A well-logging device which photographically records the borehole azimuth and deviation from the vertical. In the cartridge of the downhole instrument. a compass needle indicates magnetic north and a steel ball rolling freely on a graduated concave glass indicates the hole deviation. A lens focuses these images on photographic film which is exposed, frame by frame, when the tool is held motionless, centered in the borehole at preselected stations. Compare poteclinometer.