Macro photography is known for finicky depth of field. This is usually the limitation of available light, f/stop, and noise mitigation. Either jack up the ISO to support an f/32 photo, or sacrifice on the depth of field. What if you could get greater depth of field and stop action at the same time?
The technique is simple, just add a flash unit to your macro setup. It works best with an off camera, diffused flash triggered in commander mode (wireless), but even attached to the hot shoe, it provides decent results. Two or more flash units would allow you to get creative with lighting effects and controlling shadows. I’ve been using my Nikon D300 with an older Nikkor 105mm Micro f/2.8 D lens. (Wish I had the AF-S version!) Paired with a SB-800 Speedlight, I have all the light I need to get a greater depth of field. One extra benefit of using the flash as a primary light source, you can ditch the tripod! This is great for insect work, where the subject might be flying, hopping, or skittering through a messy pile of plant matter. The 105mm provides a nice working distance, and the subject is not so close that the lens casts a shadow in the frame. If you are particularly ambition, there are several manufacturers who produce a ring flash. Nikon sells two versions, the R1 for those who have a camera that supports commander mode (such as the D300), and the R1C1, for those who want a wireless command unit. The two Speedlights included in the kit are the perfect-sized SB-R200. Add a third, and they will all fire from the commander unit’s wireless signal.
So next time you are thinking about shooting some macros, bring along a flash unit. It may just give you that extra bit of oomph, to get the flower stamens in focus, or those insect antennae!