Bouncing an on-camera flash off a white ceiling is an extremely common way to get a softer light. Here are a series of tests to see how modifying the on-camera flash changes the look. For some of these I used the HONL flash modifier system, a very well-built and well-thought-out system.
Bottom Line: There are a number of ways you can enhance the look when you bounce an on-camera flash off a white ceiling.
Left
Right
Normal flash, bounced straight up
Normal flash, bounced straight up with small white reflector card.
Larger HONL white card with ceiling bounce.
Using your hand to throw some direct light.
Using the HONL snoot to get a smaller pattern and a more contrasty look.
Using the HONL grid to get a smaller light pattern, hence a more contrasty look.
Fong Dome in use.
Stofen Box in use.
Normal flash, bounced straight up
Normal flash, bounced straight up with small white reflector card.
Larger HONL white card with ceiling bounce.
Using your hand to throw some direct light.
Using the HONL snoot to get a smaller pattern and a more contrasty look.
Using the HONL grid to get a smaller light pattern, hence a more contrasty look.