I am contemplating purchasing a Sigma 1.4x TC but for right now I would just be using it on my 80-200 AF-S (I plan on purchasing a Bigma in the coming months and probably a 70-200 VR II), but I was just wondering if it would work and autofocus with my 80-200. Thanks for any help!
it should work but since you have the AF-S version of the lens, Nikon's extenders work too and i think they perform much better. i don't think it is worth using any extender on the 50-500. my combinations always performed about the same as just cropping the image.
In my experience, use the Sigma TCs on Sigma lens only. For example the Sigma 1.4x on the 300mm AF-S is pretty much unusable AF wise, whereas the Nikon version is a perfect match.