The Samsung Galaxy S9 has a super cool feature integrated: The Super Slow Motion with a short sequence of up to 960 frames per second. If you have tried this function for the first time, you may notice that the recorded video flickers strongly.
Now you might ask yourself: Is the camera of my Samsung Galaxy S9 defective?
The answer is usually: No! Because flickering is caused by someone else. More on this in the following:
Samsung Galaxy S9 - Why slow motion pictures in rooms with light flickering
Here we have to digress a little into the world of physics. In our homes in the USA, Europe or the rest of the world, electricity is used through the power outlet or the lamp connections on the ceilings. The current coming from the socket is alternating current and has 50 Hz for example in Europe.
This means that the current changes polarity 50 times per second. However, this also means that 50 times a zero point is passed through.
There is no current and the lamp is actually out. Our eyes do not notice this, as we only see at approx. 25 frames per second. A slow-motion camera, like the Samsung Galaxy S9 can! And that's why your picture flickers when you take a Super Slow Motion shot with your phone.
Depending on which light you use at home, the stronger the effect. LED lamps, which can nowadays be found in almost every household, intensify the effect. The only remedy here is real sunlight or a lamp that is operated with direct current.
Now you know why your Samsung Galaxy S9 produces flickering videos in super slow motion.