1. An eye/gaze tracking apparatus, comprising: at least one image registering unit configured to record at least one series of images representing a subject; a control unit configured to control an operation sequence for the at least one image registering unit; and a data processing unit configured to receive the at least one series of images from the at least one image registering unit, and based thereon produce eye/gaze tracking data with respect to the subject, wherein the control unit is configured to control the operation sequence for the at least one image registering unit such that the at least one series of images received by the data processing unit represents a repeating sequence of image frames, wherein each period contains at least one image frame of a first resolution and at least one image frame of a second resolution being different from the first resolution.