For all the canonites in AP.

More use of fluorite (less ultra low dispersion glass), less weight, sharper and clearer results expected. Cost seems to stay roughly the same.

Whilst Mongo uses Nikon because it is too late to change to canon (given the heavy investment in Nikon gear), he has always said – credit due where it is due. In Mongo’s view, Canon make better lenses than Nikon but possibly not as good camera bodies. Mongo has always believed that fluorite elements used by canon gives them a slight edge over Nikon (who gave up on using fluorite in preference for low dispersion glass decades ago).

More info here : http://photo.net/equipment/canon/500-600-II/preview/