Archive for the ‘Aperture’ Category

Non-stop flight

April 22, 2017

On 18 April 2017, a Common Baskettail dragonfly (Epitheca cynosura) was spotted patrolling part of the shoreline at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, in flight.

108mm (600mm equivalent) | ISO 100 | f/5.2 | 1/800s | -1 ev | flash fired

The photograph was taken using a Panasonic LUMIX DMC-FZ150 superzoom bridge camera and a Canon 580EX Speedlite external flash set for manual mode at 1/8 power and 105mm zoom.

Related Resource: Stop-action photography of dragonflies in flight, a blog post by Walter Sanford, featuring Phil Wherry’s answer to my question “How fast would the camera shutter speed need to be in order to freeze all motion of a dragonfly in flight?”

Copyright © 2017 Walter Sanford. All rights reserved.

Phanogomphus

April 20, 2017

Two teneral dragonflies were observed near Mulligan Pond during a photowalk at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. I was able to photograph the first one I spotted; the second flew away as soon as I approached it.

This dragonfly is either Ashy Clubtail (Phanogomphus lividus) or Lancet Clubtail (Phanogomphus exilis). Based upon the short, faded yellow markings on the dorsal side of abdominal segments eight and nine (S8-9), this individual is probably an Ashy Clubtail dragonfly. Less reliably, the 18 April date of the spotting also suggests Ashy Clubtail (for Northern Virginia).

18 APR 2017 | JMAWR | Ashy Clubtail or Lancet Clubtail (female)

Both Ashy- and Lancet Clubtail dragonflies were formerly classified as members of the genus Gomphus. Both species were reclassified recently as Phanogomphus. In the world of taxonomic classification, there are “lumpers” and “splitters.” Score one for the splitters!

Notice the first photo shows the wings folded above the abdomen. I spotted the teneral dragonfly when it flew toward me from the pond shoreline. The dragonfly rested in this location for a few minutes before it flew to a new spot (shown below) where it perched briefly with its wings unfolded. The last time I saw the dragonfly, it was flying toward the forest alongside the pond.

The other teneral dragonfly that I saw — “the one that got away” — was perched on the lawn near the walking path around the lake; it flew toward the forest when I moved closer to take some photographs.

18 APR 2017 | JMAWR | Ashy Clubtail or Lancet Clubtail (female)

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

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

All female dragonflies have two cerci (superior appendages); in contrast all male dragonflies have two cerci and one epiproct (inferior appendage), collectively called “claspers.” Contrast the appearance of the terminal appendages of this female Ashy Clubtail with a male of the same species.

The last photo in the set is a wider view that shows how well-camouflaged the dragonfly was perched on the lawn around the pond.

18 APR 2017 | JMAWR | Ashy Clubtail or Lancet Clubtail (female)

The Backstory

I was surprised to discover a Lancet Clubtail dragonfly near Mulligan Pond during late-June 2016. Knowing that Ashy Clubtails can be found in the same habitats preferred by Lancet Clubtails, I decided to look for Ashy Clubtails at Jackson Miles Abbott Wetland Refuge beginning in mid-April 2017. Apparently Mulligan Pond is a good place for both species, because I spotted two Ashy Clubtails the first time I went looking for them. Ah, if only odonate hunting were always so easy!

Copyright © 2017 Walter Sanford. All rights reserved.

Late-stage emergent baskettail dragonfly

April 18, 2017

Common Baskettail dragonfly (Epitheca cynosura) was spotted at Painted Turtle Pond during a photowalk around Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA. This individual is a late-stage emergent teneral female.

I photographed the process of emergence from the first sighting to the time when the teneral dragonfly flew away: I shot 23 photos in approximately 16 minutes; time is compressed by showcasing six (6) select photos taken at major milestones during the event.

The following photo is the first image from a time-series documenting the emergence of the teneral female. Elapsed time is expressed in hh:mm:ss format, e.g., 00:00:00 is the time when I spotted the emergent teneral female, and 00:16:08 is the total elapsed time.

13 APR 2016 | 11:38:41 am EDT | Elapsed time: 00:00:00

Notice the drop of fluid at the tip of the abdomen. Emerging dragonflies pump fluid into their wings, causing the wings to expand. Next, the same fluid is withdrawn from the wings and used to expand the abdomen. Excess fluid is expelled afterward.

13 APR 2016 | 11:40:48 am EDT | Elapsed time: 00:02:07

The next photo shows the first time the wings opened.

13 APR 2016 | 11:48:55 am EDT | Elapsed time: 00:10:14

Then the wings closed again and remained closed for a while.

13 APR 2016 | 11:51:02 am EDT | Elapsed time: 00:12:21

The wings reopened a few minutes later. Notice that several wings are malformed slightly.

13 APR 2016 | 11:54:14 am EDT | Elapsed time: 00:15:33

Finally, the wings open up, and very soon the teneral adult flies away. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 468). Princeton University Press. Kindle Edition.

The teneral female dragonfly flew away immediately after the last photo in the time-series.

13 APR 2016 | 11:54:46 am EDT | Elapsed time: 00:16:08

This individual is a female, as indicated by her cerci (superior appendages) and thick abdomen. Common Baskettail females have shorter cerci and a thicker abdomen than males of the same species.

Exuviae (in situ)

Several dragonfly exuviae were spotted at Painted Turtle Pond; it’s possible they are cast skins from Common Baskettail. More later after the exuviae are identified using a dichotomous key for dragonfly larvae.

13 APR 2017 | OBNWR | Common Baskettail (exuvia)

These exuviae are not the one from which the teneral female featured in this post emerged.

13 APR 2017 | OBNWR | Common Baskettail (exuvia)

Copyright © 2017 Walter Sanford. All rights reserved.

Common Baskettail dragonfly (male)

April 16, 2017

A Common Baskettail dragonfly (Epitheca cynosura) was spotted near Painted Turtle Pond during a photowalk at Occoquan Bay National Wildlife Refuge (OBNWR). Common Baskettail is a member of Family Corduliidae (Emeralds); this species is seen during early spring in mid-Atlantic United States like Virginia.

I thought this might be a Slender Baskettail dragonfly (Epitheca costalis) due to narrowing of its abdomen. Turns out that was wishful thinking.

13 APR 2017 | OBNWR | Common Baskettail (male)

This individual is a male, as indicated by his terminal appendages. The curved shape of the cerci (superior appendages) is a key field marker for Common Baskettail; in contrast, the cerci for Slender Baskettail tend to be more parallel. Thanks to Mike Boatwright and Paul Guris, members of the Northeast Odonata Facebook group, for reminding me of this pearl of wisdom!

I think baskettail cerci look “rubberized,” like the handles of metal tools made for working with electricity. Whenever I see this distinctive field marker, shown clearly in the following photos, I know the dragonfly is probably a species of baskettail.

13 APR 2017 | OBNWR | Common Baskettail (male)

The last photo shows a dorso-lateral view of the male dragonfly. Notice the epiproct (inferior appendage) is visible clearly in this photo.

13 APR 2017 | OBNWR | Common Baskettail (male)

Also notice the light-colored spots on the hairs covering the body of the dragonfly. The following article by John Abbott suggests the spots may be some type of pollen.

Related Resource: Identification of Male Epitheca (Tetragoneuria) in Texas, by John C. Abbott.

Copyright © 2017 Walter Sanford. All rights reserved.

Stream Cruiser dragonfly (male)

April 14, 2017

Another Stream Cruiser dragonfly (Didymops transversa) was spotted during a photowalk along Beaver Pond Loop Trail at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA.

This individual is a male, as indicated by his “indented” hind wings and terminal appendages.

Stream Cruiser dragonflies typically perch at a 45° angle because of their extremely long legs, especially noticeable in the last photo.

For another perspective on the same male, both literally and figuratively, see Stream Cruiser dragonfly by fellow photoblogger Michael Powell.

Copyright © 2017 Walter Sanford. All rights reserved.

Stream Cruiser dragonfly (female)

April 12, 2017

A Stream Cruiser dragonfly (Didymops transversa) was spotted during a photowalk along Beaver Pond Loop Trail at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA.

This individual is a female, as indicated by her rounded hind wings and terminal appendages. Look closely at the face and head of the dragonfly. Can you see why “ice cream sandwich face” is my nickname for Stream Cruiser?

The female landed long enough for me to shoot four photos before she flew away — not enough time for me to point her out to Michael Powell, a fellow amateur wildlife photographer and blogger who joined me in search of his first Stream Cruiser. Fortunately, Mike and I were able to photograph a male Stream Cruiser later the same afternoon. Look for photos of the male in my next blog post.

Addendum

I cropped the photo into a square format in order to remove a distracting element. Can you tell what I dislike about the original version? I prefer the square format. Which version do you prefer?

Copyright © 2017 Walter Sanford. All rights reserved.

House Finches

April 8, 2017

Sometime after I moved to a new apartment, I noticed some cute little reddish-brown birds that sing a cheerful song. I used the free Merlin Bird ID App to identify the bird based upon a few simple observations. Turns out my little friends are House Finches (Haemorhous mexicanus).

As time passed and months stretched into years, I realized the birds appeared in the spring, hung around all summer, and disappeared in the fall.

These newly established eastern populations have since become migratory, and now spend winters in the southern parts of the United States. Source Credit: BioKIDS.

05 APR 2017 | The Beacon of Groveton | House Finch (male)

These photos show two of several House Finches spotted recently near the top of the seven-story parking garage at the Beacon of Groveton, Fairfax County, Virginia USA. Both individuals are male, as indicated by their reddish coloration.

05 APR 2017 | The Beacon of Groveton | House Finch (male)

Copyright © 2017 Walter Sanford. All rights reserved.

Common Whitetail (teneral female)

April 6, 2017

After a seemingly endless off-season, I’m pleased to report odonate hunting season has begun in Northern Virginia!

05 APR 2017 | ABWR | Common Whitetail (teneral female)

A Common Whitetail dragonfly (Plathemis lydia) was spotted during a photowalk along Beaver Pond Loop Trail at Accotink Bay Wildlife Refuge (ABWR), Fairfax County, Virginia USA. This individual is a teneral female, as indicated by her terminal appendages and the tenuous appearance of her wings.

Copyright © 2017 Walter Sanford. All rights reserved.

Autumn Meadowhawk (mature female)

April 4, 2017

25 OCT 2016 | OBNWR | Autumn Meadowhawk (mature female)

The preceding photograph shows an Autumn Meadowhawk dragonfly (Sympetrum vicinum) perching on fall foliage at Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA. This individual is a mature female, as indicated by her terminal appendages, coloration, and tattered wings.

Copyright © 2017 Walter Sanford. All rights reserved.

Another foray into focus stacking

April 2, 2017

I used CamRanger to remotely control my Canon 5D Mark II DSLR camera with an Apple iPad 3 (with retina display). The camera was set for manual exposure and One-Shot AF. I used an aperture of f/5.6 with my Canon 100mm macro lens; I think I’ll use f/8 next time.

Apple iPad 3 (with retina display) | screenshot of CamRanger app

The CamRanger app for Apple iOS can be used to set the focus point by tapping on the iPad screen. I focused on the toy dragonfly in approximately 10 places and tapped the “Capture” button to take a photo. The following photo shows one of the resulting images, focused on the head of the dragonfly.

ISO 100 | f/5.6 | 1/200s | Manual White Balance (Flash use)

Adobe Photoshop CC 2017 was used to create a “focus stack” composite image. As you can see, most of the toy dragonfly is in focus but there are some places that are slightly blurry/ghostly. The obvious solution: Focus on more places (that is, take more pictures), although that might be unnecessary using an aperture of f/8 or smaller.

Composite image created using Adobe Photoshop CC 2017.

Going forward, my plan is to progress from manually setting the focus point by tapping on the iPad screen to using the automated focus stacking feature in the CamRanger app. Baby steps, Bob!

Tech Tips:

The following equipment was used to shoot all of the photographs in the focus stack: Canon EOS 5D Mark II digital camera, in manual mode; Canon EF100mm f/2.8L Macro lens (set for automatic focus); Canon 580EX II external flash, off-camera, in manual mode; Canon 580EX external flash, off-camera, in manual mode; and a Yongnuo YN-622C-TX E-TTL II Wireless Flash Controller for Canon plus a two-pack of Yongnuo YN-622C II E-TTL Wireless Flash Transceivers for Canon. Additional backlight was added to the scene using a Nissin i40 external flash unit (off-camera, in SF mode).

Adobe Photoshop CC 2017 was used to create the focus stack and post-process the composite image.

Copyright © 2017 Walter Sanford. All rights reserved.


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