Recently did a canal trip during which I discovered that the locks on the River Saône have convex mirrors beside the lockgates. This is a "selfie" (how I hate that word!) taken in one such mirror, hence the extreme distortion.
Had a little chat with him afterwards. He's using the Tamron 150-600mm for Canon. He got it in Feb and had to send it back for a software update. He tried to sell it to me, but he didn't take plastic.