Jura S

It can be used in both ways but push-pull is needs a little more strength and therefore effects the precision of framing.

... and it helps to stop the lens a little bit. Check the details in the concrete. This is around 40 meters away.

... well, the Sigma's OS needs few moments to stabilize. Check the exif data.

I second that. Zoom is almost a must for birding on general and BIF in particular.

I've quite successfully used it for outdoor funerals.  Where is desirable not to be in the face of the mourning  family.