Dragonflies are one of my favorite subjects. I usually use a Canon 400mm f/4 DO lens with an extension tube, a 1.4X Series III teleconverter, and then another extension tube. This combination, with the extension tubes actually magnifies the image on the sensor. These were probably 8 to 10 ft away, but still filled the frame. I also use a flash with a Better Beamer flash extender to light them. The combination of the extension tubes and teleconverter totally confuses the metering, so I manually figure out an f/stop by trial and error. But it works for these kind of shots and I am not right in their “faces”.