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.

Previews of Coming Attractions – Fall Species of Odonates

There is an annual cycle of odonate activity that can be subdivided into three broad categories: Early Season (spring); Mid-season (summver); and Late Season (fall).

As we endure the “Dog Days of Summer,” waiting for the calendar to turn to fall, it’s time to begin looking for the Late Season (fall) species of odonates.

This blog post provides a photo sampler of some of the fall species of odonates that can be seen during September, October, and November in the Commonwealth of Virginia. This post is not intended to be a comprehensive field guide that features every odonate species that can be seen during the same time period.

Full Disclosure

Some fall species are easier to find than others. And some species are flyers rather than perchers, making it almost essential to capture them in flight using an insect net. That being said, it’s richly rewarding to find any of the rare to uncommon species so do your homework and be persistent. Good luck and happy hunting!

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Editor’s Notes

Click on the date listed in the caption for each photo to see the original blog post for that image; click on the odonate name to see all of my blog posts related to that species.

Sincere thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for providing photographs of many of the rare to uncommon fall species of odonates featured in this photo sampler. Click on the word “Photo” in the caption for each of Mike’s photographs to see his original Facebook post for that image.

Every species features the following information: common name; scientific name; early-date/late-date; abundance; and habitat. All information is excerpted from “CHECKLIST OF THE DRAGONFLIES AND DAMSELFLIES OF VIRGINIA, April 2017 and April 2020 updates” by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage.

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Dragonflies (Order Anisoptera)

Family Aeshnidae (Darners)

Black-tipped Darner (Aeshna tuberculifera)

Adult flight period: JUN 30 – OCT 29. Rare to uncommon. Habitat: Montane ponds.

Photo used with written permission from Michael Boatwright.

Common Green Darner (Anax junius)

Adult flight period: FEB 27 – DEC 30. Common. Habitat: Ponds.

20 OCT 2014 | Huntley Meadows Park | Common Green Darner (female)

Fawn Darner (Boyeria vinosa)

Adult flight period: JUN 03 – NOV 07. Common. Habitat: Streams, rivers.

02 SEP 2012 | Patuxent Research Refuge | Fawn Darner (male)

Shadow Darner (Aeshna umbrosa)

Adult flight period: JUN 08 – DEC 05. Common. Habitat: Ponds, streams.

24 OCT 2014 | Huntley Meadows Park | Shadow Darner (male)

Family Corduliidae (Emeralds)

Clamp-tipped Emerald (Somatochlora tenebrosa)

Adult flight period: JUN 08 – OCT 15. Common. Habitat: Ponds, small streams.

Photo used with written permission from Michael Boatwright.

Fine-lined Emerald (Somatochlora filosa)

Adult flight period: JUL 10 – OCT 15. Rare to uncommon. Habitat: Boggy streams, swamps, marshes.

18 SEP 2019 | Occoquan Bay NWR | Fine-lined Emerald (male)

Family Gomphidae (Clubtails)

Arrow Clubtail (Stylurus spiniceps)

Adult flight period: JUN 13 – OCT 19. Uncommon to common. Habitat: Rivers.

Photo used with written permission from Michael Boatwright.

Laura’s Clubtail (Stylurus laurae)

Adult flight period: JUN 20 – SEP 26. Rare to uncommon. Habitat: Streams, rivers.

Photo used with written permission from Michael Boatwright.

Russet-tipped Clubtail (Stylurus plagiatus)

Adult flight period: JUN 15 – NOV 06. Uncommon to common. Habitat: Streams, rivers.

22 SEP 2016 | JMAWR | Russet-tipped Clubtail (male, eating)

Family Libellulidae (Skimmers)

Autumn Meadowhawk (Sympetrum vicinum)

Adult flight period: MAY 28 – JAN 03. Common. Habitat: Ponds.

22 NOV 2013 | Huntley Meadows Park | Autumn Meadowhawk (male)

Blue-faced Meadowhawk (Sympetrum ambiguum)

Adult flight period: MAY 22 – NOV 19. Uncommon. Habitat: Swamps, ponds.

06 OCT 2014 | Huntley Meadows Park | Blue-faced Meadowhawk (male)

Black Saddlebags (Tramea lacerata)

Adult flight period: APR 12 – OCT 30. Common. Habitat: Ponds.

10 SEP 2017 | Occoquan Bay NWR | Black Saddlebags (female)

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

Spot-winged Glider (Pantala hymenaea)

Adult flight period: MAY 08 – OCT 20. Common. Habitat: Ponds.

20 JUL 2016 | Fairfax County, VA USA | Spot-winged Glider (female)

Wandering Glider (Pantala flavescens)

Adult flight period: MAY 02 – NOV 17. Common. Habitat: Ponds.

04 OCT 2016 | Mason Neck West Park | Wandering Glider (male)

Damselflies (Order Zygoptera)

Family Lestidae (Spreadwings)

Great Spreadwing (Archilestes grandis)

Adult flight period: JUN 25 – NOV 11. Uncommon. Habitat: Streams, ponds.

15 OCT 2015 | Huntley Meadows Park | Great Spreadwing (male)

Spotted Spreadwing (Lestes congener)

Adult flight period: JUN 10 – NOV 11. Uncommon. Habitat: Ponds.

Photo used with written permission from Michael Boatwright.

 

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Classification of Fall Species into Sub-groups

Migratory Species

At least five major species of dragonflies known to be migratory in North America.

• Black Saddlebags (Tramea lacerata)
• Common Green Darner (Anax junius)
• Spot-winged Glider (Pantala hymenaea)
• Wandering Glider (Pantala flavescens)

Rare to Uncommon Species

• Arrow Clubtail (Stylurus spiniceps)
• Black-tipped Darner (Aeshna tuberculifera)
• Blue-faced Meadowhawk (Sympetrum ambiguum)
• Clamp-tipped Emerald (Somatochlora tenebrosa)
• Fine-lined Emerald (Somatochlora filosa)
• Laura’s Clubtail (Stylurus laurae)
• Ocellated Darner (Boyeria grafiana)
• Great Spreadwing (Archilestes grandis)
• Spotted Spreadwing (Lestes congener)

Copyright © 2021 Walter Sanford. All rights reserved.

Comet Darner dragonfly (exuvia)

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

This specimen is from Family Aeshnidae (Darners), as indicated by the following field marks: the exuvia has a flat labium that doesn’t cover the face (not mask-like); the antennae are thin and thread-like (not club-like, as in Gomphidae larvae/exuviae); and the eyes are large relative to the size of the head.

19 JUL 2021 | Ontario, Canada | Comet Darner exuvia (lateral view)

Lateral spines along abdominal segments seven, eight, and nine (S7-9) indicate the genus is Anax; the length of the exuvia indicates longipes (~6 cm, measured as is).

The Backstory

Stanley Caveney is shown in the first of several photos taken by Hugh Casbourn. Stan contacted me for confirmation of his tentative identification of several Comet Darner exuviae that he collected during July 2021. Stan kindly gave one of the exuviae to me.

Photo used with written permission from Hugh Casbourn.

I asked Stan whether he had taken photographs of the Comet Darner exuviae in situ. Stan hadn’t, so he and Hugh revisited a local pond where they searched for and found two more exuviae.

How many exuviae do you see in the next photo? Look closely — both cast skins are shown in the same image.

Photo used with written permission from Hugh Casbourn.

An exuvia from a female Comet Darner appears in the foreground of the preceding photograph…

Photo used with written permission from Hugh Casbourn.

and a male Comet Darner appears in the background.

Photo used with written permission from Hugh Casbourn.

I asked Stan for advice regarding where to look for Comet Darner exuviae.

The six exuviae found to date were mainly at the inner edge of the cattail beds, facing the open water of the pond and where the individual cattail plants were spaced out. Source Credit: Personal communication from Stanley Caveney.

Related Resource: Identification Keys to Northeastern Anisoptera Larvae, compiled by Ken Soltesz. Refer to pp. 21-22.

Editor’s Note: Sincere thanks to Derek Caveney, Stan’s son, for shipping the exuvia to me. The specimen was packed so carefully that it arrived in excellent condition, as you can see in the first photo in this blog post. I’m looking forward to shooting a complete photo set of the exuvia.

Copyright © 2021 Walter Sanford. All rights reserved.

Yellow-sided Skimmer (terminal appendages)

Female and male Yellow-sided Skimmer dragonflies (Libellula flavida) were spotted at a small pond at an undisclosed location in Prince William County, Virginia USA.

Female

The first individual is a female, as indicated by her mostly yellow coloration and terminal appendages.

17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (female)

Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

Mature male

The last individual is a mature male, as indicated by his light-blue pruinescence and terminal appendages.

17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (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”).

Immature male Yellow-sided Skimmers look similar to females of the same species. Terminal appendages can be used to differentiate the sex of immature males and mature females.

Related Resource: Yellow-sided Skimmer (male and female) – a blog post by Walter Sanford.

Copyright © 2021 Walter Sanford. All rights reserved.

Follow-up: Raynox DCR-250 close-up filter

In my last blog post, I mentioned that minor vignetting can be a problem when the Raynox DCR-250 close-up filter is mounted on some macro- and non-macro camera lenses.

Canon 100mm macro lens

In case you’re wondering whether vignetting is a problem when using two step-down rings with the Canon 100mm macro lens, it isn’t. As it turns out, the front lens element is recessed quite a bit from the lens barrel so the step-down rings cover little if any glass. Source Credit: Raynox DCR-250 close-up filter, by Walter Sanford.

The first photo shows the front lens element of the Canon 100mm macro lens is in fact recessed quite a bit from the lens barrel.

Lens barrel without nested step-down rings.

The next photo shows the nested 67-52mm and 52-43mm step-down rings that I use to mount the Raynox DCR-250 on my Canon 100mm macro lens. Look closely at the full-size version of this image and you should see the step-down rings don’t cover any of the camera lens.

Lens barrel with nested step-down rings.

Disclaimer: This might or might not be true for other makes and models of 100mm macro lenses.

Panasonic Lumix superzoom bridge cameras

The camera lens will need to be adjusted for at least some slight telephoto zoom in order to eliminate the vignetting caused by mounting a 43mm filter on a lens with a 52mm filter size. Source Credit: Raynox DCR-250 close-up filter, by Walter Sanford.

A Guide To Using Raynox Close Up Lenses on the FZ200 Camera, by Graham Houghton is the second item listed under “Related Resources” in my last blog post. Page 6 of Graham’s excellent guide describes a simple way to set-up both my Panasonic Lumix DCR-150 and DCR-300 superzoom bridge cameras so that vignetting isn’t a problem.

p. 6, A Guide To Using Raynox Close Up Lenses on the FZ200 Camera, by Graham Houghton.

For the DMC-FZ300, press the “Menu/Set” button on the back of the camera, then select the camera icon in the left side-bar. Navigate to page 7/7 and select “Conversion”; select the icon for close-up lens. When the camera is powered-on, it will zoom to 4x (121 mm) automatically and the aperture will be limited to f/4 or smaller (f/4 to f/8).

For my older DMC-FZ150, the set-up process is the same except “Conversion” appears on page 5/5. Zoom is set to 4x and the aperture is limited to f/3.6 or smaller (f/3.6 to f/8).

Using either camera, the lens can be adjusted for greater than 4x zoom, resulting in more magnification.

Copyright © 2021 Walter Sanford. All rights reserved.

Raynox DCR-250 close-up filter

I watched a video by Micael Widell recently that reminded me the Raynox DCR-250 close-up filter is a good value given its versatility.

Before I bought the Raynox close-up filter many years ago, I was skeptical that it would work. I still can’t explain why it works with many lenses I own including both macro- and non-macro lenses, but I can tell you with certainty it does work and works well!

Canon 100mm macro lens

The Canon 100mm macro lens has a maximum magnification of 1:1. Micael Widell says adding the Raynox DCR-250 close-up filter to the lens increases the magnification from 1x to 2x. According the B&H Photo Specs page for the Raynox DCR-250 close-up filter, its magification is 2.5x.

Calculating magnification is tricky and not as straightforward as one might think. In this case it doesn’t matter whether Mr. Widell or B&H Photo is correct, the fact of the matter is adding a Raynox DCR-250 close-up filter to your lens should at least double the magnification.

The first photograph shows the following equipment, couterclockwise from the upper-left: “snap-on universal adapter” for Raynox DCR-250 close-up filter; Raynox close-up filter mounted on a 52-43mm step-down ring; and a 67-52mm step-down ring.

Several mounting adapters for Raynox DCR-250 close-up filter.

The Raynox DCR-250 close-up filter comes with a “snap-on universal adapter” for mounting the filter on lenses with a filter size from 52-67mm. The universal adapter clips on the front of a lens the same as a lens cap. That’s OK for use in a photo studio but less than ideal for use in the field. In my opinion, it’s better to use inexpensive step-down rings to mount the close-up filter more securely.

Canon EOS 5D Mark II macro photography kit.

The Rube Goldberg rig shown above has a lot of parts, but for the purpose of this blog post focus on the Canon 100mm macro lens and Raynox DCR-250 mounted on the lens using nested 67-52mm and 52-43mm step-down rings.

In case you’re wondering whether vignetting is a problem when using two step-down rings with the Canon 100mm macro lens, it isn’t. As it turns out, the front lens element is recessed quite a bit from the lens barrel so the step-down rings cover little if any glass.

Panasonic Lumix superzoom bridge cameras

Both my Panasonic Lumix DCR-150 and DCR-300 superzoom bridge cameras feature a 52mm filter thread size. So it’s simple to use a 52-43mm step-down ring to mount the Raynox DCR-250 close-up filter on either camera lens.

Raynox DCR-250 not mounted on the camera lens.

The camera lens will need to be adjusted for at least some slight telephoto zoom in order to eliminate the vignetting caused by mounting a 43mm filter on a lens with a 52mm filter size.

Both cameras feature a 24x zoom lens, so when the Raynox DCR-250 is added to the kit the actual magnification will vary depending upon the focal length for which the camera lens is set.

Raynox DCR-250 shown mounted on the camera lens.

Related Resources

• 3 Ways to Increase Your Macro Lens Magnification from 1x to 2x! by Micael Widell (7:15). (00:54) 1. Raynox filter. (02:22) 2. Extension tubes. (05:13) 3. teleconverter (called an “extender” by Canon).
• A Guide To Using Raynox Close Up Lenses on the FZ200 Camera by Graham Houghton – “A fairly comprehensive look at the selection and use of the Raynox macro lenses [close-up filters] that are available for achieving close up images with the FZ200 camera.”
• RaynoxAdapterCalculator – another good resource from the Extreme Macro Web site.
• Sensor Size and Magnification – correcting a common misunderstanding, by Allan Walls Photography (20:02). The video segment from 5:48 to 14:33 is money, especially the discussion related to the “Thin Lens Formula” beginning around 11:24.
• Sensor Size Matters – Part 1 (the Front Half) – A Demonstration, by Allan Walls Photography (19:51). This demonstration is follow-up for the preceding video.

Copyright © 2021 Walter Sanford. All rights reserved.

Black-shouldered Spinyleg (female)

A Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) was spotted by Michael Powell during a photowalk with me along a mid-size stream at an undisclosed location in Prince William County, Virginia USA.

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

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

We followed the female from one location…

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

to another.

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

I was able to take no more than three shots at each perch before she moved on to the next stop.

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

Habitat

I’m not sure I’d call Black-shouldered Spinyleg a habitat specialist. I’ve seen and photographed D. spinosus along small streams in the forest, mid-size streams (like the one in this post), and large rivers.

Habitat: Rocky and muddy streams and rivers from small to large, more often in woodland. Also in rocky lakes in northern part of range. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6416-6417). Princeton University Press. Kindle Edition.

Range map

The following map shows all official records for Dromogomphus spinosus in the United States of America. Given the wide range of lotic habitats where Black-shouldered Spinyleg is found, I’m puzzled by the fact that the species isn’t more widespread than it appears to be.

Related Resource: All posts in my blog tagged with the words “Black-shouldered Spinyleg dragonfly.”

Copyright © 2021 Walter Sanford. All rights reserved.

Anatomy of a male Tiger Spiketail

The following annotated image shows a Tiger Spiketail dragonfly (Cordulegaster erronea). This individual is a male, as indicated by his hamules, “indented” hind wings, and terminal appendages.

Hamules

Hamules? What are hamules?

hamules: paired structures that project from genital pocket under second segment and hold female abdomen in place during copulation Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11618-116198). Princeton University Press. Kindle Edition.

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. 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.

Photo used with written permission from Michael Powell.

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

Indented hind wings

Male members of many families of dragonflies have “indented” hind wings near the body, with some notable exceptions.

Hind wing venation and shape can identify the sex of most dragonflies. Petaltails, darners (except Anax), clubtails, spiketails, cruisers, and some emeralds. Wing shape isn’t helpful to sex baskettails since they are largely the same. They are different in Cordulia, Dorocordulia, Somatochlora and to a lesser degree, Neurocordulia. Source Credit: Ed Lam, author and illustrator of Damselflies of the Northeast.

Terminal appendages

Identifying female versus male dragonflies and damselflies can be challenging but it’s a little easier when you know how to differentiate their terminal appendages.

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 dragonfly terminal appendages don’t look exactly the same for all species of dragonflies, but their function is identical.

Generally speaking, spiketail dragonflies have relatively small terminal appendages. That said, they must get the job done!

Related Resource: Tiger Spiketail dragonfly (male) – a blog post by Walter Sanford.

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