Alaska Eagle in Flight - focus test - page 8
This web page consists simply of a number of images of an eagle shot on my Nikon Z9 with older firmware (3.something) and a 100-400 lens. Once camera focus is achieved on the flying bird, it should have tracked the bird and kept all subsequent images in focus - but it did not. If you look closely you will see that there are often a few frames in perfect focus followed by one image that is slightly blurry, then more in-focus images. The first two images are blurry, but the 3rd one is sharp. Then the 4th one is blurry, but the next is sharp, etc.
