DIY: A Cheap and Easy Open-Top Flash DiffuserSome DIY projects take a lot of time to complete and others can be more trouble than they're worth if you don't already possess the skill set to create them. This is not one of those. In fact, this barely even qualifies as a DIY project.
Forward thinking photographer Jeff Vier swung on over to Home Depot and noticed that a particular downspout funnel would fit nicely on his flash. Specifically, it's an Amerimax Home #85208 downspout funnel, available on Amazon for $3 plus shipping.
The downspout funnel fits snugly on some flashes and a bit loose on others. Viers recommends rubber bands to solve this problem.