Archive for the ‘How To’ Category

Cobra Clubtail dragonflies (females)

June 12, 2020

At least 11 Cobra Clubtail dragonflies (Gomphurus vastus) were spotted during a photowalk with Michael Powell in Fairfax County, Virginia USA, including 10 females and one male. This blog post features photos of the first two females that I spotted.

No. 1a

08 JUN 2020 | Fairfax County, VA | Cobra Clubtail (female)

This individual is a female, as indicated by her terminal appendages and rounded hind wings. Notice the injury to her right rear leg.

08 JUN 2020 | Fairfax County, VA | Cobra Clubtail (female)

No. 1b

Inspired by Fred Siskind’s portfolio of dew-covered insects, Mike Powell and I are on a never-ending quest to find and photograph dew-covered odonates. The last photo shows my best effort to date.

As we were photographing female No. 1a, I noticed another individual perched nearby. No. 1a was perched in a sunny spot where most of the morning dew had evaporated; No. 1b was perched in a shady spot where everything was still covered by dew.

08 JUN 2020 | Fairfax County, VA | Cobra Clubtail (female)

Unfortunately, this female was quite skittish so her glamor shoot was one-and-done.

What is dew and how does it form?

Dew forms when the atmosphere is cooled until its temperature reaches the “dew point temperature” and water vapor in the atmosphere (an invisible gas) condenses to become liquid water. (The temperature when this phase change occurs is also known as the “frost point temperature.”)

The dew point temperature varies depending upon the amount of moisture in the air. Typical dew points in the mid-Atlantic states are in the 60s and 70s during the summer months, 40s and 50s during spring and fall, and 20s and 30s during winter.

Check your local weather forecast to see whether the predicted overnight low air temperature will reach the dew point temperature. Sometimes close is good enough, as surfaces that are good radiators of thermal energy can cool a thin layer of air to the dew point.

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.

Splendid Clubtail dragonfly (female)

June 3, 2020

A Splendid Clubtail dragonfly (Gomphurus lineatifrons) was spotted during a photowalk with Michael Powell at an undisclosed location in Fairfax County, Virginia USA. Easy for me to say now. As it turns out, my initial identification was incorrect.

The first photo I took of the dragonfly — the record shot — is shown below. Notice the pattern of yellow lateral marks/spots on its abdomen. Also notice the yellow blotch on the side of abdominal segment eight (S8) extends onto the club flange, as shown in the full-size version of the image. (Thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for sharing these key field marks for Splendid.)

26 MAY 2020 | Fairfax County, VA | Splendid Clubtail (female)

In contrast, the pattern of yellow lateral marks/spots on the abdomen of a female Cobra Clubtail (Gomphurus vastus), shown below, looks quite different. And the yellow blotch on S8 DOES NOT EXTEND onto the club flange, as shown in the full-size version of the image.

09 MAY 2017 | Riverbend Park | Cobra Clubtail (female)

The last photo, published in a recent blog post, is the one that caused me to misidentify the dragonfly. Notice the pattern of yellow mid-dorsal lines/marks is somewhat similar for both Cobra Clubtail (above) and Splendid Clubtail (below).

26 MAY 2020 | Fairfax County, VA | Splendid Clubtail (female)

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

The Backstory

My last blog post features an actual female Cobra Clubtail dragonfly that I spotted soon after seeing the Splendid Clubtail shown above.

The Cobra appeared to be noticeably smaller than the Splendid, and in fact it is. Cobra is 4.7-5.7 cm in total length; Splendid is 6.7-6.9 cm. In my experience it’s often difficult to judge the relative size of dragonflies in the field. That being said, a difference of ~2.0 cm in length was easy to see.

There is, of course, some natural variation in size among individuals of the same species. I walked around the rest of the day wondering why the two “Cobra” that I’d seen were so different in size. The answer seems obvious in retrospect: the larger one is Splendid; the smaller one is Cobra.

Official Records

When my friend Mike Powell submitted an official record for the Splendid Clubtail, he followed my lead and called it Cobra Clubtail. Mike included a photograph showing a dorsal view of the dragonfly that looks similar to my dorsal view.

Rick Cheicante and Mike Boatwright, two vetters for the Odonata Central records database, thought the dragonfly might be Splendid rather than Cobra. Mike Boatwright contacted me and asked to see more photos of the Splendid. One look at my photo showing a side view of the individual and Mike B. knew immediately the “Cobra” is actually Splendid.

So what’s the take-away? It’s good to be wrong, in fact, it’s Splendid! (See what I did there?) Especially when Splendid Clubtail is a new species for my life list as well as a new species for Fairfax County, Virginia USA.

And while I’m giving credit where credit is due, it should be noted that Kevin Munroe, former manager of Huntley Meadows Park, deserves credit as the first person to discover Splendid Clubtail in Fairfax County, Virginia USA. Although Kevin didn’t submit official records for his finds, he beat me to the discovery by nearly a decade!

Adult Flight Period

According to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, the adult flight period for Gomphurus lineatifrons is from May 01 to June 27. The species is classified as uncommon. Its habitat is “rivers.”

Bear in mind, Dr. Roble’s records are for the entire state, therefore the adult flight period for Gomphurus lineatifrons seems to be longer than it is in reality. The adult flight period for a single site is probably shorter. For example, according to records for Northern Virginia maintained by Kevin Munroe, former manager of Huntley Meadows Park, the adult flight period for Splendid Clubtail is May 28 to June 15.

Related Resource: Gomphurus lineatifrons (Splendid Clubtail)

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Hits and misses

May 25, 2020

This blog post might have been called “New ways of doing the same old thing.” In other words, experimenting with new techniques for shooting sets of macro photos of a familiar  subject and new variations for creating focus-stacked composite images.

80mm (120mm, 35mm equivalent) | f/16 | 1/200s | ISO 160 | 0 ev

Tech Tips

In-camera focus bracketing was used to shoot a photo set with my Fujifilm X-T3 mirrorless digital camera and Fujinon 80mm macro lens (coupled with 11mm and 16mm extension tubes for a little additional magnification).

The camera lens was focused manually on the closest point on the face of the subject. The shutter button was pressed one time; the first photo was taken after a 10-second timer elapsed, then the focus point advanced automatically from the initial focus point to a far point on the subject in the background of the photo.

RAW FILE CONVERTER EX 3.0 was used to batch-convert the resulting 50 images from Fujifilm RAF files to TIFF files. Adobe Photoshop CC 2017 was used to create five sub-stacks (10 photos per sub-stack) that were combined into one focus-stacked composite image. The final image was edited using Apple Aperture.

Analyzing the results

Most of the “misses” were self-inflicted.

For example, minimal effort was invested in arranging the subject and lighting the scene. Generally speaking, better lighting results in better photos.

Some trial and error is required in order to determine the correct focus bracketing settings for a given combination of camera and lens. The following settings were used to shoot the photo set for the focus-stacked composite image featured in this post: Frames = 50; Step = 10; Interval = 4 s.

Step size is a number from one (1) to 10, with one being the smallest increment and 10 being the largest. Although a step size of 10 enabled the camera to cover the subject completely from front-to-back in 50 frames, selecting the coarsest step increment might have resulted in small “focus gaps” that are noticeable in a few places on the full-size version of the composite image.

I cabled a Godox PROPAC PB960 to the Godox TT685C external flash unit that is used to backlight the white background. The power pack enables faster flash recycle times and increases the number of times the flash can be fired before its AA batteries run down. That was a big “hit!”

I didn’t realize the radio flash trigger was set for a power ratio of 1/4 +0.7 — that’s 2/3 of a stop slower than my preferred setting of 1/2 +0.3 that usually results in the pure white background (255, 255, 255) that is a goal of the “Meet Your Neighbours” (MYN) technique. That was a big “miss” I was able to correct in post-processing, although increasing the exposure enough to blow out the background might have degraded image quality a little.

One of many reasons the Fujifilm X-Series cameras are so popular is their retro look and feel, including lots of buttons and dials on the camera body. That’s good and bad: it’s good to be able to adjust many camera settings using either an external button or dial rather than navigating through menus in the camera’s firmware; it’s bad that it’s easy to change camera settings accidentally.

I must have rotated the back dial slightly because the shutter speed was set for 1/200 s rather than the camera sync speed of 1/250 s. Using a faster shutter speed can result in sharper images.

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.

Macromia illinoiensis exuvia (face-head) redux

May 22, 2020

A Swift River Cruiser dragonfly (Macromia illinoiensis) exuvia was collected, with permission from park staff, on 27 May 2017 along the Potomac River at Riverbend Park in Fairfax County, Virginia USA.

The preceding image shows the remnant ommatidia clearly.

From this viewpoint, it’s harder to see the prominent horn on the face that is a key field mark for larvae/exuviae in the Family Macromiidae (Cruisers). The base of the triangular horn is located above the labium (face mask), between the long, thin antennae; the apex of the triangle is pointed toward the viewer.

It’s easier to see the horn in the featured photo in my last blog post.

Tech Tips

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

20 photos of the specimen were taken using 2.5x magnification at an aperture of f/4; in-camera focus peaking was used to highlight select areas in each photo. RAW FILE CONVERTER EX 3.0 was used to convert Fujifilm RAF files to TIFF files. Adobe Photoshop CC 2017 was used to create a focus-stacked composite image that was edited using Apple Aperture.

Copyright © 2020 Walter Sanford. All rights reserved.

Macromia illinoiensis exuvia (face-head)

May 20, 2020

The following photograph of a Swift River Cruiser dragonfly (Macromia illinoiensis) exuvia shows a prominent horn on the face that is a key field mark for larvae/exuviae in the Family Macromiidae (Cruisers).

The specimen was collected, with permission from park staff, on 27 May 2017 along the Potomac River at Riverbend Park in Fairfax County, Virginia USA.

Tech Tips

The subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique. The specimen was posed on its dorsal side, so the camera was focused on the face-head-ventral view of the exuvia. The final image was cropped and rotated 180° during post-processing.

10 photos of the specimen were taken using an aperture of f/16; in-camera focus peaking was used to highlight select areas in each photo. RAW FILE CONVERTER EX 3.0 was used to convert Fujifilm RAF files to TIFF files. Adobe Photoshop CC 2017 was used to create a focus-stacked composite image that was edited using Apple Aperture.

Editor’s Note: This blog post is the last installment in what turned out to be a three-part series. The featured focus-stacked composite image is a little closer to what I had in mind when I set up the photo shoot.

  1. MYN – Macromiidae larvae/exuviae are horny
  2. RAW FILE CONVERTER EX 3.0

Copyright © 2020 Walter Sanford. All rights reserved.

RAW FILE CONVERTER EX 3.0

May 18, 2020

RAW FILE CONVERTER EX 3.0 powered by SILKYPIX is a free application available for download from Fujifilm USA. The application can be used to convert Fujifilm RAF files to TIFF files.

The application is somewhat counterintuitive. For example, if you look at the File menu (shown in the menubar) notice “Export” isn’t an option.

Instead, images are exported from the Development menu.

First, select “Development / File output settings…” and configure the menu settings as shown below (or as appropriate for your purposes).

If you’d like to export several files, then select “Development / Batch development settings…” and configure the menu settings as shown below (or as appropriate for your purposes).

Use the left sidebar to navigate to a set of RAF files, then choose the images that you’d like to convert to TIFFs. Select “Development / Batch develop selected images…” [It’s worth noting that after selecting one or more images, some of the items in the “File” menu are no longer grayed-out. Selecting “File / Batch develop selected images…” is the same as working from the “Development” menu.]

Next a pop-up window appears; click the button labeled “Batch develop.”

The following window shows the progress of the file conversion process.

Tech Tips

“RAW FILE CONVERTER EX 3.0″ can be used to edit photos too. I have no interest in learning to use a new application for editing photos — I know how to use “Apple Aperture” and “Adobe Lightroom” already. The free application from Fujifilm is simply a utility that enables me to convert RAF files that I can’t open and edit on my older Apple iMac desktop computer to TIFFs that I can open/edit.

That being said, the application appears to be fairly robust and has some features that might be worth exploring.

The step-by-step instructions provided in this guide were discovered by limited experimentation. If you know a better/simpler way to accomplish the same task, then please comment on this post. Thank you!

Related Resource: MYN – Macromiidae larvae/exuviae are horny, a blog post by Walter Sanford (see section entitled “Tech Tips”).

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Macromiidae larvae/exuviae are horny

May 15, 2020

A prominent horn on the face is a key field mark for larvae/exuviae in the Family Macromiidae (Cruisers), as shown in the following photograph of a Swift River Cruiser dragonfly (Macromia illinoiensis) exuvia.

The base of the triangular horn is located above the labium (face mask), between the long, thin antennae.

The specimen was collected, with permission from park staff, on 27 May 2017 along the Potomac River at Riverbend Park in Fairfax County, Virginia USA.

Tech Tips

The subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique. The specimen was posed on its dorsal side, so the camera was focused on the face-head-ventral view of the exuvia. The image was rotated 180° during post-processing.

My vintage 2009 Apple iMac desktop computer is too old to support drivers for importing RAF files from my Fujifilm X-T3 mirrorless digital camera into either Apple Aperture or Adobe Lightroom.

The work-around is to use a free application from Fujifilm that converts RAF files to TIFF files, which can be opened and edited with Aperture and Lightroom. Problem is I’m a big procrastinator and haven’t learned how to use the file converter application, so I simply edited one of the JPGs straight from the camera.

For the most part, the finished image looks fairly good although the eyes are blown out a little to a lot. JPG files have less dynamic range than RAF files so I was unable to recover the blown highlights.

Hmmm, it might be time to buy a new desktop computer!

Post Updates

I finally got around to figuring out how to use the free Fujifilm application to convert RAF files to TIFFs. See my follow-up blog post entitled “RAW FILE CONVERTER EX 3.0” for step-by-step instructions.

10 photos (converted from RAF to TIFF), including the one-off featured in this blog post, were used to create a focus-stacked composite image of the specimen that is a little closer to what I had in mind when I set up the photo shoot.

Copyright © 2020 Walter Sanford. All rights reserved.

Focus bracketing using Fujifilm X-T3

May 11, 2020

In-camera focus bracketing was used to shoot 35 photos automatically. Adobe Photoshop CC 2017 was used to create the focus-stacked composite image shown below.

Focus-stacked composite image

The toy is a Poliwrath, one of many Pokemon characters. The 7″ plastic ruler is from the Calvert Marine Museum. Do you know why the small ruler is 7″ long rather than the more common 6″ length? Please leave a comment if you know the correct answer.

Photo No. 1

The camera was focused manually on the closest point in the foreground, before pressing the shutter button.

80mm (120mm, 35mm equivalent) | f/8 | 1/250s | ISO 160 | 0 ev

Select photos from the 35-photo set show the focus point advancing automatically from the foreground to background.

Photo No. 5

80mm (120mm, 35mm equivalent) | f/8 | 1/250s | ISO 160 | 0 ev

Photo No. 20

80mm (120mm, 35mm equivalent) | f/8 | 1/250s | ISO 160 | 0 ev

Photo No. 35

80mm (120mm, 35mm equivalent) | f/8 | 1/250s | ISO 160 | 0 ev

Related Resources

Tech Tips

Minimal effort was invested in arranging the subjects and lighting the scene.

Some trial and error is required in order to determine the correct focus bracket settings for a given combination of camera and lens, in this case, my Fujifilm X-T3 and 80mm macro lens.

As it turns out, I shot six sets of test shots before I found settings that worked the way I wanted. The following settings were used to shoot the 35 photos for the focus-stacked composite image featured in this post: Frames = 35; Step = 10; Interval = 3 s.

The camera was set to save files as FINE+RAW. In the interest of expediency, the composite image was created using JPGs straight from the camera. Photo No. 1, 5, 20, and 35 are also unedited JPGs.

What are the take-aways?

The technique works as advertised and should help to save time by automating the most tedious part of the process of creating focus stacks. Further experimentation is planned.

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Hylogomphus adelphus exuvia (dorsal)

May 4, 2020

The following Anisoptera exuvia — collected by Freda van den Broek on 10 June 2019 along the St. Croix River in Polk County, Wisconsin USA — is definitely a member of Family Gomphidae (Clubtails), probably Mustached Clubtail (Hylogomphus adelphus).

Dorsal view

The abdomen is wider than the head. Vestigial mid-dorsal hooks are noticeable along several abdominal segments, especially segment nine (S9). A “median groove” is apparent along part of the abdomen. The lateral spine on S9 is spinulose-serrate along the outer edge.

10 JUN 2019 | Polk County, WI | H. adelphus exuvia (dorsal)

Related Resources

Tech Tips

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

15 photos of the specimen were taken using an aperture of f/16; in-camera focus peaking was used to highlight select areas in each photo. Adobe Photoshop CC 2017 was used to create- and annotate the focus-stacked composite image shown above.

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Hylogomphus adelphus exuvia (ventral)

May 1, 2020

The following Anisoptera exuvia — collected by Freda van den Broek on 10 June 2019 along the St. Croix River in Polk County, Wisconsin USA — is definitely a member of Family Gomphidae (Clubtails), probably Mustached Clubtail (Hylogomphus adelphus).

Ventral view

Notice the exuvia has a flat labium (prementum). There are lateral spines located on abdominal segments six through nine (S6-S9); the lateral spine on S9 is spinulose-serrate along the outer edge. Also notice the well-developed tibial burrowing hooks on its legs.

10 JUN 2019 | Polk County, WI | H. adelphus exuvia (ventral)

Male (vestigial genitalia)

Male odonates have two sets of sex organs: primary genitalia located on abdominal segment nine (S9); and secondary genitalia located on abdominal segments two-to-three (S2-3).

Both sets of vestigial genitalia are clearly visible on the ventral side of some (but not all) specimens, such as the H. adelphus exuvia shown above.

Related Resources

Tech Tips

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

12 photos of the specimen were taken using an aperture of f/16; in-camera focus peaking was used to highlight select areas in each photo. A subset of six (6) photos and Adobe Photoshop CC 2017 were used to create- and annotate the focus-stacked composite image shown above.

Copyright © 2020 Walter Sanford. All rights reserved.


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