It appears to me, a novice learner, that the focus is right on. The ears and the nose are a bit out of focus indicating the best point of focus is somewhere between them. As nearly as I can tell, it is at the eye lashes. Yes, the right eye lashes appear sharper than the left but I suspect that is due to the contrast between the left eye lashes and their bright, sunlit background. If the focus isn't right on, then it sure is darn close to it. Well done!

This is a moderately priced, 150-500 zoom lens, not an expensive prime. I think it did very well for such a lens. I'd consider the lens well worth using and enjoying, and wouldn't expect better sharpness. It appears to be a great lens for the price and should be a joy to use. You are going to get many fine shots that you couldn't have gotten without it.

Again, this is a novice's opinion. I'm glad to read other's view points.