Automatic flash units are connected to the camera via a hot-shoe contact or a sync cord connection and have their own automatic flash control. This means that it isn’t the camera that controls the flash, rather the flash itself responds intelligently and meters the light as precisely as required by the subject. Automatic flash units are available in manageable compact flash format in guide number classes 36 and 20. Automatic flash units are particularly suitable for digital bridge cameras with simple hot shoe flash.