I am an amateur photographer. I like to experiment with zoom lenses.  I have some pretty powerful lenses, up to 1000 mm (when using a doubler).  Lenses that can do this professionally cost 2 to 3 times (or more) what I paid for the camera.  What I have are much less expensive. So they are more difficult to use and sometimes the focus is not perfect.  But its all fun, anyway.