Macro flash technique

I'm conducting another frog and reptile workshop in St. Louis this weekend. All of the pictures are done with a macro lens and either a ring flash or a twin flash macro setup. The closer the flash is placed to the very small subjects, the more the light approaches diffused light from an overcast sky. The light raps around the animals and allows us to see all of their beautiful detail. This is a cinnamon frog from Malaysia, and I was lucky to capture it in a comical pose. I use manual exposure mode, I place the flash on ETTL (or iTTL) which is the automatic exposure mode, and I choose an aperture of f/32 for as much depth of field as possible. The shutter is the sync speed -- 1/200 in this case -- and I critically focus by moving the camera toward and away from the frogs.