My standard macro kit costs several thousand dollars (camera, $1800; lens, $1000; flash, $600; various accessories, $300). Yet, most of what I consider the more unique aspects of my style are down to a mere few cents of tape, paper clips, and plastic diffusion.
A homemade diffuser inserted below the flash heads makes a sizable difference. To my eye, the second image is miles better than the basic, out-of-the-box flash photograph. Diffusion softens and spreads the light, eliminating glare and allowing us a more detailed look at the ant's texture.
My decidedly low-tech diffuser is a double-layer of Rosculux tough white diffusion clipped via cardboard to a plastic collar made from a milk jug.
A closer look at the device, partially unclipped and happily filthy from field use:
To understand why a diffuser imparts such a significant softening effect, consider the perspective from the other end of the camera. Here is how an ant sees my gear with and without the diffuser:
The diffused light is soft, expansive, giving the impression of a cloudy day.
As one final modification of the twin flash, I have raised the heads an inch above factory standard. Why? The extra distance allows the cone of light to fall across more of the diffuser's surface. This spreading effect is apparent when the diffuser is viewed from above:
Once you learn to recognize this setup as reflected in the shiny cuticles of my little subjects, you'll know just how much I rely on it. See?
addendum: There are more ways than one to diffuse the twin flash. I love looking at the various contraptions created by others: