Sony has started to ship the incredibly expensive SAL 500mm f/4.0 G that was announced earlier in the year. At $12,999 via B&H Photo it's $2,500 more expensive than the new even lighter (7.63 lb. vs 7.03 lb.) titanium-bodied IS II Canon version. Because of their lower weight the 500's are easier to handle than either the 600/4 or 400/2.8, a point I'm reminded of now as I'm currently reviewing the Nikkor 400/2.8 VR (actually VR II) with the Nikon D4 (strange the buttons aren't all back-lit) and the D800. The Nikon lens weighs 10.1 lb, though the new Canon IS II version has lowered the weight to 8.5 lb.