You're back from a night of photography and video shoots. There were flickering lights on the screen again, although to the eye they looked perfectly flat. Wondering again why the LED lights are flickering on the camera? The same phenomenon can be seen during the day in some lamps.
When you record the lights with a mirrorless, DSLR or phone camera, they actually flicker on the screen. Led lights flicker because of the stroboscopic effect, but the human eye cannot see it when it happens rapidly (about 60-1,000 times per second or more). These aberrations can be detected by mirrorless cameras and smartphones.
When the camera and LEDs have different frame rates, the flicker effect is more pronounced. This is clearly visible when shooting video in slow motion or at fast frame rates (FPS).
Strobe effect
LED flicker is invisible to the naked eye because they switch on and off quickly. Therefore, it appears as if the lights are constantly on when they are turned off and on at a rapid rate. The videos, on the other hand, consist of several consecutive images. These video scenes are recorded at high frame rates per second (FPS), more commonly 24 or 30 frames per second. Our brains think that everything on the screen is moving in a single, smooth motion when this effect is used in combination with other "tricks".
When the frame rate (FPS) of the video does not match the frequency of light (Hz) at which the LEDs turn on and off per second, the screen starts to flicker.
The LED usually flickers so fast that the human eye cannot detect it. The flicker captured on camera is undoubtedly due to the fact that the light is working correctly. It is only when the LED flickers to the naked eye that there is cause for concern.