Stylurus sp. exuvia, ongoing work

The work to identify an unknown species of odonate exuvia continues. More focus-stacked composite images are in the pipeline to be published in one or more follow-up blog posts.

13 JUL 2018 | Amherst County, VA | Stylurus sp. exuvia (dorsal view)

Tech Tips

The preceding image is a composite of 21 photos taken using the following equipment: 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); 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.

Related Resource: Stylurus sp. exuvia

Copyright © 2018 Walter Sanford. All rights reserved.

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Stylurus sp. exuvia

The following image is a composite of 18 photos taken using the following equipment: 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); 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.

13 JUL 2018 | Amherst County, VA | Stylurus sp. exuvia (ventral view)

The Backstory

I am collaborating with my good friend Mike Boatwright, administrator of the Virginia Odonata Facebook group, to identify an odonate exuvia that he collected on 13 July 2018 in Amherst County, Virginia USA. We know the exuvia is from the Family Gomphidae (Clubtails) and are fairly certain it is a species from the genus Stylurus. At this point, several species are still in play.

Sincere thanks to Benjamin Coulter for providing guidance and related resources as Mike and I work through several dichotomous keys for identification of Stylurus larvae.

Look for one or more follow-up blog posts as the work progresses.

Related Resource: Stylurus sp. exuvia, ongoing work

Copyright © 2018 Walter Sanford. All rights reserved.

Sable Clubtail (terminal appendages)

Male and female Sable Clubtail dragonflies (Stenogomphurus rogersi) were spotted recently in Fairfax County, Virginia USA.

Male

Male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”); and a lower unpaired epiproct (“inferior appendage”). The epiproct for Sable Clubtail is essentially a wide plate with two prongs.

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

The hind wings of male clubtail dragonflies are “indented” near the body, as shown in the preceding photograph. In contrast, the hind wings of female clubtails are rounded (shown below).

Female

Female dragonflies have a pair of cerci (superior appendages) that have little or no function. The abdomen of female Sable Clubtails is noticeably thicker than males of the same species.

05 JUL 2018 | Fairfax County, VA | Sable Clubtail (female)

Copyright © 2018 Walter Sanford. All rights reserved.

Springtime Darner (male claspers)

A Springtime Darner dragonfly (Basiaeschna janata) was spotted along Popes Head Creek at Hemlock Overlook Regional Park (HORP) in Fairfax County, Virginia USA. This individual is a male, as indicated by his terminal appendages and “indented” hind wings.

23 APR 2017 | HORP | Springtime Darner (male)

(See a full-size version of the original photo, without annotation.)

All male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”) and a lower unpaired epiproct (“inferior appendage”).

23 APR 2017 | HORP | Springtime Darner (male)

(See a full-size version of the original photo, without annotation.)

Editor’s Notes

The preceding photos are new, that is, previously unpublished. Both photos are full-frame (uncropped). Springtime Darners can be quite skittish. In this case, I was very close to an unusually cooperative model.

The last photo was shot using Aperture Priority. I prefer shooting in Shutter Priority, but I like to shoot a few shots using Aperture Priority whenever I can use either a monopod or tripod. In this situation, I improvised.

In addition to my photography gear, I usually carry a Coleman camp stool when I go photowalking. The small, lightweight folding chair is good for resting while waiting for “the game to come to me.” The camp stool also enables me to get closer to subjects either on- or near the ground, such as the Springtime Darner featured in this blog post. I think it’s easier to hold my camera rock-steady when I’m sitting on the chair with my elbows resting on my knees.

Copyright © 2018 Walter Sanford. All rights reserved.

Twin-spotted Spiketail (male claspers)

All male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”) and a lower unpaired epiproct (“inferior appendage”).

Male members of the Family Cordulegastridae (Spiketails), including male Twin-spotted Spiketail dragonflies (Cordulegaster maculata), have relatively small cerci (terminal appendages) that can be mistaken for female cerci.

07 MAY 2018 | Occoquan Regional Park | Twin-spotted Spiketail (male)

Male dragonfly secondary genitalia, called hamules, are located below abdominal segments two and three (S2 and S3), as shown in the following annotated image. Hamules come in a variety of sizes and shapes, but their function is identical for all species of odonates.

07 MAY 2018 | Occoquan Regional Park | Twin-spotted Spiketail (male)

Related Resources

• Arrowhead Spiketail dragonfly (male claspers)
• Brown Spiketail dragonfly (male claspers)

Copyright © 2018 Walter Sanford. All rights reserved.

Brown Spiketail dragonfly (male claspers)

Brown Spiketail dragonflies (Cordulegaster bilineata) were spotted on two days during May 2018 at Occoquan Regional Park. Both individuals featured in this post are male, as indicated by their terminal appendages and slightly “indented” hind wings.

All male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”) and a lower unpaired epiproct (“inferior appendage”).

11 MAY 2018 | Occoquan Regional Park | Brown Spiketail (male)

Notice the epiproct for Brown Spiketail is a wide “plate” that spans both cerci, as shown in the full-size version of the following annotated image.

07 MAY 2018 | Occoquan Regional Park | Brown Spiketail (male)

Male dragonfly secondary genitalia, called hamules, are located below abdominal segments two and three (S2 and S3), as shown in the preceding annotated image. Hamules come in a variety of sizes and shapes, but their function is identical for all species of odonates. Some species of dragonflies and damselflies — such as Ashy Clubtail versus Lancet Clubtail and Southern Spreadwing versus Sweetflag Spreadwing, to name a few — can be differentiated/identified with certainty only by examining the hamules under magnification.

Copyright © 2018 Walter Sanford. All rights reserved.

Swift River Cruiser exuvia

A late-stage emergent teneral female Swift River Cruiser dragonfly (Macromia illinoiensis) was spotted on 27 May 2017 along the Potomac River at Riverbend Park in Fairfax County, Virginia USA. The exuvia was collected, with permission from park staff, after the female flew away from the place where she metamorphosed from a nymph to an adult.

No. 1 | 27 MAY 2017 | Riverbend Park | Swift River Cruiser (female)

The next image is a composite of 35 photos. The specimen is perfectly in focus from head-to-tail, including the legs.

No. 2 | Swift River Cruiser (Macromia illinoiensis) | exuvia (dorsal)

The last image is a composite of eight photos. The focus point for each photo in the set is limited to the body only. Surprisingly, all six legs are acceptably in focus except for the tip of the left hind leg.

No. 3 | Swift River Cruiser (Macromia illinoiensis) | exuvia (ventral)

The official early-date for Swift River Cruiser dragonfly is 08 May in the Commonwealth of Virginia. Since the early-date for Royal River Cruiser dragonfly (Macromia taeniolata) is 15 May, the exuvia helps to confirm the identity of the adult is Swift River Cruiser. 10 October is the late-date for both species.

Tech Tips

Photo No. 1 was taken using my Panasonic Lumix DMC-FZ150 superzoom bridge camera plus Canon 580EX Speedlite, my go-to kit for photowalking.

The following equipment was used to shoot Photo No. 2 and 3: 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); 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. 2-3 are focus-stacked composite images created using Adobe Photoshop CC 2017.

Related Resource: Swift River Cruiser (emergent female).

Copyright © 2018 Walter Sanford. All rights reserved.

Another focus stacking face-off

Here’s another face-off between a single macro photo and a focus-stacked composite image. Let’s start with the composite image this time.

The first example is a composite image created from 14 photos.

American Rubyspot (Hetaerina americana) | exuvia (ventral)

In a recent blog post, I wrote…

My goal is to shoot the fewest number of photos (using a relatively small aperture such as f/18) that will show the entire specimen in focus when the photo set is focus-stacked to create a composite image. Source Credit: More Calico Pennant exuvia composite images.

I used to shoot several photos of a single focus point, e.g., the prementum, and select the sharpest image for editing/focus stacking. Now I’m using a wider aperture such as either f/11 or f/8 (for sharpness), shooting more photos, and using every photo that I take. My rationale is simple: A single photo may not be the sharpest photo of a single focus point, but it probably shows other areas that are in focus. In this case, I think more “raw material” is better than less.

The last example is one of the better photos from the set of 14. When you click on the images they open in a new tab automatically. Toggle back-and-forth between tabs and I think you will agree the composite image is clearly better than the following single photo.

American Rubyspot (Hetaerina americana) | exuvia (ventral)

The Backstory

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.

Copyright © 2018 Walter Sanford. All rights reserved.

Why focus stack macro photos?

Why focus stack macro photos? The answer is obvious: The difference between a single macro photo and a focus-stacked composite image is like night and day.

The first example is one of the better photos from a set of 13. It is the same photo that is featured in Hetaerina americana exuvia, my identification guide for American Rubyspot damselfly exuviae.

American Rubyspot (Hetaerina americana) | exuvia (dorsal)

The last example is a composite image created using all 13 photos in the set.

American Rubyspot (Hetaerina americana) | exuvia (dorsal)

You may not notice the difference in quality unless you look at the full-size version of both images. When you click on the images they open in a new tab automatically. Toggle back-and-forth between tabs and I think you will agree the composite image is clearly better than the single photo.

The Backstory

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.

Copyright © 2018 Walter Sanford. All rights reserved.

Focus stacking workflow

By trial and error, the workflow that I use to create focus-stacked composite images has been refined to its current semi-steady state. My goal for the workflow is to maximize efficiency and minimize unexpected results. I’m not saying this is the best way to focus stack images, but it is the best way I have found to do it…so far. Suggestions for improvement are invited and welcome.

Photo editing using Apple Aperture… [or Lightroom]

Although Apple discontinued development of/support for Aperture years ago, the desktop application still works and in many ways I prefer Aperture over Lightroom.

Make all necessary edits/adjustments to one photo except Spot & Patch, Vignette, and BorderFX (a plug-in for Aperture). This process works because I shoot the entire photo set for a composite image using manual exposure and manual flash. Add metadata (IPTC and Keywords).

• Right-click on the photo; select “Lift Adjustments.” <Replace> <Stamp Selected Images>.
• Right-click on the photo; select “Lift Metadata.” <Replace> <Stamp Selected Images>.
• Select all images for focus stack; Photos / Edit with Adobe Photoshop CC 2017.app…

Editor’s Note: Aperture seems to “choke” when too many photos are selected to send to Photoshop. Alternate procedure: Select the images (to be focus stacked); export as TIFFs (16-bit), 300 dpi; save in folder entitled either “TIFF” or “TIFF versions.”

Focus stacking workflow using Adobe Photoshop…

Launch Photoshop.

• File / Scripts / Load Files into Stack…; either Add Open Files <OK> or browse to the location of the folder where the TIFF files are saved. Do not check the box for “Create Smart Object after Loading Layers.” By default, Photoshop creates a new document called “Untitled1”; either rename the document or leave it as is.
• Select all layers.
• Edit / Auto-Align Layers; Auto <OK>.
• Edit / Auto-Blend Layers; Stack Images, Seamless Tones and Colors <OK>.
• Duplicate all masked layers to a new document [backup copy].
• Select Untitled1: Layer / Merge Layers (Photoshop merges all layers into one TIFF, named after the first file in numeric sequence.)
• Straighten and Crop as necessary.
• Duplicate the layer [or drag the layer to the copy icon (at the bottom of the Layers panel)].
• Spot image (zoom in): Spot Healing Brush: 27-54 pixels, Content-Aware.
• Duplicate the layer [or drag the Spot layer to copy icon].
• Select the top layer: Filter / Other / High Pass…; adjust the radius until you can just see an outline of subject <OK>; change Normal to Overlay. Don’t oversharpen! I set the radius to around 5.4 pixels or less for composite images; ~1.5 pixels for single photos.
• Duplicate the finished layers to a New document, temporarily called “Temp1.”
• Save documents: Untitled1 (Save As… TIFF); backup copy of masked layers (Save As… PSD); Temp1 (Save As… PSD; change name to Untitled1.psd after the file is saved).
• Import the composite TIFF file into Aperture [or Lightroom]: add additional keywords, as appropriate; Export using BorderFX.

Adobe Photoshop | High Pass Filter

Related Resource: High Pass Filter: Ep 134: Exploring Photography with Mark Wallace (10:13).

Copyright © 2018 Walter Sanford. All rights reserved.