Supplementary lighting for macro

I was recently asked about a comment I had made on using flash for my most of my macro shots, by someone wanting to know if they would have to spend lots of money. The only means of flash at their disposal was the built in flash unit. They used canon kit, but I don't. Here's how I answered:

I very rarely use my on-board flash. I try to approach my macro work as miniature portraits, which usually means low fill-flash (it can be okay for this sometimes), and side/ backlighting. I try to keep it as low as possible though, and mostly use ambient light. The flashes are really there to make things sparkle a bit, or pick out some of the textures.

I'm currently using the Nikon SB-800, and the R1C1 kit, which I think equates to the Canon 580EX II and Canon MT-24EX. I think there are couple of cheaper options, but the key is being able to get the flash unit away from the camera. Unfortunately, that's the massive benefit of using nikon: wireless is fitted as standard across the range. For yourself, you'll need TTL cables or a transmitter. Cables are a bit of a faff, because if you move, the flash comes with you, but they're definitely the cheaper option.
If you haven't got one though, get yourself a five-way diffuser/ reflector. They are amazingly useful, and I know someone who uses one almost exclusively. She's got some of the best fungi shots I've ever seen, so you don't need to go all out on complex flash set-ups. Here's some of the ways I use flash in my photos:
Two R200 flash units. One at rear right for rimlight, -3.0EV. One at front left through diffuser, -1.7EV. Note that the lower-powered flash is closer to the subject, so light looks brighter, but falls off very quickly.

No flash used. Fill-light from gold reflector

Two R200 flash units. One at left for definition, -1.3EV. One at front right through diffuser, -1.3EV.

SB-800 mounted on camera, -1.3 EV for fill. Stofen diffuser dome attached.

one R200 flash unit to the rear right, 3 stops below ambient for rimlight (-3.0 EV).

SB-800 mounted on camera, -1.3 EV to freeze movement. Note that this could be done with built-in flash, but light would be harsher because of smaller flash.













Full flash (no ambient registered). One SB-800 bounced from front right off gold reflector.














No flash used. Fill-light from gold reflector


















The tricky part will always be figuring out what lighting suits what subject. That will depend very much on the situation, and the background effects you want to produce. Trial and error is a huge part of this. So in short, it's worth spending a bit of money if you really want to improve your results, it doesn't have to be too much in the grand scheme of things, but a dedicated macro light rig will certainly open up your options.