An apparatus that can measure both haze and clarity on a web moving at conventional manufacturing speeds. The apparatus uses an integrating sphere and a novel mirror arrangement. With this arrangement, the invention can utilize a calibration curve created using known samples over the range of measurement desired to convert in real time, and the response of two photo detectors that measure the wide and low angle scattering signals, to deduce the desired optical property values. This approach significantly increases the speed and response of sensor and enables either on-line single point or full web scanning for uniformity measurement and control.