Intensity distribution functions, P(I), calculated from speckle patterns measured at 30.7 m for selected q values. Panels (a), (b) and (c) correspond to P(I) for exposure times (tacq) of 0.4 ms, 0.1 ms and 0.026 ms, respectively. Solid lines represent fit curves to equation (4). Insets display the scaled P(I) as a function of I/〈I〉. The dashed lines in the inset in (a) show a better agreement with equation (4) by a higher weighting of the tail region and the resulting β values are larger (∼0.33–0.36). The inset in (c) depicts the scaled form of whole set of data from different acquisitions.