Reduce flicker and banding when shooting under fluorescent or mercury-vapor lighting during live view or movie recording. Choose Auto to allow the camera to automatically choose the correct frequency, or manually match the frequency to that of the local AC power supply.
Flicker Reduction in the Movie Shooting Menu
If Auto fails to produce the desired results and you are unsure as to the frequency of the local power supply, test both the 50 and 60 Hz options and choose the one that produces the best results. Flicker reduction may not produce the desired results if the subject is very bright, in which case you should try choosing a smaller aperture (higher f-number). To prevent flicker, select mode M and choose a shutter speed adapted to the frequency of the local power supply: 1/125 s, 1/60 s, or 1/30 s for 60 Hz; 1/100 s, 1/50 s, or 1/25 s for 50 Hz.