Beware of look-alikes!

Some species of dragonfly larvae/exuviae look similar to other species. Here are a couple of look-alikes from two different families that might fool you.

One species of Corduliidae in our region [North America], Epitheca princeps, resembles the macromiid general body shape and is nearly as large, but the legs are short compared to its body dimensions and it lacks a triangular frontal projection. Source Credit: K. J. Tennessen, Dragonfly Nymphs of North America, https://doi.org/10.1007/978-3-319-97776-8_10, Macromiidae, p. 329.

The first annotated image shows a ventral view of a Prince Baskettail (Epitheca princeps) exuvia. E. princeps is a member of Family Corduliidae (Emeralds).

Prince Baskettail (Epitheca princeps) | exuvia (ventral)

Notice the appearance of the E. princeps exuvia is quite similar to the Stream Cruiser (Didymops transversa) exuvia shown below. D. transversa is a member of Family Macromiidae (Cruisers).

Stream Cruiser (Didymops transversa) | exuvia (ventral)

The E. princeps exuvia features lateral spines and well-developed mid-dorsal hooks on some abdominal segments. Notably “it lacks a triangular frontal projection” (K. J. Tennessen), or stated more simply, there isn’t a “horn” on its face-head.

Prince Baskettail (Epitheca princeps) | exuvia (dorsal–lateral)

The D. transversa exuvia also features lateral spines and mid-dorsal hooks, as shown below. Notice the mid-dorsal hooks aren’t as cultriform as E. princeps. In contrast to the E. princeps exuvia, notice the prominent “horn” on the face of the D. transversa exuvia. It’s all about the “horn.”

Stream Cruiser (Didymops transversa) | exuvia (dorsal)

A “horn” on the face-head is a characteristic field mark for odonate larvae/exuviae in the Family Macromiidae (Cruisers).

Related Resources

• Macromiidae – It’s all about the “horn.”
• Test shots: Didymops transversa exuvia
• Exuvia from Family Macromiidae (Cruisers)
• Epitheca princeps exuvia, posted on 06 September 2018.
• Epitheca princeps exuvia, posted on 05 March 2017.

Copyright © 2021 Walter Sanford. All rights reserved.

Macromiidae – It’s all about the “horn.”

A “horn” on the face-head is a characteristic field mark for odonate larvae/exuviae in the Family Macromiidae (Cruisers).

Look closely at the full-size version of each of the following photos and you should be able to see the horn on the face of a Stream Cruiser dragonfly (Didymops transversa) exuvia that was collected during mid-April 2021.

13 APR 2021 | PNC. William County, VA | Stream Cruiser exuvia (face-head)

It’s easier to see the horn in the next photo…

13 APR 2021 | PNC. William County, VA | Stream Cruiser exuvia (dorsal)

The horn is clearly visible in the last photo. Notice there are three “bumps” located between the eyes of the exuvia: the middle bump is the horn; the antennae bases are located to the left and right of the horn.

13 APR 2021 | PNC. William County, VA | Stream Cruiser exuvia (dorsal)

Related Resources

• Test shots: Didymops transversa exuvia
• Exuvia from Family Macromiidae (Cruisers)

Copyright © 2021 Walter Sanford. All rights reserved.

Test shots: Didymops transversa exuvia

An exuvia from a Stream Cruiser dragonfly (Didymops transversa) was collected from one of the concrete abutments of a man-made dam located along a mid-size stream at an undisclosed location in Prince William County, Virginia USA.

I prefer to photograph odonate exuvia like this one “as is” — presumably its appearance is similar to the way larva looked when it lived underwater.

13 APR 2021 | PNC. William County, VA | Stream Cruiser exuvia (dorsal)

If so, then I’m guessing D. transversa larvae are bottom dwellers, as indicated by the dirty, sediment-covered dorsal side and relatively clean ventral side of this specimen.

13 APR 2021 | PNC. William County, VA | Stream Cruiser exuvia (ventral)

Post Update

The nymphs are sprawlers that cling to roots or hunker down in sediments of mixed sand and silt particles. Source Credit: K. J. Tennessen, Dragonfly Nymphs of North America, https://doi.org/10.1007/978-3-319-97776-8_10, Macromiidae, p. 330.

The Backstory

The preceding photos were shot using the prototype for a homemade curved clear plastic tray intended for staging subjects against a white background.

With a few minor tweaks, the curved stage performed better than during initial testing. I needed to add a second external flash unit to more evenly illuminate the white background.

Although I’m fairly satisfied with the results of these test shots, more testing is required to be sure the set-up is working the way I want.

Related Resources

• Macromiidae – It’s all about the “horn.”
• Exuvia from Family Macromiidae (Cruisers), a blog post by Walter Sanford featuring in situ photographs of the same specimen.

Copyright © 2021 Walter Sanford. All rights reserved.

Test shots

I have been working on the prototype for a homemade curved clear plastic tray that is intended for staging subjects against a white background.

My goal for Thursday: Test the prototype stage using a toy mini-lizard as the model for some test shots, and if the proof-of-concept were established, substitute an odonate exuvia for the toy lizard and shoot another set of photos.

16 SEP 2021 | BoG Photo Studio | toy mini-lizard

Well, you know what they say about the best laid plans! First, a line of fairly strong thunderstorms moved through the region where I live so I had to shut down my computer equipment. Second, the Washington Football Team played the New York Giants on Thursday Night Football so I had to watch the game. That’s right, had to watch. Turns out it was time well-spent.

Bottom line: I never finished the test shots of the toy lizard, and of course that means I didn’t shoot any photos of a real scientific specimen.

The curved surface of the clear plastic stage caused reflections from the single external flash that was used to light the subject. I had just figured out a work-around when the thunderstorms rolled in: I took 14 test shots; only the last one (shown above) is usable. I hadn’t intended to create a photo with a pure white background, but it was easy to adjust the image exposure during post-processing.

The Backstory

What’s my motivation? Many macro photographers use insect pins for mounting small subjects like odonate exuviae. I think there’s a big problem with that technique: The position of the pin is permanent. In other words, if the pin is attached to the ventral side of the specimen then it’s challenging at best and impossible at worst to take clean, clear shots of that side of the subject. I don’t want to use insect pins because some of my specimens are one of a kind.

For quite some time, I’ve been experimenting with the use of flat clear plastic stages as a solution for this problem. I think a curved stage might be a breakthrough, but more testing is required to be sure.

For example, notice the color fringing near the tip of the lizard’s tail — I’m not sure what caused that problem in only one part of the photo, therefore I don’t know how to fix it. Yet.

To be continued. Please stay tuned.

Copyright © 2021 Walter Sanford. All rights reserved.

Multimeter test results: GyroVu continuous power adapter for Panasonic

Eureka! I found my RadioShack Digital Multimeter.

In a recent blog post, I said I would like to use a multimeter to test the actual voltage output of the GyroVu USB TO PANASONIC DMC-GH2 (DMW-BLC12) BATTERY 40″ CABLE w/ 3.1A USB POWER SUPPLY that provides continuous power for my Panasonic Lumix DMC-FZ300 superzoom bridge camera. This blog post features the results from that test and more.

Panasonic rechargeable Li-ion camera battery

The Panasonic Lumix DMC-FZ300 uses a Panasonic DMW-BLC12 Rechargeable Lithium-Ion Battery (7.2V, 1200mAh), shown below.

Panasonic DMW-BLC12PP 7.2V Li-ion battery (front).

The positive and negative terminals of the battery are marked on the back of its case.

Panasonic DMW-BLC12PP 7.2V Li-ion battery (back).

I set the multimeter to measure voltage and touched the black test lead to the negative (-) terminal, then touched the red test lead to the positive (+) terminal. The LCD on the multimeter displayed a voltage of 07.29V, as shown below. That’s good!

Voltage output from Panasonic 7.2V Li-ion battery.

GyroVu continuous power adapter

Next, the GyroVu “USB Charger” (shown below, to the lower-left) was plugged in a 120V AC electrical outlet. The GyroVu dummy battery was connected to the 3100mA USB connector on the GyroVu USB Charger.

Product image courtesy GyroVu.com.

Although the positive and negative terminals of the dummy battery aren’t marked on its case, they are in the same places as on the Li-ion battery.

Once again I set the multimeter to measure voltage and touched the black test lead to the negative (-) terminal, then touched the red test lead to the positive (+) terminal. The LCD on the multimeter displayed a voltage of 08.36V, as shown below.

Voltage output from GyroVu dummy battery for Panasonic.

GyroVu says the output voltage of the dummy battery is 8.0V, so 8.36V seems to be within specs.

For what it’s worth, the Owner’s Manual for the model of RadioShack Digital Multimeter that I used specifies the accuracy of the multimeter is +/-0.8% of the reading, or in this case +/-0.07V.

Therefore I think it’s safe to say the GyroVu dummy battery has a slightly higher voltage than the Panasonic Li-ion battery. Is the higher voltage cause for concern?

Perhaps the more important question is whether amperage matters more than voltage. Regular readers of my blog might recall that I used my Drok USB Tester to measure an amperage of 0.45A drawn by the camera when it was connected to the GyroVu adapter and powered on. Is that amperage safe for the camera?

I’m not sure of the answer to either question, although I am certain further investigation is required.

Anker external power bank

Each GyroVu “dummy battery” adapter cable features a USB connector that can be used to connect your digital camera to an external power bank such as the Anker PowerCore+ 26800 PD 45W), shown below.

Product image courtesy AnkerDirect.

My Drok USB Tester was connected to one of two USB ports on the Anker power bank. The output voltage of the power bank was 5V, same as the GyroVu “USB Charger.”

The GyroVu dummy battery was plugged into one of two USB ports on the Anker power bank. Once again I set the multimeter to measure voltage and touched the black test lead to the negative (-) terminal, then touched the red test lead to the positive (+) terminal. The LCD on the multimeter displayed a voltage of 08.36V (shown above) — exactly the same as when I used the GyroVu “USB Charger” as the source of continuous power.

Voltage output for GyroVu dummy battery for Panasonic connected to Anker PowerCore+ 26800 PD 45W.

At this point I think it’s safe to say the Anker power bank is safe to use as a source of continuous power for my Panansonic Lumix DMC-FZ300 camera, that is, assuming the ~8.0V output of the GyroVu dummy battery isn’t a problem.

Related Resources

This blog post is one in a series of posts related to continuous AC power and long-lasting battery power for select Canon, Fujifilm, and Panasonic digital cameras.

• Anker PowerCore+ 26800 PD 45W
• Will it work? Is it safe?
• Continuous power: Canon EOS 5D Mark II
• Continuous power: Fujifilm X-T3
• Continuous power: Panasonic Lumix DMC-FZ300
• The best of both worlds at bargain prices

Copyright © 2021 Walter Sanford. All rights reserved.

Anax junius versus Anax longipes

The following photograph shows the relative size of odonate exuviae from two species in the Genus Anax: junius; and longipes. Both specimens are from the Family Aeshnidae (Darners).

Relative size of exuviae from Anax junius versus Anax longipes.

The Common Green Darner dragonfly (Anax junius) exuvia was collected on 17 June 2021 from a small pond at an undisclosed location in Prince William County, Virginia USA.

The Comet Darner dragonfly (Anax longipes) exuvia was collected by Stanley Caveney on 19 July 2021 from a pond at MeadowWoods in West Elgin, Ontario, Canada.

Taxonomy

There are five species of dragonflies in the Genus Anax for the United States and Canada: Amazon Darner (Anax amazili); Common Green Darner (Anax junius); Comet Darner (Anax longipes); Giant Darner (Anax walsinghami); and Blue-spotted Comet (Anax concolor).

Common Green Darner and Comet Darner are the only species from the Genus Anax found where I live in Northern Virginia USA.

Related Resources

• Post update: What is it? [Anax junius exuvia]
• Comet Darner dragonfly (exuvia) [Anax longipes]

Copyright © 2021 Walter Sanford. All rights reserved.

Post update: What is it?

Since I started exploring ways to provide continuous power for my digital cameras, I have been guided by two questions. 1. Will it work? 2. Is it safe? I watched a YouTube video recently that reminded me of the latter question.

External Power for Cameras, the Safest Options by Graham Houghton (14:53) inspired me to search online for an inline voltage meter with USB connectors.

Drok USB Tester

After watching several more YouTube videos, I decided to buy a Digital Meter USB Tester Multifunction Digital Voltmeter/Ammeter/Power Meter/Capacity Tester/Charger 5in1 USB Panel Meter, available from a company in the United States called “Drok.” The MSRP for the Drok USB Tester is $15.99. The one I ordered from the Drok Store on Amazon cost $9.99.

Product image courtesy Droking.com.

The device features one male USB connector for input, and two female USB connectors for output.

Product image courtesy Droking.com.

GyroVu continuous power adapter

The next photo shows a GyroVu USB TO PANASONIC DMC-GH2 (DMW-BLC12) BATTERY 40″ CABLE w/ 3.1A USB POWER SUPPLY. The device can be used to provide continuous power for my Panasonic Lumix DMC-FZ300 superzoom bridge camera.

Product image courtesy GyroVu.com.

The “USB Charger” — a small white power brick — was plugged into a 120V AC electrical outlet. Look closely at the full-size version of the following image. Notice the USB Charger output is 5V=3.1A. (3.1A = 3100mA.)

Product image courtesy GyroVu.com.

Testing the GyroVu continuous power adapter

The Drok USB Tester was connected to the 3100mA USB connector on the GyroVu USB Charger, shown above.

The USB cable for the GyroVu dummy battery was connected to “Output 1” of the Drok USB Tester; the dummy battery was inserted into the battery compartment of my Panasonic Lumix DMC-FZ300.

The last photo — the same one featured in my last blog post — shows the LED display on the front of the Drok USB Tester after my camera was powered on, indicating the output voltage of the USB Charger was 5V and the camera was drawing a current of 0.45A.

Panasonic Lumix DMC-FZ300 (121mm) plus Raynox DCR-250.

The output voltage of the GyroVu dummy battery is 8.0V so the “dummy” battery must contain a DC-to-DC step-up converter.

I plan to use a multimeter to test the actual voltage output of the GyroVu dummy battery, that is, as soon as I can find my RadioShack mulitimeter. (Someday I’ll get organized so I know where everything is!)

Sidebar: Deep Dive into Tech Specs

The Web page for the GyroVu continuous power adapter shown above says the product is for the Panasonic DMC-GH2 camera. How could I be sure the device would work with my Panasonic Lumix DMC-FZ300 digital camera?

The Panasonic Lumix DMC-FZ300 uses a Panasonic DMW-BLC12 Rechargeable Lithium-Ion Battery (7.2V, 1200mAh). Turns out that’s the same battery used by the Panasonic DMC-GH2. I know this thanks to Wasabi Power for providing a list of Panasonic cameras that use the DMW-BLC12 battery. (See the Web page for the PANASONIC DMW-BLC12 AC POWER ADAPTER KIT WITH DC COUPLER FOR PANASONIC DMW-DCC8, DMW-AC8 BY WASABI POWER, a product similar to the GyroVu continuous power adapter.)

Editor’s Note: The MSRP for the Wasabi Power continuous power adapter is $23.99 — nearly $10 less than the MSRP of $33.95 for the GyroVu USB Power Supply. You might be wondering why I didn’t buy the Wasabi Power device.

Notice the Wasabi Power device uses round connectors rather than USB connectors. I prefer the GyroVu devices because the USB connectors on their dummy batteries give me the flexibility to use them with my Anker PowerCore+ 26800 PD 45W battery as a power source for select Canon, Fujifilm, and Panasonic digital cameras that I own.

Related Resources

This blog post is one in a series of posts related to continuous AC power and long-lasting battery power for select Canon, Fujifilm, and Panasonic digital cameras.

• Anker PowerCore+ 26800 PD 45W
• Will it work? Is it safe?
• Continuous power: Canon EOS 5D Mark II
• Continuous power: Fujifilm X-T3
• Continuous power: Panasonic Lumix DMC-FZ300
• The best of both worlds at bargain prices

Copyright © 2021 Walter Sanford. All rights reserved.

What is it?

Ladies and gentlemen, children of all ages. It’s time for another exciting episode of “What is it?”

If you think you know what is shown in the preceding photo, then please leave a comment. The answer will be revealed in a post update.

Editor’s Note: OK, OK — I realize this one is beyond challenging and might turn out to be impossible to identify correctly. But hey, take a guess anyway — you might be right!

Copyright © 2021 Walter Sanford. All rights reserved.