entomology

BugShot 2011 – Lesson 2

/ Ted C. MacRae / 11 Comments

Most of my insect photography is done up close using fast shutter speeds (to prevent motion blur) and small apertures (to maximize depth of field).  This necessitates the use of full flash – the amount of light reaching the camera sensor at f/16 and 1/250 sec is not enough to show any image at all, much less one properly exposed.  Full flash photography has its own set of challenges, but for the most part it can be used to produce excellent closeup photographs of insects, even very small ones.  One thing that has always bothered me about full flash photography, however, is the “black background” effect when photographing an insect sitting up on a plant without something else in the immediate background to reflect light.  Not that I don’t like black backgrounds—they can be used to stunning effect with the right subject.  I just don’t want it to be my only option for insects that I photograph up off the ground. Of course, it is rather a simple matter to place something in the background that is close enough to reflect light but far enough away to remain out of focus, but what I really want to be able to do sometimes is have a blue sky.  I always thought this meant natural light, with its low f stops, slow shutter speeds, and the resulting motion blur and loss of depth of field. 

Of the many things I learned today, how to include a blue sky background in a closeup photograph at f/16 was my favorite.  This is accomplished by bumping up the ISO to 400 (to make the camera sensor more receptive to light) and decreasing the shutter speed to 1/60 sec.  Keeping the f stop high maintains the depth of field, but the increased ISO and decreased shutter speed allows sufficient light from a sky background to register on the sensor.  By themselves, however, these setting will still result in an underexposed subject, which is illuminated instead by fill flash.  Despite the slower shutter speed, there is no motion blur because the “effective” shutter speed for the subject is the duration of the flash pulse rather than the camera shutter speed—it’s like combining two exposure speeds in a single photograph, one for the background and another for the subject.

The following three photographs illustrate this principle—again, they are not technically perfect photos, but rather the result of quick experimentation to understand the principles involved.  Photo 1 is from yesterday’s post and illustrates what my typical settings have always been: ISO 160, f/16, and 1/250 sec.  It’s a decent photo of the treehopper, Acutalis tartarea; however, black is perhaps the least appropriate background to choose for this black species. Until now, it would have been my only option unless I tried arranging foliage in its background.  Photos 2 and 3 are of another individual of this species that I found today (fortunately in similar orientation to the individual photographed yesterday).  In both photos I kept the flash unit set to ETTL (adjusting FEC as appropriate for the shots).  In Photo 2 I bumped up the ISO to 400 but kept the shutter speed fast (1/200 sec)—you can see some effect in that the background is not truly black, having received some light from the blue sky.  It’s not enough, however, because the shutter speed was still too fast.  In Photo 3 the ISO remained at 400 but the shutter speed was also decreased to 1/60 sec.  The shutter staying open that long allows enough light from the sky to register on the sensor and, Voila!, we have a blue sky background that creates nice value contrast with the black subject.  The subject these photos is not terribly sharp, but that is just lack of focus—not motion blur from a slow shutter (sorry, I was just practicing settings rather than going for a perfect shot). All three photos were shot with the Canon 100mm macro lens + 68 mm of extension tube (total magnification ~2X).

''Typical'' insect macro settings: ISO 160, 1/250 sec, f/16

ISO increased to 400 (1/200 sec, f/16)

Shutter speed decreased to 1/60 (ISO 400, f/16)


Copyright © Ted C. MacRae 2011

BugShot 2011 – Lesson 1

/ Ted C. MacRae / 7 Comments

I’m a lucky guy! First, I’m one of the fortunate attending this weekend’s BugShot insect photography workshop. Second, this first-of-a-kind event is being held only 13 miles from my home at Shaw Nature Reserve in Gray Summit, Missouri. Third, I was “adopted” by the BugShot instructors to assist in the event. Who are the instructors? None other than John Abbott from Austin, Texas—an expert on dragonfly biology and insect action photography, Thomas Shahan from Norman, Oklahoma—master of close-up arthropod (especially jumping spider) portraiture, and Alex Wild from Champaign-Urbana, Illinois—ant photographer extraordinaire and author of the most popular insect blog on the net.  In 2009 I picked up a digital SLR camera for the first time ever—in 2011 I am rubbing shoulders, discussing exposure and lighting, and enjoying social time with three of the country’s most accomplished insect macrophotographers (and some other very cool people as well).

I have come a long way, but I still have much to learn.  Intimate understanding of lighting, exposure, and the creative use of flash still eludes me—I can do a few things well, but there is much more I can’t do at all.  Today was my first time experimenting with the effect of lighting direction, i.e. taking the flash heads off their fixed position on the front of the lens and hand-holding them in different positions.  This simple technique can have dramatic effects on the look of a photograph, as illustrated by the following two photographs.  In the first, both flash heads of my Canon MT-24EX twin flash are attached to the front of the lens (as they have been for every single flash photograph I’ve ever taken up to this point).  In the second, only the right flash head remains attached to the lens, while the left head has been detached and is being hand-held directly above the subject (in this case, the treehopper Acutalis tartarea on Solidago sp.).  Technically they are not very good photographs, but they illustrate well the dramatic differences that can be achieved by varying the position of the flash heads.  Among other things, this is a technique that I will be exploring much over the coming weeks.

Both flash heads attached to front of lens.

Right flash head attached to front of lens; left flash head held directly above subject.

Copyright © Ted C. MacRae 2011

Bumelia borer on white

/ Ted C. MacRae / 19 Comments
Plinthocoelium suaveolens suaveolens | Ozark Co., Missouri

Last weekend I visited one of my favorite collecting spots in all of Missouri—Long Bald Glade Natural Area (part of Caney Mountain Conservation Area in Ozark Co.).  Nestled at the eastern edge of the White River Hills in southwestern Missouri, its deeply dissected hills are home to numerous plants and animals that are more typical of the southern Great Plains and which have found refuge in the xeric, thin-soiled calcareous prairies (commonly “cedar glades”) that cover the area’s southern- and western-facing slopes.  These include some rather impressive insects, such as a disjunct population of Cicindelidia obsoleta vulturina, which I just found here last year as the new northeasternmost extent of the population, as well as the marvelously monstrous Microstylum morosum, North America’s largest robber fly and so far known in Missouri only from Long Bald Glade where it was discovered in 2009. 

Another quite striking insect found at Long Bald Glades (though not restricted in Missouri to the White River Hills) is the bumelia borer, Plinthocoelium suaveolens.  This beetle occupied much of my time in July 2009 as I committed to photographing the species in the wild, and it was Long Bald Glade where I finally (if not completely satisfactorily) succeeded in that goal.  This time I was visiting the Glade to look for the earliest individuals of C. obsoleta vulturina and, hopefully, document additional glades within Caney Mountain that might support the beetle.  However, in the back of my mind I was also keeping a lookout for P. suaveolens—this species is primarily active during July and August in Missouri, but I do have records of it as late as September.  As I looked for (and found) tiger beetles, I also checked out each bumelia tree that I passed hoping to see a P. suaveolens adult perched on its lower trunk.  It was not until later in the afternoon that I heard a loud “buzz” approaching from behind and turned to see one of these beauties fly right past me—legs and antennae held outstretched—before landing on a nearby tree.  Now, over the years I’ve learned a few lessons, and one is that you don’t try to take in situ photographs of the first individual you encounter of a prized species.  More often than not it gets away before you even fire the first shot, and you’re left with nothing.  My standard procedure now is to procure the first individual immediately and keep it alive.  If attempts to photograph subsequent individuals are not successful (or none are seen), then at least I have a backup for studio shots (not my first choice, but better than nothing!).  Such was the case with this individual.

Although I still lack that “perfect” beetle-on-a-branch shot that I hope to eventually get for this species, it seemed a good subject for some white-box photography.  I’ve vacilated between true white-box w/ indirect flash versus getting a white-box effect by using direct, diffused flash with the subject on a white background.  I decided now was the time for a direct comparison of the two techniques.  All of the following photographs were taken with the Canon 100mm macro lens on a Canon 50D body at 160 ISO, 1/200 sec, and f/16.  For the closeups (photos 3 and 5 of each series), 68mm of extension tubes were added.  The photos on the left are true white-box photos, i.e. the flash heads were directed up and away from the subject placed inside a box lined with white tissue (Kim-Wipes laboratory wipers).  The photos on the right mimic the white-box effect by placing the subject on white filter paper, but the flash heads were pointed directly at the subject through my DIY concave diffuser (click on photos for 1200×800 versions):

Indirect flash in white box

Direct flash w/ DIY diffuser

Indirect flash in white box

Direct flash w/ DIY diffuser

Indirect flash in white box

Direct flash w/ DIY diffuser

Indirect flash in white box

Direct flash w/ DIY diffuser

Indirect flash in white box

Direct flash w/ DIY diffuser

I must admit, looking at the photos on the camera playback screen I had the impression that I would like the direct-diffuser photos better, but after reviewing them on the computer and applying typical post-processing enhancements (e.g., levels, slight shadow reduction, and unsharp mask), the true white-box photos appear to have benefited from more even lighting, resulting in truer color, less shadowing, and minimal specular highlighting.  Not that the direct-diffuser photos are bad—they’re just not as good as the white-box photos.  I guess what this means is that my DIY diffuser, while a significant improvement over my previous diffusers, still could use some improvement (if ability to create white-box-like results is the ultimate test of a diffuser’s effectiveness).  I’d be interested in knowing your opinions based on these comparisons.

Congratulations to Ben Coulter, who wins yet another Super Crop Challenge and strengthens his lead in the overall standings of the current BitB Challenge Session #4 with 13 points.  Mr. Phidippus also correctly identified the species and takes 2nd place in the challenge with 8 points, keeping him in 2nd place in the overall standings as well.  Morgan Jackson takes 3rd place in the challenge with 7 points, but Roy’s retains 3rd place in the overall standings by way of his 6 points in this challenge.  Congratulations to these top points earners, and thanks to all who played.

Copyright © Ted C. MacRae 2011

Super Crop Challenge #9

/ Ted C. MacRae / 14 Comments

Can you name the structures in this photo (easy) and the critter they belong to (maybe not so easy)?  Because there are so many potential answers to those two questions, I’ll give 1 point for each correctly named structure (5 maximum) and taxon (primary categories from class to species).  As always, standard challenge rules apply, including moderated comments to allow time for everyone to submit their answers.  Bonus points will be awarded to early birds if multiple participants arrive at the same correct answer and possibly also for other relevant comments at my discretion.

The competition is really heating up in the current Session #4—current leader and 2-time champ Ben Coulter has 22 points, but there are at least half a dozen folks who could easily earn enough points in this one challenge to either take the lead or grab a podium spot.  If you’re stumped, remember that the pity points you earn now could be a tie-breaker at the end of the session.  Good luck!

Copyright © Ted C. MacRae 2011

Peek-A-Boo!

/ Ted C. MacRae / 4 Comments

Dissosteira carolina (Carolina grasshopper) | Jersey Co., Illinois

Despite the geographic specificity of its scientific and common names, the Carolina grasshopper (Dissosteira carolina) can be found in every state of the contiguous United States and adjacent provinces of Canada. Its large size, cryptic coloration with yellow hind wings, tendency of males to crepitate during flight (a snapping or crackling sound made by rubbing the under surface of the forewings against the veins of the hind wings), and distinctively chunky nymphs would normally be enough to attract a lot of attention were it not also among the most overwhelmingly ubiquitous of grasshoppers throughout much of its range. I could give all sorts of information about its food habits, migration and dispersal behavior, daily activities, etc., but this would be redundant given the excellent Species Fact Sheet that has been generated for it by the Wyoming Agricultural Experiment Station (Pfidt 1996).

This individual was found in a soybean field in Jersey Co., Illinois. They are extremely wary and perhaps the most difficult-to-approach grasshopper I’ve encountered yet. Considering my particular fascination with oedipodine grasshoppers, I felt compelled to take some photographs—but, my God, there are already a godzillion photos of this species on the web.  I decided to limit myself to this one rather unusual perspective and leave it at that!

REFERENCE:

Pfidt, R. E.  1996. Carolina Grasshopper Dissosteira carolina (Linnaeus). Wyoming Agricultural Experiment Station Bulletin 912, Species Fact Sheet, 4 pp.

Copyright © Ted C. MacRae 2011

Use of extension tubes for better lighting

/ Ted C. MacRae / 17 Comments

The photos in this post of Tetracha floridana (Florida Metallic Tiger Beetle) illustrate a technique that I have begun using recently to improve the lighting in my full-flash insect macrophotographs—use of extension tubes!  I know this sounds strange, and I actually just stumbled onto it myself when I started using extension tubes in combination with my Canon EF 100mm macro lens.  Okay, I can hear it now: “Why not use the Canon MP-E 65 mm macro lens?”  It’s a good question, as at magnifications above 1X there is no finer lens than the 65mm.  However, the tiger beetles that I spend a lot of time photographing are right in that size range where sometimes I need magnifications below 1x (whole body shots of medium to large species), while other times I need magnifications above 1X (small species and closeups—particularly face shots).  Fortunately, the entire spectrum of magnifications (up to 5X) is covered by these two lenses, but there is, unfortunately, no overlap.  This is where the extension tubes come in—when all 68mm are added the 100mm lens effectively changes from a 1.0X–∞ lens to a 0.7–2.0X lens.  This gives a frame width of 11–33 mm, perfect for nearly all North American tiger beetles (most species range from 6-20 mm, excluding legs and antennae). 

In addition to allowing a more appropriate range of magnifications without the need to switch out lenses, this has one other effect—it moves the lens a little closer to the subject.  That in itself is of no particular benefit, but since I use the front-of-the-lens-mounted Canon MT-24EX dual flash, it also moves the flash a little closer to the subject.  It’s not a huge distance, only about 20 mm, but keep in mind that the flash heads extend forward from the front of the lens (especially with the Kaiser shoes that I use with my diffuser), and the front of the diffuser itself lies at about 60 mm in front of the lens face.  Thus, at 1X the the front of the diffuser sits ~80 mm from the subject with the 100mm lens only, but with 68 mm of extension tubes added it sits only 60 mm from the subject.  The closer the light source is to the subject, the greater the apparent light size, and larger apparent light size results in more even lighting with reduced specular effects.

Tetracha floridana | Pinellas Co., Florida (100mm lens only)

100mm lens + 68mm extension tubes

100mm lens only (slightly cropped)

100mm lens + 68mm extension tubes

The primary disadvantage to doing this is loss of ability to focus to infinity.  Frankly, this is functionality I never used with the 100mm lens, preferring instead the 17-85mm wide-angle lens for more general landscape and habitat photos.  The other downside is that placing the lens closer to the subject can result in greater chance of “spooking” the subject and causing it to flee or behave evasively.  Again, however, my experience is that if a subject can be photographed at 1X with the 100mm lens, it can be photographed at 2X with the 100mm lens + extension tubes.

Has anybody else ever tried this, and if so what was your experience?

Copyright © Ted C. MacRae 2011

Charming Couple revisited

/ Ted C. MacRae / 4 Comments

Another view of the of Ellipsoptera hamata lacerata (Gulf Coast Tiger Beetle) that I photographed in a small mangrove marsh in Seminole, Florida. These are actually among the first tiger beetles that I ever tried to photograph at night, and the major learnings involved: 1) figuring out how to turn on the flash lamp and then compose the shot quickly enough before the lamp shut off, and 2) making sure to use the histogram in the field to ensure I’d gotten the proper flash level. My first few attempts all tended to be underexposed because the brightness of the image on the playback screen in the darkness caused me to keep undersetting the flash exposure compensation. I’d not previously gotten in the habit of using the histogram in the field since I do a lot of flash level bracketing, but perhaps this is a tool that will allow me to cut down on that to some degree. Anyway, these are two additional photos that worked out pretty well—I like the first because of the contrast between the bright white mandibles of the male versus the off-white mandibles of the female, and the second (female only after the male bolted) for its nice view of the curiously bent elytral apices that distinguish it from the female of the very similar and (in this area) sympatric E. marginata (Margined Tiger Beetle). Also clearly seen in the second is one of the distinct basolateral grooves on the pronotum that serve to receive the male mandibles during mating (compare to same area on pronotum of male). I was amazed at how easy this mating pair and other individuals of this species were to photograph at night in view of their extreme wariness during the day.

Ellipsoptera hamata lacerata | Seminole, Pinellas Co., Florida

Note curiously bent elytral apices and basolateral pronotal groove for reception of male mandibles.

Copyright © Ted C. MacRae 2011

Gnom, Gnom, Gnom…

/ Ted C. MacRae / 9 Comments

I’ve become a big fan of night-time tiger beetle photography since my early August trip to Florida.  Not only does it open up the world of nocturnal species that might go undetected during the day, it also affords the opportunity to see diurnal species engaged in behaviors that are more difficult to photograph during the day.  This female Gulf Beach Tiger Beetle (Ellipsoptera hamata lacerata) came to my blacklight at a coastal salt marsh near Steinhatchee and promptly began munching on a smaller beetle that had also come to the light.  I didn’t get a good enough look at the prey early on to identify it, and by the time I was able to zoom in big with the camera lens the prey had already been macerated to a crunchy pulp.  It was interesting to watch the tiger beetle grasp and chew the prey with its mandibles while manipulating its position with its maxillary parts.




Copyright © Ted C. MacRae 2011