Dynamic range is a term used in various fields, including photography, audio, and metrology, to describe the ratio between the largest and smallest values that a certain quantity can assume. In photography, dynamic range refers to the range of light intensities from the shadows to the highlights in a subject. Essentially, dynamic range is how far the brightest spots in an image can vary from the darkest spots in an image and still maintain proper details in a single exposure. The more dynamic range a camera has, the more it can capture scenes with a great contrast between lights and darks. In audio, dynamic range is the ratio of the loudest peak to the quietest, expressed in decibels (dB) . The human auditory system has a dynamic range of about 90 dB, and audio gear that reproduces music also has a dynamic range. In metrology, dynamic range refers to the range of values that can be measured by a sensor or metrology instrument. The dynamic range of a measurement is often limited at one end of the range by saturation of a sensing signal sensor or by physical limits that exist on the motion or other response capability of a mechanical indicator.