Canon makes two similar macro flash systems, the MR-14EX Ring Lite and MT-24EX Twin Flash. Both are intended to surround the front of a standard Canon macro lens, e.g., the Canon EF 100mm f/2.8 Macro USM , ( compare prices ) ( review ), which is the lens used for all of the example images here.

Canon MT-24EX Macro Twin Lite review by mebailey

I would not enjoy macro photography without this flash. It provides reliable, even illumination that allows me to stop down enough to get a decent DOF for the subject. It also frees me up from the tripod so I miss far fewer shots.

Cons

I would not enjoy macro photography without this flash; It provides reliable, even illumination that allows me to stop down enough to get a decent DOF for the subject; It also frees me up from the tripod so I miss far fewer shots.