Pros: Awesome optics. Some ghosting at times with wide open aperture. Awesome results in macro photography. 2 eggs for inconsistent af. see cons.
Cons: The lens in focus. Tried to shoot bird the lens goes out of focus from on end of range to the other then stops. Bird or plain gone. Very Frustrating. Many shots out of focus even in good light daytime. Focus not quite there. At 2.8 only the center af point works. What if you want your subject slightly off center. 2.8 portrates become useless. Manual is ok if used for only macro. I need a lens I can use for birds too. It is necessary for me to have all 9 af points work...
Summary: I bought this lens to shoot sports and weddings mostly. I was so unhappy. The first time I used this lens, every picture was blurry. I takes the lens several tries to autofocus and even then...doesn't always work. I'm really not happy at all. I should have saved my money and bought the Canon one...even though its double the price.
Summary: Purchased for use with a K100D that I'd previously been using with the Pentax 50-200mm 4-5.6 lens hoping for more light and better shots of soccer and lacrosse under the lights, with and without flash. As an experienced amateur, I know I have a lot to learn but this lens confounded everything I've learned about the process of photography.