Archive for the ‘Godox TT685C’ Category

Iberian odonate larvae

September 16, 2022

During late-October 2021, I was contacted by Miguel A. Conesa-García, PhD, Profesor Tutor Biología, Diversidad Animal, Ciencias Ambientales, UNED-Málaga.

Miguel was working on finishing the second edition of his book about odonate larvae in the Iberian Peninsula (Spain and Portugal). When Miguel was almost finished, an adult male Wandering Glider dragonfly (Pantala flavescens) was spotted in Spain. P. flavescens is a new species of odonate for the region, so Miguel decided to add the new discovery to the species list in his book.

Cover photo, courtesy Amazon Books.

The following screen capture shows the search string I used to find the book on Amazon.

Screen capture, Amazon Books.

The book is richly illustrated with beautiful photos and diagrams. It’s abundantly evident I could learn a lot from the book — I wish there were an English Edition!

Miguel requested permission to use a photo of a Wandering Glider exuvia in my photoblog, published on 14 November 2018. I was, of course, willing to help.

Page excerpt from Miguel’s book, featuring my photo.

I’m mentioned in the acknowledgements at the end of the book. Regrettably my first name is misspelled and the Web address cited is no longer current. I took the liberty of annotating the page from Miguel’s book to provide the correct information.

Acknowledgements, p. 539 (annotated).

Acknowledgements, p. 539 (original).

Migratory Dragonflies

Wandering Glider is one of at least five major species of dragonflies known to be migratory in North America. P. flavescens is the only species of odonate known to occur on every continent except Antarctica.

The exuvia that I photographed is the “cast skin” from an odonate larva (nymph) that was collected in the field by Andy Davidson, a graduate student at Virginia Commonwealth University in Richmond, Virginia USA. Andy reared the larva in the laboratory as part of a research project entitled “Predator-Prey Interactions in a Changing World.”

Part of the value in rearing odonate larvae in the laboratory is knowing with certainty that an exuvia is from a particular species. This is perhaps the reason that Miguel chose to use my photo.

Related Resources

Copyright © 2022 Walter Sanford. All rights reserved.

Fujifilm/Fringer/Canon MP-E 65mm macro lens

September 9, 2022

In a recent blog post I mentioned that I was looking forward to testing the Fringer EF-FX Pro II lens mount adapter with my Canon MP-E 65mm Macro lens.

The MP-E 65mm doesn’t have a ring for focusing on the subject — you set the magnification ratio (from 1x to 5x) and move the camera/lens rig back and forth until the subject is in focus. For all photos, I focused on one eye of the model.

Dimetron

The first studio model is a toy Dimetron, photographed at a magnification ratio of 1:1. The toy is ~3.6 cm (~36 mm) long. The size of the APS-C sensor in the Fujifilm X-T3 is 23.5 mm x 15.6 mm. At 1x magnification, the entire length of the toy doesn’t fit on screen.

Dimetron toy | 1:1 magnification | 1/16 flash power ratio

With the camera/lens set for the same f/stop, shutter speed, and ISO (f/5.6, 1/250 s, and 400, respectively), less light reached the sensor when the magnification ratio was increased from 1:1 to 2:1. So I increased the flash power ratio by one stop, from 1/16 power to 1/8 power.

Dimetron toy | 2:1 magnification | 1/8 flash power ratio

Triceratops

The last studio model is a toy Triceratops, photographed at a magnification ratio of 1:1. The toy is ~4.3 cm (~43 mm) long.

Triceratops toy | 1x magnification | 1/16 flash power ratio

As with the first model, when the magnification ratio was increased from 1:1 to 2:1 it was necessary to increase the flash power ratio by one stop.

Triceratops toy | 2x magnification | 1/8 flash power ratio

Gear Talk

The Fringer EF-FX Pro II lens mount adapter enables one to mount Canon lenses on Fujifilm X-Series digital cameras. As you can see, my Canon MP-E 65mm macro lens works well with the Fujifilm X-T3 camera.

The APS-C sensor inside the Fujifilm X-T3 digital camera has a crop factor of 1.5x, so the Canon MP-E 65mm macro lens has a focal length of ~98mm (35mm equivalent) when mounted on an X-T3. The net result is an increase in apparent magnification, …

Post Update Update

Just because something looks like a duck and seems to act like a duck doesn’t mean it’s a duck. And so it is with the Fringer EF-FX Pro II lens mount adapter — although it looks like an extension tube, it isn’t. Why was I deceived by its appearance? Because I didn’t understand something called “flange focal distance.”

For an interchangeable lens camera, the flange focal distance (FFD) … of a lens mount system is the distance from the mounting flange (the interlocking metal rings on the camera and the rear of the lens) to the film or image sensor plane. This value is different for different camera systems. Source Credit: Flange focal distance. Wikipedia.

For example, the FFD for Canon EF-mount is 44 mm and the FFD for Fujifilm X-mount is 17.7 mm. In order to make a Canon EF lens perform properly on a Fujifilm X-series camera body, an adapter must move the Canon lens 26.3 mm farther from the digital sensor. (44 mm – 17.7 mm = 26.3 mm)

Not surprisingly, when I remeasured the thickness of my Fringer EF-FX Pro II lens mount adapter it turns out to be closer to 26 mm than my original course estimate of 30 mm (cited below). The net result is the 17.7 mm FFD of my Fujifilm X-T3 combines with the 26.3 mm thickness of the Fringer adapter, resulting in an FFD of 44 mm — exactly the right FFD for the Canon lens to work properly on a Fujiflm X-series camera body!

It’s worth noting that “apparent magnification” is still a real thing when a camera lens designed for a “full-frame” camera is mounted on a camera with an APS-C size sensor. The image formed by the lens is exactly the same size regardless of the size of the digital sensor used to record the image, but a smaller part of the image is “seen” by an APS-C sensor than a full-frame sensor, resulting in the misperception that the image is magnified.

I hope this sets the record straight. Sincere apologies for any confusion I might have caused — I never heard of “flange focal distance” before I bought the Fringer adapter!


[Post Update: From this point forward everything I wrote is incorrect. Is my face red, or what? I’ll explain further when I have a chance to use a desktop computer to edit this post.] … although the images appear to be magnified more than can be explained by this fact alone.

In the opinion of this author, the Fringer adapter functions like an extension tube. The adapter is ~3.0 cm (30 mm) in thickness. There aren’t any optics inside the adapter but it does move the lens 30 mm farther from the camera sensor. That, my friends, is an extension tube.

I used an online, interactive Macro Extension Tubes Calculator to estimate the effect of a 30mm extension tube on photos taken with the Canon MP-E 65mm macro lens at magnification ratios of 1:1 and 2:1. The calculator shows the magnification ratio increased from 1:1 to ~1.5:1 and 2:1 to ~2.5:1 respectively.

Macro Extension Tubes Calculator | 1:1 magnification ratio

The values for “new minimum focusing distance” are in millimeters, despite the fact that the second “m” only appears when you click an insertion point in the box and scroll to the right. The values for magnification ratio seem reasonable; the values for new minimum focusing distance, not so much.

Macro Extension Tubes Calculator | 2:1 magnification ratio

[End of segment with information that is incorrect.]


Related Resources

Full-size photos of the preceding studio models are featured in the following blog posts. Those photos should help to give the reader a better sense of how much the subjects were magnified by the Fujifilm/Fringer/Canon MP-E 65mm macro lens rig.

Copyright © 2022 Walter Sanford. All rights reserved.

Fujifilm X-T3: Focus Peak Highlight

September 6, 2022

I like to use manual focus to shoot photographs with my Fujifilm X-T3 digital camera. Set the small dial on the front of the camera to “M.” The beauty of manual focus on Fujifilm X-series cameras is back-button auto-focus still works!

When the small dial is set for “M” both manual focusing and back-button auto-focusing can be used in combination with what Fujifilm calls “Focus Peak Highlight,” or more simply, “focus peaking.”

The following YouTube video by pal2tech explains a technique that makes it much easier to see the focus peaking.

The process is simple. Set the camera to record JPG + RAF [Fujifilm’s proprietary raw format]. Select one of the black-and-white Fujifilm film simulations, e.g., ACROS. [More about Fujifilm film simulations in an upcoming blog post.]

The camera display will be black-and-white. As Chris Lee (pal2tech) explains in the preceding video, it’s much easier to see focus peaking on a black-and-white background.

JPG files saved to a memory card are black-and-white too, as shown below.

Buzz Lightyear plastic toy. [Focus Peak Highlight not shown.]

RAF files are saved in full color, as shown below.

Buzz Lightyear plastic toy.

Tech Tips

“Focus Peak Highlight” can be activated when the camera is set for manual focus mode. Using back-button focus (AF-L button) in manual mode enables one to retain full control of the exposure triangle, focus quickly, and see what’s in focus before shooting a photograph.

Fuji Back Button Focus (4:06), a YouTube video by Ashraf Jandali, provides a clear demonstration of how to use back-button focus on the Fujifilm X-T1. The same technique works with the Fujifilm X-T3.

Related Resources

Copyright © 2022 Walter Sanford. All rights reserved.

Sample photos: Fringer EF-FX Pro II lens mount adapter

September 2, 2022

Oh look, it’s the “Made in the shade” monkey and Buzz Lightyear — two of my favorite studio models! Whenever I need to test new photography gear and/or techniques, they are always willing to help.

As promised in my last blog post, here are a couple of sample photos taken with my Canon EF 100mm macro lens mounted on a Fujifilm X-T3 digital camera body using a Fringer EF-FX Pro II lens mount adapter.

Single point focus was used for both photos. For the first photo, the focus point was located on the monkey’s right eye (bottom eye, relative to the photo). The real world size of the toy monkey is ~4.8 cm long.

“Made in the shade” monkey toy.

The Canon lens is controlled by the Fujifilm digital camera via the Fringer adapter. EXIF information (shown below) is available for each photo. As you can see, the photos in this set were taken using an aperture of f/5.6 and a shutter speed of 1/250 s, the default sync speed for the X-T3.

The “sweet spot” for the Canon EF 100mm macro lens is either f/5.6 or f/8. The depth of field is shallower at f/5.6 than f/8, but I thought the former might be a better test for sharpness than the latter.

Apple Preview | Inspector

Buzz Lightyear reporting for duty, sir. I don’t remember exactly where the focus point was located, but it was probably somewhere near Buzz’s face/head.

Buzz Lightyear plastic toy.

Regular readers of my blog might be happy to know Buzz will be back again for my next blog post.

What are the take-ways?

As you can see, my Canon macro lens works well with the Fujifilm camera. Does it perform better than my Fujinon 80mm macro lens? It’s too early to tell.

The APS-C sensor inside the Fujifilm X-T3 digital camera has a crop factor of 1.5x, so the Canon EF 100mm macro lens has a focal length of 150mm (35mm equivalent) when mounted on an X-T3. The net result is an increase in apparent magnification.

Some of the advantages of mounting the Canon lens on a Fujifim digital camera (rather than my older Canon DSLR camera) are really about features available on the X-T3 that enable me to get more from the same lens.

For example, there are only nine (9) focus points on my Canon EOS 5D Mark II; the Fujifilm X-T3 can be set for either 117 or 425.

The Canon EOS 5D Mark II doesn’t feature focus peaking; the Fujifilm X-T3 does. Focus peaking is a useful aid for focusing the Canon lens manually. More about this topic in my next blog post.

And of course, don’t forget that all of my Canon lenses (including several L-series lenses) can be used with my Fujifilm cameras via the Fringer adapter. I’m especially looking forward to testing the Fringer adapter with my Canon MP-E 65mm Macro lens.

In summary, the Canon/Fringer/Fujifilm rig works as expected. During limited testing, I discovered something that doesn’t work. (Again, more about this topic in an upcoming blog post.) The problem isn’t a deal-breaker and it should be something that can be fixed in a firmware update of the Fringer adapter. Editor’s Note: I just contacted Fringer as of this writing. I’m interested to see whether they are receptive to customer suggestions for improvement. I’ll update this post to include their response. Post Update: Fringer replied to my message promptly. Details in an upcoming blog post.

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Copyright © 2022 Walter Sanford. All rights reserved.

Fossil shark tooth, revisited

June 10, 2022

This blog post features a photo of a fossil shark tooth that I collected from the Lee Creek Phosphate Mine in Aurora, North Carolina. I didn’t record the exact date when I collected this specimen, but it was sometime between 1984 and 1989. The mine is currently open for phosphate mining, but it’s closed to the public for fossil collecting.

At the time I collected the tooth, the species of shark was called Carcharodon megalodon. Subsequently, the scientific name was changed to Carcharocles megalodon.

C. megalodon lived in “shallow” seas approximately 10 million years ago. 10 million years seems like a long time on the human time scale, but isn’t long ago on the Geologic Time Scale.

Size and jaw placement

The following annotated image shows one method for measuring the size of a fossil shark tooth. The “slant height” of the tooth is approximately four and one-quarter inches (~4 1/4″) long, as measured along the straighter edge of the tooth (lower edge, relative to the photo).

According to Gareth Williams, a member of the Megalodon Maniacs Facebook group, the tooth is from the upper jaw (lateral).

Lee Creek Phosphate Mine | C. megalodon (lingual side)

Photoblog post flashback

On 11 May 2020 I published a blog post entitled “Focus bracketing using Fujifilm X-T3” that features the same ruler shown in the preceding photo.

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. Source Credit: Focus bracketing using Fujifilm X-T3.

The reason the ruler is 7″ inches long is because that’s the length of the largest fossil shark teeth ever collected — the holy grail for fossil hunters!

Tech Tips

The Adobe Photoshop “Ruler Tool” can be used to measure the number of pixels between any two points along the ruler shown in the preceding annotated image.

60s ‘shop: Using the ruler tool to measure distances in Photoshop CC, by Photoshop for the Scientist (1:00) provides a clear and concise explanation of how it’s done.

The resulting value (in pixels) can be used to set a custom scale in Photoshop in order to make other measurements of the tooth virtually.

Related Resources

Copyright © 2022 Walter Sanford. All rights reserved.

Dark and moody

November 19, 2021

I spotted an emergent Uhler’s Sundragon (Helocordulia uhleri) during a photowalk along a mid-size stream at an undisclosed location in Prince William County, Virginia USA. The following photograph shows the exuvia from which the teneral adult emerged.

13 APR 2021 | PNC. Wm. County, VA | Uhler’s Sundragon | exuvia (ventral)

In the opinion of the author, larvae (nymphs)/exuviae from Family Corduliidae (Emeralds) and Family Libellulidae (Skimmers) can be challenging to differentiate and identify to the family level.

One way to differentiate Emerald from Skimmer larvae/exuvia is to look for a “ventromedial groove” in the prementum: it’s probably Corduliidae (Emeralds) if there is a ventromedial groove; it’s probably Libellulidae if there isn’t.

Look closely at a version of the preceding photo that was reformatted, rotated, and cropped to show an enlarged view of the prementum. You should notice a ventromedial groove on the basal half of the prementum, indicating this specimen is a member of Family Corduliidae (Emeralds).

13 APR 2021 | PNC. Wm. County, VA | Uhler’s Sundragon | exuvia (ventral)

Three raised structures on the underside of the prementum remind me of the hood ornament on a 1949 Lincoln automobile. (No, I wasn’t alive in 1949!)

Related Resources

Tech Tips

One reason I underexposed the photo is to add definition to the ventromedial groove and avoid overexposing the black background.

I prefer a white background for photographing odonate exuviae. Using a black background proved to be more challenging than I expected. More later in a follow-up blog post.

Copyright © 2021 Walter Sanford. All rights reserved.

Comet Darner exuvia: annotated images

October 8, 2021

My last blog post was a “sketch pad” of test shots of an exuvia from a Comet Darner dragonfly (Anax longipes) collected by Stanley Caveney on 19 July 2021 from a pond at MeadowWoods in West Elgin, Ontario, Canada. All of the shots in that post are unedited JPGs straight from my camera. This post features edited versions of the RAF (raw) files from that photo shoot, including some images with value-added annotations.

Lateral view

I considered annotating the first photo but decided to allow it to stand on its own as the latest addition to my Odonart© Portfolio.

Comet Darner (Anax longipes) | exuvia (lateral)

Ventral view

I used Adobe Photoshop to create a composite image that features the best parts of two photos from the sketch pad.

This specimen is from a male Comet Darner, as indicated by its vestigial primary- and secondary genitalia. The inset photo shows a clear view of the vestigial hamuli (secondary genitalia) that are partially obscured in the background photo.

Comet Darner (Anax longipes) | exuvia (ventral)

Prementum

The last photo shows a closer view of the mentum, a two-segment hinged “jaw” that is used to grab food: the prementum is the segment of the labium closer to the mouth; the postmentum is the segment closer to the base of the head. Only the prementum can be seen in the following photo.

Comet Darner (Anax longipes) | exuvia (prementum)

The preceding annotated image of the prementum includes labels for the moveable hooks (2 of 2) and palpal lobe (1 of 2). Notice that A. longipes palpal lobes are squared off, in contrast with the more rounded shape of the labial palps of Common Green Darner (Anax junius).

Related Resources

Copyright © 2021 Walter Sanford. All rights reserved.

Comet Darner exuvia: photo sketch pad

October 5, 2021

Sometimes I shoot test shots of an odonate exuvia that are used to plan the final shots I have in mind for an identification guide featuring annotated photos.

All of the shots in this post are unedited JPGs straight from my camera, with the exception of the first ventral view (cropped to remove a distracting element from the composition).

Lateral view

I started with a lateral view of an exuvia from a Comet Darner dragonfly (Anax longipes) exuvia collected by Stanley Caveney on 19 July 2021 from a pond at MeadowWoods in West Elgin, Ontario, Canada.

Comet Darner (Anax longipes) | exuvia (lateral)

Ventral view

The next two photos show my frustratingly poor attempts to pose the specimen for shots of the ventral side of the exuvia. Every time I positioned the subject the way I wanted, it rolled over before I could take a shot!

Comet Darner (Anax longipes) | exuvia (ventral)

The two shots combined show the vestigial primary- and secondary genitalia that indicate this specimen is from a male Comet Darner. Yeah, I know it would help to annotate those parts of its anatomy, but that’s the next step. In the meantime, please follow the embedded hyperlink shown above and you might be able to figure out what I’m saying.

Comet Darner (Anax longipes) | exuvia (ventral)

Prementum

The last photo shows a closer view of the prementum. My goal was to get a better look at the labial palps. Again, annotations would help, but if you know what I’m talking about then you can see the palpal lobes are squared off.

Comet Darner (Anax longipes) | exuvia (prementum)

Copyright © 2021 Walter Sanford. All rights reserved.

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

September 24, 2021

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

Copyright © 2021 Walter Sanford. All rights reserved.

Test shots: Didymops transversa exuvia

September 21, 2021

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

Copyright © 2021 Walter Sanford. All rights reserved.


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