Hi Alfred and Rocky,
Thanks for the quick reply. Just got back from a trip with the lens this past weekend. I was at a look out point on one of the local islands and photographed Turkey Vultures and got the same result.

Rocky, the shutter speed was 1/2000 at F/8, still that tell tale ghosting around the wing and face. I really don't think that it is a focusing problem as much as a stability problem. Some have commented that using a UV filter can cause something like this but I have not done any testing with my UV filter off (your thoughts?).

Alfred, I know what you mean about being a good BIF lens. That is why I really would like to persue a fix for this problem. It is much easier in the Spring and Summer to use a lens such as this because most of my subjects are relatively close. I am also considering getting a bush hawk to save my shoulder because now I spend quite a bit of time lugging a Wimberly and tripod around for the 500 F/4.

Steve