Archive for the ‘Aperture’ Category

Which family is it?

November 29, 2022

An odonate exuvia was collected by Cindy Haddon Andrews on 03 September 2022 along the James River, near the Maidens Boat Landing in Powhatan County, Virginia USA. This specimen is from a damselfly in Suborder Zygoptera.

Pattern recognition can be used to tentatively identify damselfly larvae/exuviae to the family level: the shape of the prementum is characteristic for each of the three families found in the mid-Atlantic region of the United States of America.

Your mission, should decide to accept it, is to identify the family to which the following damselfly exuvia belongs.

03 SEP 2022 | Powhatan County, VA USA | (exuviaventral side)

The camera lens was manually focused on the prementum, located near the anterior end of the exuvia.

Here is the same photo rotated 90° clockwise.

03 SEP 2022 | Powhatan County, VA USA | (exuviaventral side)

If you think you know the family, then please leave a comment. The correct answer will be revealed in a post update.

Related Resource: How to Identify Damselfly Exuviae to Family – a photo-illustrated identification guide by Walter Sanford.

Copyright © 2022 Walter Sanford. All rights reserved.

Archilestes grandis exuvia (female)

November 25, 2022

An odonate exuvia from a Great Spreadwing damselfly (Archilestes grandis) was collected by Edgar Spalding at a small private pond in Middleton, Wisconsin USA.

SEP 2022 | Middleton, WI | Archilestes grandis (exuvia, ventral side)

External gills (3), highlighted by a blue rectangle in the following annotated image, indicate the exuvia is from a damselfly in Suborder Zygoptera.

The camera lens was manually focused on the prementum, located near the anterior end of the exuvia (highlighted by a red rectangle). The overall shape of the prementum indicates this specimen is from Family Lestidae (Spreadwings); the unique shape of the palpal lobes (highlighted by a purple rectangle) indicates Genus Archilestes.

There are two species in Genus Archilestes in North AmericaArchilestes californicus; and Archilestes grandis. I think it’s reasonable to infer this individual is A. grandis since Wisconsin is far out of range for A. californicus.

SEP 2022 | Middleton, WI | Archilestes grandis (exuvia, ventral side)

This individual is a female, as indicated by the rudimentary ovipositor located on the ventral side of its abdomen, near the posterior end (highlighted by a green rectangle in the preceding annotated image).

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Copyright © 2022 Walter Sanford. All rights reserved.

Theory into practice

November 4, 2022

What is the “neighborhood play” in baseball?

The “neighborhood play” is a colloquial term used to describe the leeway granted to middle infielders with regards to touching second base while in the process of turning a ground-ball double play. Though it is not explicitly mentioned in the rulebook, middle infielders were long able to record an out on the double-play pivot simply by being in the proximity — or neighborhood — of the second-base bag. Source Credit: Neighborhood Play, MLB Glossary.

And so it is with the 3-D printed plastic “lens” adapter I bought recently for my Fujifilm X Series cameras. The lens adapter, assembled so that it includes all three pieces (photo credit: Nicholas Sherlock Photography), puts a 4x magnification microscope objective in the neighborhood of where it should be for optimal performance.

Naturally I was curious to know exactly where the microscope objective should be mounted  and whether the “lens” actually performs better at that distance.

Theory

I consulted the experts at amateurmicrography.net and asked for guidance specifically for my Fujifilm X-Series mirrorless digital cameras. Thanks to Mr. Rik Littlefield for his quick reply!

First, Rik referred me to an article from the Frequently Asked Questions (FAQ) forum: FAQ: How can I hook a microscope objective to my camera? In this blog post, I will refer to the following annotated image — the first one in the FAQ article.

Photo Credit: Rik Littlefield.

Let me summarize Rik’s detailed answer to my question.

Microscope objectives like the two 4x magnification microscope objectives I own and the 10x objective shown in the preceding annotated image, are designed to work with microscopes featuring a mechanical tube length of 160 mm minus 10 mm for the microscope’s eyepiece. The difference of 150 mm is known as the optical tube length, and in photomicrography, is the distance the microscope objective should be mounted from the plane of the camera sensor (as shown above).

Photo Credit: B&H Photo. Fujifilm X-T5 camera (body only).

Fujifilm X Series mirrorless digital cameras have a flange focal distance (FFD) of 17.7 mm, meaning the distance between the plane of the camera sensor and the face of the lens mount on the front of the camera body is 17.7 mm (as shown above). 150 mm – 17.7 mm = 132.3 mm. 132.3 mm is the ideal mounting distance between the “lens” and the outside of the camera body.

The next photograph shows the customized 4x magnification macro rig I was able to cobble together using photography gear I had on-hand already, following Rik’s recommendations. Briefly, several extension tubes were used to mount the “crop” configuration of my 3-D printed plastic lens adapter and 4x magnification microscope objective on a Fujifilm X-T3 digital camera.

My customized 4x magnification macro rig.

Remember, my goal was to move the microscope objective 132.3 mm from the face of the camera body. I combined two 16mm extension tubes and one 10mm extension tube (42 mm total) with the “crop” configuration of the plastic lens adapter (~90 mm from back to front). 42 mm + 90 mm = 132 mm. That’s “good enough for government work” as we say in Washington, D.C.

In contrast, the full size 3-D printed plastic lens adapter moves the microscope objective 142 mm from the face of the camera body — in the neighborhood but a little farther than it should be.

Gear I used

The following equipment list includes all items mounted on the Fujifilm X-T3 camera body shown in the preceding photo.

Finally, a few words about extension tubes designed for Fujifilm X Mount cameras.

Fujifilm makes two extension tubes, as of this writing: the MCEX-11; and MCEX-16. I bought both the 11mm and 16mm extension tubes, although in retrospect, the 11mm is the only one I recommend buying (based upon my usage). It’s good to have found a purpose for the MCEX-16.

When I bought my Fujifilm X-T1 camera more than 10 years ago, Fujifilm didn’t offer extension tubes for sale. “Fotasy” was the first third-party company to sell extension tubes with electronic contacts for Fujifilm X Mount cameras. I bought both sizes that were available (10mm and 16mm) and they worked well, that is until Fujifilm released their proprietary extension tubes — at that point the Fotasy extension tubes were incompatible with newer lenses sold by Fujifilm. Although my older Fotasy extension tubes don’t work with newer Fujifilm lenses, they are perfect in this case because my customized 4x magnification macro rig is all manual all the time.

Gear that could be used (instead of my rig)

What if you don’t have a “junk drawer” of old, unused camera gear like me? Rik Littlefield recommended the following items that could be used for mounting a 4x microscope objective on a Fujifilm X Series camera.

Theory into practice

My customized 4x magnification macro rig was used to photograph a small part of a dime, that is, a 10-cent coin in U.S. currency.

All three photos …

  • were shot handheld (not recommended for this camera rig). A single external flash unit was used to light each photo.
  • are “one-offs,” meaning they aren’t focus-stacked. At a magnification of 4x the depth of field is extremely shallow. The net result is relatively little of each photo appears to be acceptably in focus.
  • are “full frame” (6240 × 4160 pixels), meaning they are uncropped.

For scale, the letters “DIM” are approximately 5 mm wide on the actual coin.

A small part of a dime (10-cent coin in U.S. currency).

A small part of a dime (10-cent coin in U.S. currency).

A small part of a dime (10-cent coin in U.S. currency).

Are these photos better than the test shots I took when I first got the 3-D printed plastic lens adapter? You be the judge, but I think they are qualitatively better.

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Copyright © 2022 Walter Sanford. All rights reserved.

Rube Goldberg 2.75x macro photography rig

October 28, 2022

My Rube Goldberg 4-5x macro photography rig can be configured as both a 2.75x and 4-5x magnification macro photography rig. This blog post will focus on the 2.75x configuration.

The first two photos show the 3-D printed plastic lens adapter with the middle segment removed. A Reakway 4-5x microscope objective is screwed into the front of the adapter and the adapter/”lens” combo is mounted on my Fujifilm X-T3 mirrorless camera.

Photo focused on body of Fujifilm X-T3 mirrorless camera.

Photo focused on Reakway 4-5x microscope objective.

A recent blog post featured handheld test shots using the macro rig configured for 4-5x magnification. One of those shots shows the word “Liberty” on a penny, that is, a 1-cent coin in U.S. currency. Remember, the actual size of the word on the coin is approximately 5 mm in length.

A copper penny photographed at 4-5x magnification.

The same penny was photographed at 2.75x using the “crop” configuration of the lens adapter. The camera was handheld, like the 4-5x test shot shown above. Notice how much more of the coin is visible at 2.75x versus 4-5x magnification.

A copper penny photographed at 2.75x magnification.

The last image is a focus-stacked composite of four photos that were shot with the camera mounted on a tripod.

Focus-stacked composite image of four photos at 2.75 magnification.

What are the take-aways?

I own two macro lenses capable of 1-5x magnification: a Canon MP-E 65mm macro lens; and a Laowa 25mm Ultra Macro lens.

The current retail price of the Canon MP-E 65mm macro lens is $1,049.00. It weighs 1.56 pounds (710 g).

The current retail price of the Laowa 25mm Ultra Macro lens is $399.00. The Laowa macro lens is noticeably smaller and lighter than the Canon MP-E 65mm. It weighs 14.11 ounces (400 g).

The 4x microscope objectives from AmScope and Reakway cost ~$25.00 each. (Remember, you need to buy only one objective.) The weight of the “lenses” isn’t listed in their specifications, but they are relatively lightweight. The 3-D printed plastic lens adapter cost $50.00 including $35.00 for the adapter itself and $15.00 handling and shipping from New Zealand. The plastic adapter feels nearly weightless.

For me, the single biggest take-away is for ~$75 I was able to buy an extreme macro photo rig that takes photos that are as good or better quality than comparable macro lenses that cost hundreds of dollars more!

And as a big fan of lightweight camera gear for use in the field, I’m far more likely to carry one of the Rube Goldberg rigs with me than either of its bigger and heavier counterparts.

Related Resources

Copyright © 2022 Walter Sanford. All rights reserved.

Rube Goldberg 4-5x macro photography rig

October 25, 2022

By now you might be wondering “What does your Rube Goldberg 4-5x macro photography rig look like?”

The first photo shows an AmScope 4x microscope objective mounted on a plastic lens adapter designed and 3-D printed by Nicholas Sherlock.

AmScope 4x microscope objective mounted on “lens” adapter.

The next photo shows a close-up view of the AmScope 4x microscope objective.

AmScope 4x microscope objective mounted on “lens” adapter.

The next two photos show the plastic lens adapter and microscope objective mounted on my Fujifilm X-T3 mirrorless camera. A Fujifilm 11mm extension tube is mounted between the camera body and lens adapter. More about that in a follow-up blog post.

3-D printed plastic “lens” adapter mounted on Fujifilm X-T3 camera.

A close-up view of the Reakway 4x microscope objective is shown below.

Reakway 4x microscope objective mounted on the “lens” adapter.

Similar microscope objectives

Did you notice two similar microscope objectives are shown in the preceding photos? I decided to buy both of the “lenses” recommended by Nick Sherman — since they are priced so affordably I was curious to see whether one works better than the other. As far as I can tell during limited testing, both microscope objectives perform equally well.

One objective has a smooth barrel …

Photo Credit: AmScope.

The other one has a knurled barrel.

Photo Credit: AliExpress / Reakway.

The lenses are recessed from both ends of the barrel, providing protection against scratching the glass. [Photo Credits: AliExpress / Reakway.]

Both objectives have similar information printed on the barrel.

What does “Plan” mean?

A plan (or planar) objective corrects better for color and spherical aberration than either the semi-plan or the achromatic objective. Plan objectives have a flat field about the center 95% of the image. They also often have larger working distances. Source Credit: What is the difference among achromatic, semi-plan, and plan objectives? Celestron, LLC.

What do the numbers mean?

Microscope objective lenses will often have four numbers engraved on the barrel in a 2×2 array. The upper left number is the magnification factor of the objective. For example, 4x, … The upper right number is the numerical aperture of the objective. For example 0.10, … The lower right number (if given) refers to the thickness of the glass cover slip (in millimeters) assumed by the lens designer for best performance of the objective. Example: 0.17. The lower left number is the tube length in millimeters.

Sometimes objectives have a color ring to aid in identifying the magnification: black (1x), brown (2x), red (4x), …

Source Credit: What do the numbers on the barrel of the microscope objective mean? What about the letters DIN and JIS? Celestron, LLC.

I love the little plastic bottles that are used for storing microscope objectives safely.

Photo Credit: AliExpress / Reakway.

“Crop” configuration

The 3-D printed plastic lens adapter that I bought for my Fujifilm X-Series cameras is comprised of three parts that screw together. Nick Sherlock calls this version the “crop design.”

The crop design is for Sony E, Canon EF-S, Micro Four Thirds, Fujifilm X, or Nikon F crop cameras (or full-frame cameras which have been switched to crop mode) which has a segment of tube you can remove to shorten the tube.

For objectives which cast a big enough image circle, removing this middle tube allows you to reduce the magnification and focus at a greater distance (for the 4x objective I tested this reduced magnification from 4x to 2.75x, and increased working distance from about 28 to 31mm).

Source Credit: Microscope adapter for 4x macro photography with Sony E/FE, Canon EF/EF-S, Nikon F, Nikon Z, Fuji X, M4/3, M42 cameras, by thenickdude.

My Rube Goldberg 4-5x macro photography rig is even more Rube Goldergier than I realized when I bought it. As it turns out, the rig can be configured as both a 2.75x and 4-5x magnification macro photography rig. Very clever design, Nick Sherlock!

I tested the “crop” configuration and am pleased to report it works as advertised. My first impression is 2.75x magnification should prove to be more practical for use in the field than 4-5x. More later in a follow-up blog post.

Related Resources

Copyright © 2022 Walter Sanford. All rights reserved.

How to measure magnification

October 18, 2022

The magnification of any macro photography rig can be determined by using the rig to photograph a metric ruler such as the one shown below.

Plastic 15 cm (6″) ruler from the Natl. Science Teachers Assn. (NSTA).

The following photograph was taken using an AmScope 4x microscope objective mounted on my Fujifilm X-T3 digital camera with a plastic lens adapter designed and 3-D printed by Nicholas Sherlock. Notice that only a tiny part of the ruler is shown in this “full frame” (uncropped) macro photo!

Segment of an NSTA metric ruler.

The formula for magnification is as follows.

length of camera sensor, in mm / #mm visible in photo frame

Both measurements must be expressed in the same units in order for the units to cancel during division.

The APS-C digital sensor featured in the Fujifilm X-T3 is 23.6 mm long. The annotated image shows 5.35 mm of the small plastic ruler is visible in the photo frame.

23.6 mm / 5.35 mm = 4.41x

The actual magnification of the AmScope 4x microscope objective is greater than 4x due to the design of the lens adapter.

What are the take-aways?

As a result of photographing the ruler, subject selection should be easier. Now I know ~5 mm is the size limit for subjects to fit entirely within the photo frame. That’s actionable intel.

Related Resource: How to Calculate Your Camera’s Magnification in Macro Photography, by Stewart Wood (12:02).

Tech Tips

The “Ruler Tool” in Adobe Photoshop was used to measure the length (in pixels) of 5 mm along the double-headed red arrow superimposed on the plastic ruler shown above. That value was used to set a “Custom Scale” for the ruler, in millimeters.

Select the “Ruler Tool.” From the Menu bar, select Image / Analysis / Set Measurement Scale. 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.

Then the “Custom Scale” for the “Ruler Tool” was used to measure the entire length along the ruler that’s visible in the photo frame: 5.35 mm.

Post Update

Photopea” is a free Web-based clone of Adobe Photoshop — Photopea doesn’t do everything Photoshop does but it can be used to measure length (in pixels) using its version of a ruler tool.

Right-click on the “Eyedropper Tool” — located in the left sidebar of the main window — and select the “Ruler Tool.” Click and drag a line segment; record the length of the line, in pixels. Click the “Clear” button (optional) and repeat the same process for more line segments, as needed.

As far as I know, the Photopea “Ruler Tool” doesn’t allow the user to set a custom scale. No problem. Make measurements similar to mine and set up a proportion of two similar ratios.

x mm / 5 mm = #pixels for photo frame / #pixels for 5 mm

Solve for x by cross-multiplying and dividing.

x mm = #pixels for photo frame x 5 mm / #pixels for 5 mm

Remember that similar units above and below the dividing line cancel (pixels, in this case) so the final answer is in millimeters (mm).

Copyright © 2022 Walter Sanford. All rights reserved.

Connections

October 11, 2022

I’m not as dumb as I look, you know. (I have a face for blogging, not vlogging.) But I am a little slow sometimes. For example, I was slow to make the connection between the size and shape of two lens adapters I own.

When I bought the Laowa 25mm f/2.8 2.5-5X Ultra Macro lens for Canon EOS cameras, I also bought a Laowa Lens Mount Adapter for Canon EF lenses to Fuji X Series cameras. I remember thinking the adapter is oddly shaped and wondered why it wasn’t designed to be shorter/thinner.

That was before I purchased the Fringer EF-FX Pro II lens mount adapter (Canon EF lenses – Fuji X Series cameras).

The following photo shows two Canon EF to Fujifilm X Series lens adapters: the Laowa EOS-FX (shown left); and the Fringer EF-FX Pro II (shown right).

Canon EF to Fujifilm X-Series lens adapters.

Notice the two lens adapters are the same diameter and thickness (26.3 mm): the former is due to the Canon EF mount (top) and Fujifilm X Mount (bottom); the latter is due to something called flange focal distance (FFD).

The 17.7 mm FFD of my Fujifilm X Series digital cameras combines with the 26.3 mm thickness of the lens adapters (shown above), resulting in an FFD of 44 mm — exactly the right FFD for Canon lenses to work properly on a Fujiflm X Series camera body!

The Backstory

The Laowa lens adapter is manual; the Fringer lens adapter is automatic. The former doesn’t feature electronic contacts that enable auto focus, etc.; the latter does.

Soon after I bought the Laowa lens adapter I used it to mount a Canon EF 100mm macro lens on my Fujifilm X-T3 camera. Although the adapter worked to connect the lens and camera, the experiment was a failure because the Canon macro lens doesn’t have a ring for setting aperture manually, and the Laowa lens adapter doesn’t have electronic contacts that enable a camera to set the aperture of the lens. Same problem with my Canon MP-E 65mm macro lens.

Enter the Fringer lens adapter.

Copyright © 2022 Walter Sanford. All rights reserved.

Post update: What is it?

September 30, 2022

The mystery object shown in my last blog post is the back of an SD memory card; the front of the card is shown below.

“SD” stands for “Secure Digital.” This particular card is an “SD XC” memory card; “XC” stands for “eXtended Capacity.” “SD XC” designates memory cards that can store greater than 32 GB of data up to 2 TB. This SanDisk Extreme PRO memory card can store up to 64 GB of data.

Notice the Roman numeral “II” printed after “SD XC” that indicates the bus speed class of the card is “UHS II” (Ultra High Speed bus); this is the reason there are two rows of metal contacts on the back of the memory card.

SanDisk Extreme PRO SD XC 64 GB memory card.

Finally, notice a 3 printed inside of a U and a 10 printed inside of a C. These marking indicate the speed class of the memory card, in this case, the fastest speed ratings currently available.

Mystery solved

Remember the hint I provided in my last blog post?

Beware! What it is, or should I say what it represents, is not what it appears to be. Source Credit: What is it? by Walter Sanford.

OK, so we know it’s a digital memory card, but what does it represent?

An SD memory card is approximately the same size as the imaging sensor in a “full-frame” camera (36 x 24 mm). So from now on, when you look at an SD memory card be aware you are also seeing a model of your “full-frame” camera sensor. The sensor in an APS-C camera (23.6 x 15.6 mm) is smaller than an SD memory card.

Related Resources

Copyright © 2022 Walter Sanford. All rights reserved.

 

What is it?

September 27, 2022

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

Beware! What it is, or should I say what it represents, is not what it appears to be.

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

Copyright © 2022 Walter Sanford. All rights reserved.

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.


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