Test shots: Brachytron pratense exuvia (female)

As if it weren’t challenging enough to identify odonate exuviae from species native to the United States of America (where I live), I just started working with some specimens collected by a good friend during April 2018 in Vienna, Austria.

I decided to start with a specimen that I recognized immediately as a member of the Family Aeshnidae (Darners). Here’s the decision tree used to identify the family.

• The specimen has a flat labium that doesn’t cover the face (not mask-like).
• Antennae are thin and thread-like (not club-like, as in Gomphidae larvae/euviae).
• Eyes are large relative to the size of the head.

One-off

The first photo is a “one-off,” that is, not a composite image. The focus point is on the face mask/head; the rest of the subject is in soft focus. I think this is a good way to draw the viewer’s eyes to a specific part of a photo, while adding a sense of depth.

Hairy Dragonfly (Brachytron pratense) | exuvia (face/head-dorsal)

Composite images

The next “photo” is a three-layer focus-stacked composite image: The focus point is on the face mask/head in the first photo; the thorax in the second photo; and the terminal appendages in the third photo. The entire body of the exuvia is acceptably in focus, including the legs.

Notice the unusual shape of the head. Head shape can be used to identify some species in Family Aeshnidae. Source Credit: Sue Gregoire, personal communication. Kestrel Haven Migration Observatory.

In fact, several members of the “Dragonflies and Damselflies – Worldwide Odonata” Facebook group were able to identify this specimen based upon the shape of its head and eyes. Sincere thanks to Tim Termaat, Hartwig Stobbe, and Rob Strik for kindly identifying this specimen as an exuvia from a Hairy Dragonfly (Brachytron pratense), also known as a Hairy Hawker.

Hairy Dragonfly (Brachytron pratense) | exuvia (dorsal-lateral)

The last “photo” is a four-layer focus-stacked composite image: The focus point is on the head in the first and second photos; the thorax in the third photo; and the terminal appendages in the fourth photo. The entire body of the exuvia is acceptably in focus, including the legs.

This individual is a female, as indicated by the rudimentary ovipositor that can be seen clearly on the ventral side of abdominal segment nine (S9).

Hairy Dragonfly (Brachytron pratense) | exuvia (ventral)

Related Resources

• The Society of German-speaking Odonatologists (GdO)
• The British Dragonfly Society (BDS)
• List of Odonata species of Great Britain
• Odonate Exuviae (Dragonflies and Damselflies), photo-illustrated identification guides by Walter Sanford

Tech Tips

The following equipment was used to shoot both of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tube; Canon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to create the two focus-stacked composite images, as well as spot-heal and sharpen all three images.

Copyright © 2018 Walter Sanford. All rights reserved.

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Three-layer focus stack

Bob Perkins collected and reared a Widow Skimmer dragonfly (Libellula luctuosa) nymph. This blog post features a three-layer composite image of the exuvia from the odonate nymph.

Three photos were used to create the focus stack: The focus point is on the face mask/head in the first photo; the thorax in the second photo; and the terminal appendages in the third photo.

Widow Skimmer (Libellula luctuosa) | exuvia (ventral)

Due to the orientation of the subject, the entire body of the exuvia is acceptably in focus, including most of the legs. I wish I could say this happy accident is a result of careful planning!

Related Resource: Test shots: Libellula luctuosa exuvia.

Tech Tips

The following equipment was used to shoot both of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tube; Canon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to create the focus-stacked composite image, as well as spot-heal and sharpen the final output.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Libellula luctuosa exuvia

Bob Perkins collected and reared a Widow Skimmer dragonfly (Libellula luctuosa) nymph. This blog post features test shots of the exuvia from the odonate nymph.

Several field marks worth noting include the “tiger stripes” on top of its head, wing pads that are perpendicular to the body, dorsal hooks (exact number unknown without closer examination), and lateral spines on abdominal segments eight and nine (S8-9).

No. 1 | Widow Skimmer (Libellula luctuosa) | exuvia (dorsal)

The exuvia has small pointy eyes, a mask-like labium (prementum) that covers the face, and thin threadlike antennae.

No. 2 | Widow Skimmer (Libellula luctuosa) | exuvia (ventral)

Background color

In this case, “Test shots” also refers to experimentation with the background color. At the suggestion of Larry de March, Western Odonata Facebook group, I shot the test photos on a Vello 18% gray card.

For a background, I prefer something less bright than pure white to simplify exposure and stay within the dynamic range of the camera. Source Credit: Larry de March.

I edited Photo No. 1 and No. 2 a little differently in an attempt to arrive at a pleasing shade of neutral gray. Notice that No. 1 appears bluer in color than No. 2, which seems to be slighty yellowish.

Although a sample size of one doesn’t necessarily prove anything, my initial opinion is I prefer either an off-white or pure white background. Which color do you prefer?

Related Resource: Three-layer focus stack.

Tech Tips

The following equipment was used to shoot both of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tube; Canon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen both images.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Aeshna umbrosa exuvia

Bob Perkins collected and reared an unknown species of odonate nymph from a tiny stream in Carroll County, Virginia USA. The larva emerged from one of Bob’s holding tanks overnight on 23-24 November 2018 and metamorphosed into an adult male Shadow Darner dragonfly (Aeshna umbrosa). Shadow Darner is a member of the Family Aeshnidae (Darners). The following test shots show the exuvia from the odonate nymph.

Test shots of this beautiful specimen were taken using a relatively small aperture of f/16 for greater depth of field. Each photo is a “one-off,” that is, not a composite image. Focus stacks will be created sometime in the near future, after the exuvia is rehydrated and its legs are repositioned  for easier posing.

Lateral-ventral view

The focus point of the first photo is on the right eye. Given the orientation of the specimen, most of the exuvia is acceptably in focus at f/16. For what it’s worth, I really like the composition of this photo!

Notice the specimen has a flat labium (prementum) that doesn’t cover the face (not mask-like). That is a characteristic field mark of two families of dragonflies: Family Aeshnidae (Darners); and Family Gomphidae (Clubtails).

Shadow Darner (Aeshna umbrosa) | exuvia (lateral-ventral)

This individual is a male, as indicated by vestigial hamules that are visible on the ventral side of the specimen.

Dorsal view

The focus point of the next photo is on the head: the head is tack-sharp; the terminal appendages are in soft-focus. Sometimes it’s necessary to create focus-stacked composite images in order to render the subject in focus from head-to-tail and edge-to-edge.

Lateral spines on abdominal segments six to nine (S6-9) indicate this specimen is A. umbrosa.

Shadow Darner (Aeshna umbrosa) | exuvia (dorsal)

The focus point of the next photo is on the abdomen, just below the wing pads. Relative to the preceding photo, notice the head is slightly softer in focus while the terminal appendages are slightly sharper in focus.

Shadow Darner (Aeshna umbrosa) | exuvia (dorsal)

Tech Tips

The following equipment was used to shoot all of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tube; Canon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen all three images.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Tachopteryx thoreyi exuviae

Two Gray Petaltail dragonfly (Tachopteryx thoreyi) exuviae were collected on 23 May 2018 by Walter Sanford near a forested seep at an undisclosed location in Northern Virginia USA. Gray Petaltail is a member of the Family Petaluridae (Petaltails).

Although both specimens are similar, they aren’t identical. For example, twin rows of hook-like structures are clearly visible on the dorsal side of the abdomen on the lower exuvia, and almost invisible on the upper exuvia. The upper exuvia is dirtier and appears to be more “worn” than the lower one. Notice the “schmutz” on the face of the lower exuvia, probably a piece of leaf litter.

Gray Petaltail (Tachopteryx thoreyi) | exuvia (dorsal)

Both individuals might be male, as indicated by vestigial hamules that appear to be visible on the ventral side of the specimens.

Gray Petaltail (Tachopteryx thoreyi) | exuvia (dorsal)

Test shots of the specimens were taken using a relatively small aperture of f/16 for greater depth of field. Each photo is a “one-off,” that is, not a composite image. Focus stacks will be created sometime in the near future, after the exuviae are rehydrated, cleaned, and posed for better composition.

Tech Tips

The following equipment was used to shoot both of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tube; Canon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen both images.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Stylurus sp. exuvia

Joe Johnston is an avid boater and sport fisherman who kindly agreed to be my “Eyes on the Aquia,” always on the lookout for odonate exuvia to share with me. On 18 July 2018, Joe collected an especially interesting specimen from Aquia Creek in Stafford County, Virginia USA.

Abdominal segment nine (S9) is elongated, strongly suggesting this individual is a member of the genus Stylurus (Hanging Clubtails).

Stylurus sp. | exuvia (dorsal)

Did you notice the spider carcass that photobombed my test shots of the exuvia? Look for the spider along the upper-edge of the thorax in the dorsal view; lower-edge in the ventral view.

Stylurus sp. | exuvia (ventral)

This individual might be Laura’s Clubtail (Stylurus laurae). Laura’s Clubtail is within range of Stafford County, although it is unknown to occur there. S. laurae would be a new species for the Dragonfly Society of the Americas Odonata Central species checklist for Stafford County, Virginia USA.

According to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, the adult flight period for Laura’s Clubtail is 20 June to 26 September. The species is rare to uncommon. Its habitat is streams and rivers.

Tech Tips

The following equipment was used to shoot both of the macro photographs featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens plus lens hood. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Actually, back-button focus was used to autofocus the image and adjusted manually as necessary. That’s also a Fujifilm thing. Camera settings: focal length 80mm (120mm, 35mm equivalent); f/16; 1/500s.

A Godox XProF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control a pair of off-camera Godox TT685 Thinklite TTL Flashes (TT685F and TT685C) set for radio slave mode. Each flash was fitted with a snap-on plastic diffuser.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen both images.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Stylurus plagiatus exuvia

A Russet-tipped Clubtail (Stylurus plagiatus) exuvia was collected by Joe and Loren Johnston on 20 June 2018 from Aquia Creek in Stafford County, Virginia USA.

Notice that abdominal segment nine (S9) is elongated, strongly suggesting this individual is a member of the genus Stylurus. The large dorsal hook of abdominal segment nine (S9) that overhangs segment 10 (S10) is a key marker for southern specimens of plagiatus.

Russet-tipped Clubtail (Stylurus plagiatus) | exuvia (dorsal)

The “working distance” for the 11mm Fujifilm extension tube/Fujinon 80mm macro lens combo, that is, the distance from the front of the lens barrel to the subject, is long enough to be able to use the lens hood.

Hotspots from external flash units, technically known as specular highlights, are more noticeable sometimes when the flash heads are closer to the subject. It appears the lens hood may have reduced that problem; more experimentation is required to be sure.

Russet-tipped Clubtail (Stylurus plagiatus) | exuvia (ventral)

Related Resource: Stylurus plagiatus exuvia, a photo-illustrated identification guide.

The Backstory

Joe Johnston is an avid boater and sport fisherman. On 20 June 2018, Joe and his brother Loren were fishing together on Aquia Creek in Stafford County, Virginia USA.

Fish require food and shelter. Sometimes fish shelter near trees that have fallen into water, or the wooden pilings of boat docks. Joe and Loren were casting artificial fishing lures toward one of several docks that extend far into Aquia Creek, when Loren’s lure snagged on one of the pilings. When Joe moved his boat alongside the piling in order to retrieve the fishing lure, Loren noticed an odonate exuvia on the side of the piling. Joe and Loren kindly collected several exuviae, including this one, and shared them with me. Thanks, gentlemen!

Tech Tips

The following equipment was used to shoot both of the macro photographs featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens plus lens hood. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Actually, back-button focus was used to autofocus the image and adjusted manually as necessary. That’s also a Fujifilm thing. Camera settings: focal length 80mm (120mm, 35mm equivalent); f/16; 1/500s.

A Godox XProF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control a pair of off-camera Godox TT685 Thinklite TTL Flashes (TT685F and TT685C) set for radio slave mode. Each flash was fitted with a snap-on plastic diffuser.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen both images.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Pachydiplax longipennis exuvia

A Blue Dasher (Pachydiplax longipennis) exuvia was received from Andy Davidson, a graduate student at Virginia Commonwealth University.

Blue Dasher (Pachydiplax longipennis) | exuvia (dorsal)

Test shots of the specimen were taken using a relatively small aperture of f/20 for greater depth of field. Each photo is a “one-off,” that is, not a composite image. Focus stacks will be created sometime in the near future, after the exuvia is rehydrated and posed for better composition.

Blue Dasher (Pachydiplax longipennis) | exuvia (dorsal)

Extremely shallow depth-of-field is a common problem in macro photography. Depth-of-field increases as aperture decreases — in other words, they are inversely related. In this case, an aperture of f/20 was insufficient for the entire subject to be acceptably in focus so it will be necessary to create some focus stacks.

Also notice the background of the second photo looks darker and bluer than the first one. That was caused by the fact that the subject was farther from the front of the lens. There are work-arounds for this lighting problem, but hey, like the title of this blog post says these are “test shots.”

Related Resources

• Precious cargo, a blog post by Walter Sanford.
• Test shots: Pantala flavescens exuvia
• Test shots: Erythemis simplicollis exuvia

Tech Tips

The following equipment was used to shoot both of the macro photographs featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Actually, back-button focus was used to autofocus the image and adjusted manually as necessary. That’s also a Fujifilm thing.

A Godox XProF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control a pair of off-camera Godox TT685 Thinklite TTL Flashes (TT685F and TT685C) set for radio slave mode. Each flash was fitted with a snap-on plastic diffuser.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen both images.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Erythemis simplicicollis exuvia

An Eastern Pondhawk (Erythemis simplicicollis) exuvia was received from Andy Davidson, a graduate student at Virginia Commonwealth University.

Eastern Pondhawk (Erythemis simplicicollis) | exuvia (dorsal)

This individual is a male, as indicated by the vestigial hamules visible on the ventral side of the exuvia, abdominal segments two and three (S2-S3).

Eastern Pondhawk (Erythemis simplicicollis) | exuvia (ventral)

Food for Thought

This exuvia is one of three “cast skins” from odonate nymphs that were collected in the field and reared in the laboratory as part of a research project entitled “Predator-Prey Interactions in a Changing World.” Since all three nymphs were collected from the James River rock pools, I assume they lived in essentially the same habitat. I wonder why the E. simplicollis exuvia is so much darker in color than either the P. flavescens or P. longipennis exuviae.

Related Resources

• Precious cargo, a blog post by Walter Sanford.
• Test shots: Pantala flavescens exuvia
• Test shots: Pachydiplax longipennis exuvia

Tech Tips

The following equipment was used to shoot both of the macro photographs featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Actually, back-button focus was used to autofocus the image and adjusted manually as necessary. That’s also a Fujifilm thing.

A Godox XProF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control a pair of off-camera Godox TT685 Thinklite TTL Flashes (TT685F and TT685C) set for radio slave mode. Each flash was fitted with a snap-on plastic diffuser.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen both images.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Pantala flavescens exuvia

A Wandering Glider (Pantala flavescens) odonate exuvia was received from Andy Davidson, a graduate student at Virginia Commonwealth University in Richmond, Virginia USA. Sincere thanks to Andy for sharing this beautiful specimen!

The exuvia is a “cast skin” from a nymph that was collected in the field and reared in the laboratory as part of a research project entitled “Predator-Prey Interactions in a Changing World.”

Wandering Glider (Pantala flavescens) | exuvia (dorsal)

Test shots of the specimen were taken using a relatively small aperture of f/16 for greater depth of field. Each photo is a “one-off,” that is, not a composite image. Focus stacks will be created sometime in the near future, after the exuvia is rehydrated and posed for better composition.

Wandering Glider (Pantala flavescens) | exuvia (dorsal)

Related Resources

• Precious cargo, a blog post by Walter Sanford. (Hey, that’s me!)
• Test shots: Erythemis simplicicollis evuvia
• Test shots: Pachydiplax longipennis exuvia

Tech Tips

The following equipment was used to shoot both of the macro photographs featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens. The camera was set for both manual exposure and manual focus. That’s right, a switch on the camera body is used to set the type of focus. It’s a Fujifilm thing. Actually, back-button focus was used to autofocus the image and adjusted manually as necessary. That’s also a Fujifilm thing. For details, see “More Tech Tips” (below).

A Godox XProF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control a pair of off-camera Godox TT685 Thinklite TTL Flashes (TT685F and TT685C) set for radio slave mode. Each flash was fitted with a snap-on plastic diffuser.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen both images.

More Tech Tips

Focus peaking can be activated when the camera is set for manual focus mode. Using back-button focus (AF-L button) in manual mode enables one to retain full control of the exposure triangle, focus quickly, and see what’s in focus before shooting a photograph. Fuji Back Button Focus (4:06), a YouTube video by Ashraf Jandali, provides a clear demonstration of how to use back-button focus on the Fujifilm X-T1.

Copyright © 2018 Walter Sanford. All rights reserved.