Hi Christopher, I have the manual focus version of the Tokina 100-300mm f4, and it is one of the best zoom lens I have. I think the AF version has the same optics. I have tested it against the Nikkor 50-300 f4.5 ED and prime Nikkor lenses. My results were : Best = prime lens, in terms of contrast and distortion 2nd = Nikkor 50-300 f4.5 ED, contrast as almost as prime lenses. It's been given top marks by other people as well. 3rd (but not by much) = Tokina 100-300 f4.0, very slightly warm but less distortion than the Nikkor. It been rated as 'excellent' and 'best in class' by a number of magazines. The Tokina is half the weight of the Nikkor, but you still need a mono/tri-pod to hold it. It's filter ring is 'only' 77mm compared to 95mm of the Nikkor zoom. I have kept both the Nikkor and Tokina zooms because the Nikkor is too heavy for some occasions. Hope this helps. Happy shooting, Sover
