Comparison of peak surface brightnesses over total flux densities for 106 bright, point-like sources (0.9 ≤ S_t/S_p ≤ 1.1, S/N > 200) observed in up to 11 neighboring pointings at varying distances from the pointing center (gray points). The large red points and their corresponding errors indicate median values and interquartile ranges inside 5 equally spaced distance bins. The theoretical prediction of the bandwidth smearing effect is shown by the blue curve (see text for details).