I bought the 18-135 SAM to my Alpha 77. It is expected to be not quite as sharp as the 16-50 SSM, but still better than many classes "soup Zoom". The AF motor is quick and quiet, but once in place. In 18mm wide angle is (unlike the 16-50) a slight darkening of the image corners recognizable. The colors are also at maximum focal length warm and alive, the bokeh soft and very pleasing. I've had enough of the zoom range from completely and you can save when you are traveling, even a few grams of weight compared to the one great kit lens.