So far, I have to say I’m quite impressed with the Tokina 300mm f2.8 AT-X SD. Having bought the lens I was fairly sure I would live to regret it and always have that nagging feeling that I would be a far better photographer if only I’d bought the Canon lens. The reasoning was that I couldn’t afford to own both a Canon and a Nikon 300 2.8, so the Tokina would do until I finally gave up waiting on Nikon bringing out the camera I really need, and accepted that I am now a Canon man. I think I’m now just about at that point, and may be able to bear selling the last of my Nikon lenses. That will probably mean that this lens will be replaced with a Canon 300 f2.8, but I’m not in any real hurry. The Tokina 300mm f2.8 lens is actually much better than I expected. OK there are compromises, but not in the area that matters most to me - absolute sharpness - and it’s so well made that it’s far more likely to break things - like my foot if I drop it - than to get broken itself.