I read that a customer considers the excessive price. While 37 may seem expensive for a ring. * But given the price of a macro lens and the price of a macro flash MT24EX, this sum seems very low. * Then in comparison to the price of our case, the few Euros of this special ring does not represent such a large sum. The advantages: * The ring is not in "sheet", the strength is felt. Manipulations are many on this item: ** - ** When not photographing insects and flowers, I remove the flash. This could create wear on a simple ring. ** - ** When I put the lens, I remove the ring to put the cap. This unscrewing does not wear the same ring some years of good and loyal service. * The ring has no burr (as some products with few euros coming directly from the study of Chinese offices). Do not get hurt by removing a thin washer is a gift. * It has inside a thread to install another filter or Cokin system. . The only negative point (but really small): * It is no longer possible to the original cap protects the optics (it is curious that Canon had not thought of that). But just to have (or buy) a diameter of plug 58 and the front of our goal is protected ... even keeping this ring. . Note: Contrary to what I read, it is possible (keeping this ring screwed) to the sun visor of the 100mm L IS macro as well for storage as for the photo taken without the flash of course. . I forgot to specify. What is this ring? * This ring serves to (a clip) flash "annular" or MT14EX MT24EX end lens when the diameter is greater than 58 (it seems) ** The EF 180mm f / 3.5L Macro USM requires flash adapter 72C. ** The EF 100mm f / 2.8L Macro IS USM, a flash adapter 67C (that is the ring)
