Archive for the ‘Canon 580EX Speedlite’ Category

Common Five-lined Skink

November 9, 2018

A Common Five-lined Skink (Plestiodon fasciatus) was spotted during a photowalk at Occoquan Regional Park, Fairfax County, Virginia USA.

This individual is a juvenile as indicated by its dark brown color and bright blue tail.

Copyright © 2018 Walter Sanford. All rights reserved.

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Powell’s Place

November 2, 2018

A single Sable Clubtail dragonfly (Stenogomphurus rogersi) was spotted perched alongside a small stream located in Fairfax County, Virginia USA.

I nicknamed a segment of the stream “Powell’s Place” in honor of Mike Powell, my good friend and photowalking buddy, who spotted the first Sable observed at this part of the stream. “Powell’s Place” is located downstream from Hotspot No. 1, where the stream re-emerges from an underground concrete pipe.

This individual is a male, as indicated by his indented hind wings and terminal appendages. Some dragonflies tend to be creatures of habit, returning to the same spot day-after-day. Perhaps this is the same individual spotted by Mike. Who knows?

I like the juxtaposition of complementary colors in the first photo.

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

The next photo shows the dragonfly perched deep within a shaded hidey-hole.

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

The last photo is a contender for my Odonart Portfolio.

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

Full disclosure: Adobe Photoshop was used to removed a tiny distracting element from the bottom-right half of the preceding image (the point of a single blade of grass).

Copyright © 2018 Walter Sanford. All rights reserved.

Beetlejuice

October 31, 2018

Look closely at the following photograph and ask yourself “What’s wrong with this picture?”

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

Did you notice the dragonfly’s head is turned upside-down? That reminds me of the movie Beetlejuice (1988). Happy Halloween!

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

All three photos show the same Sable Clubtail dragonfly (Stenogomphurus rogersi), perched alongside a small stream located in Fairfax County, Virginia USA. This individual is a male, as indicated by his indented hind wings and terminal appendages. Notice his head is upside-up in the last two photos.

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

Related Resource: Cobra Clubtail head-tilts, featuring a female with her head positioned nearly upside-down. I guess the upside-down head thing is characteristic of some members of Family Gomphidae (Clubtails).

Copyright © 2018 Walter Sanford. All rights reserved.

Hotspot No. 2

October 29, 2018

The Backstory

A small population of Sable Clubtail dragonflies (Stenogomphurus rogersi) was observed along three segments of a tiny stream located in Fairfax County, Virginia USA. I named the segments Hotspot No. 1, Hotspot No. 2, and “Powell’s Place.”

Hotspot No. 1 is the place where I saw my first Sable Clubtail. At least five individuals, all males, were observed by the author at this location. To date, almost all of the photos of Sable that have been published in this blog were taken at Hotspot No. 1.

Hotspot No. 2 is located upstream from Hotspot No. 1, near one of several seeps that feed the creek. This is the location where a female Sable Clubtail was spotted on 05 July 2018. As it turn out, that female was the last Sable spotted during 2018.

Powell’s Place” is located downstream from Hotspot No. 1, where the stream re-emerges from an underground concrete pipe. “Powell’s Place” is named for Mike Powell, my good friend and photowalking buddy, who spotted the first Sable observed at this segment of the stream. A related blog post will be published on Friday, 02 November 2018.

Hotspot No. 2

One or more male Sable Clubtail dragonflies were observed and photographed on 12 June 2018 at this location.

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

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

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

Copyright © 2018 Walter Sanford. All rights reserved.

Do-over

October 24, 2018

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividusnymph 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).

A focus-stacked composite image was created from 39 photos focused on the face and head of the exuvia. I had relatively little experience using Adobe Photoshop to make focus stacks when I created the first iterations of the Ashy Clubtail composite image. I was never satisfied completely with the final output, so I decided to do a do-over.

After…

The updated version of the composite image was created using my “Latest focus stacking workflow.”

Before…

The version that I published in late-March 2018 was created using the RAW photos (CR2) from my Canon digital camera, without any post-processing. I tried to adjust the white balance and color palette of the resulting composite image, but was unable to get the “look” I wanted. The image is probably over-sharpened too.

Which version do you prefer?

I know the version I like more. Which do you prefer, After or Before?

Tech Tips

The preceding images are composites 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.

Field marks for identification of S. rogersi

October 22, 2018

The following annotated images illustrate field marks that can be used for identification of Sable Clubtail dragonfly (Stenogomphurus rogersi). Although there is some redundancy among the images, repetition is a good strategy for learning.

Male

Male Sable Clubtails have eyes that are green to turquoise in color, with a black occiput located between the eyes. They have a thin, black abdomen that flares to a small club featuring thin yellow flanges on abdominal segments seven through nine (S7-9).

The abdomen is marked with small pale dorsal triangles (S3-7) and tiny pale lateral spots. The number of dorsal triangles can vary individually and/or geographically, ranging from S3-5 to S3-7.

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

Dennis Paulson, originator of the classification system for thoracic stripes in the Family Gomphidae (Clubtails), describes T1-4 as follows.

T1–2 broad and complete, touching at ends and often with stripe between them restricted and topped with spot; T3–4 fine, T3 incomplete. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6089-6093). Princeton University Press. Kindle Edition.

Note: T1-4 refers to the dark areas located on the sides of the thorax, not the lighter colored lines and spots. Due to space limitations, thoracic stripes are labeled using a numeral only (e.g., “1”) rather than a letter and numeral (e.g., “T1”).

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

Their face is pale, marked with variable black crosslines (as shown in the inset photo, below).

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

Male Sable Clubtails, like all male dragonflies, have three terminal appendages, collectively called “claspers.” All male clubtail dragonflies have indented hind wings.

Female

Female Sable Clubtails have a noticeably thicker abdomen than males. The occiput is a pale color, rather than black. Dorsal triangles, located on abdominal segments three through seven (S3-7), are much larger than those found on males. The lateral spots are somewhat larger as well.

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

Female Sable Clubtails, like all female dragonflies, have a pair of cerci (superior appendages) that have little or no function. All female clubtail dragonflies have rounded hind wings.

Related Resource: Stenogomphurus rogersi exuvia.

Copyright © 2018 Walter Sanford. All rights reserved.

Please help me fix a flawed favorite photo.

October 20, 2018

The following photo is one of my favorites from a set of 101 photos of Sable Clubtail dragonflies (Stenogomphurus rogersii) that I shot on 08 June 2018. Problem is, the photo is flawed by “hot spots” on some of the vegetation shown in the picture — those brighter areas in the photo tend to distract the viewer’s eyes from the subject.

I’m not sure what caused the hot spots. The vegetation was still wet from a rain event the night before. Perhaps the brighter areas were caused by the interaction of water on the plants with both ambient sunlight and the light from an external flash unit mounted on my camera.

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

I am convinced it should be possible to use the photo-editing tools in Adobe Lightroom and/or Adobe Photoshop/Camera Raw to fix the hot spots. Easier said than done. Every time I have attempted to “get ‘er done,” the work session ended quickly with me feeling like my head was going to explode!

Generally speaking, I’m opposed to “Photoshopping” wildlife photos. In this case, the edits I’d like to make won’t affect the subject so I’m OK with tweaking the photo to improve upon nature.

I have watched several video tutorials on YouTube that suggest the repair process should be relatively simple and straightforward. What am I missing? PLEASE HELP ME! Step-by-step directions would be ideal. Alternatively, a pointer to a good “how to” video would be welcome.

The Backstory

I was sitting on my Coleman camp stool, looking down into a shallow stream channel where I spotted my first Sable Clubtail dragonfly earlier the same day. The dragonfly landed on vegetation near the top of the channel, perched almost vertically with the tip of his abdomen pointed toward the creek. The unusual position provided a good view view of the dragonfly’s face.

Copyright © 2018 Walter Sanford. All rights reserved.

Lunch

October 18, 2018

A Sable Clubtail dragonfly (Stenogomphurus rogersi) was spotted perched alongside a small stream located in Fairfax County, Virginia USA.

This individual is a male, as indicated by his indented hind wings and terminal appendages. Notice the dragonfly is eating another insect. I called the meal lunch, since the photograph was taken at approximately 12:30 p.m.

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

Copyright © 2018 Walter Sanford. All rights reserved.

Deep dive into the archives

October 16, 2018

I took a deep dive into the archives of my Sable Clubtail dragonfly (Stenogomphurus rogersi) photographs and found some buried treasure!

The photographs in this gallery were lost in the excitement of my rediscovery of Sable Clubtail in Fairfax County, Virginia USA, when I rushed to select and publish a few representative photos from the set taken on 08 June 2018.

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

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

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

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

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

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

As you can see, Sable Clubtail perches on the ground sometimes, similar to other species of clubtail dragonflies.

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

Copyright © 2018 Walter Sanford. All rights reserved.

Macromia alleghaniensis exuvia

October 6, 2018

Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, collected an odonate exuvia on 07 June 2018 along either Little Otter Creek or Otter Creek near the place where both creeks are distributaries of Otter Lake in Amherst County, Virginia USA.

A two-step process was used to identify the genus and species 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 Macromiidae (Cruisers).

  • The specimen has a mask-like labium (prementum) that covers the face, as shown in Photo No. 1, characteristic of four families of odonates: Cordulegastridae (Spiketails); Corduliidae (Emeralds); Libellulidae (Skimmers); and Macromiidae (Cruisers).
  • The teeth on the margins of the labium have a regular pattern. (The pattern reminds me of a “spork.”)
  • Its eyes are small, wide set, and stick up.
  • Image No. 2 shows there is a horn on the face-head, characteristic of Macromiidae.

Photo No. 1 shows a face-head view of the exuvia, magnified approximately three times life size (~3x).

No. 1 | Macromia alleghaniensis | exuvia (face-head)

Image No. 2 shows the top of the head of the exuvia, magnified approximately three times life size (~3x). Notice the prominent horn on the face.

No. 2 | Macromia alleghaniensis | exuvia (head-horn)

Step 2. Genus and species

Two dichotomous keys found on p. 27 of Identification Keys to Northeastern Anisoptera Larvae, compiled by Ken Soltesz, were used to determine 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 this specimen.

Key to the Genera of the Family Macromiidae

***1b. Lateral spines of abdominal segment 9 do not reach to rearward level of tips of inferior appendages [paraprocts]; Sides of head somewhat convergent behind eyes to pair of low turbercules on hind angles; Lateral setae of labium = 6; Small dorsal hook on segment 10. [Macromia]

A small dorsal hook on abdominal segment 10 is characteristic of Genus Macromia.

No. 3 | Macromia alleghaniensis | exuvia (dorsal-lateral)

Look closely at the full-size version of Image No. 4. Notice the little “nub” on abdominal segment 10 (S10), below the underside of the dorsal hook on abdominal segment nine (S9). The same structure is labeled with a white question mark in Image No. 3.

No. 4 | Macromia alleghaniensis | exuvia (dorsal-lateral)

The lateral spines of abdominal segment 9 (S9) do not reach rearward to the tips of the inferior appendages (paraprocts).

No. 5 | Macromia alleghaniensis | exuvia (dorsal)

Key to the Species of Macromia

1a. Lateral spines of abdominal segments 8 and 9 directed straight to rearward. [illinoiensis]

***1b. Lateral spines of abdominal segments 8 and 9 incurved, especially 8. [alleghaniensis]

The lateral spines of abdominal segments 8 and 9 (S8-9) are incurved, especially segment 8 (S8), indicating this species is alleghaniensis.

No. 6 | Macromia alleghaniensis | exuvia (ventral)

This individual is probably a male, as indicated by what appear to be vestigial hamules located on the ventral side of abdominal segments two and three (S2-3).

Summary

A prominent horn on the face is a key field marker for the Family Macromiidae (Cruisers), a small dorsal hook on abdominal segment 10 is one characteristic of the Genus Macromia, and the lateral spines of abdominal segments 8 and 9 (S8-9) are incurved, indicating the species is alleghaniensis. Therefore this specimen is an Allegheny River Cruiser dragonfly (Macromia alleghaniensis).

Bonus Gallery

No. 7 | Macromia alleghaniensis | exuvia (face-head)

No. 8 | Macromia alleghaniensis | exuvia (dorsal-lateral)

No. 9 | Macromia alleghaniensis | exuvia (dorsal)

Related Resources

Tech Tips

The following equipment was used to shoot Photo/Image No. 3-9: 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/Image No. 1 and 2Canon MP-E 65mm Macro lens (manual focus only, set for ~3x magnification) plus the multiple-flash setup.

Image No. 2-8 are focus-stacked composite images created and annotated using Adobe Photoshop CC 2017: Image No. 2 (eight photos); Image No. 3 (six photos); Image No. 4 (four photos); Image No. 5 (five photos); Image No. 6 (five photos); Image No. 7 (seven photos); Image No. 8 (seven photos).

Copyright © 2018 Walter Sanford. All rights reserved.


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