I've been using my 100mm macro lens with my crop sensor 7D lately to see if that would pair nicely with my 5D Mark III and 24-105mm lens for event coverage and general walking around. On a crop sensor body the 100mm lens has the field of view of a 160mm lens on a full frame body. This can be an advantage as you don't need to be as close to the subject to have the subject framed the same way.
Canon makes a 180mm macro lens but it is f/3.5 and it doesn't have image stabilization. I'm hoping this will work out nicely.
This small patch of Bee Balm had blossoms in various stages of development. These shots were all made at the same time. All are at f/8 and ISO 100. These are all full images with no cropping.