For macro work the inflatable diffuser is cheap yet very effective.
It will fit any size flash head because of the elastic fastening and the curve of the front panel sends light downwards even when used with a 1.7 tele extender and a 10 dioptre lens on the front of the Tamron 90 mm macro lens.
Although the 3 times life size image is close to the camera there is still enough light from the flash for small apertures.
In the picture of crab apple blossom the flower spray was mounted with a crocodile clip and stood in a white polystyrene box with a blue cartridge paper used as a background.
The flash used was a Minolta 4000AF with the diffuser on it held at approximately 10 inches away to the left at about 30-40 degree angle.
As the diffuser head measures about 8 to 9 inches across the light spread was enough to diminish shadows and give a natural appearance to the flowers.