Nikon SB-27 - Manual (Page 53)

53
To set up the diffuser card:
1
Set the built-in bounce flash adapter.
2
Unfold the built-in diffuser card.
Highlight your subject’s eyes using bounced flash
The SB-27 comes with a built-in bounce flash adapter for bouncing
diffused light off the ceiling. The diffuser card brightens shadows
caused by top-lighting or bouncing flash, making your subject’s
eyes appear more vibrant.