A friend from France who often travels to Greece to shoot macro in the countryside uses this simple trick: he rotates the flash head up and then inserts a white plastic card, the size of a credit card, into the slot between the flash head's shell and the front of the body of the flash. Cost? Practically nothing. Result? Beautiful, every time! He never carries any $50 diffusers in his bag. I tried the trick a few times (and I am NOT a macro photographer by even the longest shot) and, guess what, I could even produce some passable extremely "micro" photographs.