Had the opportunity to test my D4 and lenses with the Datacolor Spyder Lens Cal. Checked all focus points at max apperture on all my lenses. Every one was spot on. Also checked my D3s - same - spot on. At least Nikon set up auto focus on my D4 and D3s to be very good. That's exactly what I would expect from a Pro camera. Handy little tool the lens cal.