The light may be changing faster than you notice. The camera can collect different portions of those same changes. How can the same light look different through a camera? Rapid changes can blend into an apparently steady light. Different sensor rows begin their exposures at slightly different times. Those differences become bands across the recorded image. What you notice depends on the light and viewing conditions. Some lights are dimmed by switching rapidly on and off. Shorter pulses can reduce the average light output. This is one way to dim a light. Other lights have different patterns, including much steadier output. We will follow the pulsing example. Now consider how the camera collects light. Start with just one row of its sensor. During an exposure, that row collects light for a short interval. The light collected depends on what happens inside that interval. Here, the exposure falls entirely inside a bright pulse. Move it between pulses, and the row collects much less light. An exposure can also overlap a pulse only partly. That produces a value between the bright and dark examples. These are different possible timings for the same exposure duration. Across successive frames, that timing can shift relative to the pulses. Frame rate sets how often new frames begin. Exposure duration sets how long each row collects light. But why can one frame contain both bright and dark bands? Many cameras use a rolling shutter. Different sensor rows begin their exposures at slightly different times. Their exposure intervals can overlap. Some rows collect more of a pulse than others. Those differences become bands across the recorded image. The light changed over time. The camera turned that change into a pattern. Now make each exposure last longer. Let each row collect one complete, repeating light cycle. Every row now collects the same amount, despite starting at different times. The pulses continue. Their differences no longer appear as bands here. Real lights and camera settings vary. A different exposure duration can reduce flicker without changing the light. So return to the light that looked steady. Its rapid changes may blend together in your vision. The camera can collect different portions of those same changes. That is how a steady-looking light can become a flickering recording.