Back in 2015, when I got my first DSLR for Christmas, I also got a fully manual anubia 500mm Lens from my father. I never really liked that Lens. It is not really that good.
That is mostly because it is so extremely long, fully manual and also quite dark, starting at ƒ/8.0. It is also not very sharp.
The Lens is also not very versatile, being a 500mm Prime. And 500mm on APS-C are very long. In fact, they are extremely long, being equivalent to around 800mm. And that is almost 1 metre.
Because of that, and because of the lack of Image Stabilization, Camera Shake is extremely pronounced and you definitely would need to use a Tripod. And a (wireless) Remote. It is really that shaky.
Another Problem is Chromatic Aberration. It is extremely pronounced. And green. I really do not like that.
But the biggest downside is the minimum Focus Distance of 10 whole metres. Or almost 33 feet. That is okay for Landscape Photography, but limiting for anything else.
I guess that is why a Camera Store a few towns over uses four of those 500mm ƒ/8.0 Lenses as Door Handles. It really is not a good Lens.
But I am still absolutely grateful for that Lens because of the gesture it represents, even if I never really use it.