What does shutter speed not control when using flash?

Shutter speed plays a crucial role in photography, especially when flash is involved. However, when using flash, it does not directly control the exposure of the flash itself. The exposure for the flash is typically consistent and is determined by the output of the flash unit, not by the shutter speed. Flash duration is very brief, often much shorter than the shutter speed setting, meaning that shutter speed primarily influences how long the sensor is exposed to ambient light and not the flash exposure.

Ambient light is what the camera sensor captures during the time the shutter is open before and after the flash fires, which is why shutter speed can control the amount of ambient light in an image. Flash sync refers to the timing of the flash firing in relation to the open shutter. Color balance can also be affected by the ambient light's temperature and the mixture of light sources, not solely by the shutter speed settings.