I'm considering buying a lens for wildlife photography. I already have the Nikon 80-200mm f2.8 AF-D, but its reach is limited. I was wondering if anyone had experience using the Nikon 80-400mm and the Sigma 50-500mm and have some comparative feedback. I have a Nikon D70. I don't like much the Nikon lens because of its lack of fast AF. I played with it in a store and it's slow. I also tried the Sigma 50-500mm in the store and it's much faster, however it's bigger and heavier. Honestly, I don't really see the advantage of having VR on a lens used for wildlife photography, I see fast AF much more important, that's why I'm inclining towards the Sigma. If you need to freeze subjects in motion, you'll need a fast shutter speed anyways which will probably be enough to compensate for any camera shake that the VR is trying to help with. Even if you shoots stationary birds/animals, they usually move a bit anyways, so you still need a faster shutter speed. I agree that I'm a beginner at wildlife photography, is my judgement completely off? Thanks.