Under-eye shadows with bounce flash usually happen because all the light is coming from above after it reflects off the ceiling. To keep the soft bounced look, add a little forward fill.

A simple fix is to use a bounce card—the small white card built into some flashes, or a DIY card if your flash doesn’t have one. It sends a small portion of the flash directly toward the subject while the rest still bounces off the ceiling.

That direct fill helps open up shadows under the eyes without giving the harsh look of full direct flash. Some photographers also use accessories designed for this, such as small flash reflectors that send part of the light forward and the rest upward.

So the general solution is: bounce most of the light, but reflect a little straight ahead to fill facial shadows.