Binnur,
thanks. I do all of my bug shots with a 100mm macro lens, usually on a crop body for higher pixel density. These days, I usually go out with a 36mm extension tube, and I often try to shoot at or close to minimum working distance. That makes for an even shorter working distance than without a tube, however, so when I think I won't need it, I skip the tube. The first two here were taken with that tube. I took it off for the third one. The digger wasps are large enough that I didn't really need it, and they are skittish enough that it is hard to get close anyway.
One drawback of this is that it takes some time to add or remove a tube this large. Using the rig I showed in this thread,
Dragonfly post 15, I have to readjust the flash position and reverse the tripod ring, all of which takes a few minutes.
Dan