Sorry for the delay in completing this story. I’ve been too busy to upload any more video, but the new camera arrived and this is what I’ve concluded -
The replacement camera is exactly the same. There is a visible vignette when zoomed into full telephoto. This occurs no matter what settings are applied or turned off, image stabilization, etc., so this must be strictly a result of the optics. The bouncing of the vignette is a result of the image stabilization, and when IS is turned off, the vignette is stationary and doesn’t bounce around. But it’s still there.
So while I’m disappointed that the vignette is there at all, I suppose I tend to watch for it now rather than look at the subject. It’s not noticeable when there is a busy background, which should be most shots. It’s really only distracting when the background is flat, such as sky or a wall. I love the other features of the camera, so I’ll be keeping it and taking it with me on my upcoming trip to the Grand Tetons.
I appreciate everyone’s feedback and input. Thanks very much.