The BugPhoto Guide: Using a Flash

This is the fourth in a series of posts about the BugPhoto approach to macro photography.

DIY flash diffuser on Nikon SB-600 flash speedlight

A back angle of a DIY flash diffuser or soft box on a Nikon SB-600 flash. Diffuser materials include soda cans (2), cardboard, duct tape, packing tape, scotch tape, staples and packing foam sheets.

Raise a Light

I was not intending to write a flash article, but after a conversation with Marc from Entomacrographic, I decided I should rethink that decision. I’ve written about DIY flash diffusers before, but the premium on light in handheld macro is so high, I decided a series like this would be woefully incomplete without it. Now, I purposefully emphasize “handheld” because there is a way out of relying on flash altogether. It’s called a tripod, an apparatus that for various reasons I have shunned (weight, immobility, cost, habit, etc.). (It’s also called “being a morning person” if you’re a bug shooter, because the wee hours of the day are usually the only time insects will stay perfectly still for a photographer.) It is possible to shoot strictly handheld and get along without a flash, but I haven’t seen many good examples of it, especially when talking about greater than life-size (1:1) magnification ratios. At the high ratios, we become entangled in an inescapable compromise between our light source, shutter speed, and aperture.

stilt-legged fly portrait showing legs moving

You only have *this much room*: macro photography’s narrow depth of field dictates smaller apertures and in turn a greater need for additional lighting. (A stilt-legged fly, family Micropezidae, makes characteristic movements of the front legs.)

With most macrophotography, a photo begins and ends with the depth of field, i.e. the area in sharp focus. At a 1:1 ratio or greater, it is generally very narrow even at smaller apertures, so unless you’re going for some dreamy abstracts, a small aperture is necessary and it is going to create a heavy burden to illuminate the shot. Camera shake and the erratic and quick movement of insects and other tiny moving objects (and don’t forget the wind, our old enemy) mean that if you’re looking for sharpness, a certain minimum shutter speed is necessary. That speed will vary from subject to subject and situation to situation. I find on my D5000 and SB-600 camera-flash combo, the minimum I can go down to is 1/50th or 1/60th if I bump up the ISO setting (more on that below). Usually, however, I am shooting at 1/100th or faster (1/200th is the max shutter speed with flash on the D5000). And so we’re left needing the flash to bring us out of the darkness.

Setting the Flash

If you have a true macro lens, or extension tubes that preserve the communication between lens and camera body, TTL or i-TTL flash capability will probably remain available to you. As far as I can tell, TTL modes will render fine results — but I don’t really know for sure, because I use a reverse lens which means no lens-to-body communication, ipso facto no TTL. A reverse lens therefore requires Manual mode operation.

When I first started shooting with the D5000, I used the onboard flash and changed the output through the appropriate menu in the camera settings. Now that I use the SB-600 I change it directly on the LED screen on the back of the flash. Outputs range from full power (1/1) to 1/2 to 1/4…1/64th, with further fractions of thirds in between each output level (i.e. 1/4 +/- 0.3, 0.7, etc.). Sometimes changing the setting by one third can make a significant difference other times doubling the output doesn’t seem to do much at all. A lot of factors may contribute to what is an appropriate flash output level. Ambient light is one of the main factors: direct, full sunlight requires less flash than the diffuse, dull-edged light of an overcast day. The lightness (or darkness) and proximity of the background is another: shooting close to sandy ground or right up against a light-colored wall will reflect the light much more strongly. Magnification (at least on the reverse 18-55mm kit lens) and working distance; color and shininess of the subject; obstructions or shades between the flash and subject; etc., are other possible factors. As of late, I work in the 1/4 to 1/16 range, though usually at or close to 1/4. (The lower end of my range is reserved for more fill-flash/mixed light situations.)

the Challenge of Diffusion and the DIY Diffuser

DIY flash diffuser on Nikon SB-600 flash speedlight

A side angle of a DIY flash diffuser or soft box on a Nikon SB-600 flash. Diffuser materials include soda cans (2), cardboard, duct tape, packing tape, scotch tape and packing foam sheets.

Inevitably, shooting macro with flash is going to present the challenge of diffusion. While a flash light source provides the necessary light for macro photos, it also creates harsh reflections and glare, which can be especially troublesome on shiny, reflective subjects like (many) insects. The obvious answer is to diffuse or soften the light, so the reflections and quality of the light is eye-pleasing and unobtrusive to the subject. A reputable third-party-manufactured soft box will work just fine, but it’s kind of, sort of a badge of honor to construct a do-it-yourself, homemade version. It also is usually a very inexpensive alternative, but I think usually it’s kind of fun and adds some uniqueness to the photographic results! If you search “DIY flash diffuser,” you should come up with numerous examples. (Though perhaps for more useful or pointed results I would recommend searching for some good macro photographers and see what they use.)

DIY flash diffuser on Nikon SB-600 flash speedlight

A front-facing angle of a DIY flash diffuser or soft box on a Nikon SB-600 flash. Notice the two separate layers of packing foam sheets.

The key is going to be the diffusing material. Off the top of my head, I’ve used or have seen used various plastic containers, plastic lids, sheets of packing foam, and paper towels. Naturally, it has to be translucent so the light can pass through. In my latest DIY incarnation (and as mentioned above, you can read about my previous diffusers on this site), I follow the Lord V Coke Can Diffuser model, with some modifications1, including using sheets of packing foam for the diffusion material. (The orginal uses paper towel.) Even though it’s getting squished together a bit after a summer’s worth of shooting, I have found the effect of having two layers of diffusion works well (and undoubtedly I got the idea from someone who should be credited but whom I can’t remember). Another material that purportedly helps the quality of the light is aluminum foil (supposedly well-wrinkled is the best state); thus some will line their soft boxes with it. My diffuser’s construction uses aluminum soda cans so its walls are already metallic, on the plus side.

DIY flash diffuser on Nikon SB-600 flash speedlight

A “bug’s eye” view of a DIY flash diffuser or soft box on a Nikon SB-600 flash. Not counting the foam fringes, the diffuser is roughly 6 inches (~15cm) in diameter.

Ultimately, this is the kind of thing you can experiment with a lot, whether it’s building your own or buying different soft box or soft-lighting accessories. People have built some wild contraptions in the name of diffusion, but I’ve also seen simple designs that weren’t much more than a sheet of packing foam placed in between the flash and lens. When I shot with a high-magnification converted2 point and shoot camera’s onboard flash and later the D5000’s onboard flash, I simply used plastic lids attached to the end of the lens.

Maneuvering the Monster

Now that we have a flash, and a diffuser, and most importantly the resultant soft light, it’s time to get to work. Well, almost. A couple pieces of equipment may still be necessary. While it’s possible to take great photos with the flash directly attached to the camera’s hot shoe, I recommend an accessory like a flash bracket or friction arm to allow for optimal positioning of the flash head. I have used both (in combination with a mini-ball mount for additional flexibility), but the arm proved much more dynamic. The bracket I use (as pictured in this post) gets the job done by allowing the flash to point directly at my targets, but it is rigid and the flash only fires from the left side of the camera, sometimes creating heavy shadows (see the dragonfly photo below). My friction arm (before it broke!) allowed me to place the flash at either side and at a much wider range of angles and distances to the subject — a basic but crucial factor when a subject is facing opposite to the flash and any disturbance may send it flying off.

Portrait of a Blue Dasher dragonfly (Pachydiplax longipennis): notice how the shadows fall heavier on the right side due to the position of the flash head.

Portrait of a Blue Dasher dragonfly (Pachydiplax longipennis): notice how the shadows fall heavier on the right side due to the position of the flash head.

Placement of the flash goes hand in hand with another challenge: maneuvering the rig. At this point you may or may not realize you have some cumbersome equipment. The next time that I’m trying to one hand a shot and cursing my weak forearm, perhaps I should just remind myself I’m lucky not to have a full-frame beast like the D800. Weight certainly becomes an issue, and lighter, smaller equipment only helps for getting in and around the tight spaces in which interesting macro subjects seem to find themselves. But going lighter is not always that straightforward as I found out when I went to acquire a flash: I wanted the lighter, more compact SB-400, but it was (according to the online literature) not compatible with the D5000 in Manual mode — a giant problem for a purveyor of the reverse lens method. I bumped up to the SB-600, which is a fine piece of equipment, but I’d like a lighter assistant, to be honest.

One neat trick (not a weird one) for taking advantage of a big bulky diffuser like mine is to use it as a shield on sunny days. The full power of direct sunlight can cause harsh, distracting reflections on insects (say on the eyes of a dragonfly), but maneuvering the diffuser/rig  so that it shades the subject will eliminate those reflections and let the flash’s diffused light take prominence. (Note, you can also use your hand or arm to the same effect, assuming you can shoot one-handed. The new challenge is, can you do all this maneuvering without scaring off your quarry?)

ISO Don’t Want a Black Background

tiny parasitoid wasp on skin

A typical case of flash falloff creating a black background: this tiny wasp was shot taking a break on my hand in the middle of the day, but you’d never know from the darkness behind it.

There’s probably a lot of little things that I won’t cover concerning flash and macro, but I would be remiss if I didn’t talk about flash falloff (or fall-off) before finishing up. Falloff refers to the waning of the light the farther it travels from its source. For our interests in macro photography, this falloff becomes apparent when the background is too far away for the light to reflect back through the lens and to the camera’s sensor. The typical result is a black background (see photo below). Or possibly “The Black Background(!)” as it is somewhat notorious, sometimes disdained. I’m not aware that there is an inherent problem in it, but I know many consider it “unnatural” and deleterious to a nature photo’s value, e.g. an insect perched in daylight has a particular natural history that is misrepresented in a shot that looks like it was taken in the darkest part of the night. For myself, I hold one of the other common charges against it: it becomes tedious very fast. A shot with a black or very dark background is very easily “achieved” because flash falloff is a prevalent issue; the macro photographer therefore runs the risk of having a very uniform, and for my tastes, dull catalog of shots if s/he doesn’t take care with their backgrounds.

tiny snail on a tomato

The blue background behind the snail comes courtesy of the sky.

So how do we lighten up our backgrounds? If the setting and subject allow it, pointing the camera in the right direction is the simplest way to achieve a colorful background. Lining up a background that is either relatively close (think leaves, surrounding vegetation, etc.) to the subject or very brightly-lit by the ambient light (hello, sunshine) can help achieve a colorful background. This sounds simple enough in theory, but the narrow depth of field and fidgety nature of insects and spiders make it harder to accomplish in practice. In addition, even on so-called bright days, many times the only place truly bright enough to enliven the background on its own is the sky — not necessarily an easy angle to get, but the blue can make for a very pleasing, complementary background.

small robber fly perched on gnawed off grass stem

This light green background looks natural enough, but it is actually a dead leaf being held in the air behind the fly (tiny robber fly, Holcocephala sp., Asilidae)

In the absence of a convenient background to point the lens toward, you can add your own: I usually hold a leaf up behind the subject, but other carry colored cards or sheets of paper. The key in the artificial or constructed background is to have it far enough from the camera where interfering details (like the veins of a leaf) don’t show up yet close enough that it will reflect brightly. The other challenge is, barring additional equipment, you’ll be shooting one-handed more likely than not; it can be quite a balancing act to hold steady, front and back of the insect, all the while not scaring it off!

mating flesh flies hanging upside down from a rusty wire

The green background here was brought out by raising the ISO, slowing the shutter speed, and reducing the flash output. (Flesh flies, family Sarcophagidae, tentative ID).

Another option is to raise the ISO setting, i.e. the camera’s light sensitivity, and push the limits of the other basic settings. I.e. open up the aperture just a hair more. Slow down the shutter speed to the point of breaking…or shaking…hands, that is. (Finding something to brace against, a wall, the ground etc. helps with camera shake.) At this point, I usually lower the flash output accordingly so as not to blow out highlights on the subject. I find this strategy more effective when the background is distant yet very bright. If the background doesn’t already have a strong ambient light source, raising the ISO probably is not going to help lighten things up. (Though by allowing you to tone the flash down, it may still help with reflections on the subject. But that’s a different story.) Please note that raising the ISO generally adds more noise to your photos, but certain cameras — usually the full frame cameras, e.g. the D800 — have sensors better at handling the noise. For my D5000, I almost never go above ISO 400, because it adds to much noise.

For sure, the black background is not devoid of aesthetic merit; it can certainly enhance the drama of a photo or enhance the beauty of a subject. And especially with the fickle behavior of insects, there simply is not always time or space to set up a more desirable shot. As I said, my preference tends away from it, but I think the key is to approach it with artistic intention. Photos tend to bear witness to that and, dark or light, colors become secondary.

Phew, we made it!

Well, that rambled on. Thanks for reading through. The flash component of handheld macro photography really is crucial, so I hope it was clear and helpful. (But I’ll settle for just helpful!)

(Just one more thing, a word on the next post in this series: it may not be published (or written, yikes!) until next week. I’ll make sure to get up a post tomorrow either way.)

In the next BugPhoto Guide post, I’ll take you “into the field.” Well, sort of.

Previous BugPhoto Guide posts:

Footnotes:


1. The main modification in my design is to use two cans instead of one, creating a larger diffuser. As a consequence, I also found it necessary to add in some cardboard for a sleeve to connect the flash head with the diffuser. (In the original the ends of the cut up can are bent to serve this purpose.) My materials list includes aluminum soda cans, foam packing sheets, cardboard, duct tape, packing/shipping tape, scotch tape, and a few staples. You can probably get away with fewer tapes, I bet.


2. In case you’re wondering, I was using a Canon Powershot A620 and the lens converter adapter which allows the use of screw on-type filters/lenses. I was particularly fond of my very high magnification Raynox MSN-202 lens filter. Pretty nice image quality! The diffuser was the lid from a supermarket deli container; I cut a hole out and slid it onto the end of the lens.

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10 thoughts on “The BugPhoto Guide: Using a Flash

  1. I can see the flash really helps. You can set your shutter speed a little faster. I’m still a little hesitant about shooting video of bees using a set up like that. I’d probably have to insert still photos in my videos, which isn’t a bad idea. Thanks for sharing your set up. I know it probably took a long time, but it’s been a lot of help to me.

    1. I’m really glad you have found it helpful, Pat. In my limited experience shooting video, the flash isn’t necessary so if you drop out still photography, you can have a less cumbersome equipment set up.

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