400mm Sigma lens mount for Nikon F - (not 499mm)

Doubled checked, my Sigma will allow me to focus, but not change F stop either, but on my 7 I can change the shutter speed. On the others both shutter speed and F stop is locked.

So basically there are early, five-pin Sigma and Tokina lenses that will not work (no auto-focus, or no aperture control -- or both) on post 1st generation a-mount cameras.

Makes me wonder if there are other brands of lenses that have the same problem. I would suspect so, since both Sigma and Tokina lenses have been sold under other labels.

It also makes me wonder if somewhere out in CYBERLAND, someone has a running list of these "problematic" lenses -- or if we just have to "cross our fingers" when buying. I know I've bought a couple of Sigma a-mount lenses that were listed as working -- but didn't, except on my X-7000. Fortunately, one seller had me ship it back & the other one told me to keep it, for FREE.