(Also posted at photo.net)
This must be a prototype. The styling matches mid-late 1990s lenses like the AF 80-200/2.8 D ED (new version with tripod mount). It is a screw-drive AF lens, no built-in AF-S motor, so obviously precedes the AF-S 28-70/2.8 which appeared in 1999.
Obviously, Nikon was trying to improve on the old AF 35-70/2.8 D by expanding the zoom range in both directions, going to a more useful 28mm wide-angle and increasing the long end to 80mm to bridge the gap to the 80-200/2.8 zooms.
This lens is a highly developed prototype, it looks like a finished production lens. So why was it never produced? Maybe the 28-80 zoom range was pushing things too far and the optical quality was not good enough. Or maybe it was judged to be too expensive for the market. Or they decided to introduce the new AF-S motor, and for various technical or economic reasons they had to reduce the zoom range.
Interestingly, the zoom ratio of the 28-80 is 2.8x which is about the same as current 24-70 and 70-200 zooms.
Hopefully the new owner can clean the lens and restore it to good working condition, it would be interesting to know how it performs.
