The Graslon 4100 flash diffusers are generally designed the send most of the light to the subject, not wasting “bounce” light when there is nothing from which to bounce.
The exception is the 4100D Dome diffuser, which allows more light to travel in a broader path. It is excellent in situations where there are walls and ceilings, and is superb as a slave. A very willing slave.
These photos were taken in a large ballroom with about 20 foot high ceilings. The flash was pointed straight up in both photos. In the first photo the direct flash sends the light straight up, but with the high ceilings the light comes mostly straight back down. In the second photo the 4100D Dome diffuser sends the light everywhere. Notice the far walls.
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