The invention relates to an x-ray diagnostics device having an x-ray tube for generating x-rays operated by a high voltage generator, having an x-ray detector for converting incident x-rays into electrical signals, having an image processing system and a control device for the duration of the x-ray pulse, in which parameters of the x-ray diagnostics device can be adjusted, with a computing unit being assigned to the control device, said computing unit determining the spatial frequency-dependent signal-to-noise ratio on the basis of the parameters and calculating therefrom the duration of the x-ray pulse and/or the remaining parameters required for a recording. The invention further relates to a method of this type for controlling the x-ray diagnostics device, in which the duration of the x-ray pulse is controlled such that the recognizability of relevant, moved objects is maximal.