Evolution of the standard deviation in the OPD as a function of iteration when correcting VLT/SPHERE residual atmospheric turbulence with a wind speed of 10 m s⁻¹ and an iteration lag of 0.67 ms for 0.6 s (1000 iterations). The green curve shows the case with a filter at 44 c/p and a one-frame lag, the red curve with a filter at 44 c/p and a two-frame lag, and the blue curve with a filter at 55 c/p and a two-frame lag. The correction loop starts at time 0.