Originally posted by Clavius In person. Which I vastly prefer, to avoid these types of situations. I had asked him to bring one of his own lenses so he can sit down and properly test it. Which he did. I think he fiddled around with it for over half an hour.
If he tested it for half an hour, you're golden. I wouldn't have accepted that long a test.
I'm sure he simply turned on Clarity, or he's using an older, slow memory card. Or he can't live with a 12 years old camera with less than 10k accuations.
I'd say these things to him, politely, then leave it be.