Archive for the ‘Godox TT685o/p’ Category

MYN – Anisoptera exuvia (species unknown)

March 13, 2020

An Anisoptera exuvia (species unknown) was collected by Mike Powell, my good friend and photowalking buddy. Although the exact date and location are unknown, we know the specimen was collected sometime during 2019 somewhere in Northern Virginia.

The specimen is definitely a dragonfly, probably from either Family Corduliidae (Emeralds) or Family Libellulidae (Skimmers), as indicated by its mask-like labium and thin antennae.

2019 | Anisoptera exuvia (face-head-dorsal)

Related Resource: MYN – Anisoptera exuvia (dorsal view). [Dorsal view of the same specimen featured in this blog post.]

Tech Tips

This subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

Three photos were used to create a composite image: two photos focused on the head; and another photo focused on the prementum. I must say I’m fairly pleased by the way the final image turned out, best appreciated by viewing the full-size version of the composite.

My Canon EOS 5D Mark II is a full-frame DSLR digital camera. RAW images are 5616 × 3744 pixels. The dimensions of the composite image are 5385 × 3657 pixels, that is, slightly smaller than full-frame. It’s usually necessary to crop composite images, at least a little, because the individual photos used to create the composite don’t align perfectly, even when the camera is mounted on a tripod (as it was in this case).

For what it’s worth, the following camera settings were used to shoot all three photos: 100mm; ISO 100; f/8; 1/200 s; 0 ev. The power ratios for an array of four external flash units were as follows: Group A = 1/16 (primary backlight); Group B = 1/32 (secondary backlight); Group C = 1/4 (subject, stage right); Group D = 1/8 (subject, handheld stage left).

I’m still searching for the “sweet spot” for this camera/lens combo. The white background was slightly under-exposed by approximately 1.5 stops, so I need to increase the flash power ratios for Group A and B. The subject was exposed almost perfectly, so Group C and D are close to spot on. Trial and error is the MYN way!

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Anisoptera exuvia (species unknown)

March 11, 2020

An Anisoptera exuvia (species unknown) was collected near a small pond at Occoquan Regional Park (ORP), Fairfax County, Virginia USA.

This individual probably is a member of the Family Libellulidae (Skimmers), as indicated by its anal pyramid. The small pond where the specimen was collected is perfect habitat for skimmers.

01 JUN 2019 | ORP | Anisoptera exuvia (dorsallateral view)

Related Resource: Another unknown species of odonate exuvia – a blog post by Walter Sanford featuring a “one-off” photo (that is, not a composite image) of the same specimen.

Tech Tips

This subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

Two photos were used to create a composite image: one photo focused on the head; and another photo focused on abdominal segments seven (S7) through nine (S9).

My Canon EOS 5D Mark II is a full-frame DSLR digital camera. RAW images are 5616 × 3744 pixels. The dimensions of the composite image are 5589 × 3743 pixels, that is, essentially full-frame. It’s usually necessary to crop composite images, at least a little, because the individual photos used to create the composite don’t align perfectly, even when the camera is mounted on a tripod (as it was in this case).

For what it’s worth, the following camera settings were used to shoot both photos: 100mm; ISO 100; f/8; 1/200 s; 0 ev. I need to tweak the settings a little in order to find the “sweet spot” for this camera/lens combo: the white background was slightly over-exposed; and the subject was slightly under-exposed. Of course that means I need to tweak the flash power for the backlights and add one or more additional external flash units for more fill flash. Overall, I’m fairly satisfied with the results of my first attempt using the MYN technique with this camera rig.

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Eastern Amberwing exuvia (anal pyramid)

March 9, 2020

An Eastern Amberwing dragonfly (Perithemis tenera) exuvia was collected by Joe Johnston on 07 August 2019 along Aquia Creek at Channel Marker No. 34, Stafford County, Virginia USA.

The specimen is probably from either Family Corduliidae (Emeralds) or Family Libellulidae (Skimmers).

The rule of thumb for differentiating Corduliidae exuviae from Libellulidae is as follows: It’s probably Corduliidae if the cerci are at least half as long as the paraprocts; it’s probably Libellulidae if the cerci are less than half the length of the paraprocts.

65mm (3x magnification) | ISO 100 | f/8 | 1/200 s | 0 ev

Look closely at the full-size version of the preceding photo, showing a close-up of the anal pyramid at 3x magnification. Notice the cerci are approximately half as long as the epiproct and slightly less than half the length of the paraprocts. It’s a close call, but the latter field mark indicates Family Libellulidae (Skimmers).

A step-by-step identification guide (to the species level) will be published in a follow-up post. Stay tuned!

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – S. plagiatus exuvia (ventral composite)

March 4, 2020

Russet-tipped Clubtail dragonfly (Stylurus plagiatusexuvia was collected by Joe Johnston on 17 July 2019 along Aquia Creek in Stafford County, Virginia USA.

17 JUL 2019 | Aquia Creek | Stylurus plagiatus | exuvia (ventral view)

Related Resources

Tech Tips

This specimen was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique. I used the new variation on my old MYN studio rig and I’m still satisfied with the results.

Four photos were used to create a composite image: one photo focused on the thorax; and three other photos focused on abdominal segments two-three (S2-S3), seven (S7), and nine (S9).

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Stylurus plagiatus exuvia (composite)

March 2, 2020

Russet-tipped Clubtail dragonfly (Stylurus plagiatusexuvia was collected by Joe Johnston on 17 July 2019 along Aquia Creek in Stafford County, Virginia USA.

Two key field marks can be used to quickly identify both the genus and species of this specimen. 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.

Related Resources

Tech Tips

This specimen was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique. I used the new variation on my old MYN studio rig and I’m still satisfied with the results.

Four photos were used to create a composite image: one photo focused on the head; and three other photos focused on abdominal segments five (S5), seven-eight (S7-S8), and 10 (S10).

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Stylurus plagiatus exuvia

February 28, 2020

A Russet-tipped Clubtail dragonfly (Stylurus plagiatus) exuvia was collected by Joe Johnston on 17 July 2019 along Aquia Creek in Stafford County, Virginia USA.

17 JUL 2019 | Aquia Creek | Stylurus plagiatus | exuvia (face-head)

Notice the specimen has a flat labium that doesn’t cover the face (not mask-like), as shown in the preceding photo. This field mark indicates the exuvia is from either Family Aeshnidae (Darners) or Family Gomphidae (Clubtails). Other field marks, including club-like antennae and the shape of the body, indicate this individual is a species of clubtail.

My next blog post will feature a dorsal-lateral view of the exuvia that clearly shows the field marks that indicate both genus and species.

Related Resources

Tech Tips

This specimen was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique. I used the new variation on my old MYN studio rig and I’m still satisfied with the results.

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Unknown dragonfly exuvia (redux)

February 26, 2020

This blog post features more photos of an exuvia from an unknown species of odonate that was collected by Joe Johnston on 07 August 2019 along Aquia Creek at Channel Marker No. 34, Stafford County, Virginia USA.

The specimen is probably from either Family Corduliidae (Emeralds) or Family Libellulidae (Skimmers).

07 AUG 2019 | Aquia Creek | dragonfly exuvia (dorsal view)

The rule of thumb for differentiating Corduliidae exuviae from Libellulidae is as follows: It’s probably Corduliidae if the cerci are at least half as long as the paraprocts; it’s probably Libellulidae if the cerci are less than half the length of the paraprocts.

07 AUG 2019 | Aquia Creek | dragonfly exuvia (ventral view)

I’m having a hard time seeing the cerci clearly. If I’m seeing what I think I’m seeing, then the cerci are at least half as long as the paraprocts and the exuvia is from Family Corduliidae (Emeralds).

In order to verify my tentative identification, I need to use a higher magnification macro lens (such as my Canon MP-E 65mm Macro lens) in order to shoot a close-up view of the anal pyramid/terminal appendages (see inset diagram, lower-left corner).

Related Resource: MYN – Dragonfly exuvia (unknown species)

Tech Tips

This specimen was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique. I used the new variation on my old MYN studio rig and I’m still satisfied with the results.

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Dragonfly exuvia (unknown species)

February 24, 2020

An exuvia from an unknown species of odonate was collected by Joe Johnston on 07 August 2019 along Aquia Creek at Channel Marker No. 34, Stafford County, Virginia USA.

The specimen is definitely a dragonfly, probably from either Family Corduliidae (Emeralds) or Family Libellulidae (Skimmers).

07 AUG 2019 | Aquia Creek | dragonfly exuvia (face-head-dorsal view)

This relatively small exuvia is ~1.2 to 1.3 cm in length. Notice the dorsal hooks on the exuvia are “cultriform,” that is, shaped like a pruning knife.

07 AUG 2019 | Aquia Creek | dragonfly exuvia (lateral view)

Related Resource: Odonate exuviae collecting sites [along Aquia Creek]

Tech Tips

This specimen was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

I experimented with a new variation on my old MYN studio rig. The new set-up seems to work well, although the question remains “Does it work well consistently?” I added a second external flash unit that is used to backlight a piece of translucent white plastic (the background), and I physically separated the clear plastic “stage” from the white background. More info and photos will be featured in a follow-up blog post.

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – More Pantala hymenaea exuvia

December 18, 2019

An odonate exuvia was photographed against a pure white background using the “Meet Your Neighbours” (MYN) technique.

This specimen is a Spot-winged Glider dragonfly (Pantala hymenaea) exuvia. Spot-winged Glider is a member of Family Libellulidae (Skimmers).

80mm (120mm, 35mm equivalent) | ISO 200 | f/16 | 1/500 s | 0 ev

80mm (120mm, 35mm equivalent) | ISO 200 | f/16 | 1/500 s | 0 ev

The Backstory

This specimen was collected (near Richmond, Virginia USA) and identified by Andy Davidson. Andy is a graduate student at Virginia Commonwealth University working on a research project entitled “Predator-Prey Interactions in a Changing World.”

Tech Tips

The following equipment was used to shoot the macro photographs featured in this post: Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens minus the 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.

Godox XProF radio flash trigger, mounted on the hotshoe of my X-T1, was used to control two off-camera external flash units set for radio slave mode.

  1. Godox TT685C Thinklite Flash for Canon Cameras (manual mode), fitted with a “Vello Bounce Dome (Diffuser) for Canon 580EX II Flash,” was used to light the underside of the translucent white plastic background; the top of the flash unit was ~30 cm from the bottom of the white plastic.
  2. A Godox TT685o/p Thinklite Flash for Olympus/Panasonic Cameras (manual mode), fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier, was used to light the subject from above.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the image.

Copyright © 2019 Walter Sanford. All rights reserved.

MYN – Pantala hymenaea exuvia

December 16, 2019

An odonate exuvia was photographed against a pure white background using the “Meet Your Neighbours” (MYN) technique.

This specimen is a Spot-winged Glider dragonfly (Pantala hymenaea) exuvia. Spot-winged Glider is a member of Family Libellulidae (Skimmers).

Genus Pantala

The genus Pantala includes two species in North America: Spot-winged Glider (Pantala hymenaea); and Wandering Glider (Pantala flavescens).

Spot-winged Glider and Wandering Glider larvae/exuviae look similar. The lateral spines on abdominal segment nine (S9) are noticeably shorter for P. hymenaea (shown left) than P. flavescens (shown right) — a key field mark that can be used to differentiate the two species.

The Backstory

Both specimens featured in this blog post were collected (near Richmond, Virginia USA) and identified by Andy Davidson. Andy is a graduate student at Virginia Commonwealth University working on a research project entitled “Predator-Prey Interactions in a Changing World.”

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.


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