In 1996 Tokina created a new class of telephoto lens when it introduced the original AT-X 840 AF. This was the smallest zoom lens available that had a bright f/5.6 aperture at 400mm. Now Tokina has recreated the lens for the digital age. Still the smallest SLR lens available that zooms to 400mm, the AT-X 840 AF D has a smooth and quick internal focusing system that means the all-metal inner barrel that houses the heaviest glass elements does not have to rotate when the lens focuses, making it much faster than the previous models.
Optically, the AT-X840 AF D has new multi-coatings applied to the elements that are formulated to compensate of the highly reflective CCD and CMOS sensors in today's Digital SLR cameras. The new multi-coating greatly reduces the chance of internal flare or ghost reflections.
A built-in low-profile tripod collar makes for a well-balanced camera/lens combination when using a tripod or monopod. For best results, Tokina always recommends using a tripod or monopod with telephoto lenses.
Another feature that makes the AT-X 840 AF D an excellent traveling companion is the zoom lock switch. The zoom can be locked at 80mm to so there is not chance of "zoom creep" when the camera and lens are being carried over the shoulder.
Tokina kept ease of use in mind with the new AT-X 840 AF D, the new BH-725 lens hood with the a PL Assist spring loaded thumb wheel allows a circular polarizer or special effects filter to be rotated while the lens hood is in place. No more removing the hood to change the position of the filter.