“Perilampid Wasp” by Sam Droege

focus stacking stacked composite macro insect photography

Perilampid Wasp, Boonesboro, Maryland by Sam Droege and the US Geological Survey Bee Inventory and Monitoring Lab

There is no reason that scientific photography can’t be both informative and aesthetic. Our laboratory creates monitoring programs for animals and plants and, when necessary, creates identification guides that are largely for use by other scientists using microscopes. Identification guides require illustrations, which in the past were done as line drawings because photographing tiny things, whether under a microscope or with a high powered macro lens, had the same problem…unworkable depths of field. To obtain the level of detail needed to resolve surface sculpturing and fine hairs you ended up with a depth of field in the fractions of a millimeter. Not workable.

Enter digital cameras…and then digital processing, and clever people who somehow figured out how to combine overlapping digital photographs with different regions of focus into a single in-focus shot with as much detail as your sensor field and optical equipment permit. There are many ways to set up these focus-stacked shots and we illustrate one of our approaches here.

Our pictured subject is one buff Perilampid Wasp, a hyperparasite, designed by lifestyle to parasitize other parasites. You have encountered many of these bad boys as you walk along trails and through fields but ignored them because they are only 2-4mm and to you were just another gnat. But up close, my, how deliciously exquisite in detail and color. With such stacked shots the insect world becomes an entirely different universe, one made visible for the first time since we split from the insects a mere 500 million years ago.

This stacked shot was taken with a Canon EOS 5D Mark II and a Canon MP-E 65mm 1-5x macro lens, set to 5X in this particular case. The camera was fixed to a Cognisys Stackshot Focus rail which comes with a small microprocessor that lets us set the start of a shot, the end of a shot and the distance between shots, and then runs the camera on the sled to take the complete stack automatically. The specimen is usually fixed to an insect pin or, in this case, glued to an acupuncture needle with superglue and set in clay on a stand. We now use an old heavy laboratory jack to move the specimen up and down for ease of positioning, but in the past simply repositioned the plasticine clay for each shot.

A set of Canon MT-24EX Macro Twin Lite flashes are fixed to pieces of wood on either side of the jack stand and are angled away from the specimen towards the wall of a Styrofoam beer cooler which lies inverted over the specimen, stand and flash. The camera lens enters the cooler through a cut-out and the rear of the cooler has been nearly completely removed so that the background of the shot is a piece of black velvet (we used to use black felt, but velvet eats more light than felt) taped to the wall about 3 feet away.

Camera settings are usually set to f/5.6, ISO 100 with the shutter speed at 1/200th of a second. The flash is set to manual and is varied to get the proper lighting, which is usually just a touch on the dark side to diminish hot spots on the often bright white hairs and to bring at least some definition to what are often very black insect bodies. The low ISO maximizes sharpness and keeps the background dark, the mid-range f-stop is optimal for lens sharpness, and the shutter speed is the sync speed for the flash.

After stacking, the 115MB TIFF file is opened in Adobe Bridge Camera Raw, sharpness is set in all shots to Amount = 150 with Radius = 1.9. The exposure is tweaked (highlights often need to be lowered) and the black background is pushed to 0 0 0. Subsequently the picture is opened in Photoshop, pixel artifact halos surrounding the specimen are cleaned up with the burn tool set to burn shadows at exposure = 50-75%, the pin is erased, and lint and dust (always present) are removed with the spot removal tool; probably not a whole lot different than what is done in wedding photography. These shots are no longer documents but portraits.

As your public servants we work for you. All of our pictures are public domain and freely downloadable to scientists as well as the general public. They can be viewed and retrieved at our Flickr site. They can be used for any purpose you like, no need to ask for permission. (Our favorite shots are located in the 'Eye Candy' set.) A downloadable PDF of our basic set up is available on our FTP site and you can also find more information on what we do at our YouTube site. - Sam Droege

Equipment and settings: Canon EOS 5D Mark II, Canon MP-E 65mm 1-5x macro lens, Canon MT-24EX Macro Twin Lite flashes, Cognisys Stackshot Focus rail, inverted cooler, black velvet background - f/5.6 at 1/200th - ISO 100

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