Why it matters.
You can observe the lighting as you arrange a still image or record video.
A closer look.
Shutter time controls how long this illumination contributes to a capture. Continuous sources can be daylight or lamps; dedicated LED and HMI sources are also used for video.
Picture this
Move a lamp around a still object and observe its shadows before taking a picture.
Keep in mind.
Brightness, colour and flicker behaviour depend on the source. Continuous light does not itself guarantee motion-free pictures.