The Navitar Zoom 6000 lens system is a modular lens system that can be used to capture and analyze an enlarged image of various surfaces. Navitar Zoom lenses can be adjusted and keep the image in focus throughout the entire travel of the zoom range. This is called parfocal or parfocusing the system. Navitar Zoom lenses can be adjusted to line up the center of the sensor in the camera with the center of the optical zoom. This allows the lens to provide an image on the screen that does not wander laterally when the zoom is changed. This is called parcentricity or parcentering the zoom.