Flash - Yuck... or...
Electronic flash - especially the one attached to your camera - typically has a limited range of a few feet, produces harsh shadows and washes out highlights, creates “red-eye” (when your subjects eyes resemble a demon’s glowing gaze), produces backgrounds that are underexposed (if not completely black), and eat batteries voraciously. Even external electronic flash units have limited range, and, though you can move them further away from the lens to reduce red-eye, they still provide harsh lighting (unless diffused in some way). Also, because they are much more powerful than your on-camera flash, they take more time to re-charge after each shot - and, again, eat batteries like candy.
So, if electronic flash is a “yucky” light source, why would you want to use it for macro photography? Wouldn’t the issues just be magnified? Quite the opposite, actually. Believe it or not, when shooting close-ups, a lot of the issues associated with electronic flash are eliminated. Electronic flash is a viable and excellent method to illuminate your subjects, without the “issues” typically associated with “flash” photography.
Bumblebee Portrait
100mm macro, flash
1/60th at f22
Flash Produces Harsh Light - Not
Normally yes, but with macro photography - NO. What creates “harsh lighting” is a light source that is relatively small. If you think of the sun, you think of a huge, bright object in the sky. And when I say huge - I mean HUGE (according to NASA, it would take 1.3 million Earths to fill the Sun’s volume - now that’s huge). Now, consider subjects lit by bright sunlight - harsh shadows, washed-out highlights - all because the light source is relatively small - because the sun is so far away (if the sun was an electronic flash, it would take roughly 9 minutes for the “flash” to reach your subject) - as big as it is, the sun is a “small”, pin-point light source. Now, move the sun about 90 million miles closer (put on some sun block), and it becomes a HUGE light source - there would be no shadows (because the light would be coming from every direction - no longer a single point). An extreme example, I know - but roughly the same as taking an electronic flash from its “normal” range of 10 to 30 feet, to 1 to 3 inches.When shooting subjects at 1/2 life-size to life-size (2” x 3” to 1”x1-1/2”) That 1”x2” light source becomes a HUGE light source, providing an overall “soft” light.
Eats Batteries - Not
With a flash located so close to the subject, you don’t need to use “full power”. Most flash units have multiple power settings (or, at least a motor-drive mode that cuts the power down considerably - for my particular flash, the MD mode cuts the power to 25%). By using less power - you’re...well...using less power, and your batteries will last a good bit longer. In addition, because you’re not fully discharging the flash’s capacitor, recycling times are greatly reduced, so you’ll have power for your next shot quickly - maybe even instantly.
Limited Range - Not
Well...it’s macro photography - range really shouldn’t be an issue. Matter of fact, you’ll be shooting at relatively small apertures (f16, f22, f32 - depending on the ISO set and power of the flash unit), so depth of field will be maximized.
So, What Kind Of Flash Unit Do I Need?
For macro work, you don’t need a huge, expensive flash unit. As a matter of fact, smaller, cheaper units are (to me) preferable. The take up less room in my bag, use fewer batteries, are easier to position on a bracket, and provide plenty of power for macro use. You can probably track down a cheap unit at a yard sale, online, even the used section of you local camera store. You will also need a way to connect the flash to the camera, either with a PC cord or a dedicated off-camera cable specific to your camera. These dedicated cords work with the automatic or TTL metering modes of your camera and can be expensive. For our purposes, we’ll be shooting in full manual mode, so stick to the PC cord if expense is an issue. (If your camera does not have a PC socket, you can purchase a relatively inexpensive PC adapter that mounts onto your camera’s hot shoe).
How Do I Position The Flash?
Ideally, position the flash just above and even with the front of the lens. If you change your magnification, adjust the flash so it stays even with the lens. You can hand-hold the flash (YUK), or use a bracket that allows positioning of the flash where you want. These can be purchased, but are not cheap. With a bit of creativity and some metal straps from the hardware store, you can build your own and save a bunch.
Home made flash bracket
Home made flash bracket
OK, Moneybags - I can’t afford all that - is there a way I can use what I have?
There is a neat little trick that allows you to use your built-in flash and get similar results by using, believe it or not, a Styrofoam bowl. Cut a circle in the bottom of the bowl (make it a bit off-center to maximize the diffusion area) the same size as the lens front. Slip it over the front of the lens and you’re good to go. You’ll have to experiment with the exposure (your apertures will not be as small as with an external flash - probably around f8 or so) - but you can up your ISO if need be.
Styrofoam bowl providing diffuse light
Flower, built-in flash with Styrofoam bowl, 1/60 @ f8
Polypore, built-in flash with Styrofoam bowl, 1/60 @ f8
Establishing Exposure
The following is based on full manual control of the camera AND the flash (you could probably use one of the auto modes, but I prefer to know exactly what aperture I’m using and power from my light to maintain predictable results). First, establish the correct exposure for your particular setup by simply testing. Start by setting your camera to whatever ISO you prefer (for macro flash photography, a low ISO - 100 or even 50 - works best). Set up your system for whatever magnification you want to shoot (1/2 life-size, life size, etc.). Start at 1/60 sec (or whatever your flash synch speed is for your camera) at f16, then f22, then f32, etc. until you’re satisfied with the results. Once you’ve hit your “correct exposure”, that will forever be the correct exposure for that setup at that magnification. If you started your testing at life size, that exposure setting should also work even if you back off to 1/2 life size (think about it - you’re moving back from your subject to decrease magnification, so the flash is a bit further from your subject - BUT you’re reducing the extension to focus on your subject, so light lost to extension is reduced - about the same as the light lost from the flash from a further distance - it’s a wash) Of course, this relationship starts to disappear as you get further and further from your subject, but from life-size to roughly 1/4 life-size, your exposure will be roughly the same.
Composition Tips
Typically, when shooting macro, you're shooting subjects that are on the same plane, with backgrounds that are roughly the same distance from the camera as the subject. There are times, however, when the background may be much further than the subject. If that is the case, the background is likely to render as completely black since you're shooting at relatively small apertures. A couple of thins can remedy this.
1: Place something in the background withi9n the range of the flash. Even if it's still a bit further than the subject, the flash should illuminate the placed background - the shallow depth of field should also render the placed background softly "out of focus"
2: Extend the shutter speed to allow ambient light to render in the background - just make sure the subject doesn't move. Also take into consideration that the additional time that the shutter is open will contribute to the exposure of the subject as well - test and experiment.
3: So what? Sometimes a black background can add impact to the final image - so let it go black!

What About A Tripod
With existing light, a tripod is a must for macro photography. A tripod also allows you to compose the image more methodically. When using a flash for macro photography, however, a tripod can become more of a burdon and is not really necessary. First, you don’t have to worry about camera shake with flash. The exposure is entirely generated by the flash burst, which is about 1/10,000 of a second - you’re not going to get “camera shake” at that speed. As a matter of fact, at that speed, you shouild be able to, say, stop the motion of a bee’s wings - if you can get him to cooperate. Second, when shooting macro, you’re typically the magnification (or area of your subject) that you want in your composition. This requires you to physically move closer or further from your subject. When mounted on a tripod, this becomes more cumbersome, and a lot of the time, people become a bit lazy and just refocus from where the tripod sets. Well, this alters your magnification and, as a result, your composition. Without a tripod, you can set up your system for the magnification you want, and move your body in and out until your subject is in focus, then release the shutter.
Specialty Gear
Although not necessary by any means, there are some devices designed specifically for macro flash photography. One in particular is the ring flash. A ring flash, or macro-flash, is a flash unit that screws onto the front of your macro lens and is specifically designed for macro-photography. Although there are many benefits to these - there are a few down sides as well.
Pros:
Easy to setup and use
Screw it on to the front of your macro lens and you’re off!
Compact
Ring flashes are relatively small - they dont take up much room in you bag
Cons:
Too flat? - Check the features of your ring flash
One of the “problems” with a ring flash (other than they are not inexpensive AT ALL) is that they provide EXTREMELY uniform light - a complete ring of light surrounding your lens. Sounds great - but this “uniform light” can create a very flat result. Most of the time, it’s better to have “directional” light - a light source that comes from a single direction, instead of “everywhere”. There are ring flashes that are “sectional”, meaning that you can turn off sections of the flash to give a more directional illumination to the exposure. Problem is, because the light is attached to the lens itslef, there’s not much “direction” that can be detected in the final photograph. There may be times where I want more “dramatic” lighting - side lighting, or even slight rear lighting - you can’t acheive these lighting preferences with a hard-mounted light on the front of your lens. Ring flashes are ideal for scientific purposes, but, to me, are not for artistic photographic content.
To Sum It Up
Electronic flash is a great way to illuminate macro subjects. With a bit of experimentation and testing, the range of effects and mood is virtually endless - so get out there with you flash and get shooting!
