Here are a couple of shots... one is me shooting the bug with the Tamron I mentioned above (and sheese, I look FAT in the picture... I am not that fat) taken by my wife with the much derided (around TPF, not my house) 18-200 VR... the other is one of the dragonflies I was shooting... not sure if it is the exact one, but it was one of the ones in the waterplants.
I actually had my 105 VR f/2.8 with me at the time on my D40, but I was using the Tamron because it has a lot greater reach and those dragonflies were REALLY working during the middle of the day (Tulsa, OK Zoo in September), so they were flying all about... and I couldn't get close. Besides, leaning out any more might have caused me to go swimming, not my first choice with a couple of grand worth of unprotected camera equipment.
Anyway, here are the shots.
EXIF: 1/1000s f/5.6 ISO400 300mm (35mm eq:450mm)
No, the dragonfly isn't perfect, I didn't have enough depth of field, but I had to keep my shutter speed up because they were not still. I don't claim this is a great picture, I was just wanting to show you that even at 1:2 the macro can be usable... these particular dragonflies were about 3 inches long.
The lens was wide open when I shot this... in retrospect, I could have knocked down the SS to about 500 and closed up the lens to about F/8 for better effect. Ah well, live and learn.