for $250 75-300 zoom value for money. other reviews were right that autofocus is really bad in the dark. This lens is only suitable for use in daylight. I have a Sony a55 and have found several options to help with focusing - firstly I set the autofocus to point or local instead of wide (wide is terrible for autofocus), I also turn face detection off. finally I get the best/fastest focus in aperture mode at 4.5; In daylight, I can zoom in on an entire street and photograph moving cars and motorcycles moving at around 25 miles per hour, and the images are clear as long as I hold the camera still. I am very happy with this purchase and will definitely keep this lens, the zoom will come in very handy!