On- and off-times. Spatial distribution of the estimated on- (a) and off-times (b) overlaid with a 5th order balanced cumulant as a transparency mask. The images correspond to an average over 10 subsequences of 500 frames each. (c) Second-order cross-cumulant with different time lags, averaged over the x-y-plane and 10 subsequences of 500 frames each. An exponential fit to the measured curve is shown in black. Scale bars: 2μm.