Flashes with AF-assist light

Autofocus illumination

— the ability to use the flash as a backlight for camera autofocus. Such illumination is provided by an additional lamp installed in the flash body; most often this lamp operates in the visible range (a characteristic red-orange tint), however, there are models with "invisible" infrared illumination systems. Anyway, this function will be especially useful if you plan to shoot a lot in low light conditions: with a small amount of light and low contrast of the scene, the autofocus of modern cameras starts to “act up”, works much slower than usual, or even fails to cope with the task. Additional lighting helps to avoid these troubles.