Serious about performance?

This review is about the newer two ring version of the same lens mentioned above. If you are searching for this kind of lens, you must already now how good it is! Very fast aperture (f2.8 at all distances, you can shoot inside a cave and still have enough light!), Extremely Low Dispersion Glass for less distortion and less color aberration, metal construction and tripod mount (non-removable). Performancewise, the focusing mechanism is quite fast, but not as fast as the new AF-S. Pictures are extremely sharp at center and corners. They can also be enlarged to sizes up to 20X24 without any noticible loss of quality.
My only two complaints are the weight and the price. But regardless this is the best available in the market.