Extracto: When shooting with my new lens mounted to my 5D, the images I tried shooting (Macro, flowers) just didn't seem as sharp as those I came across when deciding on the purchase. And even after comparing the lens with a friends shot of like images, the images my new lens shot just seemed a bit softer.
Extracto: The focus ring turns only about 135 degrees from infinity to max close focus, so the manual focusing is very touchy especially at high magnification. There is an element in the lens that rattles and can visibly be seen moving around when the lens is not on the camera.
Extracto: This lens is 5 stars for sharpness, quality, and versatility. My only complain is that my copy had focusing issues right from the start. Luckily Canon, is great at getting it fixed ASAP! The warranty is great with Canon.
A favor: Consistent Output, Durable, Strong Construction
Extracto: Optical properties of this lens are excellent for macro and portrait work. Autofocus is good. However, the lens disappoints when focusing manually. The focusing threads are crude making it very difficult to find a sharp focus for macro shots (where manual focus is needed).
Extracto: This is a nice piece of glass , but I am terribly disappointed in the manual focus. It is a rough adjustment, where what is needed is a fine adjustment. Also it is easily disturbed - throwing the image out of focus with the smallest accidental touch of the focus ring.
A favor: Fast / accurate auto-focus, Lightweight, Nice Bokeh