The Tokina AT-X 840 AF D 80-400mm f/4.5-5.6 lens is amazingly compact for a zoom lens that has a bright f/5.6 aperture at 400mm. With a range from 80mm to 400mm, this is a whole range of lenses bundled into one shell.
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 improved multi-coating greatly reduces the chance of internal flare or ghost reflections.
The AT-X 840 AF D has been improved and updated with a smooth and quick internal focusing system. This means that 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.