Árpád Szendrei asked: "Can I really see what is on the opposite side of a black hole?"
Yes. Let's take this 360°x180° full panorama:
Now we zoom in one direction:
and place a black hole in front of the observer:
Now we turn around:
and move the black hole into our new line of sight:
Here we look up into the clouds:
and move the black hole into our view again:
As you can see we would see what's behind of us lensed around the black hole's shadow, but it would be strongly distorted.
The zoomed in images have a FOV of 103°x61°, the black hole has a spin of a=M. There's also a video here with the image used above, but the resolution is rather low. This video has a different background image, but higher resolution.