1. An extra-oral dental x-ray imaging system comprising: a. an x-ray source adapted for generating x-rays for an exposure of such x-rays to an object to be imaged; b. a frame mode x-ray imaging device adapted to produce multiple frames during at least part of the exposure; c. at least one rotational axis around which at least one of the x-ray source and the imaging device rotates along a spline, the axis being located somewhere between the x-ray source focal point and the x-ray imaging device; d. a manipulator adapted for moving said at least one of the imaging device and the x-ray source between the multiple frames during the exposure about the at least one rotational axis; and e. a processing device for taking inputs of the multiple frames to compose a panoramic image of a layer of the object with a focus depth which is different in a region of interest from a focus depth corresponding to a predetermined panoramic image, wherein the focus depth for the region of interest is determined automatically.