Abstract: An apparatus and method for detecting, determining and/or quantifying cable flexing for use in optical instruments or in other instruments such as strain gauges, seismometers, and other instruments in which it is desired to detect, determine and/or quantify the degree of flex of a cable or implement that includes, or may be adapted to include, such a cable. A fiber optic, light conduit or similar cable is provided, which may provide light to, and receive light from, an object or material that is being optically characterized. Light may pass from a light source to an object or material, and be returned from the object or material to a spectrometer or set of sensors for determining the optical characteristics of the object or material. A light path is provided through the cable from the object or an end point of the cable to a spectrometer or sensors to return light in order to detect, determine and/or quantify the degree of flex in the cable or changes in the flex of the cable.