Adjust Portrait Lighting Intensity
Not only does iOS 13 add a very cool new high-key monochromatic portrait lighting effect, but it’s also added the ability to adjust the amount of portrait lighting for most of the effects.
In every mode except “Natural Light,” a new hexagon-shaped button will appear at the top of the camera screen.
Tap on this, and then simply use the slider that appears to adjust the intensity from 0 to 100. It’s just like turning the brightness of an actual set of studio lights up or down, and even better, you can also adjust it by editing a portrait mode photo after it’s been taken.