This was my first lens purchased for nature photography. It features a push-pull
zoom that is very quick and easy to adjust on the fly. It has a superb optical quality
that comes close to Canon prime lenses. Its main drawback is its f5.6 aperture at the
long end, which makes it too slow for most fast action and sports. Many people
hesitate to purchase this lens because if its push-pull zoom design, and I did too.
But I can tell you that after using it for the first 10 minutes, I fell in love with it
and find the push-pull zoom to be easier to use than the conventional type of zoom.
There is also a tension adjustment on the barrel that can be adjusted to make the
zoom tighter or looser, and also prevent lens creep.