Visual inspection of an interior surface of a borehole. A housing adapted to be lowered in the borehole supports a portable camera for generating images of a portion of the interior surface of the borehole and a light source for illuminating an area adjacent the camera. A monitor receives signals from the camera and, in response thereto, displays the images generated by the camera. A viewing envelope positioned adjacent the camera defines a viewing area adjacent the camera, particularly for use in visually inspecting slurry-filled boreholes.