Canon produces two macro rings, MR-14EX and MT-24EX, and many other manufacturers also produce such rings. I have a Canon Speedlite 440EX II external flash, which I use when I don't use a tripod for my shots (that is quite seldom, actually).
The macro rings aren't exactly cheap, and my question is whether it is a good idea to get one for macro shots, or not, if you:
- 1) Use a tripod (no flash) for macro shots, what I do most of the time
- 2) Use the flash extensively while shooting macro
Remember that I already have a Speedlite, and I can remotely control it from my 7D, so I can put it at a wide variety of angles.