1. An electronic device equipped with a video imaging process capability, comprising: a camera unit configured to produce image frames from an imaging view which includes a region-of-interest ROI, an adjustable optics configured in connection with the camera unit in order to focus the ROI on the camera unit, an identifier unit in order to identify a ROI from the image frame, a tracking unit in order to track the ROI from the image frames during the video imaging process, wherein the tracking unit is configured to perform the ROI tracking on macroblock basis in which ROI tracking is configured to be decided whether the pixels of the current macroblock of the current image frame belong to a ROI region or to a background region and the decision is configured to be based on the color content of the previous image frame in which the ROI region is already known, and the tracking unit is further configured to: define the ROI region and the background region in a search area of the previous image frame which definitions are configured to be based on a ROI mask of the previous image frame, form color histograms of the ROI region and the background region of the search area, analyze the color histograms of the ROI region and background region and on the basis of the results of the analysis, determine the status of the pixels of the current macroblock of the current image frame whether they belong to the ROI region or to the background region, and update the current ROI mask based on this determination, an auto-focus unit configured to analyze the ROI on the basis of the tracking results provided by the tracking unit in order to adjust the optics and the device being configured to determine the spatial position of the ROI along the Z-axis in order to detect the movement of the ROI in depth of the imaging view, determine the spatial position of the ROI from the produced image frames, determine the Z-axis position of the ROI from a change in the size of the ROI between produced consecutive image frames, and adjust the optics on the basis of the determination in an established manner.