I'm considering purchasing a macro lens. I have the older (but still very sharp and reliable) 100mm USM, but thought of updating it with a macro. Frequently on shoots, I'm doing a full-length shot, then come in tight for beauty, then the client asks me to shoot a tight detail of, say, the earring. At that point, I have to stop, change lenses to my 24-70/4, shoot some frames, then go back to full-length -- for which I generally will switch back to the 100. (I rarely shoot fashion with less than an 85, though have, on the right girl, shot with a 50 upon occasion.)
My other ulterior motive for the macro is to copy some older film I'd like to preserve. I've always found scanning film to be laborious, and massively time-consuming, with each image taking 5-10 minutes to setup in SilverFast, only to have to refine more in Photoshop. On average, 20 to 30-minutes per image -- the whole reason I love digital. With my 5Ds 50MP sensor, it suddenly opens up a whole new avenue of speed, resolution and quality. (There are some good posts elsewhere on the forum discussing this.)
I'm looking for some real-world experience with this lens, preferably not the bug-and-flowers kind of shooting, for comments. I had also considered the Sigma 105 macro OS, though not as keenly since I have exposure issues with my Sigma 50 Art. Interestingly, DxoMark (for what it's worth) rates the old Canon 100mm more highly than the 100 macro IS. Thanks for the thoughts.