Binocular microscope. A Zeiss optical microscope with a ear of wheat under the lens. This microscope has two eyepieces (at upper right) making it binocular. Under the eyepieces is the main body of the instrument, containing lenses. At left to this is the stand to which the body is attached. Turning the large circular knob moves the body up and down the stand, focusing the image. The wheat is placed on the specimen stand (at lower centre). No light source is visible. Optical microscopes are instruments which use combinations of lenses to enlarge images of small and close objects.