I know this may seem like a stupid question, but I wanted to know how I could literally weaken the light of my flash. I take photos of a prayer group at night, and in general, it is very dark, but people also move quite a bit, so that a fast shutter speed is required. So I need to resort to using a flash, even though it runs the risk of disturbing the people praying. So I was looking for a diffuser, such as an octabox for the flash, but I'd like to hear from you guys, is there some way of making the flash weaker in order not to disturb people so much? At home I put a piece of paper in front of the flash – but is there some more professional way of doing this? Thanks.
This is an approximate human translation of the original question submitted in Portuguese. See the edit history for the original.