Thanks for your contributions to this thread. With enough heads together, I'm sure we can help Bob.
Agreed: faster shutter speed may quickly identify a vibration issue ... unless it is a focus issue as others have suggested.
In Bob's initial post, he indicated he was shooting at 1/500 second, which is a bit slow if we believe in the 1/focal length rule of thumb for shutter speed.
If I were going to take that configuration to a national park for some wildlife images, I would like to be able to shoot in low light situations, at maximum aperture when necessary, where faster shutter speeds are not possible. I would also like to shoot at base ISO and RAW format for maximum image quality. These conditions require a very stable platform and excellent long-lens technique.
True confession time: I tend to overkill when faced with challenges like this.
Thanks again for joining the discussion.
HBB in Phoenix, Arizona Nikonian Team Member
Photography is a journey with no conceivable destination.