I took it out of the box again. And shot some pictures with it. And realized why it’s been sitting in the box -untouched- for about four years now. It’s just a piece of crap, sorry to say. After shooting with the higher-end lenses, the (over a decade old, gotta give it that, at least) Sigma 170-500mm isn’t up to the job anymore. I might’ve got away with it when I was using it on film last century, but it’s just not good enough anymore.
And it took me already quite some fixing to get it like this. But… no matter how good you are with Photoshop and/or Lightroom, you can’t make a good picture out of a crap picture.
Nonetheless: you are mooned 😀