Sigma 500mm f/4.5

I own a Nikon 500 f/4 Non VR. A close friend owns the Sigma 500 f/4.5. We go birding together all the time.

IMHO these lenses are in a very different category. The Nikon is superb wide open, while you have to go all the way down to f/8 with the Sigma to get really sharp pictures.

If you have a good tripod VR will not be missed, but if you use a monopod (or handheld) VR will be very useful.

Regards,

Eduardo.