The LEDs on the back of your phone can’t compete with the bright flashes built-in to many cameras, so the $85 Godox A2 integrates a xenon flash tube into a magnetic iPhone accessory with a rechargeable battery good for about 400 photos. The A2 can be used remotely up to almost 50 feet away if you want to experiment with flash placement, but it does require you to use Godox’s own iOS camera app to trigger the flash when you press the shutter button.