A few further examples. On the first one, you see an example of the flare that lens can produce, the sole instance I could trigger so far : oblique rays near the corners. It is not an effect of light rays; the sky was ovecast, by the way.
You will see the same pattern in other pics. Frankly, it does not disturb me, being a decent and predictable behaviour. What does disturb me is when "reviewers" swear the never could see any...
Otherwise, there is nothing to complain about. First shot at f/8 and 12800 ISO (brave Df !), second one at f/2.8.