Rolling shutter

Imagine a tiny camera in your hand that takes pictures very fast by opening and closing a tiny window. Now, imagine that instead of just taking one picture, the camera takes many pictures very quickly and then puts them together to make a video.

When the camera takes pictures, it doesn't capture the whole picture at once. It captures small bits of the picture, one after the other. This is called a rolling shutter.

Think of it like playing peek-a-boo with your hands. When you cover your face with your hands and then move them away quickly, your eyes see your hands moving from top to bottom one after the other. It's the same with a rolling shutter camera.

When you watch the video made with a rolling shutter camera, things can look a bit strange. If someone moves their arm quickly, you might see the top of their arm before the bottom of their arm. Or if a car drives fast by the camera, the car might look like it's bending in the middle.

This happens because each part of the image is captured at a slightly different time. It might be just a tiny difference, but it's enough to make things look weird sometimes. But don't worry, rolling shutter is a normal way of making videos and it's used in many different types of cameras, from the ones on your phone to the big ones used in movies.