Archive for March, 2018

Ashy Clubtail exuvia focus stack

March 30, 2018

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividus) nymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuvia from the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

Tech Tips

The preceding image is a composite of 39 photos taken using the following equipment: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (manual focus only, set for 3x magnification); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites set for “Slave” mode.

Adobe Photoshop CC 2017 was used to focus stack the photos and post-process the final output.

According to the “Focus Stacking Step Size Calculator” embedded in the “Focus Stacking” Web page, the “safe step size” is 0.213 mm for an aperture of f/11 at 3x magnification using a full-frame DSLR. That’s right, 0.213 mm! The safe step size is the incremental distance at which the in-focus areas of two photos overlap. The ruler on the inexpensive focus rail that I use is marked in millimeters only, so I attempted to move the focus rail in tiny increments in two passes: one pass moving from front-to-back; and a second pass from back-to-front.

Copyright © 2018 Walter Sanford. All rights reserved.

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Previews of coming attractions

March 28, 2018

Several test photos were taken for an upcoming identification guide for exuviae from Slaty Skimmer dragonfly (Libellula incesta).

The exuvia has a mask-like labium with smooth crenulations, indicating this specimen is a member of the Family Libellulidae (Skimmers), the largest family of dragonflies.

No. 1 | Libellula incesta | exuvia (face-head-dorsal)

Also notice the exuvia has “pointed” eyes, rather than “rounded” eyes like the exuvia from a Carolina Saddlebags dragonfly (Tramea carolina) shown below.

No. 2 | Tramea carolina | exuvia (face-head)

The pointed- versus rounded eyes dichotomy is a somewhat subjective decision, but if you make the right choice then this marker can be used to narrow the range of possible Libellulidae genera.

Exuviae from three genera of Libellulidae have pointed eyes: Libellula (18 species); Orthemis (3 species); and Plathemis (2 species). Slaty Skimmer (Libellula incesta) is one of 18 species in the genus Libellula.

Exuviae from all other genera of Libellulidae have rounded eyes.

No. 3 | Libellula incesta | exuvia (dorsal)

This specimen needs to be rehydrated/relaxed in order to remove some distracting debris and reposition the legs for better photo poses.

No. 4 | Libellula incesta | exuvia (ventral)

To be continued…

The Backstory

A Slaty Skimmer dragonfly (Libellula incesta) nymph was collected by Bob Perkins on 29 May 2017 along Pine Creek in Carroll County, Virginia USA. The nymph was reared in captivity until it emerged on 29 June 2017 and metamorphosed into an adult male. This specimen is the exuvia from the nymph.

Copyright © 2018 Walter Sanford. All rights reserved.

Ophiogomphus incurvatus exuvia

March 26, 2018

Disclaimer

Soon after I began creating illustrated identification guides for odonate exuviae, I shared a pointer to Perithemis tenera exuviae on the Northeast Odonata Facebook group. Ed Lam commented on my post. The operative sentence is as follows.

I don’t expect anyone to identify Perithemis tenera larvae from Walter’s blog post but it gives a novice a better sense of what larval identification is all about and that has value. Source Credit: Ed Lam, Northeast Odonata Facebook group.

I disagree with Ed’s comment, although I let it go at the time in deference to Ed’s considerable expertise. I do expect anyone can use my guides to identify the species of odonate featured in each guide. Otherwise, what’s the point of making the guides? After I read Ed’s comment I tweaked the specific blog post and retooled the template that I use for most guides.

All of that being said, in my opinion it would be challenging at best to identify an exuvia from Ophiogomphus incurvatus to the species level using only the dichotomous key in Dragonflies of North America by Needham et al., the best resource currently available — significant sections of the key are unclear and unreliable. In contrast, Bob Perkins and I know the identity of the specimen because Bob observed the species of adult dragonfly that emerged from the exuvia.

For what it’s worth, this blog post features a fairly complete set of annotated photos of an Ophiogomphus incurvatus exuvia. Perhaps the photo set can be used in combination with the dichotomous key in order to make identification easier for others.

The Backstory

An Appalachian Snaketail dragonfly (Ophiogomphus incurvatus) nymph was collected by Bob Perkins. The nymph was reared in captivity until it emerged on 20 March 2017 and metamorphosed into an adult male. This specimen is the exuvia from the nymph. Appalachian Snaketail is a member of the Family Gomphidae (Clubtails).

A two-step process was used to attempt to verify the identity of the exuvia.

  1. Determine the family.
  2. Determine the genus and species.

Step 1. Family

First, determine the family of the specimen. For reference, watch the excellent Vimeo video Identifying dragonfly larva to family (8:06). Here’s the decision tree used to identify the exuvia as a member of the Family Gomphidae (Clubtails).

  • The specimen has a flat labium that doesn’t cover the face (not mask-like), as shown in Photo No. 1, 5, and 6.
  • Antennae are club-like (not thin and thread-like, as in  Aeshnidae larvae), as shown in Photo No. 1.

It’s simple and straightforward to recognize this specimen is a clubtail. Expect a bumpy ride beyond this point!

No. 1 | Ophiogomphus incurvatus | exuvia (face-head)

Step 2. Genus and species

The size of specific antennal segments is a significant marker for identifying some species of Ophiogomphus. In this case, the antennae on the specimen will need to be cleaned in order to count segments and measure their dimensions.

No. 2 | Ophiogomphus incurvatus | exuvia (dorsal)

Lateral spines are present on abdominal segments seven through nine (S7-S9). Dorsal hooks appear to be well developed on segments eight and nine (S8, S9); they resemble “dorsal abdominal processes” on most other abdominal segments.

No. 3 | Ophiogomphus incurvatus | exuvia (dorsal-lateral)

The cerci are approximately three-fourths (3/4) as long as the epiproct and paraprocts.

No. 4 | Ophiogomphus incurvatus | exuvia (anal pyramid)

Photo No. 4 and 5 show ventral views of the exuvia.

No. 5 | Ophiogomphus incurvatus | exuvia (ventral)

The vestigial hamules shown in both photos indicate this individual is a male.

After emergence

The next photograph shows the Appalachian Snaketail dragonfly after emergence from one of Bob Perkins‘ holding tanks. Ophiogomphus incurvatus is 40-43 mm in total length (Paulson, 2011).

Image used with permission from Bob Perkins.

This individual is a male, as indicated by its “indented” hind wings, hamules, and terminal appendages.

Image used with permission from Bob Perkins.

Related Resource

The dichotomous key for Ophiogomphus that appears on pp. 261-262 in Dragonflies of North America, Third Edition by Needham et al. was used to attempt to verify the genus and species of the exuvia. Markers that match this specimen are highlighted in boldface green text. Three boldface green asterisks (***) are used to highlight the thread for identification of O. incurvatus. Disclaimers are highlighted in boldface red text.

p. 261

1. Abdomen without lateral spines or dorsal hooks; antennal segment 4 minute, much narrower than segment 3. [howei]
***1’. Lateral spines present on abdominal segments 6 or 7-9; dorsal hooks usually well developed, if vestigial then antennal segment 4 more than 1/2 as wide as segment 3. [2]

2(1’). Antennal segment 4 more than 1/2 as wide as segment 3 (Fig. 319a); dorsal hooks on abdominal segments 2-9 low and blunt, or vestigial. [3]
***2’. Antennal segment 4 minute, much less than 1/2 as wide as segment 3; dorsal hooks normally prominent, usually hook-like, on at least some of abdominal segments 2-9 (sometimes low in O. carolus). [4]

p. 262

4(2’). Lateral spines on abdominal segments 6-9 (Fig. 323d). [5]
***4’. Lateral spines on abdominal segments 7-9 only. [6]

***6(4’). Dorsal hooks on abdominal segments 2-4 in lateral view usually less than 2/3 as high (measured from lowest point at intersegmental margin) as dorsal length of their respective tergites (along sclerotized, granulated cuticle only), in dorsal view with obtuse apices not extending backward beyond posterior border of tergite (Fig. 322a). [7*]
6’. Dorsal hooks on abdominal segments 2-4 in lateral view 2/3 as high, or more, (measured as above) as dorsal length of their respective tergites, in dorsal view with acute apices extending backward beyond posterior border of tergite (not beyond smooth intersegmental membrane; Fig. 322e). [14*]

***7(6). Antennal segment 3 not more than twice as long as wide. [8**]
7’. Antennal segment 3 is 2.3 to 3.0 times as long as wide. [10**]

***8(7). Antennal segment 3 is 1.7 to 1.8 times as long as wide; dorsal abdominal hooks highest and subequal on segments 2 or 3 to 4 or 5. [incurvatus**]
8’. Antennal segment 3 is 1.8 to 2.0 times as long as wide; dorsal abdominal hooks highest and subequal on segments 2 and 3 (Fig. 322a). [9**]


* Interpretation of this couplet in some individual cases may be ambiguous; if in doubt try both choices.
** Separation based on antennal measurements may be difficult in practice. Careful attention to shape of antennal segments (Fig. 319) should also help.

Tech Tips

The following equipment was used to shoot Photo No. 2, 3, and 5: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites set for “Slave” mode. Photo No. 1, 4, and 6Canon MP-E 65mm Macro lens (manual focus only, set for 2x magnification) plus the multiple-flash setup.

Adobe Photoshop CC 2017 was used to annotate Photo No. 1-6Photo No. 2, 4, 5, and 6 are focus-stacked composite images.

Bob Perkins’ photos were shot using a Canon EOS Rebel T3i camera body and Canon EF-S 60mm macro lens.

Copyright © 2018 Walter Sanford. All rights reserved.

More composite images

March 24, 2018

Adobe Photoshop CC 2017 was used to create two simple two-image focus stacks. The composite images are perfectly in focus from head-to-tail.

Photo No. 1 is a composite image of two photos: one photo focused on the head; another photo focused on the anal pyramid.

No. 1 | 100mm | ISO 100 | f/22 | 1/500s | 0 ev

Photo No. 2 is a composite image of two photos: one photo focused on the prementum; another photo focused on the anal pyramid.

No. 2 | 100mm | ISO 100 | f/22 | 1/500s | 0 ev

The Backstory

An Appalachian Snaketail dragonfly (Ophiogomphus incurvatus) nymph was collected by Bob Perkins. The nymph was reared in captivity until it emerged on 20 March 2017 and metamorphosed into an adult male. This specimen is the exuvia from the nymph. Appalachian Snaketail is a member of the Family Gomphidae (Clubtails).

Tech Tips

The following equipment was used to shoot both photos in the composite image: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Adobe Photoshop CC 2017 was used to create the composite image by “round-tripping” with Apple Aperture.

Copyright © 2018 Walter Sanford. All rights reserved.

Head-to-head, reprise

March 22, 2018

Head shots of an odonate exuvia from an Appalachian Snaketail dragonfly (Ophiogomphus incurvatus) were taken using two macro lenses: Canon EF100mm f/2.8L Macro lens (smallest aperture = f/32); Canon MP-E 65mm Macro lens (smallest aperture = f/16).

No. 1 | Canon EF 100mm Macro lens | f/22

Although there is more depth of field at f/22 than f/16, the more dramatic shot appears to be the one taken at higher magnification (2x) using the Canon MP-E 65mm Macro lens (shown below). Which photo do you prefer?

No. 2 | Canon MP-E 65mm Macro lens | f/16

The Backstory

An Appalachian Snaketail dragonfly (Ophiogomphus incurvatus) nymph was collected by Bob Perkins. The nymph was reared in captivity until it emerged on 20 March 2017 and metamorphosed into an adult male. This specimen is the exuvia from the nymph. Appalachian Snaketail is a member of the Family Gomphidae (Clubtails).

Tech Tips

The following equipment was used to shoot Photo No. 1: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites set for “Slave” mode. Photo No. 2Canon MP-E 65mm Macro lens (manual focus only, set for 2x magnification) plus the multiple-flash setup.

Apple Aperture and Adobe Photoshop CC 2017 were used to edit both images.

Copyright © 2018 Walter Sanford. All rights reserved.

Ophiogomphus aspersus exuvia

March 20, 2018

A Brook Snaketail dragonfly (Ophiogomphus aspersusnymph was collected by Bob Perkins on either 10 SEP 2017 or 03 OCT 2017 (the date is uncertain) along the New River in southwestern Virginia. The nymph was reared in captivity until it emerged on 31 OCT 2017 and metamorphosed into an adult female. The following specimen is the exuvia from the nymph. Brook Snaketail is a member of the Family Gomphidae (Clubtails).

A two-step process was used to verify the identity of the exuvia.

  1. Determine the family.
  2. Determine the genus and species.

Step 1. Family

First, determine the family of the specimen. For reference, watch the excellent Vimeo video Identifying dragonfly larva to family (8:06). Here’s the decision tree used to identify the exuvia as a member of the Family Gomphidae (Clubtails).

  • The specimen has a flat labium that doesn’t cover the face (not mask-like), as shown in Photo No. 1, 4, and 5.
  • Antennae are club-like (not thin and thread-like, as in  Aeshnidae larvae), as shown in Photo No. 1.

No. 1 | Ophiogomphus aspersus | exuvia (face-head)

Step 2. Genus and species

The dichotomous key for Ophiogomphus that appears on p. 262 in Dragonflies of North America, Third Edition by Needham et al. was used to verify the genus and species of the exuvia. The eleventh couplet [11, 11′] is as follows.

11(10). Lateral margins of prementum slightly convergent in distal 1/2 (Fig. 320c); lateral abdominal spines about 1/8 length of lateral margin of corresponding segment; in dorsal view, cerci about 2-1/2 times as long as basal width; dorsal hooks on abdominal segments 3-6 erect (Fig. 322d). [aspersus]

11’. Lateral margins of prementum parallel or slightly divergent in distal 1/2 (Fig. 320K); lateral abdominal spines each about 1/5 length of lateral margin of corresponding segment; in dorsal view, cerci each about twice as long as basal width; dorsal hooks on abdominal segments 3-6 appressed (Fig. 322d). [rupinsulensis]

No. 2 | Ophiogomphus aspersus | exuvia (dorsal)

The word “process,” as in “dorsal abdominal process,” is defined as follows.

An upstanding prominence, usually narrow and rod-like or spine-like. Source Credit: Glossary, Dragonflies of North America.

The dorsal hooks, a.k.a., dorsal abdominal processes, on abdominal segments three through six (S3-S6) are erect. Hey, call them whatever you like, including “erect” — there are raised bumps along most of the mid-dorsal abdomen, some of which are raised more noticeably than others, as shown in Photo No. 3.

No. 3 | Ophiogomphus aspersus | exuvia (dorsal-lateral)

The next two annotated images show ventral views of the exuvia.

No. 4 | Ophiogomphus aspersus | exuvia (ventral)

The flat labium doesn’t cover the face and the lateral margins of the prementum are slightly convergent in the distal half, as shown in Photo No. 5.

No. 5 | Ophiogomphus aspersus | exuvia (prementum)

Lateral spines are present on abdominal segments seven through nine (S7-S9) only. Did I measure the length of the lateral abdominal spines to see whether they are about one-eighth (1/8) the length of the lateral margin of the corresponding segment? In a word, no — the length looks about right to my unaided eye.

The cerci are about two-and-a-half (2-1/2) times as long as their basal width. Again, the length looks about right to my unaided eye.

No. 6 | Ophiogomphus aspersus | exuvia (anal pyramid)

The rudimentary ovipositor shown in Photo No. 4 and 7 indicates this individual is a female.

No. 7 | Ophiogomphus aspersus | exuvia (rudimentary ovipositor)

After emergence

The next photograph shows the Brook Snaketail dragonfly after emergence from one of Bob Perkins‘ holding tanks. Ophiogomphus aspersus is 44-49 mm in total length (Paulson, 2011).

Image used with permission from Bob Perkins.

This individual is a female, as indicated by its rounded hind wings and terminal appendages.

Image used with permission from Bob Perkins.

The last close-up photo shows a ventral view of the subgenital plate.

Image used with permission from Bob Perkins.

Tech Tips

The following equipment was used to shoot Photo No. 2-4: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites set for “Slave” mode. Photo No. 1 and 5-7: Canon MP-E 65mm Macro lens (manual focus only, set for 2x magnification) plus the multiple-flash setup.

Adobe Photoshop CC 2017 was used to annotate selected images.

Bob Perkins’ photos were shot using a Canon EOS Rebel T3i camera body and Canon EF-S 60mm macro lens.

Copyright © 2018 Walter Sanford. All rights reserved.

Hetaerina americana exuvia

March 18, 2018

An American Rubyspot damselfly (Hetaerina americananymph was collected by Bob Perkins on 06 August 2017 along the New River in Grayson County, Virginia USA. The nymph was reared in captivity, albeit briefly, until it emerged on 09 August 2017.

Pattern recognition can be used to tentatively identify damselfly larvae/exuviae to the family level: the shape of the prementum is characteristic for each of the three families of damselflies that occur in the mid-Atlantic region of the United States of America; mnemonics can be used to remember each distinctive shape.

Family Calopterygidae (Broad-winged Damselflies) features a prementum with a shape that looks somewhat similar to Family Coenagrionidae (Narrow-winged Damselflies). Look for an embedded raindrop shape, located toward the upper-center of the prementum.

Also notice another marker for Calopterygidae: the first antenna segment is equal to or longer than the length of the other six (6) segments added together. (Editor’s Note: Some of the smaller antennae segments are missing. It’s likely those delicate parts broke off during shipping and/or cleaning.)

No. 2 | Hetaerina americana | exuvia (ventral)

Two markers verify the genus and species of this specimen as Hetaerina americana: the labial cleft extends only to the base of the palpal lobes, as shown in Photo No. 1; and the external gills are 8.5 mm to 10 mm long (Daigle, 1991), as shown in Photo No. 2.

Before and after

Photo No. 3 shows a dorsal view of the exuvia before it was cleaned in order to remove unknown fibers covering the body and dirt/debris that obscured the labial cleft in the prementum.

No. 3 | Hetaerina americana | exuvia (dorsal)

Photo No. 1, 2 and 4 show the exuvia after cleaning. The operation appears to have been successful, other than collateral damage to two legs.

No. 4 | Hetaerina americana | exuvia (dorsal)

The next photograph shows the damselfly during emergence from one of Bob Perkins‘ holding tanks. Good timing, Bob!

Image used with permission from Bob Perkins.

The last photo shows the adult American Rubyspot damselfly sometime after emergence. Hetaerina americana is 38-46 mm in total length (Paulson, 2011). This individual is a male, as indicated by its hamules and terminal appendages.

Image used with permission from Bob Perkins.

Related Resource: Florida Damselflies (Zygoptera) – A Species Key to the Aquatic Larval Stages, by Jerrell James Daigle. Technical Series, Volume 11, Number 1, December 1991. State of Florida, Department of Environmental Regulation.

Tech Tips

The following equipment was used to shoot Photo No. 2, 3 and 4: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); Canon MT-26EX-RT Macro Twin Lite. Photo No. 1 , 2 and 4: the Canon MT-26 was set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites were set for “Slave” mode. A Canon MP-E 65mm Macro lens (manual focus only, set for 2x magnification) plus multiple-flash setup was used for Photo No. 1.

Adobe Photoshop CC 2017 was used to annotate selected images.

Bob Perkins’ photos were shot using a Canon EOS Rebel T3i camera body and Canon EF-S 60mm macro lens.

Copyright © 2018 Walter Sanford. All rights reserved.

Composite image

March 16, 2018

Among many useful tips for better macro photographs shared by Lester Lefkowitz in Close-Up and Macro Photography, by B&H Photo (1:54:02), Lester emphasized trying to keep the focal plane parallel to the subject. Good idea. The problem is many subjects, such as odonate exuvia, aren’t flat and macro lenses are well-known for extremely shallow depth of field.

Focus stacking can be used to increase depth of field. Adobe Photoshop CC 2017 was used to create a composite image of two photos: one photo focused on the prementum; another photo focused on the anal pyramid. The two photos were shot at f/22, so the head and tail were acceptably in focus in both images. In contrast, the following composite image is perfectly in focus from head-to-tail.

100mm | ISO 100 | f/22 | 1/500s | 0 ev

The simple two-image focus stack worked better than some composite images that I have created using many more layers. I routinely shoot macro photos of the same specimen that are focused on different key markers for identification. Encouraged by success, I think I’ll take a second-look at my photo library to see whether there are more candidates for creating simple composite images.

The Backstory

A Brook Snaketail dragonfly (Ophiogomphus aspersusnymph was collected by Bob Perkins on either 10 SEP 2017 or 03 OCT 2017 (the date is uncertain) along the New River in southwestern Virginia. The nymph was reared in captivity until it emerged on 31 OCT 2017 and metamorphosed into an adult female. The preceding specimen is the exuvia from the nymph.

Tech Tips

The following equipment was used to shoot both photos in the composite image: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Adobe Photoshop CC 2017 was used to create the composite image by “round-tripping” with Apple Aperture.

  1. Open the photos as layers in Photoshop. (Two, in this case.)
  2. Edit/Auto-Align Layers…
  3. Edit/Auto-Blend Layers…
  4. Layer/Flatten Image
  5. Save

Copyright © 2018 Walter Sanford. All rights reserved.

High-speed sync flash photography

March 14, 2018

Background information

DSLRs and many, if not most mirrorless cameras require a mechanical shutter in order to properly expose larger digital image sensors. The default flash sync speed of my Canon EOS 5D Mark II DSLR is 1/200s: external flash units work with the camera at shutter speeds of 1/200s or slower; a black bar will appear on images at shutter speeds greater than 1/200s.

That’s a problem, especially if you prefer to shoot at faster shutter speeds. What’s the solution? High-speed sync. Rather than a single burst of light, high-speed sync uses imperceptible rapid pulses of light that enables your camera to work properly at shutter speeds greater than its default sync speed. Sounds great, right? Not so fast. As it turns out, the power output of external flash units is reduced by using high-speed sync.

Among other reasons that I bought the new Canon MT-26EX-RT Macro Twin Lite recently is because it supports high-speed sync (HSS), unlike the older model it replaced. I experimented with HSS so I could use a faster shutter speed in order to diminish/eliminate camera shake/vibration, a big problem in high-magnification macro phototography. Problem is, the Guide Number of the macro flash isn’t powerful enough to shoot HSS indoors. (Outdoors should be fine.) Again I ask, what’s the solution? More power! (Grunt, grunt.)

I  used wireless multiple flash photography by setting the macro flash in “Master” mode and two Canon Speedlites (580EX and 580EX II) in “Slave” mode: one of the macro twin lites is Group A, the other macro twin lite is Group B, and the other two flashes are Group C. All flashes fire at the same settings automatically, as configured currently. If the master flash is set for HSS, then the slave flashes also fire using HSS. The system works in either ETTL- or Manual modes. (I prefer Manual mode for macro photography.)

Test shots

Photo No. 1 is a test shot of the lens cap for a Canon EF 100mm Macro lens using high-speed sync flash photography. Notice the shutter speed is faster than the default sync speed of 1/200s.

No. 1 | 100mm | ISO 100 | f/18 | 1/320s | 0 ev

Photo No. 2 shows a Brook Snaketail dragonfly (Ophiogomphus aspersus) nymph that was collected by Bob Perkins on either 10 SEP 2017 or 03 OCT 2017 (the date is uncertain) along the New River in southwestern Virginia. The nymph was reared in captivity until it emerged on 31 OCT 2017 and metamorphosed into an adult female. The following specimen is the exuvia from the nymph.

No. 2 | 100mm | ISO 100 | f/22 | 1/500s | 0 ev

Notice the f/stop is smaller and the shutter speed is faster than the first test shot. As you might guess, that means I increased the power output of the master- and slave flashes until the image was exposed properly.

Tech Tips

The following equipment was used to shoot Photo No. 1 and 2: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Copyright © 2018 Walter Sanford. All rights reserved.

American Rubyspot damselfly exuvia

March 12, 2018

An American Rubyspot damselfly (Hetaerina americana) nymph was collected by Bob Perkins on 06 August 2017 along the New River in Grayson County, Virginia USA. The nymph was reared in captivity, albeit briefly, until it emerged on 09 August 2017.

This individual is a member of the Family Calopterygidae (Broad-winged Damselflies), as indicated by the length of antenna segment 1 (shown below). See Hetaerina americana exuvia for a more detailed explanation.

No. 1 | Hetaerina americana | exuvia (dorsal)

If you look closely at the full-size version of both photos, then you should notice the specimen is covered by a lot of fibers of unknown origin.

That nymph was in the final instar when I collected it. Therefore it didn’t shed the algae and debris that had collected on its bristles. Source Credit: Personal communication with Bob Perkins.

A quick look at the prementum (below) shows the labial cleft, a key field marker for verifying the species, is obscured by some of the “debris” that Bob mentioned. As of this writing, the exuvia is soaking in a soapy water bath in the hope that it can be cleaned sufficiently to see that marker clearly.

No. 2 | Hetaerina americana | exuvia (ventral)

To be continued

Tech Tips

The following equipment was used to shoot Photo No. 1 and 2: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite.

Two Sunpak LED-160 Video Lights (each with a white translucent plastic filter) were used for both photos.

Adobe Photoshop CC 2017 was used to annotate both images.

Copyright © 2018 Walter Sanford. All rights reserved.


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