IS for flash macro?
If you examine the MTF curves of both 100mm macro lenses on the Canon Lens home
you will find that the IS lens is sharper. That's the best reason to buy it.
If you shoot a hand-held macro in ambient light, then IS is the second best reason to buy it.
|Sit on rainbow by frapeace|
|Icelandic landscape by BoDrey|
from Best Landscape of the Week 1