1. A method for positioning a semi-transparent diaphragm when radiologically observing a body region of a patient using a radiological device, the method comprising: producing an image recording of the body region using the radiological device; analyzing the image recording for identifying a less absorbent image region in the image recording; and determining a position for the semi-transparent diaphragm based on a result of the analysis; wherein the position for the semi-transparent diaphragm is adjusted by an actuator that is activated by a control device based on the determined position.