Have you ever taken a close-up look at a dragonfly’s amazing compound eyes? Dragonflies have the largest compound eyes of any insect; each containing up to 30,000 facets, and the eyes cover most of the insect’s head, resembling a motorcycle helmet. According to a wonderful article by GrrlScientist, “each facet within the compound eye points in a slightly different direction and perceives light emanating from only one particular direction in space, creating a mosaic of partially overlapping images.”
How exactly does that work? Scientists are still not sure how this visual mosaic is integrated in the dragonfly’s brain. If you can get close enough for a shot, you can actually see the individual facets, technically known as ommatidia. The first image below is a cropped image of an unusually cooperative Uhler’s Sundragon (Helocordulia uhleri) that I encountered last Friday while exploring a stream in Prince William County. If you click on the image, you can see the pattern of facets in the eyes.
The second image is an uncropped version of the first photo. I like the way that I as able to capture so many details of the dragonfly as it perched, like the spiky hairs on its legs and the stubble on its face as well as the pollen on its body.
The dragonfly in the third shot is another Uhler’s Sundragon that I spotted later in the day. From this angle, you can see the dragonfly’s tiny feet as it grasps the dried stalk of vegetation.
I love close-up images and will often try to capture them after I have taken some initial shots. When I am at close range, the angle of view is particularly important, because the depth of field is so shallow—some legs of the dragonfly, for example, will inevitably be out of focus, so I have to choose carefully what I want to be in focus.
Hand-holding and breathing techniques are also really important, because any movement will cause the fine details to be blurred. This is a bit of a challenge with the 180mm macro lens that I use because it does not have any built-in image stabilization.
© Michael Q. Powell. All rights reserved.
Mike Powell 