The snow is pretty much gone, and plants are starting to come up, so I braved the cold wind today to snapa few handheld images with my 100mm L. It was blowing hard, and two cold to spend much time, so there are not the best the lens can do. Just natural light. all were at f/8.
Its plenty sharp, but the depth of field is shallow as you get close, and its hard to focus precisely. F/16 would have more of it in sharp focus. Don't worry about losing sharpness at f/16, the increased depth of field will more than make up for it.
We have some Chive plants in our front yard, and with a very late spring, they are just blooming. Bees love them. i do not have the patience to make a complex macro setup, I just walk up and shoot away. The 100mm l is not really any sharper, but its easier for a person like me to get reasonably sharp hand held photos.