Well, if you know what you're looking at here, then you know that you want it. This is Canon's Holy Grail of macro lenses. It's the lens of choice for nature macros, for two very important reasons:

• the long focal length allows you to maintain a decent camera-to-subject distance, so you don't have to get up close and personal with all the bugs and creepy-crawlies and you won't scare them off;
• the backround is thrown out of focus much more effectively than with a shorter macro lens.

Suggested extra: You might find the Manfrotto MN454 micropositioning sliding plate useful when mounting this lens on a tripod.