber containing a second liquid that absorbs X-ray radiation, and a flexible membrane that separates the first chamber from the second chamber. Using the flexible membrane, a layer thickness ratio of the first liquid and the second liquid may be varied. A heating apparatus that heats the second liquid is arranged in the adaptive X-ray filter. The second liquid is a liquid metal.