I find the more magnification I try to use, the harder it is to get good sharp pictures. This one was a lucky shot I guess, on the one hand I managed to get the rows of eyes to come out, but on the other I could have gotten more depth of field and a sharp[er overall picture with 50mm extension tubes instead of the 75mm used here (135mm Makinon lens)
Same here, Damselfly taken a little earlier with the same setup, the ones taken with 50mm of tubes were sharper overall, but more detail here with 75mm.
Things like the little hairs don't turn out as sharp as they might with a little less magnification. Also I think the 50mm with extension tubes does a better job overall, almost always noticeably sharper results, but I rarely get dragonflies or insects in general to let me get that close. While the 135 lets me get a foot away or more, the 50mm requires within less than 6 inches. Insects usually don't want you that close...but it's great for tiny flowers...