The EF 100mm f/2.8L IS Macro requires Macro Lite Adapter 67C. The EF 180 mm f / 3.5 L Macro requires Macro Lite Adapter 72C (each sold separately). Macro Lite adapters are available in sizes 52mm, 58mm, 67mm and 72mm.
The Macro Ring Lite MR-14EX can be attached direct to the following lenses: EF 50mm f/2.5 COMPACT MACRO, EF 100mm f/2.8 MACRO USM, EF 100mm f/2.8 MACRO and the MP-65mm f/2.8 1-5x lenses. To attach it to the EF 180mm f / 3.5 L MACRO USM, the Macro Lite Adapter 72C (sold separately) is required.
You should either move closer or increase the ISO. The table on the reverse side provides a guide to minimum and maximum shooting ranges for the EF-S 18-55mm f / 3.5 -5.6 IS zoom. Do not use the 320EX in the extended position at a focal length of 18mm or less, or the edges of the frame will be darker than the center.
