All images shot with a Canon 40D, Canon MPE65 1X-5X macro lens and Canon MT24EX Twin Flash with DIY Diffuser.
There is just this one thing that bothers me though - the twin catch lights in subjects with big reflective eyes, such as my favorite spider - jumping spider! In the image above, the highlight/catch lights in the eyes have been toned down in PP. It was much brighter originally!
Now compare it to another jumper shot lit with a big bowl diffuser:
I prefer a single, bigger catch light like this.
For more lighting comparison, please check out A Comparison of Different Lighting Setups.
Now a couple of sample shots from the newest diffuser:
The dome is transparent PP material from a mineral water bottle, covered with 2 layers of polystyrene sheets. Idea from Stephen's cup diffuser (SteB1) on Juza forum.
I used 3M medical tape to hold the concave diffuser in place. But i think I will get some moldable plastic to DIY a better holder!
3M medical tape
Now the sample shots:
Definitely nicer catch lights in the spider's eyes. However, the catch lights seem to be much brighter in the smaller pair of front-facing eyes though.
More to be improved on the newest diffuser. Perhaps a more opaque material Stay tuned.
Edit: slightly improved version of the cheap but great DIY Concave Diffuser is here.