I recently have been shooting some macro flash, and I was asked what worked the best. Here is the good news. Lighting principles work the same, whether you are photographing a model on the beach or a butterfly in the garden. All light has direction, quality and color, the three characteristics you work with using light. With macro photography, your set is very small, maybe only a few inches across and a foot deep. But macro adds some unique challenges.
The biggest challenge with macro is you might only be 5 inches from your subject. That doesn’t give you much room to work with in terms of angle of light and how soft it is. One big variable is the lens you are using. If I am shooting my 60mm macro, I am about 2 inches away from my subject when I have 1 to 1 life-size reproduction (true macro=subject is life size on your sensor). I really can’t do much with my flash, maybe hold it off to the side, but this is very close and will scare live subjects away. I like to use a 105mm macro. This allows me to be about 7 inches away from my subject, far enough to use two lights and alter the flash angle and intensity for interesting light. I use the Nikon R1C1, a twin flash macro set up that fits right on my lens (see image at top). This handy bracket allows me to change the angle and location of the flashes, producing creative results in the final shot. I often pop off one SB R200 and hold it even further to the side. You can hold bigger speed lights off to the side as well. This is a good technique if you are using the 200mm F4 macro lens since you are farther away from your subject.
Why use macro flash in the first place? Because macro subjects are often in dark areas, and the flash duration will freeze the action. Last summer I photographed dart frogs in Costa Rica, and using a flash was critical on jungle walks due to low light. And since the flash is illuminating the entire scene, flash duration of 1/1600 (SB R200 at full power, much faster as power decreases) freezes any subject movement. Flash also allows you to backlight subjects on vegetation.
Another handy thing about using flash with macro is it allows you to control your background exposure. Take a look at the shot above. The butterfly looks okay, but the background is white and distracting.
If I use macro flash, I can set my background exposure to be darker, while my subject still looks good since the flash is illuminating it. You can control the background darkness. Some photographers like lighter backgrounds for more natural effects (butterflies are out in the daytime); I like my background a little darker so my subject really pops of the image. You can shoot macro flash at your local zoo in the winter, or somewhere warm. These images were taken at the Denver Butterfly Pavillion.