During a visit on Monday to Occoquan Bay National Wildlife Refuge, I noted that many of the summer dragonfly and damselflies are starting to appear. I was particularly delighted to spot several Big Bluet damselflies (Enallagma durum). As their name suggests, Big Bluets are relatively large damselflies, with an overall length of about 1.7 inches (43 mm).
Big Bluets tend to active and a bit skittish, so it’s a bit tough to get a decent shot of one, especially when I am shooting with a zoom lens. The auto-focus of my Tamron 18-400mm zoom often has trouble focusing on a damselfly, because their bodies are so thin and they clasp their wings together over their bodies. Consequently, I frequently end up focusing manually and it is an advantage with this lens that the minimum focusing distance is 17.7 inches (45 cm), so I can get pretty close to my subject.
I was delighted to be able to capture this beautiful image of a female Big Bluet. My focusing was spot on and the background blurred out nicely. If you look closely, you may notice that the depth of field, i.e. what was in focus, was so shallow that much of the stalk of vegetation on which the damselfly was perched was out of focus. In case you are curious, I tried to position myself so that I was on a parallel plane with the damselfly’s body to get as much of it in sharp focus as possible.
One interesting factual tidbits about Female Big Bluets is that, like several other damselfly species, they come in two different color variants. This one is the blue form and there is also an olive form. What that means is that I cannot rely exclusively on the color of the damselfly to determine its species and must also look at other features like the shapes of the eyespots and markings on the terminal appendages.
© Michael Q. Powell. All rights reserved.
Mike Powell 